EdwardETraylorIII

Hello,

I'm building a 2,000 + HP C5 and am trying to figure out which transmission to install and how it will fit.

1. What are the issues, as far as fitment, when installing a 4L80E?

2. Can a built 6L80E handle obscene power like a built 4L80E can?

3. are the outer dimensions of the 6L80E going to be similar to a 4L80E or is it going to be even more of a PITA to make the 6L80 fit?

I already have a PCM that will control the transmission, so that isn't an issue.

4. Can you think of any other gotchas I'll encounter while trying to install one of these transmissions into a C5 that started at as a manual?

Furthermore, if you have any experience with rear-ends (think: cars, guys!!!) then please let me know what you think about a 12 bolt?
Can I keep the stock rear end and expect any type of life if I turn the boost down and am only making around 1,200-1,300 HP? Is a 12 bolt a must? I surely do hate to fork up the handling on this thing with a 12 bolt. I want it to be a daily driver as well as a weekend warrior.

Thanks in advnace for your input!

ChipN

Just curious, what do you need to do to get one of these engines up to 2,000 HP?

Lovin It!!! - C5

The 4L80 is much larger than a 4L60 and is definitely not gonna fit without a huge investment in reworking the tunnel (which is the backbone of the car) not good.

The 6L80 is a more viable prospect, but if you wait till next year you can get a 6L90 instead. Its the tranny planned for the Corvette SS with a 700+HP 6.0 motor. LS9 I believe.

At 2000 horses, I'm real interested in what you'll do for a rear-end. Especially if your planning to drag race. The case is prone to cracking under heavy side-loading of the pinion. I've never heard of anyone making one last at the power your planning. Better plan on buying a few. DTE can make them stronger, but 2,000 is a huge leap.

Good Luck, sounds like a heck of a project.

mdhmi

4L80 wont fit and wouldn't be a good fit for your hp level anyway. Get a power glide and back half that baby. Are you trying to build a 5 or 6 second drag car?

Mark

Face

You're going to need to backhalf the car and install a T400 and 12 bolt or 9" rear.

mdhmi

2,000 HP and "street car" doesn't work, unless you're taking about towing your 2,000 HP car with your daily driver.

What type of 1/4 mile times did you have in mind and what power adder were you thinking of?

Mark

EdwardETraylorIII

Thanks for so much interest in my project.

The car is going to be a streetable 2,000 HP C5. I'm going with a hydraulic roller for streetability. 160# Injectors controlled by a Big Stuff 3 Fuel Management system. It's a World Castings "Warhawk" block - for those unfamiliar, that is a 454 aluminum block built to handle serious power. Needless to say, all forged internals going in. I have two 76mm turbo's that I'm fabbing up on the car.

The rear-end will be a 12-bolt or possibly a 9". I haven't yet made that determination. Either of those should hold the level of power I'm talking about.

So, from the few responses I've gotten, the 4L80E is a real PITA to install in one of our cars. Has anyone here tried this and made the necessary modifications? Did it seriously weaken the structural rigidity/frame by removing material from the torque tube tunnel area? How much material was removed? Any tips?

Someone inquired about my ET goals - I see no reason this car shouldn't run in the 8's on pump gas once it's tuned properly and the suspension is set up properly for the track and hopefully hit some 7's on good gas.

I base those numbers on weight, proper gearing, good traction, and 1,100-1,200 RWHP on pump gas and around 1,500-1,600 on race gas. Anyone have any better insight on my projections? Sound reasonable to you?

Back to the tranny woes... One person mentioned that a 4L80E wouldn't hold the type of power I'm trying to achieve. I beg to differ. a 4L80E is basically the same transmission as a TH400 but with overdrive.

Now, a 4L60E I would agree with you. Not strong enough. 4L80E? I think it has plenty of potential to handle this level of power. Please educate me if I'm wrong. I'm ALL ears!

EdwardETraylorIII

I believe I should have posted this in the forced induction/nitrous area. I'm copying it and opening the same thread over there. Hope you guys will keep posting!