4l80e swap on a 98 z28 camaro
100% correct. But you really don't need overdrive unless you want every mile possible from your gas. A th400 can be built to handle the same power, is lighter, usually cheaper, and easy to tune (not electronically controlled) Back in the day, th400's were in chevelles, el caminos, impalas, camaros, heavy and light duty trucks, etc. and everyone drove them. no overdrive. I drive mine on the highway w/ a 3600 stall converter and it's great. Very fun on the street

mark jr.
The Best V8 Stories One Small Block at Time
I'm really curious how you have determined that the 4L85E uses so much power?
Where does the power go?
I've seen this mentioned on this site numerous times and I think it is time to dispel the myth.
What makes one transmission consume more power than another (theoretically)?
How many people have actually done a swap and tested the power consumption vie dyno or ET (preferably ET)?
I think most of the people making this statement wouldn't know if they were looking at a 4L60E or a 4L80E, have not done ANY testing, and are just regurgitating some BS they heard or read elsewhere.

Where does the power go?
I've seen this mentioned on this site numerous times and I think it is time to dispel the myth.
What makes one transmission consume more power than another (theoretically)?
How many people have actually done a swap and tested the power consumption vie dyno or ET (preferably ET)?
I think most of the people making this statement wouldn't know if they were looking at a 4L60E or a 4L80E, have not done ANY testing, and are just regurgitating some BS they heard or read elsewhere.
I'm guessing you are saying you engine dyno'd the combo, then put it in the car with the 4L85.
What other trans did you compare it to?
You are going to have a considerable power loss from dyno conditions (ideal with little or no accessories) to in the chassis running less than ideal conditions, a trans, a rear diff, etc. You have no way of knowing what was consuming the most power.
The pump in a 4L80/85E isn't going to consume much more power than a TH400, maybe slightly more than a 4L60E.
The internals aren't going to consume much power on a chassis dyno, the converter maybe. Hopefully you aren't running a stock converter?
Yes the internals are heavier than a 4L60E but the additional rotating mass will only consume more power when being accelerated (or decelerated). Steady state speed the only difference is parasitic loss (pump, driving through clutches or bands, friction at the bushings and thrust surfaces).
I've done quite a bit of transmission testing in car, some vey consistant bracket cars, and I've done back to back tests with TH350s-TH400s with the same converter and never seen the "power loss" so many claim in that case, cars turn the same ET's and MPH.
We've even done a Th400-4L80E swap and ordered the converter from the same vendor to match the 400 converter, same flash, and that car is actually faster with the 4L80E than it was with the 40 lb lighter TH400.
Greater rotating weight theoretically takes more power to accelerate, but the weight difference isn't as critical as the rate of acceleration.
In a 10 second car or slower, the transmission you choose is not important based on our testing. Choose a trans based on reliability, budget, fitment, but all the BS that gets tossed around about "X" transmission consumes way more power than "Y" transmission is pretty much just that.
Your converter selection is much more critical.
if i do a comp swap will i gain any more HP using a 99-02 computer?
is it worth the extra money? considered changing comp. a couple weeks ago and was gonna buy a new one but no auto parts here could get one for 99-02 or a 98. i dont know whats up with that, says that they can get them until they order it from warehouse with the warehouse showing none. and this was 4 diff auto part stores. not even the Chevrolet place could get them so im stuck for now with the 98.
thanks guys for the help but now we are gettin to the nitty gritty on how to set this 4l80 up. so its streetable and affordable. the computer tci controller and the tune could reach over 1400 bucks! so im ready to back up and punt again.
appreciate it all
I'm guessing you are saying you engine dyno'd the combo, then put it in the car with the 4L85.
What other trans did you compare it to?
You are going to have a considerable power loss from dyno conditions (ideal with little or no accessories) to in the chassis running less than ideal conditions, a trans, a rear diff, etc. You have no way of knowing what was consuming the most power.
The pump in a 4L80/85E isn't going to consume much more power than a TH400, maybe slightly more than a 4L60E.
The internals aren't going to consume much power on a chassis dyno, the converter maybe. Hopefully you aren't running a stock converter?
Yes the internals are heavier than a 4L60E but the additional rotating mass will only consume more power when being accelerated (or decelerated). Steady state speed the only difference is parasitic loss (pump, driving through clutches or bands, friction at the bushings and thrust surfaces).
I've done quite a bit of transmission testing in car, some vey consistant bracket cars, and I've done back to back tests with TH350s-TH400s with the same converter and never seen the "power loss" so many claim in that case, cars turn the same ET's and MPH.
We've even done a Th400-4L80E swap and ordered the converter from the same vendor to match the 400 converter, same flash, and that car is actually faster with the 4L80E than it was with the 40 lb lighter TH400.
Greater rotating weight theoretically takes more power to accelerate, but the weight difference isn't as critical as the rate of acceleration.
In a 10 second car or slower, the transmission you choose is not important based on our testing. Choose a trans based on reliability, budget, fitment, but all the BS that gets tossed around about "X" transmission consumes way more power than "Y" transmission is pretty much just that.
Your converter selection is much more critical.






c ome on guys ready to drive!!! ok,4l80e it is. 2003 with 8 thousand miles on it.if it robs hp, so be it, atleast it wont blow the tires off as bad!!
and it will hopefully be strong enough. can someone read my post above and tell me which way to go please.
thanks guys,,, herehrc....
Last edited by alyssa18sue; Sep 3, 2009 at 10:10 PM.






