Taller 5th gear

a320 · 04:43 PM

Anyone ever install a taller fifth gear for highway driving(80sc, 3.0, heads p/p, 964 cams, new p/s, ssi, 915 trans). Reduce engine noise? Increase milage? Any thoughts?

Thanks

TimT · 05-04-2013, 04:36 PM

Your question has to many variables....

What transmission do you want to put a taller 5th into?

What engine? displacement?

What year car?

Etc..

a320 · 04:46 PM

Thanks Tim

(80sc, 3.0, heads p/p, 964 cams, new p/s, ssi, 915 trans).

Phil

spuggy · 05-05-2013, 11:58 AM

Yes, I've done it on a 915 combination, had a 38:29 5th in that. And about to use a 31:41 (G50/50 5th) into a G50/01 for the same reason (much cheaper than an Albins 10:1 CWP, which would be the "best" way to do it - stretches ALL the gears, not just 5th).

It's great for "real" driving; leaves you the lower gears for squirting it (e.g. merging, passing) and then you shift into a tall gear for a relaxed cruise. Seem to remember 80-85 indicated was 2600-2800 RPM on the tach for the 38:29.

With a 3.0, you'd have to shift down to accelerate - but you probably would anyway. Yes, you'll likely accelerate slower from the top of 4th (120MPH or so) to maximum speed (probably aero-limited by horse power). I didn't consider that a problem.

At one time, I ran a tall 2nd as well as a tall 5th. Gave you 1st for moving around in traffic, 2-3-4 close ratio and a tall 5th for cruise. Works great, if you can pull the 2nd without it being an issue - e.g. due to RPM drop.