PCA track event at California Speedway, Recommended Gear Ratios? Options

[race914]

I just received an announcement on our local PCA email list regarding the PCA Speed Festival at California Speedway this March:

http://www.pca.org/zone8/Z8SFest.htm


I've never run this track, and by the map

http://www.californiaspeedway.com/uploads/..._coursemaps.pdf

it looks like my 901 M-S-X setup, which works great at Laguna Seca, is going to top out pretty early.

Can anyone share their 914 experience on this track, top speed, and a recommended gear setup?

Thanks,

Greg

[Aaron Cox]

john rogers runs cal speedway.... i think he also runs an M S X tranny with a six....

[john rogers]

Since I put in the 2L six I went to K-Q-V and the car tops out at about 135 at 7400 RPM as the lower torque six could not wind up well. The original box I had (still for sale) with M-S-X worked great for a stroker four and would top out at about 6500 RPM. Depends on what engine you have I'd say. The CA Speedway at 135 in a 914 with no wings or large spoilers is pretty exciting rounding turns 1 and 2 with your foot to the floor.

[race914]

After I setup my first close ratio 901, I went to Thunderhill with a KA-Q-V setup. I was running around at redline on the straights watching people pass me.... That was with a 2.0 four @ 6000 RPM. Wanted to avoid that this time if possible!

Sounds like my M-S-X setup will work OK with my current 2.2 four (6500 RPM redline) at the California Speedway

Appreciate the input!


I am concerned about turns 1 & 2. My car only has the small trunk lip spoiler and starts danc'n @ 110!

Sounds like my aerodynamics will be the limiting factor, not my gearset.

Going to make some mods being discussed on the "Lifting rear of roof" Thread: http://www.914world.com/bbs2/index.php?act=...=ST&f=2&t=43570

Thanks again for the info! (IMG:http://www.914world.com/bbs2/html/emoticons/beerchug.gif)

[drew365]

I have a 2.7 twin plug with a Ka,Q,V box. I don't have a speedo but was told my top end with 16" wheels would be 132. I have my electromotive rev limiter set at 7500. I hit the rev limiter well before the end of the straight. I then have to taper off the gas and cruise the rest of the straight and into 1. I guess I don't have as big cajones as John because I can't take 1 and 2 without breathing off the throttle and then squeezing it back in exiting 2 while drifting towards the outside wall. That point is the biggest pucker factor for me of any track I've been to. Having to keep your foot in the throttle as the wall, and those big old black tire spots, keep getting closer. (IMG:http://www.914world.com/bbs2/html/emoticons/icon8.gif)

[john rogers]

There are a couple of things you can do to make the car more stable. Have the front alignment changed to 0 or maybe 1/8 inch toe in, slightly less negative camber on the left, more on the right (like the good 'ol boys), get a corner balance done and if necessary set the weight slightly to the left. There is only one fast/hard right turn so set the car for going left and/or straight smoothly, you don't want any twitchiness at all. I'd recommend using a set of new tires since that is a very fast and smooth track and a 914 with no aero aids should be able to go flat out once you hit the main straight just past NASCAR turn 4. You can also check with the local PCA folks up there where you live as there is a video that Wayne Baker made several years ago before the first PCA club race there and it details exactly how to drive all the track with very good instructions by Wayne. It was in Stanley Gold's 2L challange series 911 so it is not in some monster engined RSR.

[race914]

Here are my current alignment specs:


Corner Balance with driver:

Left Front: 480 Right Front: 480
Left Rear: 604 Right Rear: 596

Alignment:

Left Front: -2.2 Right Front: -2.2
Toe .12 .12


Left Rear: -2.8 Right Rear: -2.0
(turns out car was hit on right rear. found body work and this is all the neg camber we can get)
Toe .23 .23


Looking at my alignment sheet, this is actually from 4 years ago! Didn't realize until now my last setup was that long ago. But on the positive side.... sounds like the weight I've gained will help bias the weight to the left (IMG:http://www.914world.com/bbs2/html/emoticons/wink.gif) so check that improvement as 'done'

I think I'll get my car re-aligned & corner balanced and work with my shop on the recommendations you listed.

Thanks!

Looking forward coming down south to a new track!

[slivel]

race914,

In answer to your question about gear ratios at CMS, I also run a box with AFMSX ratio's and rear tires with a diameter of 25.6 inches (275/45/16). With this setup I found that I was at redline (7000 rpm) in top gear when I passed start/finish - which is shortly after entering the oval portion of the track. Therefore I had to feather the throttle all the way around the track until getting to turn 3 and the infield. Last time I ran CMS I lossened a flywheel - I think because of having to sit at redline allthe way around the oval. If you are running huge diameter tires or are going to spin your engine to 8000+ rpm, this is what you can expect. I am not going to run CMS anymore unless I get my spare transmission built with a Y 5th gear.

Steve

[john rogers]

Hi Steve, I thought you had the tranny all ready to go? You have to remember he has one of those "monster motored" 914's and not a puny 2L car!!

[race914]

QUOTE (slivel @ Jan 17 2006, 07:38 AM)

race914, In answer to your question about gear ratios at CMS, I also run a box with AFMSX ratio's and rear tires with a diameter of 25.6 inches (275/45/16). With this setup I found that I was at redline (7000 rpm) in top gear when I passed start/finish - which is shortly after entering the oval portion of the track. Therefore I had to feather the throttle all the way around the track until getting to turn 3 and the infield. Last time I ran CMS I lossened a flywheel - I think because of having to sit at redline allthe way around the oval. If you are running huge diameter tires or are going to spin your engine to 8000+ rpm, this is what you can expect. I am not going to run CMS anymore unless I get my spare transmission built with a Y 5th gear. Steve

Thanks for the info Steve.

My engine builder said I can shift at 8000+ if I want, but I can only do it once... (IMG:http://www.914world.com/bbs2/html/emoticons/huh.gif)

I'm running 205x50s (23.1" diameter) and redline @ 6500 so I'll top out around 120 and have to live with that. Never been to CMS so I might go with the M-S-X just to go!

All the tracks up North aren't as high speed. With my four, the KA-Q-V works great a Laguna, and Sears, and the M-S-X works great at Buttonwillow and Thunderhill.


Thanks again to everyone for the info and I'm looking forward to meeting you guys at a track event sometime.


Greg