I have searched all over and keep getting pages of info about the B13/B14's.

What I would like to know is what is the sensible lowering limit for a P10 chassis, below which the roll center climbs??

Mike

interested as well..

The rear of a P10/11 is limited in the same fashion as a B13/14. P10 rears run into big bumpsteer issues when you lower them much more then an inch. I do wonder about the fronts. If I had the specs of all the attachment points I could put it all into autocad and give a pretty good estimate of what happens at different points. Problem is getting all the frame attachments points and then the length of all the arms, etc. You could look for bumpsteer issues for the 300zx TT and see what they say. It's a similiar design isn't it? Maybe Rockwood has some ideas.

I read on one of the links I followed that the P10 rear had better rear link ratios than the B13/B14?? maybe not a lot better?? I will take me 2-3 days to find it again...LOL
Hmm?? like the 300zxTT, cool I will see where that info takes me.

Mike

I could be wrong. Not a P10 guy but I could swear thats what others told me. Of course that does not mean much.

The B13 and P10 share rear suspension designs, although the control arms may be slightly longer (this has yet to be verified). The rear suspension doesn't have too many problems.

The front suspension is a lot better than a B13/B14. The main problem you will run into is travel and axle binding issues. All FWD SR powered cars run into the same issue with their axles when you lower them too much. When its lowered too much, the axle will bind and contribute to understeer. The front shocks only have about 1/2" of travel when just lowered with a set of Tein S-techs (1.2"). The main reason for this is the bumpstop tabs are about 2-3" down from the threaded part of the shock shaft. If you were to find a shock without these tabs right there, you would instantly gain more travel then you would ever need but that would mean some sort of custom threaded body shock like a Koni 3011 ($450 each).

So, after all this blabbing, you probably want an answer:

I wouldn't lower it much more than 2".

The P10 rear control arms are noticeably longer than the B13.

Longer control arms would effect the camber curve. It's the lateral link (one pointing to the front of the car) that effects the bumpsteer issue. Wonder if it's the same or not?

Well on my journey to work there is only one corner that gives me any hiccups, it is a fast righthander with a manhole cover just as you exit, and not positioned flat either, so the car gives a little step as the rubber leaves the tarmac, other than that I havent really noticed bumpsteer, might be different on a ractrack though??

Mike

Bumpsteer is not exactly as the name implies. It occurs as the suspension compresses as you corner. As the rear of a B13/P10 suspension compresses the rear suspension goes thru a arc that causes the toe settings in the back to change. It happens on every car pretty much. As you go lower in the back it gets much worse.

Well I thought that when cranked into a corner you want the rear outside tyre to toe out, and the inside tyre to toe in as that will reduce the understeer.

Mike

Get out the way! Here comes a dead thread!


Steve and Rockwood, are the S Techs even stiff enough to keep the p10 off the bumpstops? 150/140 Springrates IIRC.

If they are not ideal, what out there do you recommend? I couldnt find any springrate info over here at the g20.net site either.
http://www.g20.net/forum/showthread.php?t=22364

Im picking up a P10 tonight with GAB struts on there, and if I can find a decent deal on springs I would like to give her the propper treatment :) Not looking to do the noisy GC "coilovers" either. Just a spring and strut setup if possible.

Steve Im also going to PM you in case you dont see this.

Well the UK eGT spring rate is more than that I believe.

The reason for my original question was to find the optimal drop, below which the roll center climbs again and you need higher rates to keep the roll under control.

Mike

No they are stiffer than eGT springs Mike.

http://www.g20.net/forum/showthread.php?t=44895

I'll let this thread go as it wasnt originally mine, but yet I decided to hijack it :) I started a new one in the Road Race/ Rally / Auto-X section.

http://www.sr20forum.com/showthread.php?t=161563

Thanks!