Veloce Raptor

LMAO...hey, say what you want about me, but I put the k back in kwality.

jrgordonsenior

Chris do you really run that setup? I would think you'd push it right off the track on your first turn. Can you please explain for me why that config. works especially going full soft in the rear...

Thanks,
JRG

RSRRacer

I know it's probably not the right setup, but the nitrous and 4.2 liter cheater motor I run helps me overcome the lack of grip.

Yep, thats the setup I run. I am not a suspension guru so I really don't know why is works.

When I bought the car from Mike Levitas at TPC this is how he recommended that I run the car as an amateur. He indicated that I would be leaving a bit on the table but that it was a more conservative setup. This is the setup I have run in every race.

Perhaps I will try a new setup during Friday at R Atlanta.

Larry Herman

I raced a cup car setup like that, and it really didn't work that well. I started dialing out the understeer, but was so new to the car, and so unfamiliar with the way it should handle that I didn't go very far with the adjustments. If/when I get a chance to race another one, I know exactly what I want it to do.

jrgordonsenior

Well that's really interesting Chris. I'm not an expert by any means, but that combination of full stiff/front, full soft/rear, should give you massive understeer and all but eliminate any chance of snap-oversteer. Your cup should turn in like the QE2 yet it obviously doesn't based on your very successful past year. It makes me want to soften my full-stiff rear bar and see what happens. I remember you posting that you experienced snap-oversteer at Sebring with the Michelin Blues and stating that had never occured before. I wonder what would happen if you stiffened the rear and soften the front a notch. Hell you might be running with Leh....

Bryan Watts

A stiff front setup (spring and bar) and "softer" rear setup (no bar at all) is very popular in the BMW world. Obviously the cars are different, but the common denominator is the front strut. The strut generally isn't all that great from a roll center or camber curve perspective. A "stock" geometry front BMW strut setup needs all kinds of spring rate in order to keep the suspension from rolling too much and entering the pitiful portion of it's camber curve. Adding spring rate, to a point, actually adds grip to the front of a lowered E30, E36, or E46 BMW.

Now, I don't know enough about the front strut on the Porsche, or the geometry changes made to the suspension on the Cup cars, to know if this might be a similar situation, but it seems like a possible explanation. Has anyone else seen this trend in Porsche's?

Veloce Raptor

Bryan, wouldn't this all predicate very heavy spring rates? I know on my M3, I do not have enough spring rate for this set up to work, but for the guys running 900 pound + springs, it seems to work great.

Bryan Watts

We don't run spring rates that high. Spring rate is only part of the equation though. Suspension geometry, roll rate, corner weights and all sorts of other things are very important, and likely not at all similar on the BMW and Porsche. All of that said, the Macpherson strut still has the same problems in most any application, which is I would think that higher spring rates might sometimes actually help the grip on the front of a 911.

leif997

Chris, why mess with your recipe for success? if it ain't broke; don't fix it!

MarkPcar

OK, follow-up.

I ran two weekends back-to-back at Thunderhill, PRC the first and a SCCA Double National the second.

In PRC I finished 8th of 10 Cup cars in the first race and 7th of 7 in the second race (after a little incident). Fast lap for the weekend was a 1:58.6.

On Thursday of the following week we worked all day on the set-up and found a 'better' set of used tires for the weekend (Why can't anyone deliver Cup tires???).

For the SCCA weekend we had 6 cars in the GT2 class - 3 Cup cars and 3 other cars. Saturdays race ended in a second place finish and Sundays race was my first ever racing win! Fast lap was a 1:56.6 which is within 1/2 a second of the fastest Cup cars from the PRC weekend.

Whooohaaaa - I'm now the North Pacific division SCCA GT2 points leader! Maybe I should plan for the Runoffs where Analog Mike took 6th place in 2005 with my car. Still lots to learn but it sounds like fun.

I love driving this car!

analogmike

Awesome!!

Glad you are getting the hang of it! Sorry the setup was off, it was professionally aligned with no track time on the new alignment after the bodywork was completed.

I just got back from several days in the FL Keys, will answer your email asap.

Have fun and hope the car gets it's 2nd SCCA divisional championship this year!

David 23

Mark, congratualtions, you should be very pleased with your performance. Keep up the reports, and maybe a photo of the car to feed my envy.

MarkPcar

Early morning practice at Thill.

Jerseybean

Great shot, who took the photo. They did a nice job.

MarkPcar

Head On Photos shoots at a lot of the Nor Cal events and then sells CD's and prints at the track.