951 Street/Mild Track Suspension Setup???
09-09-2004, 01:16 AM
#1
Burning Brakes
Thread Starter
951 Street/Mild Track Suspension Setup???
I posted this question on the standard 944 forum but those guys were no help. I just installed koni yellows and want to know a good spring set up. I don't really want to mess with the torsion bars so I would like a coil over set up so I can match the front height to the rear after lowering with the eccentric. What spring rate should I use? I was told to use 300# but have since learned that may be too stiff. So what's a good rate? 200, 225, 250? And are the Hypercoils the way to go or anyone know about the Rennbay Eibach coilovers?
Also, I would love a cheap rear helper. I wish someone would make one to fit over the standard koni yellows. Everything I've seen for rear helper set ups starts at $700 and up. Anyone know of a cheaper helper?
Thanks and all suggestions appreciated. Mainly street but mild track use also.
Also, I would love a cheap rear helper. I wish someone would make one to fit over the standard koni yellows. Everything I've seen for rear helper set ups starts at $700 and up. Anyone know of a cheaper helper?
Thanks and all suggestions appreciated. Mainly street but mild track use also.
09-09-2004, 02:27 AM
#2
I think it's all about personal preference. Some people think 400lb. springs are tolerable, others won't go over 200lbs. I would say your best bet would be the Ground Control coilover system over the front konis and new t-bars to match in the rear. If you really don't want to mess with the t-bars than don't do anything to the front spring rates because (regardless of what everyone says) it will mess up the balance.
If you go with rear helpers you will have to mess with the t-bars anyway.
I have (2) 275lbs. Hypercoil springs for use with the Ground Control system for sale if you decide that's the rate you want.
If you go with rear helpers you will have to mess with the t-bars anyway.
I have (2) 275lbs. Hypercoil springs for use with the Ground Control system for sale if you decide that's the rate you want.
09-09-2004, 02:56 AM
#4
Burning Brakes
Thread Starter
jc,
Do you have the whole kit for sale or just the springs? How much?
As far as the torsion bars, I thought it would be easier to leave them stock and lots of people do, but I'm starting to realise that maybe I'll have to deal with changing them. How difficult are they to change/index? And if I do change them, what's a good set up? I want a streetable car (it is my everyday driver) but I don't mind a firm ride. I just don't want anything so stiff it beats the hell out of me and the car. I know it's hard to be exact with such subjective characteristics but some suggestions would be helpful. Also, I don't really want to lower it more than an inch or so--I have to deal with curbs and driveways everyday, after all. Thanks--
Do you have the whole kit for sale or just the springs? How much?
As far as the torsion bars, I thought it would be easier to leave them stock and lots of people do, but I'm starting to realise that maybe I'll have to deal with changing them. How difficult are they to change/index? And if I do change them, what's a good set up? I want a streetable car (it is my everyday driver) but I don't mind a firm ride. I just don't want anything so stiff it beats the hell out of me and the car. I know it's hard to be exact with such subjective characteristics but some suggestions would be helpful. Also, I don't really want to lower it more than an inch or so--I have to deal with curbs and driveways everyday, after all. Thanks--
09-09-2004, 02:58 AM
#5
Addict
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Contact Paragon Products (RennList Sponsor and very nice). They have used/sold Koni for a very long time. Jason at Paragon races 951s and will be of great help to you.
09-09-2004, 03:03 AM
#6
Burning Brakes
Thread Starter
yeah, I've spoken with him in the past. I just want to know what different people out there have tried, used, driven, etc. loved and/or hated. I don't think it was him, but some vendor told me to use 300# springs and yet everyone on Rennlist says it would understeer badly. So I want to hear from people with these set ups on their cars . . . .
09-09-2004, 05:50 AM
#7
Drifting
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I've been using Ledas for the past 3 yrs.
Pretty good stuff. Am running 300lbs
front with 400lbs rear without T bar.
Handling is good. The problem with
understeering with 300lbs front springs is
when people upgrade the sway bar to
a stiffer set -up. You should stay with
the standard ones if you're going 300 fronts.
BTW, if the road conditions are slightly bumpy,
I would advice you to go lower like 220 or max
250lbs for the front & 350 for rears if you opt
for coilovers all round.
Pretty good stuff. Am running 300lbs
front with 400lbs rear without T bar.
Handling is good. The problem with
understeering with 300lbs front springs is
when people upgrade the sway bar to
a stiffer set -up. You should stay with
the standard ones if you're going 300 fronts.
BTW, if the road conditions are slightly bumpy,
I would advice you to go lower like 220 or max
250lbs for the front & 350 for rears if you opt
for coilovers all round.
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09-09-2004, 11:10 AM
#8
I have only the springs for sale. I would take $50 for the pair. I think they run $60 each new. I also have 2 upper spring perches for the GC system. All you would have to buy would be the threaded collar and lower spring perch to have a complete system. PM me if you're interested.
Of course it would be easier to leave the t-bars alone but if you do, you really shouldn't change the front spring rates. Some people do anyway and dial it out with a larger rear sway bar but I think that is a half-a$$ way of doing things. I can't understand why anyone would take a car that understeers in stock form and stiffen up the front only to make it understeer more.
Hosrom, the GC system is for the front only.
Of course it would be easier to leave the t-bars alone but if you do, you really shouldn't change the front spring rates. Some people do anyway and dial it out with a larger rear sway bar but I think that is a half-a$$ way of doing things. I can't understand why anyone would take a car that understeers in stock form and stiffen up the front only to make it understeer more.
Hosrom, the GC system is for the front only.
09-09-2004, 12:01 PM
#10
Race Director
Well if you don't want to mess with the t-bars the most you can do is 250lbs front and stiff rear sway bar. Not ideal, but a little better than stock.
Ideal is probaly 250-300 lbs front and 28-29 mm rear torsion bars.
You can go higher up to about 400 to 450, but then run into the limits of the koni yellow. Plus the street ride is very marginal. Some accept it some hate it.
Changing t-bars is not super hard, but does take time. I have done two t-bar changes on my 944-spec car and wrote a proceedure to reindex them properly.
PS in 944-spec racing we do not allow rear coilover due to their cost. cheaper to just change torsion bars.
Ideal is probaly 250-300 lbs front and 28-29 mm rear torsion bars.
You can go higher up to about 400 to 450, but then run into the limits of the koni yellow. Plus the street ride is very marginal. Some accept it some hate it.
Changing t-bars is not super hard, but does take time. I have done two t-bar changes on my 944-spec car and wrote a proceedure to reindex them properly.
PS in 944-spec racing we do not allow rear coilover due to their cost. cheaper to just change torsion bars.
09-09-2004, 03:50 PM
#12
8th Gear
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I upgraded the suspension in my 1986 944 Turbo this winter after extensive analysis (I used to be a mechanical engineer) of various offerings, both factory (e.g. 968 Club Sport, 968 Turbo S) and aftermarket.
I came to the conclusion that to keep costs low, select a rear spring rate and replace the rear torsion bars -- if adjustments between front and rear need to be made, it is easier to swap front springs than to swap rear coil over springs and continually reindex the torsion bars.
So I bought the Paragon conversion Koni coil overs, and a 29 mm rear torsion bar, along with M030 anti roll bars. My original goal was to duplicate the 968 Turbo S suspension, which the European press raved about way back when. The data I have indicate that this came with 200 lb/in front springs, the stock for '86 23.5 mm torsion bar, plus coil over rear springs of 375 lb/in (bringing the rear up to around 290 lb/in at the wheel -- esentially that of a 29 mm bar), and of course M030 anti roll bars.
Jason at Paragon said that most people choose the 300 lb/in front springs with the 29 mm anti roll bar, but PowerHaus told me to use 250 lb/in fronts. I went with the 300s, but after driving a few DEs this year, I've found the car to be less tossable (read: too much undesteer vs. the 1986 stock suspension), but the car rolls much, much less. (I was looking for a 50% reduction in roll, since the stock suspension allows the rear suspension to compress to the point that the INSIDE of the rear tires wears too fast). On the street it's stiff but fine.
I've tried stiffening the rear antiroll bar, but it's only 3-way adjustable, and I can only conclude that the combination of 300 lb/in front springs and a 30 mm dia front bar (perhaps 100% stiffer than stock, assuming a 27 mm effective rate) makes the front roll rate far too high vs. the rear -- at least for me. What we're talking about, however, from my calculations is a car that understeers more like, but less than, a 968 Club Sport than the 1986 944 Turbo, and a lot less than the 944 Turbo S.
It is entirely possible that the damping settings for the front and rear suspension may be at fault -- by stiffening the rear dampes further, I could induce transitional oversteer, which would disappear once the suspension settles in a fast corner. So I have one more adjustment I could try. But failing that, I have to conclude that a 250 lb/in front spring is better with a 29 mm diameter torsion bar and the M030 anti roll bars than the 300 lb/in spring.
Bear in mind that your anti roll bar choice will affect this greatly. Go with a stiffer rear bar and/or a softer front bar, and the stiffer front springs will be required. That said, I don't know the answer to the question "Why did Porsche on the 968 Turbo S go with relatively soft front springs and a stiff anti roll bar, and relatively stiff rear springs and a soft anti roll bar?"
Similarly, the 968 Club Sport had VERY soft front springs and the M030 anti roll bars front and rear, along with fairly stiff rear springs (relative to the 86 944 Turbo). So perhaps Porsche is on to something here.
I'd like to add that many people stiffen their suspensions without really understanding what they're looking for. In my case, it was a stiffer suspension to reduce roll (and minimize tire wear and keep the chassis off the ground under high g loads) and to maximize traction on bumpy U.S. tracks. So I went fairly soft. Many other owners I talk to at DEs say that their car with 400 lb/in front springs is "fine" on the street, and that may indeed be the case, but I suspect these cars are fairly hard to drive in the wet, espencially on bumpy surfaces.
I came to the conclusion that to keep costs low, select a rear spring rate and replace the rear torsion bars -- if adjustments between front and rear need to be made, it is easier to swap front springs than to swap rear coil over springs and continually reindex the torsion bars.
So I bought the Paragon conversion Koni coil overs, and a 29 mm rear torsion bar, along with M030 anti roll bars. My original goal was to duplicate the 968 Turbo S suspension, which the European press raved about way back when. The data I have indicate that this came with 200 lb/in front springs, the stock for '86 23.5 mm torsion bar, plus coil over rear springs of 375 lb/in (bringing the rear up to around 290 lb/in at the wheel -- esentially that of a 29 mm bar), and of course M030 anti roll bars.
Jason at Paragon said that most people choose the 300 lb/in front springs with the 29 mm anti roll bar, but PowerHaus told me to use 250 lb/in fronts. I went with the 300s, but after driving a few DEs this year, I've found the car to be less tossable (read: too much undesteer vs. the 1986 stock suspension), but the car rolls much, much less. (I was looking for a 50% reduction in roll, since the stock suspension allows the rear suspension to compress to the point that the INSIDE of the rear tires wears too fast). On the street it's stiff but fine.
I've tried stiffening the rear antiroll bar, but it's only 3-way adjustable, and I can only conclude that the combination of 300 lb/in front springs and a 30 mm dia front bar (perhaps 100% stiffer than stock, assuming a 27 mm effective rate) makes the front roll rate far too high vs. the rear -- at least for me. What we're talking about, however, from my calculations is a car that understeers more like, but less than, a 968 Club Sport than the 1986 944 Turbo, and a lot less than the 944 Turbo S.
It is entirely possible that the damping settings for the front and rear suspension may be at fault -- by stiffening the rear dampes further, I could induce transitional oversteer, which would disappear once the suspension settles in a fast corner. So I have one more adjustment I could try. But failing that, I have to conclude that a 250 lb/in front spring is better with a 29 mm diameter torsion bar and the M030 anti roll bars than the 300 lb/in spring.
Bear in mind that your anti roll bar choice will affect this greatly. Go with a stiffer rear bar and/or a softer front bar, and the stiffer front springs will be required. That said, I don't know the answer to the question "Why did Porsche on the 968 Turbo S go with relatively soft front springs and a stiff anti roll bar, and relatively stiff rear springs and a soft anti roll bar?"
Similarly, the 968 Club Sport had VERY soft front springs and the M030 anti roll bars front and rear, along with fairly stiff rear springs (relative to the 86 944 Turbo). So perhaps Porsche is on to something here.
I'd like to add that many people stiffen their suspensions without really understanding what they're looking for. In my case, it was a stiffer suspension to reduce roll (and minimize tire wear and keep the chassis off the ground under high g loads) and to maximize traction on bumpy U.S. tracks. So I went fairly soft. Many other owners I talk to at DEs say that their car with 400 lb/in front springs is "fine" on the street, and that may indeed be the case, but I suspect these cars are fairly hard to drive in the wet, espencially on bumpy surfaces.
09-09-2004, 04:38 PM
#13
Burning Brakes
Thread Starter
Originally Posted by David Floyd
Gee, Thanks 
But apology to David and thanks to Hunter.
09-09-2004, 05:27 PM
#14
Drifting
Does anyone have any hard data about deleting torsion bars for use on the street and the excessive wear and tear on the shock mounts? I have read a couple times that this is a problem as the loading is too high now that the entire weight of the car is resting on the shock mounts. If this is a problem, is there a way to strengthen/ stiffen the chassis to accept coilovers without T-bars?
Justin
Justin