Looking for Bill Pickering
04-05-2008, 05:32 PM
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Looking for Bill Pickering
Bill, with all of the spec box talk going on I am hoping you may be on this sight. I was reading an older post on "boxster racing board" where you talked about your suspension set up. You stated you are, or were, using PSS9's with Eibach springs of 450 and 500 pounds (F & R). You also stated the stock PSS9 spring rates are about 260 / 328 or so. The question, I have been running the stock PSS9 springs for a few years and want to understand how the Eibach springs would change the handling? What is the benefit of the higher spring rates? Quick background on the car, Full race car with welded cage, striped down to 2538 w/ half a tank w/o driver, R6 Hoosiers, Adjustable swaybars front and rear w/ adjustable drop links. Corner balanced. Non-stock motor w/ Motec M800 engine management system.
Can you tell me more about how these heavier springs would make the car handle better or differently?
Anyone else feel free to chiming in.
Can you tell me more about how these heavier springs would make the car handle better or differently?
Anyone else feel free to chiming in.
04-05-2008, 10:24 PM
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Hi Brinkley,
I just checked in here and I'm on the way out the door to a concert. When I get back I'll post my impressions of the 450/500 combo with the PSS9's. Sorry to bug out but were just going out the door.....
Talk to you in a little while!
Bill P.
I just checked in here and I'm on the way out the door to a concert. When I get back I'll post my impressions of the 450/500 combo with the PSS9's. Sorry to bug out but were just going out the door.....
Talk to you in a little while!
Bill P.
04-06-2008, 08:48 AM
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Aren't the Speedsource guys running RX-8"s ? i.e. front engine cars??
04-08-2008, 12:28 PM
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Hello Brinkley,
It took me a couple of days with work getting in the way, but I've got some time now to answer your questions. I'm sure more knowledgeable people than myself will help with the discussion as well.
Yes, I am running 450lbs/in fronts and 500lbs/in rear springs. This is the Spec Boxster mandated combo. I can't swap the spring rates front and rear. You can run the PSS9's (and now 10's) with the stock springs or go to the heavier rates. You cannot have the shocks re-valved. We also run adjustable AR bars front and rear. We run camber plates AND GT3 adjustable control arms up front. In the rear, we are looking at running a monoball setup.
When I talked with Bilstein about the pre-defined rebound and compression in the PSS9's (I called their offices in Poway), their only concern with the stiffer springs was that the valving would be at the upper end of the spectrum for the spring rates, meaning that the springs would be maxing out the capabilities of the shocks. I've found that with my driving style, the rebound damping has been the issue. When I put the car is a position where a quick rebound occurs, it feels like the springs overpower the shocks. PSS9's were put in as a cost containment, so I'm not complaining, merely relating what I can feel.
It would seem the better the capabilities of the car and more importantly the driver, that higher spring rates apply. Also the tracks you frequent will influence your choice of spring rates as well. A smooth track you may be able to run stiffer springs, while a bumpy track may take the softer setup. The stiffer springs help in grip of the car, keeping it planted. But to utilize this grip, the driver needs to have the skill to put the car where it needs to be as well as handle a car that can loose grip quickly as it "skates" around a turn due to being so stiff.
As an example, on my previous car, a 911 with big slicks and lots of HP, we ran a rather mild setup of 350/550 coilovers. Another driver in my class who was a much better and more experienced driver was using a 800/1000 combo on basically the same car. And he was significantly faster. The stiffer springs also help (along with AR bars) to minimize body roll and also dive during braking and squat during acceleration. Weight transfer is good, but not at the expense of grip at either end.
Also, the stiffer springs may help the overall aerodynamics of the car as it keeps the car in a "position" that does not change the air flow over the car. This applies mostly to the big motor Boxsters, but it would seem you wouldn't want your big splitter or rear wing having disturbed air run over them from excessive motion.
The SpeedSource Boxsters ran heavier springs up front than the rear in what I have read. I can't confirm this. I do know of other cars on the west coast using stiffer spring combo's than the Spec Boxster rules with 2.7L and 3.2L motors and on the track they seem to look like they are handling great.
A big part of the equation is the driver's preference. Front to rear weight balance (and the overall corner balance of the car) must play a part in this. We've gotten to a point where we have started doing our own alignments on our car. We have scales, camber gauge and strings. The GT3 arms have 2 preset caster angles, but we're using the stock location currently. What we have found is that the boxster, being mid-engined, can be weight biased very easily. For example, I can easily swing the car's front/rear weight bias from 48%/52% to 52%/%48 front to rear with a few quick turns of a spring collar. With my 911, there was no way I could do that with my coilovers due to the weight distribution of the car. Perhaps the cars with heavier springs up front have more of a neutral (50/50) or slightly front weight biased setup that works for their drivers.
Not being a pro driver (just a weekend guy) I'd have to say that the softer setup seems to be the easier to drive. My first track car was a 2.8L 914-6 and it was setup really stiff for the weight of the car. You'd kind of bounce around from point A to B on the track and the car would skate at times. On my 911 and now the Boxster, while the spring rates were mongo stiff compared to a street car or stock PSS9 rates, they are basically half the spring rates of what pro drivers and teams use.
I hope this helps with your questions and I'm sure some of the other's on this board can chime in with their experiences.
Thanks,
Bill P.
It took me a couple of days with work getting in the way, but I've got some time now to answer your questions. I'm sure more knowledgeable people than myself will help with the discussion as well.
Yes, I am running 450lbs/in fronts and 500lbs/in rear springs. This is the Spec Boxster mandated combo. I can't swap the spring rates front and rear. You can run the PSS9's (and now 10's) with the stock springs or go to the heavier rates. You cannot have the shocks re-valved. We also run adjustable AR bars front and rear. We run camber plates AND GT3 adjustable control arms up front. In the rear, we are looking at running a monoball setup.
When I talked with Bilstein about the pre-defined rebound and compression in the PSS9's (I called their offices in Poway), their only concern with the stiffer springs was that the valving would be at the upper end of the spectrum for the spring rates, meaning that the springs would be maxing out the capabilities of the shocks. I've found that with my driving style, the rebound damping has been the issue. When I put the car is a position where a quick rebound occurs, it feels like the springs overpower the shocks. PSS9's were put in as a cost containment, so I'm not complaining, merely relating what I can feel.
It would seem the better the capabilities of the car and more importantly the driver, that higher spring rates apply. Also the tracks you frequent will influence your choice of spring rates as well. A smooth track you may be able to run stiffer springs, while a bumpy track may take the softer setup. The stiffer springs help in grip of the car, keeping it planted. But to utilize this grip, the driver needs to have the skill to put the car where it needs to be as well as handle a car that can loose grip quickly as it "skates" around a turn due to being so stiff.
As an example, on my previous car, a 911 with big slicks and lots of HP, we ran a rather mild setup of 350/550 coilovers. Another driver in my class who was a much better and more experienced driver was using a 800/1000 combo on basically the same car. And he was significantly faster. The stiffer springs also help (along with AR bars) to minimize body roll and also dive during braking and squat during acceleration. Weight transfer is good, but not at the expense of grip at either end.
Also, the stiffer springs may help the overall aerodynamics of the car as it keeps the car in a "position" that does not change the air flow over the car. This applies mostly to the big motor Boxsters, but it would seem you wouldn't want your big splitter or rear wing having disturbed air run over them from excessive motion.
The SpeedSource Boxsters ran heavier springs up front than the rear in what I have read. I can't confirm this. I do know of other cars on the west coast using stiffer spring combo's than the Spec Boxster rules with 2.7L and 3.2L motors and on the track they seem to look like they are handling great.
A big part of the equation is the driver's preference. Front to rear weight balance (and the overall corner balance of the car) must play a part in this. We've gotten to a point where we have started doing our own alignments on our car. We have scales, camber gauge and strings. The GT3 arms have 2 preset caster angles, but we're using the stock location currently. What we have found is that the boxster, being mid-engined, can be weight biased very easily. For example, I can easily swing the car's front/rear weight bias from 48%/52% to 52%/%48 front to rear with a few quick turns of a spring collar. With my 911, there was no way I could do that with my coilovers due to the weight distribution of the car. Perhaps the cars with heavier springs up front have more of a neutral (50/50) or slightly front weight biased setup that works for their drivers.
Not being a pro driver (just a weekend guy) I'd have to say that the softer setup seems to be the easier to drive. My first track car was a 2.8L 914-6 and it was setup really stiff for the weight of the car. You'd kind of bounce around from point A to B on the track and the car would skate at times. On my 911 and now the Boxster, while the spring rates were mongo stiff compared to a street car or stock PSS9 rates, they are basically half the spring rates of what pro drivers and teams use.
I hope this helps with your questions and I'm sure some of the other's on this board can chime in with their experiences.
Thanks,
Bill P.
