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+--- Thread: 987 (/showthread.php?tid=2661)
- Mark Fox - 03-16-2011
Larry,
I was wondering wha weight oil you were using in the 987 and if you happen to know the suggested ride height? Even with the 19"s it just looks high. Thought I would start here before considering possible change in springs, but being a non PASM am a little concerned about ride quality out comes. Thanks.
P.S. Very nice parts 1 & 2 suspension write ups.
- Larry Herman - 03-25-2011
Mark, I am using the Amsoil 5W-40 European formula. That is what I also use in Cheryl's Cayenne.
As ride height goes, I have not done anything to mine, yet, as I have H&R lowering springs still in the box from 2 years ago. They drop the front about 1.2" and the rear about 1.4" as these cars sit pretty high when stock. According to H&R, they do not degrade the ride much at all. Maybe I should hold a clinic on how to change springs?
- Mark Fox - 03-27-2011
Hi Larry,
Roughly 2-3 years ago I was talking with a 986 owner who had lowered his car with the H & R springs and noted no change when driven on the street. Are they also progressive? I'm a non PASM car so I don't want to make it any stiffer. Although a little bigger bar up front reducing the understeer would be nice.
I'm guessing you read the Leh Keen drive of the spyder and GT-3 RS. He lost the spyder twice very unexpectedly, when fully set mid corner while encountering an area of transitioning pavement. He felt he bottomed out the strut. With a similar valued spring, but 1 1/2 inches shorter length, would this not potentially cause a greater possibility of this occurring? And yes a class on strut changes would be interesting. Thanks
- Larry Herman - 03-28-2011
Mark, they look like they are progressive, though H&R does not say. When I get them installed, I will be able to check on that. And yes, if you lower a car and do not increase the spring rate, then you do run the risk of contacting the bump stops during extreme cornering, and it could be of concern on the track, but not on the street.
Also, you want a stiffer REAR bar if you want to reduce the understeer.
- Mark Fox - 03-28-2011
Thanks Larry, is that a stiffer rear bar in addition to the front or leave the front alone and just increse the rear. Is there set up closer to 911's
I have never been with student who spun a 987 or 986. Any idea as to how they will let go? I am thinking initial lateral movement followed quickly by oversteer.
And in case you didn't see the article with Leh Keen, his spins did happen while driving on the tail of the dragon.
- Larry Herman - 03-28-2011
Mark, I did not see the article. Where is it & do you have a link?
With the sway bars, you need to make sure that the rear bar has a greater increase in stiffness than the front if you are changing them both. A simple comparison of the area (pii * R squared) will do it. How much though is a guess. You can call me if you want to compare numbers.
Finally, a Cayman or Boxster will not break loose any easier, but will come around faster due to their lower polar moment of inertia. And what many confuse as "snap oversteer" is really cause by a push-loose condition (to coin a Nascar term) that has the car going from understeer to oversteer very quickly. It happens in 944s too, but the car swaps ends more slowly.
- Mark Fox - 04-02-2011
Larry the article is in the 4-11, pg. 54 Excellence. Leh Keen, "Twice now i have bottomed it's struts and each time it whipped around on me so fast it caught me off guard. I have to say, I think it's fairly dangerous."
This is compounded by bopping around not anticipating the unexpected as he is in the GT-3 RS.
- Vidal - 04-03-2011
Larry, I would be interested in a spring-swap clinic. Thank you also for the brake clinic at the club meeting. I picked up a few new facts - it was all very informative.
- Mark Fox - 04-04-2011
Larry,
I warmed up the 951 yesterday and the suspension is so nice on the car. A direct extension of the driver responding to every input in a linear consistent fashion. Then I took out the 987S to warm it up before dumping oil, understeer, hard set turn in, then more understeer. I am thinking more negative camber if any is available along with some bigger bars might help a little.
At this point I don't know what bar options are available. I think the correct way to address the suspension shortfall is probably to do coil overs allowing ride height adjustment and tenders up front for small bump compliance. Anyone going to Idaho so I can get a power ball ticket.