dman535

Given that I have the ability to make power that high, I was just curious as to the life expectancy of my trans at that RPM. What are the factors that appeft high rom performance on these transmissions ?

page62

Try it...and let the rest of us know! :D

GrandSportC3

What does the RPM have to do with that??? It's all about torque and traction.. On street tires - you wouldn't have to worry about anything because the tires break lose before breaking anything...

Let's assume that you run slicks and your peak torque is at 3500 RPM..

For example - if you shift from 1 - 2 at 6000 RPM and the RPM drops to 3500 RPM after the shift - this shift would be more violent than shifting at 6500 because the RPM would only fall let's say to 3800 RPM which in this case would be past peak torque...

With other words - if you shift so that your RPM drops to the RPM where you have most torque - this would be the most violent shift for the transmission..

jdunne

Mine does behind a strong 383 in my 74R.......I REGULARLY hit on or slightly over 6500 on 1-2 shifts and on 2-3 shifts and irregularly on 3-4 shifts.....given i have a 3.08 diff those are some significant speeds..6500=55mph in #1,6500rpm =104mph in#2 & 6500rpm =170mph in #3...very irreg on 3-4 shift for obvious reasons....the 700R4 has been substantially upgraded and works very well......left in drive it shifts under hard accel at about 5800 rpm.....john :seeya


[Modified by jdunne, 6:16 PM 4/26/2004]

GrandSportC3

I'm actually going to have a TH700R4 built to 800 HP with transbrake and fully manual valvebody... I'm going to run a 4500 - 5000 RPM stall converter in that transmission...

Jasonty

I drop the 6500 rpm shifts in my 383 with a Turbo 350... No problems yet, but my tranny is built up pretty good...

jdunne

jason,the o/drive is fantastic on the open highway and at a recent track day i drove the whole circuit in second gear and just let the torque work its magic.....john :seeya

gkull

GrandSportC3 - When you order your racing 700R4 full manual make sure and get the billet 13 vane pump. they are the new hot thing that keeps the pump from cavitating at high rpm.

I personally would not use a full ever again. I tried and the 700r4 first gear is so low that it was hard to consistantly shift with my 4.11 rearend. Request the govenor of your choice. I own two a 6800 rpm everytime and a 5000 for street driving.


[Modified by gkull, 12:58 PM 4/26/2004]

dman535

I was under the impression that the 700r4 was developed in an era that did give thought to high rpm readlines. I has a front pump go on me once, was just curious if the 700r4 had RPM limitations based upon is early 80's sub 5500 rpm roots.

The Money Pit

I toasted mine the first time I tried a 6500 rpm shift.Took out the 2/3 clutches.I have 10" tires and 500lbs of tq. ,both of which will add stress to the transmission.This weekend I managed to smoke the first three gears without a problem,so maybe it'll take some abuse.I never came close to 6500 rpms this time though.Just left it in Drive and matted the pedal. :D

gkull

If it's any consolation. I have not installed the billet 13 pump yet and I have done 2-3 and 3-4 shifts at 7500 rpm. The 2-3 @90 mph or so spins the tires.

IMO - Trannies aren't RPM limited. I'm talking about sub 8500 rpm. They are mechanically limited as to what stresses they can handle. Which is a TQ/HP factor.

The money pit blowing his the first time he shifted at 6500 rpm is a no brainer :jester

Just think of what your doing to everything from the motor to the tires. Your spinning 6500 rpm and instantly the motor is told to told that it can only go 3500 rpm. Something has to give.

If your tires don't spin, your U-joints don't break, your rear end doesn't blow, your driveline doesn't rip apart, and your crankshaft and torque converter didn't break - It has to be the tranny - Somethings got to give.