Yep, it does depend on your driving. And honestly, I can't recall anyone with any racing or competitive driving experience saying:

"Gee, I'd really like to have a lot of understeer. Can you set the car up like that for me?"

 

I am on the same boat as Glen running an '87 944 with no rear sway bar. With the stock front sway, would it be a good idea to go with the adustable 19mm rear sway bar as a first option? Or would doing something like this throw off the balance of the car too much. Would this be the same story with a sway bar from a 951 (16 or 18mm is it?).

 

Techno Duck, look for front & rear sways from a 951 or S2.
I put 86 951 sways on my old 85.5 and it really made a nice difference.


Serge, sway bars and springs do not perform the same function.

 

Tifo is right.

You can't properly balance 250 lbs springs with a sway bar alone.

It will work, but not as well as the proper spring rate. I have posted many times here about how I used the 22mm weltmeister to balance my 350 frt and 28 mm t-bar rear. It worked better than not, but hurt me in corner exit traction. When I did it right and put in 30 mm t-bars the car was much nicer to drive and faster.

Glen depeding on how far you want to take this can how much of track compromise you want will determine what the best spring rates.

I typicall advice 250lbs springs with 28 mm t-bars and 300 lbs/29 and 350/30 combos. There are a couple nice things you get from the paragon coilovers.
First the ride height adjustments allow for better corner balancing. Also you can convert to camber plates too. These are nice sine you want a little more negative than stock allows. These keeps the tire wear more even.

 

Oh... Glen 15" wheels with 225/50's will be faster than 16" with 225 or 245's
A guy in an 88 924S tested this and was 2 seconds faster on 15" vs 16"


These cars run better with shorter and lighter tire. Plus you save money by being able to rotate tires to get longer wear and the tires are cheaper.

a set 15x7 phone dials can be had for under 300 easy. Maybe even 200.

 

I agree with the above. I have a small amount of regret regarding the huge brake calipers I installed on my car, in that they keep me from being able to run 15" wheels/tires on my car for auto-x. The smaller wheel/tire combo is faster for the n/a 944 cars, INHO.

 

Wait a minute...

You're saying that the 15", higher profile tires will be faster than 16" wheels with a lower profile?

 

225/50/15 is a lower profile tire than 225/50/16 in terms of sidewall height. Guys, everyone makes mistakes but jumping all over someone will result in eventually no one wanting to answer. Just let someone be corrected in this case.

 

So what about the rear coilover kits from paragon? What # should you go with if you are keeping the torsion bars if you have one of those combos stated before like 300lb/28mm or whatever they were....how do you match the rear coilover with the torsion bar so you dont over do the front?

 

My tone did come acrossed a little more harsh than was intended. Sorry 'bout that Serge.

 

In terms of tires...
Torque = weight x length

tires of a 215/50 15 will be faster simply because they take less effort to move (torque). In the equation, length means length from the center of the tire. The weight being closer to the center of the tire will be easier to move - 15" wheels, not 16's have the advantage here. Weight will be the weight of the tire/wheel combo. The 15's should be lighter than the 16's when you weigh them. Will the 15's being lighter, and the weight being closer to teh center, the laws of physics simply put support the statement that the smaller tire should be faster.
Thank you, I will now retire to the nerdery.

 

I was thinking that you'd want (OK, I'd want) to maintain the same diameter so the speedo is right.

Lego, those sidewalls would be the same. (225x0.50) The overall height would be one inch less.

For a moment I thought someone was suggesting using a taller tire on a smaller wheel to get more speed. (Or were they?)

 

it'll be a smaller outside diameter. The 225/50 15 is about 1 inch smaller than the 225/50 16. It's the same sidewall height and the same width on both tires, but the rim size makes the difference. The bigger wheel simply moves the weight of the tire out from the center of the wheel 1 inch.

Use the ES100 specs as a guide:
http://www.tirerack.com/tires/Spec.j...omCompare1=yes

 

Glen,
I should have stated so, but that is what I was refering to.

A 225/50 on 15" rim has smaller diameter than a 225/50 on 16" rim.

You gain with a 15" wheel in a number of ways

1) smaller overall diamter = shorter final drive this tends to improve acceleration since these cars are drag limited vs redline limited especially at race tracks. Even at the fastest tracks is hard to redline a 944 NA in 5th (even shorter 5th) on 225/50 R15 tires.

2) smaller dimater = less roating weight. So for example 16" Phone dials will weigh more than 15" phone dials. This is not true of all wheels, but the same wheel type will be more in 16" vs 15" although some expensive 16" wheels are lighter than cheap crappy 15". The tires will also weight less since there is less carcass

3) rotating inertia is less due to a smaller overall diameter.

4) Tires are cheaper in 15" than 16" sizes in most cases

5) 225/50-15 on each corner mean rotations which extend tire life.

The biggest benefit from 16" wheels are the ablity to go with larger diameter brakes. In spite of their look NA brakes are actually quite good and unless you have are having issues and have tried everything to solve them stay with the stock sized rotors and stock calipers.

 

I know that 225/50 is supposed to be 50 percent of 225 mm (height of sidewall). However, in real life, when I measure 15s against 16" tires, the 16s have more sidewall. I am not sure why but thats what I found. Also, different manufacturer of 225/50/15 are supposed to have the exact same sidewall height but I have never found 2 to be the same. Go figure.