rad_951

I am currently building a 86 944 T track car. So far I have focused on maintenance. I have changed the water pump, timing and balance belts, all cooling system hoses, vacuum hoses, brake rotors, brake pads, all fluids, radiator, cycling valve, and filters. The car was more of a basket case than I thought. I removed the AC system and an alternator mount from Lindsey Racing. I plan to remove the interior soon. The car is running well and ready for some mods (I hope).

I want to be most efficient with my first mods and I want to focus on handling. Would big wheels, that would allow the most tire under the fenders, or a spring/shock/sway bar combination with the stock wheels yield the best times around the track assuming the same brand and model tire?

From what I have read about wheel upgrades is that the contact patch does not get any larger, just the shape changes (not putting any more weight on the wheel). If that is the case, then the improvement from bigger wheels must come from increasing the track width, which reduces weight transfer. Similarly springs improve handling by lowering the center of gravity, which reduces weight transfer. Does this sound correct? If so, would this favor wheels or suspension? There is only so much room to adjust either.

Also, I forgot to mention, I have a Vitesse chip, 3 bar FPR, and KISS oil cooler to install.

Thanks.

Tony
1986 944 T track car
2002 M3 daily driver

333pg333

I guess it depends on what you're changing from. In other words if it's totally stock, then if it's a choice between suspension and tyres, suspension is going to yield a better response. However you should possibly upgrade them in concert so that you can see what adjustments are available or needed.
Are you planning on changing the bodywork as this will have an effect on what wheels/tyres you can use. Plenty of stuff available through the search button

dime1622

Wider wheels will give you a bigger contact patch. You won't get any more weight, but a larger contact patch will allow you to hold more frictional force before slipping.

Springs won't do much about the center of gravity. Your 951 sits low enough anyway. What it DOES do, along with sway bars, keeps the body from rolling so much, which keeps a more even distribution of weight on your tires. The more weight you can keep on your inner tires on a turn, the less likely the wheels will be to break free.

kevincnc

Dude.. I can't tell if you're talking about a car or your avatar.

rad_951

The car is stock. The front springs have two yellow dots, so somewhere between 150-175 lbs/in rate. The wheels are aftermarket but the same size as stock, 7x16 front and 8x16 rear.

I have searched the archives and have not found any "bang for the buck" wheels vs suspension threads. Most people seem to suggest going with very high spring rates/bigger sway bars but don't compare if this is more effective than larger wheels. I have heard a track car needs the softest spring it can get away with so the tires have a better chance of staying in contact with the road. However, I do not know if the stock springs are too soft for big wheels. So far, I am inclined to go for the biggest tire and wheel combination and use Toyo R1A tires. Any suggestions on wheels and tire sizes? I will roll the fenders, if needed.

Thanks

Skip Wolfe

Spring/shock/sway bar combination with the stock wheels will by far, no contest, be the best bang for the buck for increased track performance. The most I would worry about wheels at this time is to pick up another set of 8" wheels and run 8" with 245's all the way around. Going to wider 17's or 18's will make a difference only after the rest of your suspension is set.

Is this a DE car? Any street or just track? What sort of budget are you working with?

future

If you are after some excellent and extremely light wheels for track then you need to look in the direction of the German company ATS.

I fitted these to my old 993 C2 after having previously run Veloce GT1's which I still have but removed them simply because they are no longer in production - but still among the very best to own.

The ATS DTM competion wheels will not be to everybodies taste regarding looks but are very light and come in loads of different size if you go to there website: http://www.ats-wheels.com/ and you can get them in silver or black (blacks best)

You can see them fitted to my old blue 993 at the bottom of this page: http://www.alloywheels.com/product.a...ria=&PT_ID=96# (they look much better in person than in pictures

I think you will find it hard to find any thread which is a like-for-like based comparison purely because there are not many of us who have had the pleasure or budget to try many configuration but at the end of the day by reducing as much rotational and un-sprung weight is the key and you can even go down the route of running rear coilovers inverted which I do!

As your car is an early offset 86 you actually have more choice regarding wheel/tyre combos.

Suspension wise you are nbot going to go wrong with KW Var3's based on quality, price and performance

dime1622

You know you're turned on, Kevin. I'll bring you a poster of her some day. Of course, she's hotter in person. I hear the camera adds about 10 pounds.

rad_951

I realize now that I have asked a bad question. Most people are not going to know the the benefit of suspension and wheels individually. They will know the benefit of one or the other individually but not both.

I have not decided on how much to spend on this project. I want to buy components that help reduce lap times. For example, if I buy bigger wheels and track tires but I gain no more performance than I would have by putting track tires on my stock wheels, then I wasted money.

At first i plan to use this car for DEs. Eventually, I would like to drive in SCCA events.

A fellow I met at the track had camber plates, 450lb/in front springs, and a 32mm torsion bar on his 951. I don't know what he had for sway bars. Would this be a good set-up for DE car? Matched with Toyo R1A tires? Too stiff?

f1rocks

The advantage of an 18" wheel in combination with a stiff suspension will be sidewall reduction.

I'm currently running 800 pound springs up front/600 pounds w/torsion bars rear. If you tried that with a 16" wheel/tire combination it would not hold up well and tires would be smoked quickly.

At 450 pounds up front the RA1's (now 888's) would do well in any combination.

You can do a suspension upgrade for $1500-1700, less if you can find some used stuff.

I'd go 968 bars front and rear (30mm/19mm)

Your best money will be spent in seat time of course.

Skip Wolfe

245 Toyo RA1's on 8" phone dials all around would be just fine until you got everything else in place - bigger wheels without doing the suspension first would be purely for looks and do little to nothing for performance.

Spirng rates are going to depend if you drive this on the street at all. If so then 400-450 fronts are about as stiff as you would want to go, if you are going to trailer it then 550+ are they way to go. The Bilstein Escort Cup setup is a great bang for the buck track suspension along with the 968 sways (with delrin bushings) that f1rocks referred to, unless you have the money for Tarrett sways. For a pure track car then I would recommend ditching the rear torsion bars and going with coilovers all around.

Some other things you would need to think about:

- Aftermarket front control arms - stock arms are tghe weak point in stiffly sprung track car - would recommend Charlie arms if you can find them and Racers Edge if not

- Spherical bearings - must for any track car - Racers Edge and Elephant Racing have a nice selection - I would probably lean towards Elephant Racing because of price and a better spring plate bushing setup.

- Safety equipment - should be high on your list. A bolt in roll-bar at the absolute minimum, but if you want to run SCCA then you should just spend the money on a nice custom cage that ties in the rear shock mounts - make sure it's built to SCCA rules which will cover whatever race series - PCA or NASA - you are also going to run. Also 1 piece racing seats will drastically improve the "seat of the pants" feeling of what the car is doing, along with a good 5/6-pt harness.

- Good corner balance and track alignment.

- Finally wheels - I would recommend 17 or 18 - 9" fronts and 10" rears running 245 or 255 fronts and 275 rears. There is a performance difference with 18" wheel over 17" but it is fairly minimal, however the price of tires is subtantially higher with 18". I had 17" Fikse for my DE car and specifically stuck with 17" BBS for the racecar because of the minimal performance increase with large increase in r-compound tire price. Go with a light weight forged wheel - BBS, CCW, Fikse, Kinesis, Forgeline, etc. Keep your eye open on Rennlist and Pelican and you can usually pick them up used for a decent price. It is also important to remember with increased size can mean increased weight. It is important to get a lightweight forged racing wheel that is a as light is possible or you will cancel out any performance gains.

f1rocks

To elaborate on Skip's points,

Make sure whatever you do to the car fits the class that you want to eventually race in. For example, PCA you cannot make significant engine modifications if you want to run in E or F class. Chassis is open but wheels you are limited to 8's up front and 10's in the rear.

I ended up "out classing" my first attempt, a 911, and this and had to do a "do over" on the Turbo S. Not cheap.

rad_951

It sounds like suspension is more important than tire/wheel size.

I have been looking at the Bilstein Escort Cup kit. I t appears this kit works with the torsion bar set-up using a helper spring for the rear. If I go with a 450lb/in rated spring in front, what would be the best rear helper spring rate with a stock torsion bar? Do I need camber plates (can't get enough camber stock)? Would this suspension provide benefit with stock wheel sizes and R1As?

Thanks!

jerome951

Yep, here's a data pont.

I upgraded from stock turbo S wheels 7 & 9x16 to 8.5 & 10x17. Gained ~2 sec using same type of tire.

I then updgraded my suspension (full-blown race setup) and gained an additional 5 seconds.

However, I'll recommend another option. Unless you've had a significant amount of track time, don't upgrade suspension or tires yet. Spend the money on learning to drive the car well and safety/reliability upgrades, then look at other mods.

f1rocks

Not initially, there's better places to spend money.

You should find a local member of whatever organization you want to play in, lay out your budget and start by figuring out where the car is going to end up (full blown SCCA, PCA Stock, NASA, SP3 etc.)

How many track events have you attended?
How many do you want/plan to attend per year?
Are you going to tow the car to the track?
Are you going to bolt most of this on yourself? Nothing sucks worse than having to do 3 or 4 alignments because you keep adding bits to the car.

If, like me, you are budget limited, you don't have to buy all the fancy stuff right away. Too many people think the equipment is the only thing to make them faster.

You'll get faster spending a significant amount of time on the track, with and without an instructor.

Just my .02 worth (after spending $12,000 in suspension upgrades only to park the car to go SP1 racing for a while....)