I have been hearing people mention, or read things about people saying that putting an 80e behind a 5.3/4.8, you will have quite a bit of power loss because of how big and beefy the transmission is. I plan on putting in an sts at the beginning of the new year and just using my stock internals until I can get the money for a good turbo cam. Can anyone explain to me why there is a power loss, or if there is any at all?

thanks,
david

 

Part of it is that there is some more power loss through it then the 60e because the parts are just bigger which takes more power to turn obviously. The big killer with the 80e is the shitty first gear ratio. 2.48 as opposed to the 3.06 of the 60e. Basically the difference between a stock converter and a 3K stall is what I would compare it to. The 80e sucked big time with my old baby cammed 420, maybe with a 3200ish stall it would have been alot better.

 

The hugher 1st and 2ng gears mak eteh 89e FEEL like it loses moe power than it does. its only 2-3% less effecient tan the 60e.

But way better for drag racing IMO.
peace
Hog

 

I've got the 80e with my setup and i like it.
You will get used to it after a while and its well worth the money spent.

 

The 4L80-E has three planetary gear sets inside and a center support and shaft. The 60 has no such center support - everything is supported by the tailshaft and the input shaft through the pump, and the 60 only has two planetary gear sets, fewer bushings, fewer clutches, less value.

I wish you could see a photo of a 4L60-E planetary next to 4L80-E overdrive planetary side by side. Quite a difference. Perhaps someone with these parts laying around could make it so....

 

The only thing I noticed was the closer gear ratio, which is awesome. Sure first is a bit taller but trust me, the turbo won't mind the load. Expect to see boost come on a bit sooner. The only true down fall is the shorter od. You'll be happy with it though.

 

How well does it fair on the freeway as far as like 60 rolls or the upper gearing?

 

As far as the overdrive ratio goes, if you have 30" tires and 3.73 gears for example, you would be used to 2200RPM at 75MPH with the 4L60-E.
With a 4L80-E with those same tires and gears at the same 75MPH, RPM would be 2350.

So, figure that on the freeway you can expect engine RPM to be 7.14% higher with a 4L80-E. This 7.14% is the difference between the 0.70:1 overdrive ratio of the 4L60-E versus the 0.75:1 overdrive ratio of the 4L80-E.

It's not much of a difference.

Many people complain about the shallower first and second gears of the 4L80-E but keep in mind that these ratios are identical to a TH400, and that has no overdrive. Because the ratios are closer together you get a lot less RPM drop with each shift. Even with a stock converter the 4L80-E will not cause the engine to fall flat on its face in power after the 1-2 shift the way a 4L60-E does. The 4L60-E has this problem because that gear ratios are far apart - too far in my opinion. The overall gear range of the 4L60-E would be a better suited to five speeds instead of 4. (Ironically, the combination of a 4L80-E and Gear Vendors Overdrive provides exactly that.)

 

I agree, the 4l80 does not need a loose torque converter, I can post up some scans of my 4l80 and a stock converter at the first second shift.

 

Just checked my logs from my 11.x runs. I shifted first to second at 5400 rpm, the rpm droped to 4550, then I shifted second to third at 5550, at which point the rpm droped to 4278, keep in mind I lock my converter as soon as I hit second gear an it stays lock threw the shift, but with some slip......