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Adjustments++++++++++++++++++++Decrease Understeer++++++++++++++Decrease Oversteer++++++++++++++++++++++
Front Tire Pressure--------------------------Higher---------------------------------------------Lower--------------------------------------------------------
Rear Tire Pressure--------------------------Lower----------------------------------------------Higher--------------------------------------------------------
Front Tire Section----------------------------Larger-------------------------------------------Smaller------------------------------------------------------
Rear Tire Section----------------------------Smaller--------------------------------------------Larger------------------------------------------------------
Front Wheel Camber-----------------------More Negative-----------------------------------More Positive---------------------------------------------
Rear Wheel Camber-----------------------More Positive-------------------------------------More Negative--------------------------------------------
Front Wheel Toe----------------------------Toe-Out---------------------------------------------Toe-In-------------------------------------------------------
Rear Wheel Toe-----------------------------Toe-In-----------------------------------------------Toe-Out----------------------------------------------------
Front Wheel Caster-------------------------More Positive-------------------------------------More Negative-------------------------------------------
Front Springs---------------------------------Soften-----------------------------------------------Stiffen-----------------------------------------------------
Rear Springs----------------------------------Stiffen-----------------------------------------------Soften-----------------------------------------------------
Front Anti-sway Bar-------------------------Soften (Thinner)----------------------------------Stiffen (Thicken)----------------------------------------
Rear Anti-sway Bar--------------------------Stiffen(Thicker)-----------------------------------Soften (Thinner)-----------------------------------------
Weight Distribution---------------------------More Rearward----------------------------------More Forward---------------------------------------------
These variables are quite dynamic in nature. As with all setups, one parameter effects the other. So there are infinite amount of adjustments. These guidelines are not absolutes and there are other parameters such as tire pressure, rubber compound, track conditions, temperatures, driver preference etc.....
ADMIN --- Can you assist in deleting this post for me ? The reformatted layout made the post unreadable. I'll try to figure out how to format and redo it again. Thanks
not sure given the nature of the car and its AWD/PCAS that it will ever be understeer-free under track conditions pushed near its limits in mid/tight turns, for that matter C2's aren't either
what i am getting from the wonderful, old articles is:
use thicker/stiffer rear sway
lower and apply some forward rake
add more front camber
use stickier wider rubber
lower tire pressures
all of which makes perfect sense... load up the front into turns and help the front end turn
i am sure more modern coilover kits (since the old articles were written just after the C4 was launched) like pss10 and kw series can also be set up this way like the old B6's/H&Rs
Hi,
exactly right ! I pressure my 18 to 30 front 34 rear .
Make sure all your bearing wheels, wishbone bushes , drop links, tie rods are in perfect condition ,
it does make a huge difference .
If you can afford to upgrade to 993 RS front uprights and ERP tie rods with 993 inner tie rods , it will ride super sharp .
Great thing is you have plenty of options depending on your driving style and if upgrading is what you intended to do. If simply trying to dial out understeer, you can be as cheap or as expensive as you like when you go through all the options offered.
Picked up the new (to me) 964 C4 finally and got it up on the lift to see exactly what suspension it is fitted with
- Eibach lowering springs (nice rear to front rake and moderate lowering) - I am happy w this ride height
- Black stock factory Boge shocks... based on service records they were replaced not long ago (not worn out in the least) with fresh sway bar and drop link bushings
- Stock 20 mm front and rear ARB's
- stock suspension parts otherwise
The car came with very stiff sidewall BFGoodrich Rival 1.5's that were well worn so the car felt planted and flat on the 400 mile drive home from LA but the suspension was hammering over expansion joints and moderate road imperfections even with the tires at 30 psi cold.
Wider (24 mm) H&R ARB ordered for the rear already, and on its way.
So, given this is NOT going to be a track car, but for fun backroad blasts taken at high speeds (for road driving), what should I do? I will run 17 in Cup wheels or equivalent... will not go 18's on this car I don't think
A) leave as is, change out to some new more street-able tires and see (default option)
B) get a set of Bilstein B6's to replace Boge's ($1000)
C) go PSS10 ($3200)
D) go KW V1/2/3 ($1500-2800) - 964 buds who **** money recommend these highly
E) go Ohlins R&T ($4500) - ditto plus...
I am leaning B at the moment... C/D/E nice way to blow $$ not sure I will get good return on performance given my intended use of the car.
I would go for B and spend the rest of the money on uprated bushings, tyres, and a geometry setup :
This is my daily driver on crappy French country roads which look like they haven't been repaired since the war....
- Eibach springs - not too harsh for road use and doesn't bottom out - Koni FSD shocks - not too harsh for road use and definitely an upgrade over the Boge. - Stock ARBSs - my only complaint with my current setup is the amount of roll - fitting H&R ARBs today - Powerflex bushings everywhere - don't believe it when people say not to do this on a road car : not too harsh on the road, really tightens up the handling, no squeaks, 7 years and around 100,000kms and not worn out yet - Rose jointed rear arm plates - the original plates were dead and these were half the price. Tightened up the handling and I haven't really noticed any more harshness. 4 years and around 50,000kms and not worn out yet
- 17" BBS Sport Classic wheels from a Boxster - perfect fitment, no tyre rub, very light. Fitted with Bridgestone RE71s. Much more precise than 16" and still comfortable. I tried 18" and found that it wrecked the ride.
- Geometry and ride height set as a Euro RS - Lowering and adding 1 degree of negative camber to the front makes a huge difference to improving turn-in and reducing understeer.
Picked up the new (to me) 964 C4 finally and got it up on the lift to see exactly what suspension it is fitted with
- Eibach lowering springs (nice rear to front rake and moderate lowering) - I am happy w this ride height
- Black stock factory Boge shocks... based on service records they were replaced not long ago (not worn out in the least) with fresh sway bar and drop link bushings
- Stock 20 mm front and rear ARB's
- stock suspension parts otherwise
The car came with very stiff sidewall BFGoodrich Rival 1.5's that were well worn so the car felt planted and flat on the 400 mile drive home from LA but the suspension was hammering over expansion joints and moderate road imperfections even with the tires at 30 psi cold.
Wider (24 mm) H&R ARB ordered for the rear already, and on its way.
So, given this is NOT going to be a track car, but for fun backroad blasts taken at high speeds (for road driving), what should I do? I will run 17 in Cup wheels or equivalent... will not go 18's on this car I don't think
A) leave as is, change out to some new more street-able tires and see (default option)
B) get a set of Bilstein B6's to replace Boge's ($1000)
C) go PSS10 ($3200)
D) go KW V1/2/3 ($1500-2800) - 964 buds who **** money recommend these highly
E) go Ohlins R&T ($4500) - ditto plus...
I am leaning B at the moment... C/D/E nice way to blow $$ not sure I will get good return on performance given my intended use of the car.
Thoughts?
I had pretty similar setup and and thinking to go same route than you. Then FVD has sale for PSS10 top mount. I did have those top mounts 2 years un-boxed. Two month ago demon-tweeks has quite good sale for PSS10 so I push a button and order these. I haven't hear any negative comment about PSS10 so why not buy them. Bit expensive yes but whole 964 scene seem to became quite expensive now days,
Oh, and remember alignment. Make big difference. Now I'm used same as RS. Works for me.
If your car has the early rear towers, i have a set of bilstein b6 fitted with eibach springs, oem top hats front and rear that are essentially ready to bolt in. You could buy these and sell yours and for very little money in the end have the upgrade you are looking for. My B6 don't have a ton of miles on them...i traded up for KWV3 a few years after installing them. For street use, the bilstein b6 are basically perfect.
Remember when you go down the upgrade road, the "better" you make the car, the faster you have to go to have fun. Which only increases the crash speed should something happen.
I've had more fun driving spec NA Miata's than i ever have had in the porsche, on and off the track. All at lower speeds. Most of what we have when we are having fun is "the feel" - not the actual speed itself.
So balance the car so it handles right, and leave a bit of lean in it, and don make it too sticky- just make it as predictable as you can....which is not all that easy in a 964...(in relative terms to something like a Miata, boxter, cayman, etc)
And then enjoy yourself. But no need to spend huge money to make the car feel "right" for what you are looking to accomplish.
+1 on the B6 shocks
perfect road setup,
Really like Normandy's table.
Only thing I would add, is the 964 is sensitive to rake.
You don't have to spend a ton of dough to get the car to work for you.
Some time making adjustments with ride height, tire pressures will surprise you in the front end feel
Cheers
FS
Gougary helping me out with B6 set - try that next... just put fresh tires on...suspension feels much more compliant... less banging over tiny bumps and expansion joints
03-23-2018, 03:56 AM
