Track Car Setup - Advice Needed!

[dahughes]

A group of friends purchased a 1988 Supra built for Lemons/Chump Car racing. We recently found out that neither series will be racing near us in 2013 and we really don't want to keep up with all the rule changes so we have decided to run in local 8 hour endurance races. Local track is a flat 2.15 mile course with 13 turns. The car does well on the straights but the stock (mostly) 1988 suspension is a glaring weakness. The car has been stripped so additional weight savings will be tough. We are planning on switching out the exising sawblades for a lighter wheel/tire combo which should help. The car does have upgraded sway bars front and rear but I believe that is the ONLY change from stock. This car will be a track only car so we are not worried about comfort/ride, only going fast!

This is our first racing experience so please offer suggestions on setup / improvements we can make. And we are not Penske or Gibbs so budget minded items are always appreciaded.

Thank you in advance!

 

[destrux]

Bigger brakes to help with the added heat, a bigger radiator with a clutch type fan (like stock) to shed engine heat, a better engine oil cooler, and quality coilovers. Save making extra power for last. Also, if it doesn't already have a cage, you should add one.

 

[adampecush]

1. Brakes. If you are strapped for cash, upgrade the pads to racing compounds and make some ducting.
2. Cooling. Install a bigger radiator, bigger oil cooler, and power steering cooler. Get rid of the AC condenser
3. Suspension. Stiffer springs and new shocks (koni adjustable) are a good start. Go for a good set of coilovers if your budget allows (most of the low dollar ones won't survive racing) You shouldn't need adjustable arms for the rear as the extra camber after lowering will be useful for you. Might need adjustable upper front A-arms if you can't get enough camber though.
4. Tires/wheels. I'd start with a set of FD RX7 wheels. 16x8 and very light. Tires depends on budget. Anything from full slick to something like a hankook rs-3 will be good.
IIRC, cages are mandated by chump/lemons, so you should be good there.

Take the suggestions for what they are - suggestions. I'm by no means a racer, but have tracked various vehicles.

 

[hvyman]

Lots of negitive camber in the front and some negitive camber in the rear.

 

[themadhatter]

Invest in a good set of bilstein sports or koni yellows , then pair them with a set of ebay/QA1 sleeve type coil-overs and order what ever springs you want from summit racing. Should run you 700-800$ and be a fantastic setup or if you want to just keep it simple buy a set of BC racing coilovers, for a budget entry level coilover there well made and well sorted.

 

[hvyman]

Just use h&r with kyb. Kyb have lifetime warrenty so if they blow can get new ones for free. H&r handle great and with sway bars will be nice.

 

[dahughes]

Wow thanks for the quick responses! The car does have a full roll cage and EBC red brake pads with ducting. I don't think we are ready to spend the money on a set of good coilovers so we will probably go with the H&R springs with either Koni Yellows or KYB's.

I like the idea of the RX-7 wheels as they are much lighter and I should be able to find a set cheap. As they are a 16 x 8 rim what tire size would you suggest?

One final question.....Some folks have talked about cutting the existing springs and adding spring rubbers. As this is going to be only a track car is this a good or bad idea?

 

[adampecush]

I'm sure you could get away with a 255/45/16 tire on that rim (if that size is made). Stock on our car is 7" wide with 225. 30 mm wider tire section on a 25 mm wider wheel will be fine. Just a warning though, with wider and stickier tires, you will be putting a lot more heat into your brakes, which might necessitate upgrade. FYI, for some reason, I remember that there are a few years of FD wheels prone to cracking - you'll have to do more research into this before you buy.

With how cheap lowering springs are, don't bother hacking up the stockers. You'll still have the same spring rate, which is way too soft for these pigs on track, even if you've put the car on a diet.

(I enjoy answering legitimate questions about tracking the car, it is a refreshing change from "why does my oil look like a milkshake" or "I chopped up half my engine harness, tell me how to put it back together, now!")

 

[dahughes]

Looks like 255/45/16's are tough to find. Tirerack.com does have some 245/45/16's but all are $200+ per tire and I'm not sure we want to spend almost a grand for an 8 hour race. For us its more about the experience and having fun that taking home 1st place. I think we will go with a 225/50/16. Its not quite as wide but seems to be more selection and a lot cheaper. And like you said, it will keep some of the heat out of the brakes which is important in a 8 hour race!

 

[scottiedawg66]

i have no experience racing cars, but i think some ducting to the brakes would make sense( fog lamps seem like an ideal "intake"). I found the front and rear strut tower race was a cheap and did improve feedback as well. I'd imagine replacing the bushings in the subframe and suspension would also be a good idea. it sounds really, fun! post some pics

 

[Poodles]

Way back when these cars were raced competitively, the failures they had were power steering related In other words, use a bigger cooler.

 

[te72]

I like the idea of the RX-7 wheels as they are much lighter and I should be able to find a set cheap. As they are a 16 x 8 rim what tire size would you suggest?

Looks like 255/45/16's are tough to find. Tirerack.com does have some 245/45/16's but all are $200+ per tire and I'm not sure we want to spend almost a grand for an 8 hour race. For us its more about the experience and having fun that taking home 1st place. I think we will go with a 225/50/16. Its not quite as wide but seems to be more selection and a lot cheaper. And like you said, it will keep some of the heat out of the brakes which is important in a 8 hour race!

Tires: http://www.discounttiredirect.com/d...?pc=40304&tmn=NT-01&typ=Passenger/Performance

Wheels: http://www.tirerack.com/wheels/Whee...ing&wheelModel=RPF1&wheelFinish=Black+Painted (I'd recommend a 16x8 personally, offset in the +20 range)

Body: Cheap carbon fiber hood, perhaps replace the glass (all of it if you never plan on street driving the car again) with something like Lexan. Lots of speed wax. Move the battery to the rear seat.

Chassis: Brake upgrade, if you find that your brakes aren't up to the task. Urethane bushings (pricey, but offer the least amount of give in a bushing). Some sort of lowering spring or reasonable priced coilover.

Driver: The best one you can find.

Just a few suggestions, on what I'd do on a track only car. Pretty much everything covered above are good suggestions as well.

 

[Van]

A group of friends purchased a 1988 Supra built for Lemons/Chump Car racing. We recently found out that neither series will be racing near us in 2013 and we really don't want to keep up with all the rule changes so we have decided to run in local 8 hour endurance races. Local track is a flat 2.15 mile course with 13 turns. The car does well on the straights but the stock (mostly) 1988 suspension is a glaring weakness. The car has been stripped so additional weight savings will be tough. We are planning on switching out the exising sawblades for a lighter wheel/tire combo which should help. The car does have upgraded sway bars front and rear but I believe that is the ONLY change from stock. This car will be a track only car so we are not worried about comfort/ride, only going fast!

This is our first racing experience so please offer suggestions on setup / improvements we can make. And we are not Penske or Gibbs so budget minded items are always appreciaded.

Thank you in advance!

I've a few questions:
1. What shape are the engine, transmission and dif in?
2. What improvements have been made to the brakes?
3. What condition are the tie rod ends and ball joints?
4. What condition are the suspension bushings?
5. Any cracks on the rear sub frame collar that goes over the Dif?
6. Any fluid leaks?
I'd start with those first, then go with the upgrades. I was refused entry on occasion at my local track because of those items on my Supra that didn't pass Tech at the event the night before, I had to fix them or not race that weekend. So, start with those items avoid the hassle, then start getting all the safety gear that meets your local SCCA/NASA rules, and have fun! Van

 

[dahughes]

I (we) really appreciate all the feedback. As a quick recap, we purchased this Supra to run Lemons races but have since decided to just run local 8 hour endurance races instead. We have one under our belts and it was a blast. Our goal was to finish which we did. Weak link is our ability but we all saw vast improvement over our 60 laps each. Our overall goal is making the car faster while keeping budget and reliability in mind. We didn't build the car and have varying degrees of automotive knowledge so I'll answer your questions the best I can:

1. What shape are the engine, transmission and dif in? Engine was rebuilt with forged internals not all that long ago. Just replaced the head gasket, had it machined and replaced higher quality gasket and ARP bolts. Racing clutch with no issues. No fluid out of the rear diff.
2. What improvements have been made to the brakes? calipers I believe to be oem, but running slotted rotors with EBC yellows.
3. What condition are the tie rod ends and ball joints? running much heavier front and rear sway bars with new heim joints.
4. What condition are the suspension bushings? I'm not looking at it right now, but there are no visible issues with the steering components, and I believe the previous owner had mentioned upgrading some bushing, although not sure if they were included as part of the sway bar upgrade or if they were touched at all in the other areas of the suspension. Springs are stock. Shocks have been replaced but with a stock equivelent.
5. Any cracks on the rear sub frame collar that goes over the Dif? I did not notice any subframe cracking, but also wasn't really 'looking' for it either. We'll have to see next time we get it up on the hoist.
6. Any fluid leaks? Had a little radiator fluid leaking issue, but it was just a problem with the overflow venting. After sitting in the garage for a month there appears to be a couple small leaks front and rear but I'm not sure if these are new stains or not. Will have to clean and inspect under the car soon.

A couple questions:

1. It seemed like we generated a lot of under the hood heat (7MGTE). Why couldn't we cut 2 or 4 holes in the hood to help extract heat? If so how big and where. I know this is pretty redneck but remember the goal.....faster on a budget.
2. A lot of the posts talk about larger power steering coolers, radiators and oil coolers. Where can I get theses on the cheap?

Thanks Again!

 

[dahughes]

And all glass has been removed and the batter has been moved to the rear next to the fuel cell. Interior has been GUTTED with only a cage, racing seat, detachable steering wheel and gauges/switches.

 

[spoolme]

radiator wont be cheap, unless you all pitch in. lol
power steering cooler you can get at carquest or something as they all should have universal bigger transmission and oil coolers...which wouldnt be hard to adapt for power steering.

Post some Pics!!! pics are always good.

 

[Poodles]

You can use a factory oil cooler as a power steering cooler.

Also, junkyards for parts like that

 

[Van]

I've had good results getting my racing equipment through Driftmotion, Porterfield http://porterfield-brakes.com/keySearch.php?search=supra&manufId=&_pge=2&_sby=&_ord=and IO Port Racing http://www.ioportracing.com/index.html.
With regard to radiator choice, I picked a Koyo Racing and added a surge tank to add another gallon capacity to the cooling system. For heat removal, I still run an engine undercover, then have the rear of the hood lifted with a few washers on the hood hinges. I used not to run a fan as most of the time I was going fast enough not to need one... I was running a 18 pound radiator cap and 16 pound surge tank cap. The 7MGTE was typically kept above 3500 RPM and mostly in the 4 - 6K RPM range where the engine I had built was designed to run. The engine uses Amsoil 10-30 100% synthetic oil. This August on a 90 degree day I noticed the temp rose to mid way on the gauge. So our engines can get quite hot! I needed to run with short shifting for about five minutes before the temps returned to normal. The engine I run also has a seven quart sump. Sounds like you and the guys have a well built start on a track Supra.
I'm finding RSR racing springs and KYB GR2 are a good set up for endurance racing on a budget. When you can afford it, get the Koni yellow. I also find that the Porterfield R4-1 in front works well with the stock brakes. I use the TRD pads for the rear. I'm finding the stock brake bias adequate for the speeds I'm able to drive. I had to bleed all the stock brake fluid and switched to Castrol SRF, 100% synthetic fluid. A great improvement in reducing brake fade, even on very hot days. Well worth the extra cost. Van

 

[scottiedawg66]

Van. what is your experience with stainless steel brake lines? I know from my motorcycle racing experience the best bang for the buck upgrade on a race bike is stainless steel brake lines. They vastly improve feedback when fluid is changing temperature. I imagine with a heavy car like a supra some stainless lines would probably be a good affordable upgrade?

 

[Van]

Van. what is your experience with stainless steel brake lines? I know from my motorcycle racing experience the best bang for the buck upgrade on a race bike is stainless steel brake lines. They vastly improve feedback when fluid is changing temperature. I imagine with a heavy car like a supra some stainless lines would probably be a good affordable upgrade?

Yes it is one of the usual upgrades for the reasons cited and for durability. I also found the brake booster stabilizer from Beech Performance was an added benefit, as it allows for less movement of the firewall, sending more force to the brake master cylinder. Van