My sad suspension
08-28-2006, 06:12 PM
#1
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My sad suspension - FIXED
What? Another thread on Bill's suspension woes? Yep. I need to take a fresh look at this.
When I bought my 89 in 2000 it seemed to drive like a dream and turn on a dime with its sport suspension. A year or two later at 95K miles, high speed road tests showed the shocks weren't damping bumps at high speed very well and the car wallowed when upset by bumps at high speed. Still good in the lower speed twisties, however.
New Konis on the original springs (2 blue stripes in the rear) immediately destroyed the daily driving smoothness and stable feel in the twisties but improved the high speed bump behavior. Tried various rebound stiffness settings. I hated them overall but rode on them for 3 years until it was clear from fender bounce testing and developing high-speed instability that the Konis were bad.
Recently, newer Konis on the original springs lead to much firmer fender test and better high speed stability in a straight line, but downright awful behavior in very high speed turns. As soon as the weight of the car shifts to the outside from the steering input, the nose shifts in and then out, the rear end tends to wallow side to side, as if the car is pivoting back and forth around a center. A very loose and scary feeling. No tire squeal or over/understeer (I can't exert that much turning input - too unstable). Just an unsettling feeling that the car is shifting around over the wheels. Some up and down movement, some side to side, some directional shift. Very unstable. This requires pretty good g forces that you don't often encounter long enough to really load up the suspension long enough to wallow. If I slow down 10-20 MPH the car will corner OK. I am not cornering too fast as there is no loss of grip whatsoever.
The alignment is fresh with -5 caster, slight toe-in, midrange -camber. The ride height does look high in front but measures 155, rear 165. Sure, that's not terribly low, but it's not high. The steering rack is original at 170K miles but seems tight and leak free, and has been recently locked down with large washers. Balljoints are good. Tires are the same Yoko ES-100s I have been using for years and are fresh.
George Suennen has Konis with stock springs in his 90 with 100K miles and it handles well enough - far better than mine.
At the last alignment there appeared to be some play in one front A-arm bushing, but I found it hard to duplicate. Since the problem is largely at high g-loading, that may not be a surprise. How would you demonstrate bad front A-arm bushings?
After this last weekend of problems at the Pony Express, I concluded I should do the front bushings with polyethylene replacements. There are a bunch of rear bushings. They all look good, and I'm not sure how to evaluate them and which should be replaced.
When I bought my 89 in 2000 it seemed to drive like a dream and turn on a dime with its sport suspension. A year or two later at 95K miles, high speed road tests showed the shocks weren't damping bumps at high speed very well and the car wallowed when upset by bumps at high speed. Still good in the lower speed twisties, however.
New Konis on the original springs (2 blue stripes in the rear) immediately destroyed the daily driving smoothness and stable feel in the twisties but improved the high speed bump behavior. Tried various rebound stiffness settings. I hated them overall but rode on them for 3 years until it was clear from fender bounce testing and developing high-speed instability that the Konis were bad.
Recently, newer Konis on the original springs lead to much firmer fender test and better high speed stability in a straight line, but downright awful behavior in very high speed turns. As soon as the weight of the car shifts to the outside from the steering input, the nose shifts in and then out, the rear end tends to wallow side to side, as if the car is pivoting back and forth around a center. A very loose and scary feeling. No tire squeal or over/understeer (I can't exert that much turning input - too unstable). Just an unsettling feeling that the car is shifting around over the wheels. Some up and down movement, some side to side, some directional shift. Very unstable. This requires pretty good g forces that you don't often encounter long enough to really load up the suspension long enough to wallow. If I slow down 10-20 MPH the car will corner OK. I am not cornering too fast as there is no loss of grip whatsoever.
The alignment is fresh with -5 caster, slight toe-in, midrange -camber. The ride height does look high in front but measures 155, rear 165. Sure, that's not terribly low, but it's not high. The steering rack is original at 170K miles but seems tight and leak free, and has been recently locked down with large washers. Balljoints are good. Tires are the same Yoko ES-100s I have been using for years and are fresh.
George Suennen has Konis with stock springs in his 90 with 100K miles and it handles well enough - far better than mine.
At the last alignment there appeared to be some play in one front A-arm bushing, but I found it hard to duplicate. Since the problem is largely at high g-loading, that may not be a surprise. How would you demonstrate bad front A-arm bushings?
After this last weekend of problems at the Pony Express, I concluded I should do the front bushings with polyethylene replacements. There are a bunch of rear bushings. They all look good, and I'm not sure how to evaluate them and which should be replaced.
Last edited by Bill Ball; 02-26-2007 at 03:52 PM.
08-28-2006, 06:19 PM
#2
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Quoting Mark Kibort:
George's car handles fine - it is much lower. (120/130). Tim & Cheryl's car is 125 front. I suppose I could drop the ride height, but it did not have this problem before at the same height I have now.
How about this observation? - the car never bottomed with the original shocks. As soon as the Konis were swapped onto what should have been my original sport springs (I didn't do the swap), the car exhibited bottoming in the front corners, even with the same 155 ride height (actually it was 160 back then). A complaint about that resulted in a heavier swaybar being recommended and installed.
If the bushings aren't responsible then what is? The Konis and stock sport springs should work.
maybe the spring rates are just too soft now. the eibachs for racing were a little challenging, but obviously handing at 150 vs 100mph is a little different.
Still, got to wonder if it was someting else. dont think the bushings can cause that kind of handling issue. was the " wollowing" more like a suspension softenss issue? how does it compare to Georges car at speed? maybe its alignment. are you toed out a bit, that would cause some wondering at speed.
Sorry to hear. Thats got to be frustrating. I would say, cut a spring loop out of the eigbachs. It really made scots car handle well and i drove it last night on some speed runs, and it is really smooth compared to mine (holbert car cranked down devek level II koni/hypercoil) with your heavier weight, it should be even softer and will certainly handle better.
ride hight? could be too high in front? it looks realy high in front, based on your picture. since i run at 112/135mm front to rear, i would think that any proportions higher for your car would work well.
MK
Still, got to wonder if it was someting else. dont think the bushings can cause that kind of handling issue. was the " wollowing" more like a suspension softenss issue? how does it compare to Georges car at speed? maybe its alignment. are you toed out a bit, that would cause some wondering at speed.
Sorry to hear. Thats got to be frustrating. I would say, cut a spring loop out of the eigbachs. It really made scots car handle well and i drove it last night on some speed runs, and it is really smooth compared to mine (holbert car cranked down devek level II koni/hypercoil) with your heavier weight, it should be even softer and will certainly handle better.
ride hight? could be too high in front? it looks realy high in front, based on your picture. since i run at 112/135mm front to rear, i would think that any proportions higher for your car would work well.
MK
How about this observation? - the car never bottomed with the original shocks. As soon as the Konis were swapped onto what should have been my original sport springs (I didn't do the swap), the car exhibited bottoming in the front corners, even with the same 155 ride height (actually it was 160 back then). A complaint about that resulted in a heavier swaybar being recommended and installed.
If the bushings aren't responsible then what is? The Konis and stock sport springs should work.
Last edited by Bill Ball; 08-28-2006 at 07:11 PM.
08-28-2006, 06:24 PM
#3
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Quoting RonH
So, the poly bushings are too SOFT? That's counter to their promotion.
Bill, do you have aftermarket upper control arm bushings or are they the original stock bushings? Devek installed aftermarket bushings in my car after not being able to find original type bushings with the steel inserts. They seem too soft to me. But they do alright at 160, and seemed solid in turns. However, recently I have noticed the same behavior: sudden overreaction to steering inputs and little changes turn into drastic movements. I noticed it alot in Oregon and I haven't been driving the car since. Scary. I have Konis also, but on stock springs. They have about 45,000 miles on them, but don't do what you described yours as doing: the Cadillac bounce after a bump. They snub and damp most bumps in one cycle like they should, though I would like them to do it faster. I think I agree that it is the bushings. I have tried to find some original bushings in Germany, but unsuccessfully so far. It seems what is left on the remaining cars is what we have. If the source I know can't get them I doubt they may be found.
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08-28-2006, 06:26 PM
#4
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Quoting dr. bob:
For racing I am using my old stock 16" wheels and the same Yoko ES100 tires as before. Nothing special, but they should work as they did before the suspension went South.
Bill--
My memory is that you made a tire-and-wheel change since last year. How's my memory?
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My memory is that you made a tire-and-wheel change since last year. How's my memory?
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Bob Fuelleman <-- Why is my name here? So you can more easily figure out who posted this message!
Last edited by Bill Ball; 08-28-2006 at 06:58 PM.
08-28-2006, 06:30 PM
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I have no idea whether this will help, but, as we all know, the eccentrics wear with time. Maybe your alignment is getting squirelly at high Gs. Any sign of alignment "drift" after hard driving?
08-28-2006, 06:32 PM
#6
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Am I missing something, or does the common denominator sound like the Koni's? The only thing you've been changing is the shocks. It makes sense that you don't want to spend big bucks on all new shocks if there's something else that's wrong, but after following the several threads to see how things turn out, I'm not seeing how something else is the problem. Is George running stock springs with Konis as well, which is what you have, correct? Are the springs the same length, just ride height adjusted, or has he cut some of the spring length?
You're using the same wheel/tire combo this whole time right, you race on the flat dish 16's? - edit, you verified this while I was posting it.
You're using the same wheel/tire combo this whole time right, you race on the flat dish 16's? - edit, you verified this while I was posting it.
08-28-2006, 06:33 PM
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Bill, unfortunate about the performance after all your hard work to prep for the Pony Express.
You know I agree that the poly bushings up front will only help and seem a natural effort while doing the spring/shock swap.
Your description of behavior reminds me of an undersprung Sprint car on a rough track. The wollow or loose body-on-top-of-the-wheels feeling typically indicates the spring is unable to handle the G-load when backing into a corner. It can be somewhat minimized with shock adjustment (rebound and/or compression), but increase in spring rate or progression is how to correct it.
Sounds like your springs are sacked. 170k is a lot of use and it could be that they're fatigued at speed, and the nose wiggle is the stiffer shocks trying to compensate.
My .02, swap out the bilsteins/progressives 1st - it does seem that the poly bushings would aid in a more solid feel, but increased labor.
You know I agree that the poly bushings up front will only help and seem a natural effort while doing the spring/shock swap.
Your description of behavior reminds me of an undersprung Sprint car on a rough track. The wollow or loose body-on-top-of-the-wheels feeling typically indicates the spring is unable to handle the G-load when backing into a corner. It can be somewhat minimized with shock adjustment (rebound and/or compression), but increase in spring rate or progression is how to correct it.
Sounds like your springs are sacked. 170k is a lot of use and it could be that they're fatigued at speed, and the nose wiggle is the stiffer shocks trying to compensate.
My .02, swap out the bilsteins/progressives 1st - it does seem that the poly bushings would aid in a more solid feel, but increased labor.
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08-28-2006, 06:44 PM
#8
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Bill
Kirt has a good point.....170K is alot on springs (even sports)....I would swap out the bilstein/eibachs and try it?
The only other thing I can think of is bad bushings.....but that would be more localized to one corner...not all 4 at the same time?
Let me know if you need any help!
Kirt has a good point.....170K is alot on springs (even sports)....I would swap out the bilstein/eibachs and try it?
The only other thing I can think of is bad bushings.....but that would be more localized to one corner...not all 4 at the same time?
Let me know if you need any help!
08-28-2006, 06:59 PM
#9
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Bill, I am not certain that the aftermarket bushings are the source, or that they are too soft. I simply noticed a difference in crispness when I got the car with the new bushings. But my car has always had steering problems. When in Oregon, it became extreme. The paving material changed noticeably when I crossed the state line. It seemed more "pebbley" and rough and the trucks have obviously worn noticeable ruts in the roads particularly in the right lane. The ruts lead to more pronounced crowns, or maybe the crowns are more pronounced by design because it rains so much there. Anyway, slight corrections in reactions to road crown pull produced scary over reactions far greater than steering input, and resultant counter reactions when correcting the other way. I was swearing all the way up I-5 and back down again. *$@%!&#$**steering ! Sounds like your situation somewhat. In constant radius sweeping turns and "reasonable speeds" the steering was fine and stable. I am to the point that I will save to buy NEW uppper control arms simply to get the new ball joints and original factory bushings. Examine them carefully to notice how much better they should perform. And I still have the original steering rack, which Devek said is OK, but others have condemned. 
My tires allways wear out on the inside edges at all four corners. Must be something related to the pull of the moon or whatever. 
Three sets in 1 1/2 years and I don't do burnouts.
My tires allways wear out on the inside edges at all four corners. Must be something related to the pull of the moon or whatever. Three sets in 1 1/2 years and I don't do burnouts.
08-28-2006, 07:03 PM
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I have a friend who should know, and who can "smell" problems by walking by a P car. He is convinced that Bilsteins are better shocks in all aspects. FWIW. He put Konis on my 911s but I wasn't giving those cars such a workout. (hey, they were in Hawaii, so where can the car even get up to temperature?)
08-28-2006, 07:06 PM
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Chris:
I have been trying to give the Konis a chance as they have worked well for George and others. The first set of Konis, although severly underdamped in my opinion, did not exhibit the awful turn behavior I am seeing now.
Maybe the springs are shot. The car certainly handles like it is undersrpung. The funny thing is it felt undersprung the day I got the car back together after the first set of Konis were swapped onto my springs (or what should be my springs - I didn't do the swap).
Note I have a heavier than stock swaybar upfront - that was added after I complained that the front corners were bottoming on hard turns after the first set of Konis were installed - again, something which never happened before that swap. I attributed it to underdamping on compression, but it could have been the springs. It's just odd that it started immediately after the Koni install.
I have been trying to give the Konis a chance as they have worked well for George and others. The first set of Konis, although severly underdamped in my opinion, did not exhibit the awful turn behavior I am seeing now.
Maybe the springs are shot. The car certainly handles like it is undersrpung. The funny thing is it felt undersprung the day I got the car back together after the first set of Konis were swapped onto my springs (or what should be my springs - I didn't do the swap).
Note I have a heavier than stock swaybar upfront - that was added after I complained that the front corners were bottoming on hard turns after the first set of Konis were installed - again, something which never happened before that swap. I attributed it to underdamping on compression, but it could have been the springs. It's just odd that it started immediately after the Koni install.
08-28-2006, 07:32 PM
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Bill, it would seem that if your old konis were toast and causing a lot of bounce it might speed up the springs demise since they then have to work harder and are subject to much more movement. Also, don't the Konis work harder on rebound than compression? That would help explain the bottoming out feeling. Another consideration that I can't remember if you addressed would be tires. What were you running when you first got the car?
08-28-2006, 07:39 PM
#13
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Originally Posted by Bill Ball
Chris:
I have been trying to give the Konis a chance as they have worked well for George and others. .
I have been trying to give the Konis a chance as they have worked well for George and others. .
08-28-2006, 07:51 PM
#15
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if the car is bottoming out on the new shocks, the shocks could be the problem as far as their bump . shocks can be bad and can go bad.
the springs can be shot too. you are bottoming out. if the bottoming out happens at only the high speed, sounds like it could be shocks, as the bump keeps this from happening over quick movememts. however, springs play a part here too. I cant imagine a bushing that bad that would make your car that "darty". i have original bushings on both A-arms. one has a little ball joint "click" movement that is not getting any worse over the last 3 years of racing. 100-120mph high speed turns are a regular deal at thunderhill, and my car is as solid as a rock.
Im wondering if you got an alignment that has just gone south or wasnt what you thought it was when you got it. do some measurements yourself of the front rims as they align to your driveway with a magic marker. the front sides of the rim should be 1/8 to 1/16" closer than the rear of the rims. that gives you just a little toe in , close to spec. camber is easy to check with a level, but that wouldnt give you such handling issues.
?????? mystery!
MK
the springs can be shot too. you are bottoming out. if the bottoming out happens at only the high speed, sounds like it could be shocks, as the bump keeps this from happening over quick movememts. however, springs play a part here too. I cant imagine a bushing that bad that would make your car that "darty". i have original bushings on both A-arms. one has a little ball joint "click" movement that is not getting any worse over the last 3 years of racing. 100-120mph high speed turns are a regular deal at thunderhill, and my car is as solid as a rock.
Im wondering if you got an alignment that has just gone south or wasnt what you thought it was when you got it. do some measurements yourself of the front rims as they align to your driveway with a magic marker. the front sides of the rim should be 1/8 to 1/16" closer than the rear of the rims. that gives you just a little toe in , close to spec. camber is easy to check with a level, but that wouldnt give you such handling issues.
?????? mystery!
MK