[TheMirror]

Thanks Wes, very informative post. I'm interested in a few details:



What kind of wheel and tire combination were these cars running?

What setting were the Koni's set to on the stiff 951, and were these the single adjustable yellows?

Did the stiff 951 have standard rubber suspension bushings, or were they aftermarket delrin or bearing versions?

How streetable on bad pavement are the Bilstein Escort and Leda setups, and what kind of suspension bushing setups do the cars you drove have?

I'm thinking about my local back roads here.



Welcome again,



-Mirror

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[whakiewes]

951 has/had stock bushings. 968 stock bushings as far as I am aware. I will check once I get a chance...cars not even in my possession yet, so I have yet to sit down and pull it all apart. Koni's on the 951 were at full stiff as far as I am aware, with Welt 250's.



North Carolina has the 5th worst roads in the country, even above those pesky northern roads. We have pot holes...not like NYC, but definantly to the point where I find myself often slaloming my cars. That said, the Escort cup kit was stiff. There is a difference though in stiffs. Ride in a car with HR Race springs and Koni's...stiff to the point of bone jarring even though the springs may only be 300lb/in. Then ride in a car with well designed coilovers like the Bilsteins or Ledas, and yet its more comfortable and stable than that stiff setup. If you were in my car, you would notice it had a suspension for sure. Quite a bit stiffer than the stock 968's I have rode in. Not near as stiff as my friends BMW with Groupe G racing shocks and 770/870 springs <img src="/forum/images/smilies/968/smile.gif" class="smilie" alt="" /> .



Another example was my dealer BMW 330i Performance package. He installed Bilstein PSS9's with stock sways. In the times I drove it even though it was nearly twice as stiff, and half as high, it felt better to me than a stock 330i ZHP. I could easily drive it anywhere...across the country, in NYC, etc... On full soft on the PSS9's, I swear it was softer than the stock suspension, and at full stiff at the track, it handled on rails.



One more things to take into account when I have shopped before for suspensions. Your going to spend $650 on Koni Sports, $300 on HR Sport Springs, and whatever else you may buy. So for shock/springs alone your going to be in $1000 minus labor. For $600 more or so, you can have a fully adjustable, proven coilover. For another $1000, you can have one of the best coilovers for the money (LEDA's). I am in the process of talking with D2 Racing (a japanese company) about custom coilovers. They already do some P-Car work, so they have a stout interest in it. In short, what we are talking is anodized aluminum bodies, 32 way adjustable, custom springing/dampening, double adjustments on the spring as to be able to adjust the height without changing preload and all those other things. Pricing should be about $1700 retail, but with it being a japanese product, dealers should see them for about $800. ETA may be never, as its just hot air right now...but I am always trying new things, and unfortunately the Japanese tuning companies make some banging products for the money. What would an inverted double adjustable Bilstein run...more than my house <img src="/forum/images/smilies/968/smile.gif" class="smilie" alt="" /> .



Wes



Edit : Both my 968 and the 951 with Welts were on stock 968 16's with ZR tires. The 951 with Leda's was on 17" OEM Turbo 2's with R-Comps.

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[968bill]

I finally broke out the credit card for this project. Working w/ Jason @ Paragon I ordered:



- M030 Sway Bars, front and rear

- Delrin bushings for front and rear sway's

- KLA Rear drop link kit, KLA front bar support kit

- Koni Sports front and rear

- The progressive front springs

- new strut dust cover and bump rubber



Since my car has 106K on the original parts I should notice a pretty big change in the handling. Maybe I'll get lucky and they will also improve my driving ability! Just hope it doesn't take me 3 weeks to install them.

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[flash]

cool - you'll love it when it's done



i finally took the shots and i'll do the write up this weekend on the delrin bushing modification that prevents the "walking" problem, and eliminates the noise they tend to make

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[SMuCK007]

Just a thought on oversteer-understeer,



One setup I was considering to do was to put Koni Adjustable shocks all around the car, setting the rear to medium stiffness and leaving the fronts on full soft. This arrangement should slightly lean the car into the oversteer side-of-the-fence. (Note that I am only considering just shocks at this time.) By doing this, you have the capability of tweaking in as much understeer as you'd like by setting the fronts to medium or full-stiff. This is the information I gleamed off a Rennlist forum so I may be incorrect.



Once you do this, you can put heavier linear springs up front and thicker torsion bars in the rear. By calculating the rear-front effective spring rate ratio, you can begin to change the over-or-understeer tendency of the car. I believe the higher the ratio (in other words, the higher the rear effective spring rate relative to the front), the more your car will favor oversteer. I believe neutral is somewhere around 60-70%. IIRC from my own research/calculations, the factory setup in the 968 has it favoring more understeer as a safety percaution, but I could be wrong.



Then you can further tweak by adjusting the front/rear swaybars, adding a front strut brace, using different tire-sizes, adjusting tire pressures, etc.



Ride harness will be dependent upon the the spring rate you decide to put on the car. I have a friend that runs a 944 S2 with around 400 pound springs up front and 31mm hollow torsion bars in the rear. He has the m030 sway bars adjusted to favor a neutral-handling car. I have yet to hear any complaints from him about ride harshness - and this is in the northern NJ/NYC area! But then again he is an excellent autocrosser so he is probably able to get around all the potholes like a champ.

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[flash]

these cars are unusually tolerant of heavier springs - there is a noticable difference, and a very subjective result to be sure, but do indeed seem to have a far less abrubt change with stiffer springs



springing and seeking oversteer/understeer balance is a slippery slope - there is no fixed formula out there yet, and some of the information out there right now, that you would use to calculate this stuff, is wrong - it has been a long arduous path for me to sift through this stuff. with stops along the way to find the original porsche engineering data, and confirm it with eibach, and detailed physical measurements of the car itself, so as to try to figure out what will work, and not just do it by trial and error (though there has still been a lot of that) - and i'm still not quite done



anyway - moving on



yes - the car is set up with understeer for safety precautions - they assume that most people need that to keep them out of trouble - they are right - almost all car manufacturers do this



currently the stock setup is 160 front and 175 rear - that is 91% of the rear spring rate is shown up front - given that the hardtop is rear heavy by 66lbs, a minor change in rear stiffness balances things out nicely and induces slight oversteer - that is why the M030 setup works so nicely - they add a small spring to the rear - cabs are a bit light in the rear, so much less change is necessary to induce the same oversteer, and too much spring quickly brings on too much oversteer



a brief word on the adjustments to shocks and struts - these are not intended to increase suspension stiffness - they are only supposed to calm down the springs



setting the car up should be done with springs for the first 90% of the desired handling, and then the last 10% is tweaking with shocks and springs - a lot of people tend to crank up the shocks thinking they "feel" stiffer, and therefore would make the car handle better, but in reality, they are only creating more problems - doing this quickly leads to bump oversteer/understeer



it's really a bit of a symphony when done right, with everything working together



have fun - if you're a math geek, this can be a real hoot - in any event, the car is great to play with

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[gbarrier]

Since I saw it said earlier in the thread that the (very reasonably priced) KYB is good enough for the rear in street application would it be acceptable to run a KYB cartridge on the front also?

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[flash]

"good enough" is relative - it's a bit soft, but passable for commuter use - not very good for spirited driving though, especially on a hard top, which is heavier in the rear than a cab



as for running it up front, have you found a cartridge for the 968? i wasn't aware they made one - if so, do they have the necessary modification instructions to adapt it to the housing? are they different than the koni?

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[TheMirror]

I don't think KYB makes a cartridge for the front of these cars. Not certain though.

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[Jason@Paragon Products]

No KYB insert for the sealed strut 944/968.

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[Renalicious]

Just so I'm understanding correctly: the 160 front / 175 rear setting is in lbs/inch?

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[flash]

yes - those are the factory rates

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