a/x trans gear set options, what works? |
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a/x trans gear set options, what works? |
Trekkor |
Jun 15 2005, 08:49 PM
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#21
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I do things... Group: Members Posts: 7,809 Joined: 2-December 03 From: Napa, Ca Member No.: 1,413 Region Association: Northern California |
What is your favorite combo.
I need to stay in the 4500-6500rpm powerband. I can tach out at 7-7300rpm on the limiter. I have a spare trans I can build up now and then install... whenever. KT |
nine14cats |
Jun 16 2005, 09:39 AM
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#22
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Bill Pickering -- 914-6 GT aka....Leeloo Group: Members Posts: 2,618 Joined: 10-February 03 From: Campbell, CA Member No.: 287 Region Association: None |
Hi Trekkor,
I saw Randal at lunch yesterday and he said he e-mailed you my gear spreadsheet. That should help you in looking at the power band. To give you an idea on my "Q" tranny, 99% of the time I would use 2nd and 3rd during Bay Area auto-x's. At longer courses like Alameda, sometimes 4th, but that was VERY rare. I would spin my motor to 7200 and like you are thinking, if I needed more rev due to the course design, I'd switch my limiter selector to 7400. Your 901 has a 7.3:1 R&P, a 911 box normally has a 8.3:1 (at least in 915 boxes). In other words a 911 usually has a taller gear box. At many of the tighter courses, the taller 2nd gear makes it hard to keep the motor in the torque curve, and when they shift to 3rd, it's too high, creating a flat spot in the torque curve. For "The Beast", we are regearing the box to make the RPM drops between shifts very close, allowing the motor to be spooled up all the time. From my experience, regearing a transaxle is a bigtime gain in performance. Once I did that, my car was normally in the Top 5 of a Zone 7 auto-x and on the track we could run down 3.2 carrera's, and Doris and I both own "Y" class lap records at Buttonwillow (CW direction) for PCA-GGR Time Trials (Admittedly, we had a warmed over 2.7 (IMG:http://www.914world.com/bbs2/html/emoticons/rolleyes.gif) )......... (IMG:http://www.914world.com/bbs2/html/emoticons/laugh.gif) Basically, when you put a revving six in there, match the gearing, and sort that suspension, you can get fast in a short period of time. Doesn't make for a great cruising on the street, but my car was track only, and yours is getting there..... Oh...and did I mention you have to start cutting metal out of the doors, f/g hoods, etc., to get your car light?..... (IMG:http://www.914world.com/bbs2/html/emoticons/happy11.gif) Feel the power of the dark side....young Trekkor.....(insert Darth Vader's breathing here)..... Bill P. |
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