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silverlock silverlock is online now
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Join Date: Aug 2023
Location: New York City
Posts: 398
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Quote:
Originally Posted by Bill Verburg View Post
It would be informative to use the engine torque curve as an input

also what rear tires? That affects the speeds.

from what you posted
opt 1 has drops of
42% 25% 19% 33%
which outs you @ x in the next gear when shifted at 7500
x: 3918 5122 5540 4585


opt2 has drops of
42% 25% 19% 33%
which outs you @ x in the next gear when shifted at 7500
x: 4557 5357 6110 5057

using the torque curve for an input allows for this sort of comparison where you can easily se that 3-5 are a bit too short
Good points!

Tire size is in the linked calculators - 225/50R16 / 24.9” dia (based on the RE71RS’ I’m running)

I don’t have an up-to-date dyno chart on this engine but an almost identical build (3.4 not 3.2) looks like this w/ 993SS cams and similar intake/exhaust/TB/porting mods - the blue line here:



Shift point here is much more ideal at 6.5-6.8k, not 7.5k. 3.2SS/3.4SS just can’t breathe enough to make any real power > 7k. 4.5k+ RPM on the torque curve is where I want to be, which also matches my experience here. Shifting into 3rd at (e.g.) 6.5k drops you down to 4.3k, right below where you want to be.

When you say 3-5 are a bit too short: expand? Which option?
__________________
1978 911 SC (3.2SS, EFI, 993SS cams + the trimmings)
Dynamic Comp Ratio calc: https://dcr.questionable.services/ • Gearset & Ratio calc: https://ratio.questionable.services/

Last edited by silverlock; 11-24-2025 at 01:19 PM..
Old 11-24-2025, 12:53 PM
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