944 tire problems

[ttweed]

... excellerating too hard before the apex, causing the rear to compress/front to lift too fast ... and understeer. Try feeding the throttle just a tad slower/smoother on the exit of a turn.

Yeah, Dan, I know you 944 guys are always almost pulling wheelies when you stomp on the loud pedal too hard! All that power is hard to control!

...Just joshing ya...smooth is good...
and you're a 911 guy now, anyway...

TT

[Dan Chambers]

Yeah, Dan, I know you 944 guys are always almost pulling wheelies when you stomp on the loud pedal too hard! All that power is hard to control!

Good one, Tom!

[Jad]

You can probably find 16 or 17" Boxster take off for almost nothing....

Jad-
If he has an '85.5 944, wouldn't he use the early offset wheels that are the same as the early 911? I think he would need big spacers or adapters to fit the late offset Boxster wheels, no? It was only in '87 that 944s changed to the bigger (late) offsets, IIRC. Once you add the cost of 1"-1.5" spacers or adapters, the cheap late-offset takeoffs are not as great a deal.

For an 8" rim, I think you would want an offset of about 11mm to fit the early cars. The later model rims have offsets in the 40-65mm range, I think.

TT

You are basically right, but I did run 16" Boxster rims on my early offset 944 without any issue. It did cost me a little bit of track width as I did not use spacers, but otherwise they fit fine and are CHEAP now. I didn't run the rears in front, just the Boxster 7 & 9 setup, but think they should work fine, or with a small spacer. Stock is best and this entire thread would be gone if he just had stock front springs... I used the Boxster rims as street wheels and ran phone dials as the track rims thinking I could save tires. Turns out the track rims ruined the outer edge of tire, the street rims ruined the inner edge so I actually went through tires twice as fast So I sold the Boxster rims.

[bibbetson]

I've got to side with Jad. That car will always fight push with 400lb front springs and stock rear torsion bars. You have made the front suspension 100% stiffer than the rear. Sway-bar, wheels, alignment, etc are tuning aids to make minor adjustments in a correctly sprung car. Fix the root of the problem - put 225 - 250 lb front springs on, get it corner balanced and aligned by one of the race shops and go have fun. If you want to go faster then remove weight and adjust the alignment to improve balance and grip. Like Paul said, these cars are extremely sensitive to alignment settings and there isn't one perfect setting for all cars. After driving the car at events for 4-5 years you will know what to do next AND you will know what those adjustments will do to the car (if you still want to do it to that car). Every driver hates to hear it, but there is no replacement for seat time.

...or save all your money and trouble and go buy a 944 SPEC car.

Another good data point is to get someone else to drive your car that knows the model and its particulars. Sometimes they will say "that's not bad, just adjust this or that" or they will say "that's just terrible" and you will know it wasn't you but the car.

[Jackie C]

Josh,
Looks like all good advice from the guys. I recommend getting whatever mods you need to push you up into GP (Why not get rid of the weight, doesn't cost a dime...) and come and race against David Rey, Mark Rondeau and the rest of us in the class. We'll help you get faster. Seat time grasshopper, seat time...Just a few more months until you get on the big tracks, then you'll really be ready to chase us around, or vice versa!

[Josh Y]

jackie,
its going to be a little longer than a couple months before you and everyone else in the 944 class will be chasing me around tracks...
haha well thanks everyone, i think im going to try to make the rear stiffer and maybe add springs to the rear to try to balance out.... and just drive drive drive...

[Bob McLaughlin]

Josh, You might double check the width of the wheels. Are they are the same fifteen inch wheels that were on the car when you purchased it? My memory recalls a different width.
Paul Young's suggestion regarding alignment seems to me to be right on target. The type of alignment you use can make a huge difference. However, when I last drove it, I thought that the car had a perfect balance for a combination of street and track usage: 250 Lb springs, Bilsteins, added sway bar in the rear. Of course, your intended use might be different than mine.
If you intend to go in the direction of a spec. car, check with Chuck, Jackie, and some others that have their cars dialed in to see how their car is set up.
If you want a street-track set up what you have will work.

[harnishclan]

The rear does not have springs, the twist of the torsion bar is the "spring" that is why a larger bar is equal to a higher spring rate. So you have torsion bars, shocks, and sway bar to make up the rear suspension. There are also the bushings (stock, delrin, metal) as a nice "while you are there" kind of job. I have done torsion bars on a few 944/924 cars now (and it usually takes more than once each time to get it right. This is not a cheap task nor is it for the faint of heart. Just getting the 24mm and 30 mm bolts off is enough to stop many, but doing the geometry to get the height right and the car level does most of the rest in.

Bottom line is good shocks all around, adjustable sway bars all around, 200-250 springs up front, fresh bushings, matched tires and rims, and a good alignment will net you the most satisfaction. If you do choose the 30mm torsion bar route, and still drive on the street make sure your significant other has lots of sports bras!

[harnishclan]

Oh and the 16/17 inch tire wheel thing isn't too good since they are usually much heavier and is all unsprung weight. Takes too much horsepower away from the primary task of moving what you already have moving forward. And you don't have HP to spare! Equal width 15" Fuchs, then phone dials, and finally cookie cutters is the ideal wheel tire combination.

[Jad]

Oh and the 16/17 inch tire wheel thing isn't too good since they are usually much heavier and is all unsprung weight. Takes too much horsepower away from the primary task of moving what you already have moving forward. And you don't have HP to spare! Equal width 15" Fuchs, then phone dials, and finally cookie cutters is the ideal wheel tire combination.

I completely agree you don't want to go big, (18"'s or anything like that) but a few years ago when I had a stock 944 n/a, the 16"'s seems to be the best choice based on available tires. 16" are small enough that they don't have to be too heavy to get strength and the lower sidewall improved response and reduced rollover. Always check the available sizes in the tires you want to run, before buying rims, but if you find a nice set of 16" phone dials I certainly wouldn't worry about them not being optimal as both the 15's and 16's work very well.

[ChuckS]

Josh: You have received a lot of good advice here. Maybe we should set up a "tech Session" and try some tuning and education. Who's in?

From riding in your car before the changes, it seemed nicely balanced. Adding the stiffer springs without the stiffer torsion bars (rear springs) and adjustable sway bars has compromised the balance. We could try some adjustments after we determine exactly what your current set up is, but until you have some matching rear torsion bars, it will be difficult. 400 lb springs are stiffer than even what is in our spec car.

Let's see if we can get a group of guys together and help you out.

[Josh Y]

maybe at the first autocross of '08 , if the stinkin chargers would loose....

[Josh Y]

i know this is off topic and has probably been asked a million times, but i cant find in the new rules that you have to have racing seats with intended slots for harnesses to use the harnesses
so does this mean i would have to buy a race seat in order to use my 5 point harness? or was this just a rumor?
thanks

[ttweed]

i know this is off topic and has probably been asked a million times, but i cant find in the new rules that you have to have racing seats with intended slots for harnesses to use the harnesses...

Josh-

Jerry Griffin just asked the same question in another thread. See here for my take on it: http://forum.pcasdr.org/forum/viewtopic.php?p=18315#18315

Further discussion and clarification under that topic would be encouraged, IMHO.

TT

[lrayner]

As I'm starting to build a 944 spec. car, I'd be all for a tuning/set up tech session as suggested by Chuck. I'll even bring the beer. Sorry Josh, soda for you.

While I'm weighing in on this kind of late,here is my two cents for your set up problem. The cheapest and easiest solution to getting the balance back in your car is to throw on some weltmeister 250# AX springs on front. You could sell the 400lb springs and be out less than $100.

Oh, and Josh, don't listen to all that driving advise. The real secret to avoiding that nasty understeer is Slow in, Slow out. I guarantee it will work.