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Racecars - Building a car for competition

A big shout to TomRich for putting this together.

We were talking the other day, and decided we’d try and put together some information on what is involved in turning a humble Golf into a car which is happy to go racing.

This is not going to cover all bases, it is not going to give a hugely in depth or deeply technical run down of everything that is possible, and some things won’t be covered at all, but hopefully it will be mildly interesting or at least informative for people who have thought about doing this or just wondered what is involved.

We’re going to skip the first step where you either dismantle your chosen complete car or collect a bodyshell, and we'll also skip any component, part, tool or kit purchases you need to make. Just straight into the work itself in a series of posts starting at the ground up. The pictures are compiled from various cars we’ve had around, so when it changes colour repeatedly don’t worry!

An important note before starting, please understand what’s meant by a racecar here, we mean competition cars.

We are not talking about cars that may see a one off track day, though fair play to these folks  :thumbs:
Nor are not talking about cars which go quickly on the road and have a few fruity bits fitted to them, also fair play  :cool:  
And definitely not ‘race inspired’ show field clutter. If that's your thing, go grab a pumpkin spiced Latte or something  :bout ye:

No disrespect to anyone or their pride and joy, if it’s your car and you enjoy it then more power to ya, but we’re talking cars which are built for the purpose of getting the kind of stick you can only give a car on track. Even people calling occasional track cars 'racecars' is irritating, so just cool it on all that crap and enjoy what you're doing without any misrepresentation. Preemptive rant over.

More importantly than that, it is incredibly important to look into what series or events are available to your chosen car, looking at the regulations of those series (and others) to see which way to go and making a plan which will work and trying to stick to it. Don't get sucked into trying to build a BTCC car on an individuals budget. Getting out and having fun in a lesser spec’d car, and improving on it later, is more valuable than going to town and spending years in the garage… ask me how I know. Seat time is king!  :thumbs:

Some series like the Production GTI Championship is very conservative with what you’re allowed to change on the car, leading to great racing and (fairly) evenly matched cars. Some like the Classic VW Challenge give more scope for modifications and have some very serious cars in the field, organiser Ken Larks Corrado for example, and some like the Scottish Saloon championship and Pembrey’s Welsh Sports & Saloons championship are incredibly liberal letting you run big turbo’d 20v’s and slicks and whatnot and even featuring ex-BTCC cars on occasion  :shock:


As said we'll be starting at the beginning, so the first post will be on the car itself in the most basic state.

Thanks,
Tom

The Shell

It’s always a good idea to kick things off with the bodyshell itself. In a perfect world, you’d have a brand new pre-production shell, which you’d have had pulled off the production line before the seat belt brackets and so on, underseal, all those things have been put on, you’d send it off for acid dipping to get the coating off the metals, your staff would weigh it, crack the computer design and simulated testing, complete the fab work, moulding and final assembly in some insanely rapid time frame and you’d forget about it until turning up to pre-season testing without a care in the world to get busy behind the wheel. BUT we’re assuming for the sake of this thread, and real life, that your build starts like most of ours.

So in stark contrast to the above, you pick up a shell which has seemed like a winner to you, the best you can find for the money you have or simply all that is available, and you’ll hopefully have a fairly solid starting point to get cracking on with. Prepare to spend the next few days / weeks / months covered in metal dust, sucking in toxic fumes, burning yourselves, and generally being a badass.



First things first, get yourself a clean slate. Get rid of all that bitumen, sound deadening, underseal, all those things that make your road car a nice pleasant place to be. In some pics, it is already removed, but all locations are outlined whether they’re there or missing.
Interior wise, there are individual patches on the rear panel



Inside the rear quarter panels rearward of the rear turrets



Inside the rear quarter panels behind the interior rear quarter cards



Inside the front doors



On both of the interior surfaces of the front wheel wells



And on the shifter tunnel



These are easily removed with a wallpaper scraper and a heat gun. It is handy to sharpen one side of the wallpaper scraper *slightly* with a sharpening stone, a belt sander or something along those lines, but leave the other side, which will meet the panels while scraping, to avoid skagging the metalwork or making the bottom of the scraper an uneven surface which will make your life harder. As far as the amount of heat required, you’ll get an eye for it very quickly. Do small areas at a time as it cools quickly, heat the area moderately, it doesn’t need to smoke or bubble, you just need to warm it up a touch, get that portion out of the way and move on.

The firewall’s interior side is also covered in these, so they've gotta get it too. On top of this, both the front and middle sections of the floor pan are covered in a bitumen kind of coating, which is deceptively weighty once it’s all clumped together.



This comes off better without heat for the most part, as when it’s cold it chips and isn’t stuck as rigorously as the individual pads, so with a good sharp scraper and moderate force at the right angle you can take it all off without much grief. It’s worth eyeing up where there are seams and joins in panels etc as well so as not to keep smashing a scraper into the OEM seat crossmember or similar.
There is a big sound proofing mat, seemingly made of clothes from the holocaust blended with some leftover disgusting felt stuff and a black rubbery backing. There is some under the carpets, some covering the firewall / bulkhead, and some with the rubber backing stuck directly to the inside of the roof and the metalwork beneath the dashboard.



After this, the actual body is properly exposed. What may have looked like a very solid car may now not look like it did with a thick coating of tar, but hopefully it’s all okay. Identifying, assessing and sorting out any corrosion, holes or anything structural makes sense at this point. A good straight base is invaluable, so take care of anything that needs taking care of so your work later isn’t wasted on a rust bucket.



The next logical step in our opinion is to bin the unused brackets and mountings that you will no longer be needed. Off the top of my head, the washer bottle bracket in the bay, moving to the inside the rear seat base, the rear seat upper brackets on the rear suspension turrets, the rear seat belt mounting bolt plate in the C Pillars and behind the rear turrets.
With some of these, such as the front seat crossmember and the front seat rails, your best approach is to cut off the bulk with a mix of angle grinder, air saw and even tin snips to minimise the amount of grinding back you need to do afterwards. The reason for my opinion on this, is due to the shear volume of spot welds attaching them. Cutting the bulk off and grinding then flap disc-ing down the remainder is much quicker.



So once you’re left with this, for example, just grind out what’s left until this skin is thin enough to lift, just don’t prise skins apart with force, as you’ll just bend the one you’re keeping and make a mess.




With others, like the washer bottle bracket, rear seat belt upper bracket (pictured), the easiest approach is to drill out the handful of spot welds which attach this ‘skin’ to the panel beneath it, as they're much less concentrated than on the areas covered before.



Seam sealer and the rubberized stone chip stuff is the final hurdle in terms of now-unnecessary crap stuck to your shell. There’s a mountain of this, seam sealer all around the engine bay, on many of the panel joins in and under the car, coating all four wheel wells and the entire underside of the car. This definitely shouldn’t be any kind of priority, but if seam welding or going full bore to keep weight down you’ll find yourself doing this at some point, at least to some extent. Same old heat gun and scraper job here with the wire wheel on a drill or preferably angle grinder and a rag with paint thinner or panel wipe to finish up the job.



It’s worth remembering the panels themselves have a little weight to give up as well, the inner skins of the doors for example, but before getting too keen on cutting things up this is one of those check and check again moments for your rulebook. Interestingly, the MSA excludes bolt-off panels from its definition of “bodyshell” in its regulations, so that’s nice ;)



By this point, hopefully you’ll end up with a nice bare shell, with the factory weight and provisions for a nice quiet car well and truly having gone out the window.

Roll Cage

The next thing to address is the lack of anything resembling a climbing frame. A well built roll cage can save your life, and a badly built one can kill you, or at the least not help if needed.
A lot of the time it doesn’t come to this, and of course that’s a good thing, but with things like roll cages, seat mounts, brakes and whatnot, it pays to think in this way as if things do go wrong and luck isn’t on your side, it can be this serious, and you can’t race or party if you’re dead. There are countless videos on Youtube from British circuits in ‘regular’ tin top racers, it is a very real concern.



It’s important to check the regulations again here, most series in the UK simply reference the MSA’s Competitor Safety section, which gives all the information you need to build a compliant cage. Read, re-read and keep it handy whilst building :thumbs:
The basics, and I mean basics, are that mounting feet must be 3mm thick steel and cover an area of 120cm2. The cage should be as close as possible to the pillars etc and follow them properly. All mandatory tubes which must be present in any cage - the Main Hoop, the A Pillar bars, the Windscreen bar, the rear Upper Stays and the one mandatory Diagonal, which can be set across either the rear Upper Stays or across the Main Hoop - must all be made from 45mm O/D seamless tube with a 2.5mm wall thickness. Optional tubes, such as rear lower stays, harness bars, etc, can be made of 38mm OD 2.5mm thick or 40mm OD 2.0mm thick tube, which can save a little weight but sometimes it saves money and keeps things simple to just use 45mm OD 2.5mm thick tube across the board. Specs vary for T45 tube compared to steel, but it’s all in the Competitor Safety section.
It’s also worth noting, some cages do not comply to these regulations but are still legal. As an example, the Safety Devices Mk2 Golf cage was designed, originally built and then homologated and certificated when regs were more lax. This means the tubing is 38mm OD throughout, so while if you made your own cage like this, or modified one of these cages, you would not pass scrutineering, as an off the shelf item from Safety Devices with the certificate they provide it is still legal for competition now, even after the regulations have been updated. Never black and white, always check and re-check, always do your own research and always ask (MSA, a local scrutineer, etc) if you are unsure.

Here’s an example of a weld in cage, kept basic to keep weight down, going for a full bore WRC looking cage will look very nice but there’s already upwards of 60kg of weight in a basic cage, so bear that in mind.



If you choose to fit a weld in roll cage as opposed to a bolt in (which will still require proper welding of mounting plates to be legal and effective) you can increase the rigidity of the chassis even further. Often these are gusseted to additional points on the car besides the tubes mounting locations, most noticeably the A Pillars, and frequently there are additional tubes passing through the firewall to fully tie the front suspension turrets into the rest of the roll cages structure. This is obviously very good for very stiff suspension, very sticky tyres and a healthy dose more power in an aging shell.



There’s loads more to this, but this is simply an overview for the sake of this thread.

Seam Welding

Seam welding is a good place to go once the cage is in. This is tricky, as generally it’s dirty ‘car metal’. You need to be committed when you fire the welder up, as bits will blow through and you don’t want to leave holes, so get stuck in. The best way we’ve found is to wire wheel the areas that are getting your attention, blow torch them briefly to get the sealant to run out from between the skins, let it cool, wire wheel it again and that will minimise how much runs out when you start welding, but you’re bound to get some, so keep it in mind. You wouldn’t want to do more than an inch on to an inch off, so inch welded, inch skipped, inch welded, and so on. A lot of people say an inch every two inches, but either way I find it useful to map this out with a Sharpie before starting as I lose track once I start otherwise, and a massive irregularity can look a bit odd if you’re concerned about that. We weld 20mm, skip 40mm, peachy.



We never go further forward than the front suspension turrets, or further rearward than the rear suspension turrets, so you still have some form of worthwhile crumple in the shell in a big impact. Think about it this way, what good is it going to do stiffening up areas of the car that have no bearing on handling or anything anyway, if it has a cost. And that cost will be more force transmitted to YOU in a big smash after hitting something at pace. Not cool.
Seam welding is fairly time consuming and with a proper weld in cage, there’s a fair question over whether it’s worthwhile for an individual building a car for clubman use. If you have the time to kill between buying parts, feel like you should give it a go, or just plain think “if the pro’s have it, there must be something to it, so I want it” then by all means crack on. I’ve done it on mine for all three of those reasons. But likewise, there are fast cars competing without any noticeable seam welding and others with just key areas like suspension turret-to-shell joins for example seam welded, rather than doing every join on the car outright.




Seat tubes

Mounting your seat is as important as anything else. I’ve seen a seat come out simply under acceleration on a trackday, I’ve seen a seat
pull it’s mounting bolts through their mounting points in a crash, and you don’t want this happening when it’s your ass that’s planted in the seat in question. Typically, seat tubes are welded in, with spreader plates at either end and brackets coming off them forwards or rearwards to put the seat where it’s wanted. Once fully welded in, these are bombproof. Most kits have brackets with floating nuts to allow different width seats to be fitted and allow a small margin for error in bolt holes, and most side mounts which bolt to these to then bolt to the seat have numerous holes in them to allow for angle changes to the seat and movement forwards and backwards to suit a shorter or taller driver in the future, within reason. An important note here is to use properly sized washers on the bolts from the seat tube to the side mount, to stop them pulling through, and also to use a washer on the bolts from the side mount to the seat itself.



Interior and safety

Moving onto the actual parts and whatnot for a moment, obviously all this info is out there too, so I’ll keep it relatively brief. Starting with the seat a seat which should be a fixed bucket with a suitable harness, so a 5 or 6 Point with a proper buckle. You can’t really release road car style seatbelt buckles if you’re upside down with your weight tensioning the belt, so that’s why those are illegal for race use. Both the seat and harness need to be FIA approved items and also in date, as they’re lifed for about 5 Years from the date of manufacture. For the steering wheel, it pays to have a proper (not eBay crap) quick release boss kit to aid in getting out of the car over the seat and door bars. Remember GTI International the other year when a mickey quick release boss let go? Yeah, you don’t want that at 130 odd :thumbs:
Then it comes down to an extinguisher, battery kill and the rest of the things you need, i.e. dash, clocks, pedals / pedal box, shifter, the usuals really. The extinguisher will be regulated by the MSA with regard to size and is also a lifed item. The killswitch should be wired properly so it doesn’t let the car run on with power from the alternator, but as said this is an overview and wiring diagrams are easy to come by. Both the extinguisher and kill switch need to be operable by the driver in their normally seated position with the harness fastened and also by a Marshal outside the car, so you will run pull cables, or wiring if electrically operated, to the scuttle panel to activate these as well as having them within reach of the driver. The battery kill needs to isolate all circuits on the vehicle, excluding the extinguisher system if it’s electrically activated, and the extinguisher needs to be the correct extinguishant, properly charged and at least 2.25 litre capacity with lines to a nozzle for the engine bay and the interior of the car.



Again there is way too much going on to cover an entire interior and all the parts it is made up of in detail, so please take this as a basic run down to spark your own research.


Re: Racecars - Building a car for competition

Reply #1
Paint

Capping off the previous post, and something I cut from the end to fit, is paint. Once the shell is all finished and the groundwork is complete and the shell is suitably prepped, it’s time to make it shiny. Suitably shiny anyway, paint on racecars are generally good enough, often they aren’t the bodged runny bubbly messes people call them out as, and the majority of the time they are perfectly good. Anyone who saw Matthew Petts car at the National Meet last year can attest to the quality of cars people turn out for competition use.

Being realistic you have to accept that the car will get knocked, scratched, leant on by people and other cars, gather some battle scars, and there’s every possibility it’ll get crashed outright. With this in mind, direct gloss colours are your friend. You want something easy to touch up between rounds, as many series have a requirement for cars to remain presentable throughout the year and any previous damage repaired before the next outing. My red shed is getting covered in its original Tornado Red, the black Mk2 we built was a simple Gloss Black RAL colour and we are building a Mk2 at the moment which will be finished in Ford Frozen White. All these are even available in rattle cans just walking into your local Halfords if you get desperate, so they’re perfect.



One thing worth saying is that usually seam sealer, underseal and stonechip are skipped when repainting. While the cars will obviously get wet and get driven, they won’t see much, if any, salt or road grime and they’ll typically go back inside after each day out and get cleaned off for a full spanner check fairly soon after, so the needs aren’t the same as a road car.



That’ll do for that, I’m no bodywork guy and we’re not here to talk about making things pretty :D

________________________________________________________________________________

The Chassis

This is something which is very much worth your time, in my humble opinion. In the simplest terms, think back to the early days of modern car racing. Little Mini Coopers smoking cars with twice the power. They did so because they were lighter cars that could outhandle the lazy high powered barges they were up against.  A similar story, was our little black 1.8T Mk2 getting dusted off by a 1.8 8v PGTI car, pedalled by racer Roy Rothergill, at Castle Combe last year, a circuit which has its share of straights :thumbs:

Springs and dampers

As far as this stuff goes, there are so many options and opinions, with many of them perfectly well suited to the job at hand, before you even get to the part where personal preference gets involved. Purely as an example, I know people racing successfully and putting in legitimately fast times on GAZ monotubes while most people in the world of German cars would think you were insane for considering them. I won’t try and tell anyone what to buy, but do your own research, we’re lucky to have some very clued up people racing Mk2 Golfs these days and many of them are good guys who are happy to respond to threads / posts looking for information. You can’t expect anyone to hand over hard earned and worked for set-up information, so don’t be offended if certain things aren’t forthcoming :P The one thing you’ll find in common across the board is height and rebound adjustment as a minimum requirement.
It’s fairly well accepted that running the same spring rates front and rear will give a Mk2 which won’t be too snappy you but won’t be lazy, and it’s thought of as a safe bet around this way, with many people still opting to put stiffer springs on the rear. We tried 560lb front and rear on our black Mk2, with some additional weight from a 1.8T up front and Combe being a bumpy track, and it was a good predictable drive that wouldn’t misbehave unless you carried too much entry speed or intentionally provoked it :D Some of the PGTI guys have gone crazy high, 1000lbs out back no less, and the Vento Challenge racecars were spec’d in standard kit form with 1000lbs fronts and 1100lbs rear. There’s no advice here simply some background on the kind of ranges you’re looking in.
Obviously your dampers will need to suit the springs you choose, there is usually some scope for moving up or down a bit but most companies can re-valve their dampers for more sizeable changes in spring rate.
Camber is important with the Mk2’s suspension layout at the front, and when the suspension is compressed, such as being lent on when the car is in a corner, you will actually lose camber, so that’s why the majority seem to have a healthy dose up front when sat still in the paddock.
Caster is often added to push the front wheels further forward, making the car more stable and handily reducing the amount of negative camber which is lost whilst cornering.
A lot of the quick VW racecars run a little droop at the front end, that is travel that allows the inside front wheel to remain in contact with the ground when it is unweighted, typically about an inch, but at the rear there is usually next to none to get the weight transferred as quickly as possible.
There’s no ‘answer’ for suspension set up or geometry / alignment settings, and the subject is beyond the scope of a ghetto-ass thread on slapping a racecar together, but there are some awesome threads dotted about on the F1 Technical page, Nige Pinders blog Pinderwagen has some good tips hidden throughout it and there are some great books from folks with familiar sounding names like Carol Smith, though in that particular example it’s an older deal so a few little bits may need to be taken with a pinch of salt. There’s still some gold in there to give a handy indication on useful ways to think about things.

ARB’s

 A lot of people, when allowed, ditch anti roll bars entirely. I was discussing this with Ben Straker not long ago, who is the clued up chap with the black Mk2 ABF who cleared up at Curborough’s Mk2OC meet last year, and he and I are of the opinion, as many others are, that when springs and damping are sufficiently stiff for circuit use anti roll bars are not required. The stock one in the rear beam is obviously worth leaving where it is, but up front all you’ll probably end up doing is having the downside of reducing the independence of each front wheel while receiving no upside in return. Some of the really quick PGTI cars, where the front ARB had to be retained, used to loosen off the drop link nuts as much as possible to try and take it out of the equation while still having it attached, and I can remember unbolting drop links completely and cable tying them out of the way for a quick fix on a well know VW saloon racer in the past on a first race day of a season.

Bushings.

This is one of those times where you want to check your regs. In a perfect world, you’d run spherical berarings in adapted housings to fit in their respective bushing positions, but in some instances you aren’t allowed, some even stipulate rubber over poly for bushes, old school Group N for example. Powerflex do a spherical bearing bushing Mk4 / TT front wishbone rear bush, which is the bush that you want to have proper articulation, so that’s cool. Front the front wishbone front bush your choice is really to go with spherical from SCCH in the states, have something fabricated for you or just resort to the stiffest poly you can find as these really just need to stay put and let the wishbone rotate, so we go for the Powerflex Black Series 95 Shore hardness items, and the same goes for the rear beam, literally the same story. For the steering rack, you can get solid bushes off the shelf for manual racks, but with PAS racks you’re back to fabbing your own or going for poly, so we go to Black Series again as they’re near solid anyway and we also weld L Brackets either side of the solid rack section to keep it from moving laterally.



Track Width

First things first, Chris Eyre put a table together a while back, which I’ll ask him to post in here when he has time, giving details of all narrow and wide track options in 4x100 and 5x100 flavours. Calling all other things equal, typically a track width increase will improve handling by reducing the load transfer to the outside wheel slightly, which mean – ding ding ding – that the inside wheel maintains more grip. We like this. Considerations are that the wider track width affecting the roll centres, the scrub radius and load on the bearings if increasing with spacers or offset rather than wishbones as well as giving more leverage to act on the suspension so you’ll need it to be stiffer to compensate and behave in the same way.



Corner Weighting

Corner weighting is exactly what it says on the tin. Taking the car in race ready condition, simulating the weight of the driver in the seat, and aiming for numbers that you may not be able to achieve, but are damn well going to try to :D It basically falls into the static weight distribution and the cross weight. The static distribution is going to come down to where the weight is in the car. You can re-jiggle it a bit by moving components but any big changes are going to be relatively hard to come by in a production car where things are largely ‘the way they are’. Of course you can move the battery, and yeah you can probably shuffle a few more components and get some lighter panels, but you are kind of had by the balls on this one. I’ve never done anything with it myself, not intentionally at least. The other side of this, is the cross weight, which you can do something about. I was told, in true South West style, think about a wonky chair. If you need to stick a bit of card under one of the legs, cool, get it done. What the aim of this is, is to get the front left and rear right, and the front right and rear left, to have the same combined weights. This will mean the car should handle in the same fashion whether turning left or right. Imagine if on right hand turns the car felt peachy, but on left turns you had a different experience, making it hard to predict, you don’t want that sh-t.
People who do this for a proper living, suspension set up experts who do nothing else for example, can do some trick stuff with this, tailoring a car to a circuit and accounting for shortcomings in other areas, but again there are far better places to learn the ins and outs of this and we have our cars, and cars for customers, set up by someone who entirely specialises in this area.



Bump Steer, Roll Centre shenanigans, etc etc

I’ll be honest here, when I started looking into this, along with Ackermann and some other confusing sh-t years ago when I was keen on drifting, it blew my tiny mind. Even now, there are COUNTLESS people who can explain it in an infinitely better way than I can. I still need to think things through in my head thoroughly when thinking about things like this or applying a change to them myself, but bump steer especially I would say have a read up on. You’ll find VW specific threads easily and some have some excellent testing work and explanations in them. There are lots of bits to facilitate changes in this area, but all need looking into, working out and tailoring for your own car :thumbs:



Seam welding

This extends to the bolt on chassis components too. Mk2 Wishbones benefit from stitch welding, as do Mk2 / Mk3 subframes to a lesser extent. Mk3 VR6 / GTI wishbones are already welded practically the entire way round instead of being spot welded together, so I haven’t touched those, but something to bear in mind. Just as a side note, it’s worth having a good luck at the rear beam too nowadays, these are shonky old cars in reality and Monkey has broken one of the ‘legs’ back to the stub axle away from the lateral part of the beam due to corrosion and he’s not alone, and I’ve also seen the metal around the beam bushing rust through entirely and the bush fall out downwards, so if any welding is needed (though in the second example there, the beam would be fit for the bin rather than a repair, sensibly) get busy.




Tyres

Tyres are heavily regulated, with few saloon / hatchback series allowing full bore slicks. Most series simply nod to the MSA’s rule book again as far as tyres are concerned. I’m gonna go light on this and break it down into the three categories for treaded tyres, with a couple of examples of worthwhile versions of each, so I hope this helps shed a little light on it.

List 1A
Eagle F1
Yokohama Parada Spec2



List 1B
Toyo R888R
Yokohama AD08R



List 1C
Nankang AR-1
Yokohama A050



Brakes

Brakes are one of those things where it’s easy to get caught up. On one hand, if your engine doesn’t make every last bit of power it could or your geometry is a little off kilter or if you’re having an off day, you won’t be the fastest out there, but if you’re brakes pack up... yeah... that’s a biggie  :-?  Remember the Reeves Mk1, still on Wilwoods just for arguments sake, going off BIG at Castle Combe? Out of Bobbies, absolutely pinned, carrying a pace very few others could or would, heading towards Camp Corner, and nothing... still going waaay too fast. It was savage, and fortunately Trevor, partly due to his immense driving skill, got out without injury but the Mk1 did not.

On the other hand, a good thing to remember is that some people are absolutely flying while still using stock 16v kit with just decent pads, like Ferodo DS3000’s, decent fluid like Motul’s posh racey stuff whose name eludes me right now or ATE Super Blue and good quality plain or drilled discs. I’ve always been of the mind that switching to anything OEM but larger than G60’s (or 288’s from a Mk3) is a fail, as the weight there will be mega and unsprung weight is not your mate. If you want more, you’re going to start looking at aftermarket solutions.

Going beyond the OEM items is a pricey game to do properly. I figure if you have the need to go beyond the OEM options, your only next real step is grabbing a set of AP Racing calipers and putting together a kit based around them. If you walk around a paddock at a clubman event, the usual AP CPxxxx range of calipers (CP5040 in most Mk2’s case) are what you’ll see the most of, and if that’s the case then you pretty much know that that’s the way you should be going.

Besides that, which does effectively say it all, they’re available for various rotor diameters and widths and once you’ve got them there is a massive range of pads, so the fitment and options and characteristics are all within your control. The final winner for me, is that info is readily available and AP themselves are super helpful, which is surprisingly Gammon in companies dishing out motorsport kit.

There are a couple of options in fairness, some of the pricier Hi Spec offerings or anything with an Alcon logo obviously. Second hand Brembo race calipers (not the OEM Seat items that scene kids jump up and down about) are another option if you can find them, their monoblock GT car calipers are made good use of by the Reeves Golfs among a few others.

To be totally honest I don’t like the idea of spending upwards of £1500 on front brakes any more than the next person, BUT, if that’s how it is then that’s how it is. For some context, everyone I know who has gone for cheaper aftermarket options like Wilwood Superlites or similar have upgraded to AP’s later… I’m not keen for the extra step, extra work and extra expense of fitting something that still needs upgrading later when you could do it right the first time, in an area like braking.

Brake Bias

Not too much to say here, but typically you'll bin the OEM brake pipe routing, which is Front Left and Rear Right on one circuit and the opposing on the other, and have one M/C outlet, or M/C itself if using an aftermarket pedal box, for both front brakes and one for both rear brakes. This of course means the rear brake compensating valve isn't going to cut it.

Typically you have three ways of going about this. An in-line brake pressure reducer for the rear brake circuit, a brake bias valve such as the lever or turn-knob style items from people like AP, Tilton or Wilwood, which also fits in-line in the rear brake circuit which can be adjusted to in turn adjust the pressure the rear brakes see, and finally a balance bar for individual brake master cylinders which mechanically pushes one cylinder more than the other.

There's not too much to say about these, beyond the types available and the function.


Re: Racecars - Building a car for competition

Reply #2
Engine Choice

So you’re not too keen on cutting your floor pan out and getting your Flintstone on… I get that, not really viable and it definitely wouldn’t be fast  :roll:  We’re quite lucky with the Mk2 Golf though, all told. I have no idea how to structure these, so here's a sketchily arranged list.

The 8v options
8v engines from the Mk2 range, like the 1.8 8v GTI
The bigger 2.0 versions from the Mk3 2.0 8v GTI
The Mk4-Era crossflow 2.0 8v

The 16v options
The 1.8 16v engine from the Mk2 GTI 16v
The Mk3-Era 2.0 16v
The Mk5-Era 2.0 16v
The Mk5-Era 2.0 16v Turbo

The 20v options
The Mk4-Era 1.8 20v
The Mk4-Era 1.8 20v Turbo
The B6 Audi A4 ALT 2.0 20v

The 6 Cylinder options
The 2.8 and 2.9 VR6 12v from the Mk3 Golf  and Corrado respectively
The 2.8 and 3.2 VR6 and R32 from the Mk4-Era and Mk5-Era cars respectively

Hybrid Stuff

Also something that we’re fortunate with in the VW world, a lot of things fit together straight out the crate or with minor modification. Some examples :

Mk2 1.8 8v or 16v heads on Mk3 2.0 8v or 16v bottom ends
Mk4-Era 2.0 8v crossflow heads on Mk2 or Mk3 1.8 or 2.0 8v bottom ends
Mk4-Era 20v heads on Mk3 2.0 8v or 16v bottom ends
You get the idea
 
Forced Induction…

Obviously turbochargers can be added to pretty much any of these you choose, superchargers are an option as well but there’s not much point getting into that, as this isn’t a drag racing forum :D If regulations allow, this is going to be the fastest route to strong power from a VW motor. The obvious trade off is going to be response, so on a lot of UK circuits and especially with a light FWD car, going for a smaller turbo than worrying about making 500hp is a way smarter move.

Interestingly, the Reeves Mk2, which is the measure of a fast Mk2 in my book and many other peoples, is capable of around 400bhp with the boost turned up but has the benefit of an absolutely top notch racing driver and most of its visits to the track are around Brands Hatch. Seems contrary to what I said above, right? Well think of a Mk4 Golf, bigger car, heavier car, blah blah, well remember the yellow Gulf Air Mk4 Golf that briefly competed in the British GT Car Championship? Then it got banned, or the regulations got re-written to exclude the humble Golf to be more precise, as it was going too quickly and upset some Ferrari and Porsche fans? Well that beauty still ran a K04 turbo. So bear that in mind when you think you need a GTX35 :razz:



…And No Forced Induction

So your regulations don’t allow any boost, you simply don’t want any as you remember the good old days of Group A screamers or you just plain prefer the throttle response and weight saving of an N/A set-up? Getting power from Naturally Aspirated engines is much more difficult and just as importantly, in racing where you pick up the tab yourself, much more expensive.

Some series like the PGTI have strict regulations, allowing you a control camshaft, or shafts if going 16v, an exhaust where of course all the front runners go for Trackslag’s finest, a drop in panel filter and that’s about it as far as engine modifications go.

Some are much more liberal, allowing basically the full works of individual throttle bodies, cams as lairy as you can fit in the head, solid lifters, a valvetrain that’ll cope with sustained mega-RPMs, serious porting and polishing work, boring out to the limit of the class the car is entered into, high compression pistons, steel rods, wedged cranks, ARP studs, nuts and bolts everywhere, some even allow dry sumps and other trick sh-t.

Some folks are making a good solid 220bhp and beyond from a well driveable ABF / 9A style 2.0 16v, as people like JMR are doing great work with them and have a list of clients going very quickly across the country. More is possible, some Berg Cup guys make over 250 but with that will come lifed components, frequent rebuilds and engines which just want to be riiiight up in the revs at all times and helped along by a lot of moneys worth of sequential gearbox, but long story short be wary of anyone who tells you they can get you more than the low 200’s out of an old-generation VW 16v.

To cap off the basic rundown on 4-Cylinder N/A options, some folks have been following Seat Sports lead from their early 00’s Touring Car programmes, and using N/A 20v engines and even N/A FSI engines due to their cylinder heads abilities surpassing those of the older generation multi-valve VAG offerings. ABF’s etc are acknowledged as not being able to hold their own against engines like Shocking choice in vehicle’s XE or Ford’s Zetec range. The newer generation of VAG engines, especially the FSI’s, are of a much better design and have been used to good effect in mainland Europe and South Africa, but are largely an untapped resource over here.

The 6-Cylinders are pretty good to give them their due, and the immediate examples which come to mind are the former VAG Trophy V6 abusers like Ken Lark’s awesome Frazero built Corrado and Paul Taylors race winning Mk4 R32. Aside from the companies widely documented issues, Grant from GMS once told me while I was doing some work for them, you won’t drive a FWD car that handles better than a well sorted VR6 Corrado, which initially I thought was a bit weird, but in reality the weight difference between a V6 and a 1.8T with the extra turbo and intercooler and such isn’t as big as you’d think, although I’m still a little un-sold on the weight being so far forward with the V6’s. People clearly make them work though and maybe not for their size but in terms of outright power they still perform so I’d hate to neglect mentioning them.



Sound levels

This one leads nicely into another area where Mk2 guys are blessed, largely thanks to Trackslag. I’m sure I don’t need to introduce them, but they started out on earlier model Golfs and by this point in time almost any way you want to go with your engine they can practically cover the whole system. The reason we always put Trackslag specifically right at the top of the list is that besides fitting properly, mounting more resiliently than other systems and looking as blinging as anything else, they’re proven on the track. The majority of the Mk2 PGTI cars use their systems, loads of other VAG racecars use them, and the bonus to this besides the obvious (they clearly let the engines make the power) is that you aren’t going to be sweating buckets hoping your car will pass the noise test! Nobody’s got time for going home before you’ve even started as your car is too loud, or shelling out for a decibel killer on the day and bodging that onto the end of your existing system.

I won’t bang on about that too much, as I will openly admit I am biased and don't see the point in looking beyond Trackslag in most all cases – as a LOT of other VW folk are also of the opinion. We’ve used them time and again and they’ve proven themselves time and again, but I don’t want this to read like an advert… the sponsored content South Park episodes come to mind :D

Long story short from our point of you, if they fit right, last forever, make the power and do it quietly enough to go to any track day or race day you please, that’s an undeniable case made  :thumbs:



Another consideration is that beyond the static exhaust noise limit, typically 105 db(A) measured at ¾ throttle with the sound meter held a half metre away from the exhaust at 45 degrees, for test days and race days which is of course higher than track day limits, is that you will most likely be monitored throughout the event while on track. So if you lose your exhaust, or more concerning if you have a screamer pipe from your turbo’s wastegate or a set of throttle bodies off the front of your 16v, you can be caught out here.

As this is the case, you’ll see most turbo cars that do have an external wastegate to worry about having the screamer pipe plumbed back into the main exhaust and most throttle bodied cars will have not only a filter over their trumpets but also an air box around them. This can be a benefit to keep radiator heat away from the bodies’ openings, but at the same time you are quite short of space for a sufficiently sized airbox in most VW bays, so you may need to get creative. Think side mount radiators like on Honda Civics and even cut out slam panels as seen in a pic here from when we did some freelance work for another company.



Cooling

This is an important one, as of course if your coolant loses its poo or your oil turns to p-ss then you’re not only going home but you’ll also be getting your wallet out, not sure which is worse, but we can agree they both suck especially hard if it could have been prevented.

Generally 1.8T’s are pretty peachy, with a front mount intercooler and only a small oil cooler and OEM radiator, you can easily get through a 20 minute stint with a K0xx sized turbo. Obviously if a bigger blower goes into the mix and you start producing more power and more heat you may need to tailor things to your findings, but with a K03S our little black Golf 1.8T would stay out for 25 minutes at near full throttle with just a Toyosports ‘stashed behind the grill’ sized intercooler and a stock Mk2 16v radiator, it didn’t even have an aftermarket oil cooler though of course the standard coolant-oil heat exchanger was still in place.

The 16v’s and 6-Pot engines seem to run hot when they’re making power, we know of one which ran for years with an ABF on ITB’s with just a 16v radiator and a skinny 16-Row oil cooler, but now needs a hefty Mk3 sized rad and a 235mm 19 Row oil cooler to keep it happy. The 6-Cylinders even in standard form need an oil cooler really, some of the 3.2’s come with them standard, but on most of the 6-Pot racecars I’ve had anything to do with they’ve had 235mm 25-Row oil coolers and as big of an aftermarket ally radiator as can be squeezed in the available space.

In a perfect world you're keep your oil at about 90 degrees, but in reality anything up to 110*c isn’t going to give you any grief, and the odd spike a little over that isn't going to hurt if you're heavily wringing the cars neck or you end up out for longer or it’s an unusually hot day, this is understandable and liveable with though not ideal, but if you’re regularly or consistently seeing temperatures North of that then you should take a look at what you can do to bring it back down to healthy levels, bigger rad, bigger oil cooler, a different grade of oil, there are a few avenues, drag cars even run rich to the point that a fair portion of their fuel is burnt off before it makes it into the combustion chamber to aid cooling, but take that as a vaguely interesting side note more than an option to explore.

One thing which can make a huge difference is ducting and it makes total sense when you think about it. Again massively simplifying, but if your grill is a certain size and half of it passes through the radiator and the other half goes straight past it and just buffers around in the engine bay, how much better would it be if all that air passed through the rad? Twice as good haha  :razz:

You’ll see on most factory racers and a lot more private cars these days, Tony Barbers red Mk2 comes to mind as a recent and damn fine example, that some impressive time, thought and work has been put into making sure the radiator and oil cooler are being fed a decent amount of cold air and any air allowed into the front of the car is made the most of… after all, it’s costing you in terms of drag, so it needs to pay its way! We did a very basic and/or ghetto version of this on our little black Mk2 1.8T to make sure all air through the inner spot light holes and grill itself passed through the intercooler  and in turn the radiator, and the bumper holes up to the radiator, and even just this re-purposed undertray plastic made a difference :D



Of course it doesn't stop with the engine and brakes and even gearbox oil will very much appreciate additional cooling, although much more relevantly to most of us brake cooling is worth your time in considering.

* * Unfinished rambling, so will update / add to as time permits * *

Re: Racecars - Building a car for competition

Reply #3
Race Day

So you’ve assembled yourself an awesome rolling collection of top brand name motorsport kit all concealed within your car of choice, at great expense and exerting an insane amount of your time and energy, or you’ve done the sensible thing and bought a car ready built which you’ve refined and serviced or a car you’ve been consistently evolving while getting as much seat time as you can in between, and hopefully it's had a pretty good shake down and a thorough check-over before bringing it out to go at it for real… but that’s by the by, as more importantly, it’s go time!! READY?! :D

You’ve gotten there bright-ish and early, as however difficult it is to get out of bed at 06:00 to go to work, you literally can’t wait to get to the track. We get you, don’t worry :thumbs: You roll into the paddock feeling equal parts ‘like a boss’ and ‘not knowing if those butterflies in your stomach are trying to kill you’ and you pitch up in your favourite spot, or wherever you’ve been allocated, or even wherever is left in some cases. Get the car off the trailer, bang the splitter back on, put the ratchet straps and sh-t away, have an iced coffee in our case, then figure out what you’re doing next  :-?  :thumbs:



Sign on, briefing, scrutineering

Obviously you need to sign on, and all being well you will have time to go and get the car checked out before it’s time for your briefing. You’ll need your race license and your club membership details for signing on and for scrutineering you’ll obviously need your car, but also your kit, as they’ll need to check that your clothing as well as your seats and harnesses are in date and also your helmet to check it’s a type which complies with the safety standard required.

They’ll go over the whole damn lot in most instances, though locally by the time you’ve been a few times and got a few ‘passed’ stickers on the car it gets quicker and easier. Clubs and circuits vary on how liberal the scrutineers are and you may well get the odd one who just plain doesn’t like you or your car at some point, but the best way to think about these guys is they’re still there because they enjoy cars and 90% are good guys, after all, these checks are to make sure you’re safe and make sure you’re all on an even playing field. As much as anybody, they won’t appreciate attitude and if you’ve built your car to a decent standard and it complies with the regs and rules you shouldn’t have a problem anyway.

You’ll be amazed how often people do get caught out though, so it’s certainly worth double and triple checking the rule book while building and the dates on your seat, harness, extinguisher, suit, gloves, boots and the sticker on your helmet.



Checks in the paddock

The car should be dialled from leaving the workshop from a fresh dose of fluids and a full inspection and spanner check, but it’s common sense to do the basics now even if you know it's good. You need to go out and concentrate on the job at hand, you don't want to be wondering if this is tight or if that's right and that's why the car felt a little off in the last corner  :roll:

Wheel nuts torqued, tyre pressures done, dampers still set where they should be, fluids good, battery on, extinguisher pin out / switched to live instead of test, run the car up to temperature ahead of going out, all that sensible stuff that either needs doing or just saves you headaches or worries.

Have a chat to folks, see what the track’s like today, let yourself relax / get fired up as appropriate (I know plenty of people who do one of the other, whatever puts you in the right mood to get to work), have a slash as driving without taking one feels like driving p-ssed up haha, the usual stuff.



Set-Up Sheets

Set-Up sheets are both very basic and very useful. Generally you’ll have a sheet of paper with the date, circuit, temperature and weather to give an indication of that particular sheets relevance. After this, spring rate, damper settings, geometry like camber, caster and toe, tyre pressures, even anti roll bar choice. Some even include brake bias when they aren’t allowed to adjust it in-car on the fly.

A part of this which I personally like is having a notes section. Numbers are great, numbers give a quantifiable and definite scale of where each thing is at, and that’s invaluable, but I am a big fan of knowing what it actually feels like… ‘feel’ is priceless, it’s feel and confidence in the car which makes mere mortals fast or slow. Some of the lads who’ve grown up karting or have an immense talent or guys / girls with a lot of experience will still push a scary or sketchy car to the limit but it goes without saying that even these badasses will go quicker if they’re experience trust and predictability from the car.

I’ve included an example below, but of course it isn’t the only way to skin this cat, I know quick guys who simply have a lined note pad and guys who don’t even bother, but I like it – for whatever that’s worth, as I’m actually pretty slow :D Generally pre-made ones, like the Longacre item pictured, have corner weights on there but in fairness I’ve not worked on anything at a level where we checked them at the track, so we’ve got that little lot omitted from the ones we use. I’ve seen some single seater folks in the paddock using them, but in the clubman saloon game it’s a bit OTT.



The rest of the day

I’m the wrong guy to be giving advice on this, as I’ve worked with plenty of race cars on race days and I’ve raced karts, motocross and mountain bikes, but truth be told I’ve not actually done a legitimate circuit race in a car yet, just a healthy amount of track days and obviously the experience working with drivers on race day.

Generally you’ll have everything prepped as above, you’ll be ready to go yourself (Slayer through the head phones at an antisocial volume in my case haha) and off you go to qualifying. Of course you’ll know the outcome of this as soon as you’re out of the car, and it’ll be confirmed shortly after, but one of the coolest things in my opinion is TSL Timing’s live link. TSL is a website which has lap times from practically all races in the UK, and you’ll be on there assuming your transponder is working correctly, so you have the info at your finger tips as well as from your mate with the stop watch or timer on your dash. There’s usually a few screens in the pitlane and of course it’s as simple as looking on your phone back in the paddock.

When race time rolls around, the MSA have strict guidelines on everything from lining up on the grid to warming your tyres and brakes on the warm-up lap, but that’s not what you’re concerned about is it? :razz: Anything to do with actually driving or racing is wayyy beyond the scope of this little guide and as said above I’m by no means someone you’d want to be giving you advice on this side of things, so I’ll just skip over this.

When you’re finished doing your best, and not getting a trophy just for showing up, you’ll basically be done for the day, unless you’ve got an additional race in which case it’s time for the whole ‘check over everything you can in the paddock’ thing again, and then back out to hoon some more. With all said and done, you’re loading up and heading off and things are undoubtedly really good or really bad, but either way you know you’re f—king awesome and you’ll be back :thumbs:



/THREAD

To wrap this up, I just wanna say thanks for reading to anyone who did and I hope this has helped or at least given some insight into what goes into this whole racing lark.

If you’re sensible and realistic, going racing on some level or another isn’t beyond anyone and if you feel that trackdays are just not cutting it for you then I’m sure you’re already looking into it. Whichever way you go, it’s all for fun, nobody’s making money in clubman racing and as the old saying goes “the only way to make a small fortune in motorsport is to start with a big one”, so if you’re putting your time and resources into it, make sure you get the most out of it. That is, by having as much fun as you can, doing as well as you can, learning as much as you can and meeting as many like minded people as you can. As with everything, it’s all about that sweet spot between f—king around and taking things too seriously. Cheers :thumbs:

Tom,
water|werks