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S197 Rear gear question 355 vs 373

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steveespo

Lord knows I'm a Voodoo Child
Moderator
4,116
2,257
Exp. Type
W2W Racing
Exp. Level
10-20 Years
Cookeville TN
Steve, he has a 2014 V6 manual, so it should be an MT82.
3.55 gears he would have top speed of 130 mph at 6000 rpm, 3.73 Top speed of 123.5 at 6000. 3.73 would work better if the car can carry 6300 as gears 2-4 are taller (lower numerically) than a V8 MT-82. 3.73 would give better acceleration, 130 is about the top end for a mild V6 on most tracks like VIR, Road Atlanta, Watkins Glen.
 
65
68
Exp. Type
HPDE
Exp. Level
Under 3 Years
The Central Valley of California
With some math, you can take your track tire circumference and calculate mph at redline in 3rd and 4th gear (or 2nd gear for autocross), and also your street tire circumference and rpm at highway cruising mph. If you have a track you run at most of the time, take your apex mph for the 2 or 3 most important corners (leading to long straights / passing zones) and calculate what rpm you'd be at with each gearing - is it a good range for drive off the corner, or are you either bogging or nearly at redline?
This is hurting my brain. I am dumb driver I see corner, I try apex.
I am beginning to think I should stay 3.15s until I learn how to drive faster.
 
85
95
Exp. Type
HPDE
Exp. Level
3-5 Years
Stockton, CA
My situation is a bit different running a 3v with TR3650 but I'll share my experience going from 3.55 to 3.73. The car accelerates faster coming off slow corners but power flattens out quicker toward the end of the straights. A definite negative I experienced was higher oil, trans, and coolant temps since my avg. rpm was increased at every track I run. In my opinion, unless you're modifying your engine to raise the power band, which is what I intend to do, I would stick with 3.55.
 
65
68
Exp. Type
HPDE
Exp. Level
Under 3 Years
The Central Valley of California
My situation is a bit different running a 3v with TR3650 but I'll share my experience going from 3.55 to 3.73. The car accelerates faster coming off slow corners but power flattens out quicker toward the end of the straights. A definite negative I experienced was higher oil, trans, and coolant temps since my avg. rpm was increased at every track I run. In my opinion, unless you're modifying your engine to raise the power band, which is what I intend to do, I would stick with 3.55.
3v is the closest I can find to good info for me...kind of the only person I know of going to build a Time Trial S550 V6....so your input is extremely valuable!

Later on I will be building this engine full NA...maybe stroker 4.0 kit even...

But that is once she is no longer street-able (unlikely) or I move out of Commiefornia. So 3.55 might be my ticket, as there are V6 diffs with those gears from factory...

What is the (your) 3 valve's max rpm/powerband? I will dyno my car someday soon to get some more data.
 

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