ITS VR6 gearing

[Eric Parham]

I'm gradually getting my GTI VR6 going, and trying to hit the right R&P the first time. My number crunching tells me a 3.94 without accounting for part of the aero. A fudge to 4.23 to account for the missing aero seems about right, but I wouldn't want to run out of gear at WGI. Anyone have advice? Bill (Bildon) in the Corrado? Mine's going to be a GTI, so it might have worse aero that I'll have to account for. Anyone else run a VR6 yet at WGI, Lime Rock or NHIS? TIA

[Greg Amy]

Eric, I've got a 4.437 in the NX and I *never* run out of gear. Never at WGI, never at Road Atlanta. Yup, I use fifth...gear ratios 3.333, 1.826, 1.286, 0.975, 0.756.

At WGI I shift into fifth just as I crest the top of the esses, and max RPM there is 7200.

[Eric Parham]

Thanks Greg, that is very helpful. The GTI has a 0.838 5th. Thus, your numbers would be equivalent to my running an imaginary 3.99 in the GTI. I can get a 3.94 or a 4.23. Sounds like the 4.23 might work since you're not shifting until the top of the Esses (thus 4.23 not necessarily better than the 3.94 at WGI, but hopefully not top-speed limiting), but then again, ITS might see a slightly higher top speed than ITA -- even yours ;) If I can get away with the 4.23 for WGI, I think it might actually pay off at Lime Rock and NHIS.

EDITs: Oops, wait a minute . . . Maybe I'm stuck thinking in Scirocco mode, which really didn't go much faster between the top of the Esses and the Inner Loop kink. Sounds like the 4.23 could still be too much (i.e., like you running an imaginary 4.70). Think you'd run out of gear there if you were using a 4.70 (i.e., do you think you're over 6800 at the end of the Back Straight with current gearing)?

[Eagle7]

Don't forget tire size.

[Greg Amy]

225/45-15 for me...

[Eric Parham]

225/45-15 for me...[/b]

Dang MacStruts. That's my plan too.

[evanwebb]

According to Bildon a 4.24 is OK at WGI in his ITS Corrado...

[Eric Parham]

Thanks :happy204:

[Bill Miller]

Eric,

Talk to Matt Yipp, he runs a 4.20 in his ITA 16v car, and he runs at The Glen. You may not run out of gear w/ it but you have to look at where you are in the power band for your motor. Without doing any testing, my gut would be to go w/ the 3.94 for someplace like The Glen. For sure at Road America (maybe even a 3.67).

[JamesB]

VR6 powerband is nothing like a 16v. But the 4.2 should still work well. I would shoot an e-mail to bildon.