Turbo S suspension woes
10-26-2010, 12:55 PM
#1
Instructor
Thread Starter
Turbo S suspension woes
So I have a 88 944 Turbo S that I have now taken to two DE events. First was at Watkins Glen, long fast sweeper turns, car felt nice and planted. This past weekend was at Thunderbolt at NJMP. Some much tighter turns really showed how soft even the Turbo S's suspension is. Through the tight stuff the rear end felt really loose, lots of body roll, and the rear tires just felt greasy. As I progressed a bit through the weekend, I used this to throttle steer around the tighter stuff, but coming out of the turn the car would be prone to wobble a bit back and forth.
The car only has 45k miles on it. Front suspension is stock, when I got the car some OEM black shocks were on the rear and the yellow Koni's were gone for some reason. Replaced them with some new yellow Koni adjustable shocks, left the adjustment as is out of the box, which from what I read should be set to the middle. Plan is to tighten these all the way up to see if it helps control the "wobble" and rear end looseness feeling. Tires, are Toyo T1R's. Not R-compounds, but pretty sticky summer tires. Tires were not even singing that much when the rear end was feeling loose. Tire pressures were set to 34 psi all around cold, and got up to about 41 when hot.
I think that's enough information to get the ball rolling.......Suggestions?
The car only has 45k miles on it. Front suspension is stock, when I got the car some OEM black shocks were on the rear and the yellow Koni's were gone for some reason. Replaced them with some new yellow Koni adjustable shocks, left the adjustment as is out of the box, which from what I read should be set to the middle. Plan is to tighten these all the way up to see if it helps control the "wobble" and rear end looseness feeling. Tires, are Toyo T1R's. Not R-compounds, but pretty sticky summer tires. Tires were not even singing that much when the rear end was feeling loose. Tire pressures were set to 34 psi all around cold, and got up to about 41 when hot.
I think that's enough information to get the ball rolling.......Suggestions?
10-26-2010, 01:00 PM
#2
Race Car
10-26-2010, 01:03 PM
#3
Instructor
Thread Starter
Still looking at keeping it streetable. Whats a good compromise setup? I thought the Turbo S had one, I can live with something stiffer on the street, as the existing suspension is "comfy". Any rear bushings that are known to cause this "looseness" feeling when they start to go? Mileage is low, but of course the age factor is there.
10-26-2010, 01:20 PM
#4
Burning Brakes
Join Date: Nov 2007
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I don't remember what the Turbo S spring rates are, but i remember they're pretty weak (175ish?).
The question is, how much do you want to spend? If you've got money to spend, i'd say to "do it once, and do it right!". Pick up a set of KW v3's or Motons and talk to the person you buy them from to get you set up right (i hear the KW v3's let you run a much stiffer spring without really hurting street performance). The v3's seem to go for about $2200.
Otherwise, if you want to keep it on a budget, i would say a 300 or 350# spring is about the limit for the Konis on the street. I run a 300# front and a 28mm (250#) rear and i'm very happy with the way my car rides on the street....it's right at the limit.
The next step up is 350# and 29mm.
For sways, i would recommend the 968 M030's, no question. I got mine for about $325/shipped for all bushings and hardware from Sunset Porsche.
Anyways, good luck!
The question is, how much do you want to spend? If you've got money to spend, i'd say to "do it once, and do it right!". Pick up a set of KW v3's or Motons and talk to the person you buy them from to get you set up right (i hear the KW v3's let you run a much stiffer spring without really hurting street performance). The v3's seem to go for about $2200.
Otherwise, if you want to keep it on a budget, i would say a 300 or 350# spring is about the limit for the Konis on the street. I run a 300# front and a 28mm (250#) rear and i'm very happy with the way my car rides on the street....it's right at the limit.
The next step up is 350# and 29mm.
For sways, i would recommend the 968 M030's, no question. I got mine for about $325/shipped for all bushings and hardware from Sunset Porsche.
Anyways, good luck!
10-26-2010, 01:22 PM
#5
Drifting
Certainly check all of the bushings, even in the front. A bad front sway bar bushing could cause oversteer.
Next event try stiffening the rear shocks then lowering the rear tire pressure a couple lbs if needed.
If it still feels oversteery, have the alignment checked. You can easily change the behaviour of the car by going to a more aggressive alignment but still retaining good streetability.
I'd strongly suggest learning to drive the car w/ a stock suspension. You'll be a smoother driver for it.
Next event try stiffening the rear shocks then lowering the rear tire pressure a couple lbs if needed.
If it still feels oversteery, have the alignment checked. You can easily change the behaviour of the car by going to a more aggressive alignment but still retaining good streetability.
I'd strongly suggest learning to drive the car w/ a stock suspension. You'll be a smoother driver for it.
10-26-2010, 02:33 PM
#6
Rennlist Member
Dollars to doughnuts, it needs to be corner balanced, too.
Also keep in mind that WGI and T-bolt are very different tracks - and, ultimately, will require different suspension settings. Thunderbolt is also known for having a horrendous amount of rubber on the track that gets picked up by your tires - and can compromise traction.
Has the ride height on the car been changed? That could play a role, too.
Also keep in mind that WGI and T-bolt are very different tracks - and, ultimately, will require different suspension settings. Thunderbolt is also known for having a horrendous amount of rubber on the track that gets picked up by your tires - and can compromise traction.
Has the ride height on the car been changed? That could play a role, too.
10-26-2010, 02:49 PM
#7
Instructor
Thread Starter
The Koni's I have on the back have to be taken off to adjust, have to read up on the procedure for tightening them up.
I was going to drop a couple PSI in the rear, but the wear on the shoulder of the tire was right where it should be at, right on the line before the sidewall starts.
As for the alignment, I just had one done for my first DE with the car in August. They did a little bit more aggressive than stock, from a shop that specializes in 968/944/951's. The RS Barn.
I don't believe I am driving over the limits of the stock suspension yet, but the way the rear is wobblying coming out of the turns and the amount of time it takes to settle is a bit unnerving.
Are the 968 sways that much thicker than what comes on the Turbo S? My plan of attack is right now is to tighten up those rear shocks, see what difference that makes. If that doesnt help significantly Ill look at some stiffer springs. Will the yellow Koni's be able to dampen 300 /250 # springs or am I looking at replacing the struts/shocks as well. I was eyeing up the Bilstein Escort Cup setup from Lindsey. Speaking to someone that has the Turbo Cup suspension on his 89 Turbo, is that they are too stiff for the street and too soft for the track, but this maybe alright for me.
The car is pretty mint, and being a Turbo S, I would feel guilty doing anything to it that is not easily reversed. The interior will get some seats and bolt in cage/harness bar, but that's it.
I was going to drop a couple PSI in the rear, but the wear on the shoulder of the tire was right where it should be at, right on the line before the sidewall starts.
As for the alignment, I just had one done for my first DE with the car in August. They did a little bit more aggressive than stock, from a shop that specializes in 968/944/951's. The RS Barn.
I don't believe I am driving over the limits of the stock suspension yet, but the way the rear is wobblying coming out of the turns and the amount of time it takes to settle is a bit unnerving.
Are the 968 sways that much thicker than what comes on the Turbo S? My plan of attack is right now is to tighten up those rear shocks, see what difference that makes. If that doesnt help significantly Ill look at some stiffer springs. Will the yellow Koni's be able to dampen 300 /250 # springs or am I looking at replacing the struts/shocks as well. I was eyeing up the Bilstein Escort Cup setup from Lindsey. Speaking to someone that has the Turbo Cup suspension on his 89 Turbo, is that they are too stiff for the street and too soft for the track, but this maybe alright for me.
The car is pretty mint, and being a Turbo S, I would feel guilty doing anything to it that is not easily reversed. The interior will get some seats and bolt in cage/harness bar, but that's it.
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10-26-2010, 02:57 PM
#8
Instructor
Thread Starter
Ride height is stock. Only suspension changes, that I know of, besides the mildly aggressive alignment is the new rear yellow koni's. Suspension feels great on the street. It does still have the acceleration squat in the rear, which makes me point to the rear shocks need to be firmed up. Thunderbolt did have lots of marbles off the line, notorious for chewing up tires there.
10-26-2010, 03:27 PM
#9
Race Car
10-26-2010, 03:48 PM
#10
Rennlist Member
The 88 TS cars had 26.8 front, 18mm rear bars. They did not drop the rear bar to 16mm until part way thru the 89 model year production run. The early 89Ts came with an 18mm rear.
If the rear shocks had been swapped, good idea to check some of the other parts to see if the original S pieces are also missing (e.g. the sway bars).
Can you better describe "wobblying" rear end? Does it feel like the car is understeering or oversteering? Or does it feel like the car just too soft in transition or very high speed turns?
May want to make sure something isnt loose in the suspension, bolts, bushings, etc.
I dont know that koni's come adjusted to a middle setting. Definitely pull them and check the setting. Stiffen them up if possible.
A lot of feel is from the tires. There can be a lot of sidewall flex in street tires that creates a mushy feel when cornering. 16's, 17's ? Stiff sidewall r-comps give a stiffer feeling and ride.
The stock M030 front struts can handle somewhat stiffer than stock springs (approx 160 lb/in). 250-300 lb/in springs should be ok for the max damping setting. I do know that Turbo Cup springs do exceed the damping rate of the M030 struts.
Rear will need additional spring to match any increase in the front. You can either go larger with the rear t-bars, or go with the 968 M030 rear shock (w/ barrel helper spring) or go to a full coilover (like the bilsteins). All require re-indexing or replacing the rear t-bars.
Bilstein turbo cup suspension, although not cutting edge technology, is not too soft for the track. Especially a DE car that is not a dedicated race car. I do agree that it is extremely aggressive for the street and can be much too harsh for personal taste.
Before falling off the modification/upgrade cliff - as mentioned above, make sure everything is mechanically sound on the car, do some tuning of the shocks and tire pressures, then spend some time learning to drive the car as-is. Bone stock, 89T is certainly a dated design, but its not a slow car. And its a good, forgiving platform to learn to drive with.
If the rear shocks had been swapped, good idea to check some of the other parts to see if the original S pieces are also missing (e.g. the sway bars).
Can you better describe "wobblying" rear end? Does it feel like the car is understeering or oversteering? Or does it feel like the car just too soft in transition or very high speed turns?
May want to make sure something isnt loose in the suspension, bolts, bushings, etc.
I dont know that koni's come adjusted to a middle setting. Definitely pull them and check the setting. Stiffen them up if possible.
A lot of feel is from the tires. There can be a lot of sidewall flex in street tires that creates a mushy feel when cornering. 16's, 17's ? Stiff sidewall r-comps give a stiffer feeling and ride.
The stock M030 front struts can handle somewhat stiffer than stock springs (approx 160 lb/in). 250-300 lb/in springs should be ok for the max damping setting. I do know that Turbo Cup springs do exceed the damping rate of the M030 struts.
Rear will need additional spring to match any increase in the front. You can either go larger with the rear t-bars, or go with the 968 M030 rear shock (w/ barrel helper spring) or go to a full coilover (like the bilsteins). All require re-indexing or replacing the rear t-bars.
Bilstein turbo cup suspension, although not cutting edge technology, is not too soft for the track. Especially a DE car that is not a dedicated race car. I do agree that it is extremely aggressive for the street and can be much too harsh for personal taste.
Before falling off the modification/upgrade cliff - as mentioned above, make sure everything is mechanically sound on the car, do some tuning of the shocks and tire pressures, then spend some time learning to drive the car as-is. Bone stock, 89T is certainly a dated design, but its not a slow car. And its a good, forgiving platform to learn to drive with.
10-26-2010, 04:14 PM
#11
Instructor
Thread Starter
If the rear shocks had been swapped, good idea to check some of the other parts to see if the original S pieces are also missing (e.g. the sway bars).
__Everything else looks original. In some of the paperwork the replacement of the rear shocks is listed because of a blown shock. Looks like they just replaced them with the incorrect part, or previous owner didn't want to pay up for the correct ones.
Can you better describe "wobblying" rear end? Does it feel like the car is understeering or oversteering? Or does it feel like the car just too soft in transition or very high speed turns?
___The car feels pretty balanced, with a feeling of more of a tendency to oversteer. More like the suspension is just too soft. The wobbly feeling is in transition. High speed straights the car feels pretty solid. Quick passing manuevers at high speeds shows the softness again.
May want to make sure something isnt loose in the suspension, bolts, bushings, etc.
I dont know that koni's come adjusted to a middle setting. Definitely pull them and check the setting. Stiffen them up if possible.
__Will def. try this first. It's free.
A lot of feel is from the tires. There can be a lot of sidewall flex in street tires that creates a mushy feel when cornering. 16's, 17's ? Stiff sidewall r-comps give a stiffer feeling and ride.
___Tires are mount on the stock 16" club sports. I have Toyo T1R's in the rear. Basically new, have about 1k miles on them.
The stock M030 front struts can handle somewhat stiffer than stock springs (approx 160 lb/in). 250-300 lb/in springs should be ok for the max damping setting. I do know that Turbo Cup springs do exceed the damping rate of the M030 struts.
Rear will need additional spring to match any increase in the front. You can either go larger with the rear t-bars, or go with the 968 M030 rear shock (w/ barrel helper spring) or go to a full coilover (like the bilsteins). All require re-indexing or replacing the rear t-bars.
Bilstein turbo cup suspension, although not cutting edge technology, is not too soft for the track. Especially a DE car that is not a dedicated race car. I do agree that it is extremely aggressive for the street and can be much too harsh for personal taste.
Before falling off the modification/upgrade cliff - as mentioned above, make sure everything is mechanically sound on the car, do some tuning of the shocks and tire pressures, then spend some time learning to drive the car as-is. Bone stock, 89T is certainly a dated design, but its not a slow car. And its a good, forgiving platform to learn to drive with.
__ I did have the car completely gone over by the RS Barn when I got the car back in January, and they do my tech inspections for the DE events. All major bolts for the suspension have been paint marked to see if there is any movement, but all is good. I am not looking to really modify the car much more, but would like to address this feeling as it just does not produce a very confidence inspiring feeling.
__Everything else looks original. In some of the paperwork the replacement of the rear shocks is listed because of a blown shock. Looks like they just replaced them with the incorrect part, or previous owner didn't want to pay up for the correct ones.
Can you better describe "wobblying" rear end? Does it feel like the car is understeering or oversteering? Or does it feel like the car just too soft in transition or very high speed turns?
___The car feels pretty balanced, with a feeling of more of a tendency to oversteer. More like the suspension is just too soft. The wobbly feeling is in transition. High speed straights the car feels pretty solid. Quick passing manuevers at high speeds shows the softness again.
May want to make sure something isnt loose in the suspension, bolts, bushings, etc.
I dont know that koni's come adjusted to a middle setting. Definitely pull them and check the setting. Stiffen them up if possible.
__Will def. try this first. It's free.
A lot of feel is from the tires. There can be a lot of sidewall flex in street tires that creates a mushy feel when cornering. 16's, 17's ? Stiff sidewall r-comps give a stiffer feeling and ride.
___Tires are mount on the stock 16" club sports. I have Toyo T1R's in the rear. Basically new, have about 1k miles on them.
The stock M030 front struts can handle somewhat stiffer than stock springs (approx 160 lb/in). 250-300 lb/in springs should be ok for the max damping setting. I do know that Turbo Cup springs do exceed the damping rate of the M030 struts.
Rear will need additional spring to match any increase in the front. You can either go larger with the rear t-bars, or go with the 968 M030 rear shock (w/ barrel helper spring) or go to a full coilover (like the bilsteins). All require re-indexing or replacing the rear t-bars.
Bilstein turbo cup suspension, although not cutting edge technology, is not too soft for the track. Especially a DE car that is not a dedicated race car. I do agree that it is extremely aggressive for the street and can be much too harsh for personal taste.
Before falling off the modification/upgrade cliff - as mentioned above, make sure everything is mechanically sound on the car, do some tuning of the shocks and tire pressures, then spend some time learning to drive the car as-is. Bone stock, 89T is certainly a dated design, but its not a slow car. And its a good, forgiving platform to learn to drive with.
__ I did have the car completely gone over by the RS Barn when I got the car back in January, and they do my tech inspections for the DE events. All major bolts for the suspension have been paint marked to see if there is any movement, but all is good. I am not looking to really modify the car much more, but would like to address this feeling as it just does not produce a very confidence inspiring feeling.
10-26-2010, 04:59 PM
#12
Rennlist Member
Didn't see anything mentioned about tyre pressures? Apart from the good advice above, what pressures were you running and did you check these through the day? If you started with normal pressures you might have got too hot and that will certainly hurt performance.
The stock setup is really too soft for trackwork. Changing to a more contemporary brand of shock / spring setup will help enormously without affecting how your car 'looks' if you want to keep the stock look. I have banged on many times at how good KWs are. Not just for the track, but for the street as well. Very comfortable, yet firm enough to run on the track. Well worth thinking about.
The stock setup is really too soft for trackwork. Changing to a more contemporary brand of shock / spring setup will help enormously without affecting how your car 'looks' if you want to keep the stock look. I have banged on many times at how good KWs are. Not just for the track, but for the street as well. Very comfortable, yet firm enough to run on the track. Well worth thinking about.
10-26-2010, 05:17 PM
#13
Instructor
Thread Starter
I was running 34 psi cold all around. Got up to around 41 hot all around. I let a couple psi out of the rears for the last run of the day, but didn't notice much of a difference. Tire wear was right on the indicator line of the shoulder of the tire where it meets sidewall.
10-26-2010, 05:45 PM
#14
Burning Brakes
Join Date: Nov 2007
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It sounds like others disagree, but honestly...i was really disappointed in how my Turbo handled when stock. The Turbo S gets some upgrades, but they're not massive differences (20# difference in the springs, a few mm on the swaybars it sounds like).
I think your average Toyota Corolla has higher spring rates these days. Dampers have come a long way, and spring rates have gone up with them!
I would forget about "book value" and just make some sound modifying decisions. A correctly modified 944 will be worth more than a stock 944. These cars (even the Turbo S) have no book value worth bragging about, anyways.
I think your average Toyota Corolla has higher spring rates these days. Dampers have come a long way, and spring rates have gone up with them!
I would forget about "book value" and just make some sound modifying decisions. A correctly modified 944 will be worth more than a stock 944. These cars (even the Turbo S) have no book value worth bragging about, anyways.
10-26-2010, 06:53 PM
#15
Rennlist Member
Just my 2 cents.