joseph mitro

eyal, that sounds pretty cool. i'd love to have the escort cup setup. are you keeping the torsion bars? if so, have them reindexed and factor in the spring rate with them. your rear rate with coilovers would then be around 435-450 using paragon's rate of 0.56 effective spring rate. then you can use the rear sway bar to fine tune the handling. get a good alignment and good tires and you'll be romping on the track.

Eyal 951

I'll be deleting the torsion bars I beleive. I'll go with a 550 pd spring rate on the coil over. The tires I have now will not do, I have ES 100's 225 front, 245 rear. I'll eventually get a set of wide CCW's, but not before I start to make some more money, I need to start investing, and saving instead of spending. Until then, I may just get a second set of ohne dials, and throw some victo racers on em. I have yet to get the porsche on the track, though it is signed up again, for buttonwillow may 8th. Lets see if it will co-operate this time, it seems to be throwing a hissy fit at me lately.
~Eyal

luckett

My car is non-M030.

You can quote all the numbers you want, but what really matters is how the car is balanced at the limit. Mine handles very nicely and is well balanced on the track. That's all the convincing I need to know that it is a well matched F/R spring rate ratio.

Danno

"I am wondering what I can do to improve the grip/handling without spending an arm and a leg."

R-compound tyres will make a bigger difference in grip than any other upgrade for the money... lap-times show the biggest improvement with sticky rubber, about 2-3x the gains of suspension mods alone.

"I would like new springs/shocks (I'm sure mine are tired), and perhaps new torsion bars...but I want it to be BALANCED. I see a lot of people stiffen the front by 40% (springs) but they leave the rear suspension stock. This confuses me...doesn't this upset the balance of the car?"

There's a difference between a street car and a race car. There is no such thing in between and you will sacrifice drivability on the street to make a car that's slow on the track. Pick one or the other. A race car will be set up for maximum speeds around the track. Look into the ALMS, IMSA-GTU/GTO, Trans-AM cars (even NASCAR ) and check out what they run for spring-rates and you'll be surprized at the front to rear ratios... they are optimized for drive-traction coming out of corners, so that you can get on the throttle as early as possible to get as high a speed down the straight as possible. This is not how a street car is driven. Also understeer/oversteer effects is only noticeable once you're driving over the traction limits of the tyres... which is not how a fast race-car is driven...

So you're talking about making an improved street car that "feels" better, not necessarily one that's gonna be the fastest in all conditions; that's just not possible. In that regard, I'd recommend the 968 MO30 sway-bars first. They make the most improvement in handling for good bang-for-the-buck value. They also keeps the most ride-comfort for the handling-improvement as well. You won't need to change springs or shocks; those should be done at the same time and matched.

L8 APEKS

The factory sets the car stiffer in the front, no doubt because of the engine weight. You'd be shifting the balance of the car if you made the rear stiffer than the front perhaps?? I don't know, just something to think about. Stock setup is roughly 12% stiffer in the front (~140) than in the rear (~126) isn't it?

Danno, you know I love ya man, but I'm gonna have to disagree there! There IS such thing as in-between. A perfect example? A 944-Spec car. Not quite stock, and not quite a race car either. There are ALL SORTS of in-betweens! Sacrificing driveability on the street? Well, I've driven all sorts of cars on the street that had modifications that some would consider to make them "less driveable" on the street (ie super stiff suspension, 7-lb flywheel, very loud or totally open exhaust, very peaky powerbands, dusty/squeaky race brakes, etc). They were certainly more enjoyable on a racetrack than they were on the 405 freeway or light-to-light running errands. But that didn't make them impossible to drive, or even difficult to drive on the street. At worst, they may have been "undesireable" to drive in traffic, depending on my mood on any given day. But it was certainly not like driving an F1 car to work.

But I do have more than one car to drive, and I don't mind the compromise. The fact remains...in-between DOES exist. I will have a car that will still retain 75% of it's stock manners (gaining some stiffness and a little noise), but will be perhaps 25% better on a track than in stock form. Nothing wrong with that as far as I'm concerned!

I may end up turning it into a race car eventually, but for now I'm gonna try to get it where I want it, and take it one day at a time. I want to play with it for a while (get your mind out of the gutter!). If it ever does reach that point to where it's "too much for the street" (I've never owned a car with that label yet, and I doubt an N/A 944 will ever reach that point)...then I'll make it a track car. No worries!

joseph mitro

i agree there's an in-between. and even more importantly than having a race suspension is knowing how to use it. doesn't matter if you've got IMSA-style handling if you don't know how to drive the car. having a car that handles better than stock but without kidney-rattling ride is adequate enough to teach beginners like myself how to drive.

Legoland951

The 3 944 spec race cars I worked on all have 400 (or more) front springs, coil over fronts, camber plates, adjustable struts, 28mm weltmeister HD sway bar and 22 rear along with 30mm torsion bars and koni adjustable rears. Having the weight of a street car, I am not sure whether they even make a torsion bar big enough (maybe 33mm and they don't exist) for it to be equal to the spec cars. There is something inbetween which will be less comfortable than a street car and not ideal for the track. It all depends on what you want to accomplish. I personally don't mind driving on a race suspension on the street but most people can't stomach it (compared to a GSXR with fox shocks etc its soft - after an hour ride, your bladders will feel like they have been elogated from bouncing).

Serge944

Eyal's setup does upset the balance, but in a different way than you're thinking. He's going to be using coilovers for the rear which have a different effective rate compared to torsion bars.

The magical coefficient of .56 comes into play, making the "550#" closer to a 300# effective rate.

In this case, the 450# in the front will cause the car to understeer. 350# front sounds MUCH better.

In case you're lost: http://www.tech-session.com/kb/index...x_v2&id=22&c=4

robG

I've found this link to be invaluable for a general grasp of various suspension possibilities:
http://dspace.dial.pipex.com/town/pi...reparation.htm

Eyal 951

Great info, I'll check that out, thanks.
~Eyal

L8 APEKS

What a great thread. Lots of info here, lovin' it guys. Thanks for all the posts!

Robby

1st- I'm almost positive it is Sway-A-away that makes torsion bars, as one other poster seemed to confirm- I still can;t remember the name of the other compoany, but, it's NOT weltmiester- Weltmeister also HAD BOTH hollow AND solid....


Joseph- I'll PM you right now- I might very well want those t-bars- they SHOULD be 29mm if 30mm actual- I think it's 30.2mm = 29mm effective... anyway, I'll PM you & we might be able to work something out...

Also- for those of you who think that stiffer springs automatically = rougher ride, etc.... here's a little input for you... My LEda situation is horrible- they beat me to death over bumps, skip, make noise, etc.... I hate them.... the funny thing is, that Karl had them "Custom valved" for 250lb springs- I had them on 225lb springs first w/100 lb rear helpers- the car oversteered- he exchanged the 225's for 275's (he did not have 250's) & the car did not oversteer anymore- it does, however, still beat me to death- it's not much rougher though. the funny thing is, that when it's REALLY cold outside, the ride feels much more comfortable- this should tell you something- first, the oil thickens when cold & the shock is, therefore, stiffer... this means that the shocks are probably not valved stiffly enough for the springs- it's very interesting how all this works, but, you would be amazed at how stiff you can go w/springs w/the right shock valving.... there are tons of variables, etc.... but, I just thought you might appreciate hearing this...

ALSO- Sean- I COMPLETELY agree w/you about not changing tired old shocks, springs & t-bars, etc... I, personally, think you should go through most of your suspension bushings & get factory replacements wherever neccessary- do NOT go w/spherical bearings or Poly-U, etc, for street- even an '89 951 would have 16yr old shocks & springs.... how many shocks would you expect to last that long? Also, Koni's have a rep of wearing out quickly & I agree that street shocks would be more prone to wear than track shocks b/c of all of the constant surface irrgularities of streets... MY T-bars were GONE.... the rear squatted horribly.... the worst were the shocks.... of course, the Ledas don't feel MUCH better than the worn-out koni's, but, paired w/200lb springs, I think the Ledas would feel pretty good.... just my opinion.... anyone wanna buy some LEdas for cheap...? :-)

pete95zhn

I've collected following data from different more or less reliable source.Front wheel rate for 944's can be calculated from spring rate with ratio of 0,9.Similarily generally agreed ratio for rear coil-overs has been 0,56.But according to a thread I just now couldn't find ( sic! ),it is a misprint and the real value should be 0,65.T-bar wheel ratios are mentioned in several places.Next data can be achieved if calculated with these ratios ( 0,9 / 0,65 ).

Stock wheel rates for 951 are:

-> '88 Fr: 112 / Re: 126 = 1:1,125
'88 M030 & '89 Fr: 143 ( progressive )/ Re: 175 = 1:1,223
'90-> Fr: 143 / Re: 175 = 1:1,223

968 CS M030 wheel rate:

Fr: 143 / Re:~228 ( t-bar + helper ) = 1: 1,594

944 Turbo Cup wheel rate:

Fr: 370 / Re: 635 (both progressive coils,rear also with t-bar) =1: 1,716

There's also one bolt-on aftermarket full coil-over suspension from H&R ( available at least in Europe ) ,RSS-37-827-1/1.

http://www.hr-spezialfedern.de/index...t-h&sprache=de

It has TÜV -approval for the street and it is specially developed for club racing.Wheel rates for that set are:

Fr:360 / Re: 556 =1:1,544

J Chen

Pete,
What measurements are the spring rates in Lbs or Nm.
If it's Fr 143 / Re 228 lbs, it seems pretty soft. I hear that
the CS version is somewhere at Fr 200lbs.

pete95zhn

They are in lbs/in,you get N/mm by dividing with 5,709.

According to PET 968CS uses spring # 944 343 531 09,but 968 M030 ( which also has that helper at the rear ) uses #944 343 531 01.And that is also used in 944 Turbo M030 from MY '88 -->.