4l80e overdrive
04-06-2007 | 10:40 AM
#11
Unlocked, with a converter efficiency of 95% (5% slip), you would need to shift at or above 6400 rpms to avoid 4th gear. What is your power band, that would REALLY help to answer your question though. 
You could step up to 3.73s and spin the engine to 5900 and trap 125 MPH. Many ways to skin a cat, but one variable is missing (peak power rpm).
You could step up to 3.73s and spin the engine to 5900 and trap 125 MPH. Many ways to skin a cat, but one variable is missing (peak power rpm).
04-07-2007 | 11:20 PM
#13
I posted a video in the multimedia section this afternoon. The first clip in the video is a punch from 70 to 110mph. (Driving on a curve too.) There is a 3-4 shift in between. This is a 4L80-E with STOCK overdrive clutches, a Transgo shift kit, zero torque management, 10.5" converter run by a TCI stand-alone controller. It's probably shifting nearly 700ft-lbs in this video and a 4L80-E can do this dozens of times every day over and over again. Mine does.
http://bertok.us/pics/9psi-wot.mpg
http://bertok.us/pics/9psi-wot.mpg
04-07-2007 | 11:46 PM
#14
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Originally Posted by 12secSS
Unlocked, with a converter efficiency of 95% (5% slip), you would need to shift at or above 6400 rpms to avoid 4th gear. What is your power band, that would REALLY help to answer your question though. You could step up to 3.73s and spin the engine to 5900 and trap 125 MPH. Many ways to skin a cat, but one variable is missing (peak power rpm).
You could step up to 3.73s and spin the engine to 5900 and trap 125 MPH. Many ways to skin a cat, but one variable is missing (peak power rpm).
04-07-2007 | 11:48 PM
#15
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Originally Posted by James B.
The 4L80-E can tollerate a WOT 3-4 shift. There is a set of Raybestos Blue-Plate special clutches available for the 4L80-E fouth pack. Not sure if you've ever seen a 4L80-E overdrive setup, the clutches are so large in diameter you could slide the entire geartrain from a 4L60-E right through the center. Also, the 4L80-E overdrive has its own dedicated planetary and roller clutch - these components are heavy and strong. There are only four clutch discs in the overdrive pack but the large diameter seems to get the job done.
The 3-4 shift in a 4L80-E is softer than the 1-2 and 2-3 shifts. You can compensate by drilling out the feed hole in the separator plate larger. For example, if you have a TransGo shift kit in it, drill hole "A" out the next stage larger than the other two.
I have done countless WOT 3-4 shifts on a 4L80-E with stock type fourth clutches and have never experienced any hesitation or unpredictable behavior.
Best of all, if you do smoke those clutches, replacing them is simple since they're so easy to get to - right after the front pump.
The 3-4 shift in a 4L80-E is softer than the 1-2 and 2-3 shifts. You can compensate by drilling out the feed hole in the separator plate larger. For example, if you have a TransGo shift kit in it, drill hole "A" out the next stage larger than the other two.
I have done countless WOT 3-4 shifts on a 4L80-E with stock type fourth clutches and have never experienced any hesitation or unpredictable behavior.
Best of all, if you do smoke those clutches, replacing them is simple since they're so easy to get to - right after the front pump.
04-07-2007 | 11:54 PM
#16
I know with my 4L80 and 4.10's on a 32" tire I can pull third out to 6000rpm and I am doing 150mph. It was 158 when I had 3.73's. I havent ever gone over that on the street or dyno or let it shift into 4th, but at those speeds I really didnt want to.
04-10-2007 | 12:10 PM
#17
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From: Behind the TIG welder
Originally Posted by TurboBerserker
With the turbo, he'll likely lock up the converter
Good info about the 4l80e and over drive there James B.
Why only 28 inch tall tires Turbo8? Are you planing on slicks,et/street or something?
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