Jordan927

iTrader: (1)

Guys on HP tuners are running 650rwhp in G8's with no issues....

I don't know..I think 500 in a truck should be fine.

They make red alto clutches for them now

I dont know how much more stout a 90 is over an 80

rjwz28

There are also a couple vettes on built 6L80s running over 800 to the tires. With a rebuild and a smart setup, I don't see 500 being a problem for the trans in our trucks.

Lucille

I also see posts about these vette guys having to rebuild every 30-50 runs. Not to mention how many of us are going to stop at 500 on our trucks?

Not to thread jack but how do you like the new Goodyears?

Jordan927

iTrader: (1)

One dude over on HP just ran his 1062nd race last Sunday on a stock 6L80E, 3200 stall, no TM, max line pressure, and pushing about 650 at the rear wheels.

Also, the truck isn't going to hook up near as hard, unless you pop slicks and a 5 link in.

rjwz28

No complaints whatsoever on the Duratracs, however, I've yet to drive on them in any sort of inclement weather. They are rated for severe weather conditions, so I doubt that will be a problem. I spent a few hours on rocky desert trails with them with no issues. They seem more aggressive than my BFG A/Ts were, but without the on-road compromises of the mud tires on the market. As a reference, I drive on Dynapro MTs, Destination MTs, and MT/Rs on a regular basis, so I've got a pretty solid basis for my opinion.

rjwz28

Back on topic, the cars I saw running 800+ rwhp to a built 6L80E were built primarily for street use, but were run for fun on a sticky tires occasionally. If your truck is putting down upwards of 600rwhp and you intend to make passes at the drag strip regularly, I can see the 6L80E as something you may want to swap out. Otherwise, I believe you should be able to build it to handle your truck.

Jordan927

iTrader: (1)

Yeah, I'm pretty sure your getting to its limits at around 600whp in a truck...unless you have a SCSB...and even than you'd be close.

I have heard of guys that have 650whp in they're G8GT's and have over 80K miles on them with no issues...no TM, or anything. But thats a car...I would say 500whp in a truck would be absolutely fine...600 is pushing the limit.

bdubb

iTrader: (2)

I can only guess, but I should be around the mid to high 500's flywheel and have not experienced any issues with mine. This is with a AWD crew cab and heavy 22" wheels and 12.89 1/4 times. Most of the issue with the 6L80's and 90's to my understanding is the tuning. There are a few companies out there making new hard parts for the 6L80's and changing up the clutches and steels. Take a browse at the circleD website for some information on what is being done to beef them up some.

Jordan927

iTrader: (1)

No one making steels for em thats for sure...they are clutch to clutch transmissions. They also have all the "hard" hard parts...that you can get from the factory.

From what I have been reading, most failures come from having too much TM in the trans program. It is apparently trying to mimic speed matching for shifts, causing slipping, this ends up burning the clutches.

TrueBlueGTO

I'm told by Circle-D build guy that stock 6l80's have shown failure at around 500 whp in FI trucks. 6L90's stand a bit of a better chance, but as has been said many times, the key is in the tuning. I know a guy with a 550+ whp FI/NOx AWD TBSS on a factory 4L70. Circle D has a 800 whp build that they use and in addition to billet parts it adds MORE clutches that are in it of themselves stronger than factory clutches.

I, personally, plan to see the limits of the 6L90 when I beat the **** out of it in our THROWDOWN event.