Out with the 6L80, in with the 6L90!

[IDRIVEAG8GT]

Hey everyone! Robbie here. I have an 08 Pontiac G8 GT that will be the test mule for this thing. As some of you may know there has been several threads strewn across the internet of people starting to attempt this particular swap, but every one of them came to a dead end, or guys decided to go with a different transmission. I am in a predicament now where I HAVE to do this swap from start to finish, and I figured all you guys would really like to know what all has to be done. The nice thing about this is that I own RHX Tuning here in Roswell so I will be able to inform everyone of what it takes not only to physically install the transmission, but also the amount of tuning that it takes to make it perform correctly. So here's the skinny;

I broke the transmission a few weeks ago, and I am in no way dissing the 6L80E. It handled over 600WHP for over 40,000 miles, so I am a happy camper. Recently I started doing a little bit of business with LMR, and I got offered up a deal that I absolutely could not refuse on a brand new Century built 6L90E that was initially going to be utilized in a Cadillac CTS-V. Knowing this transmission would still be able to offer me all the features that the 6L80E had, including TUTD, a 12 month/12,000 mile warranty, and the capability to handle in excess of 1000ft lbs of input torque in a 4000 lb car it was right up my alley. Not to mention I have a tight budget that it fit in, so it's on it's way.

Along with the transmission I will be installing a Reactor products SFI rated machined aluminum flexplate, ARP hardware, and a 9 1/2 inch FTI 3200 stall converter. Greg and I talked long and hard about building a converter that would have a small enough stator to allow excellent in gear idle quality for my reasonably sized cam, allowing it to make maximum vacuum and couple hard under boost. It has a pretty good sized pump, and is a small triple disk setup so that I can lock it up under WOT for high speed runs in Mexico or whatever. Driveshaft will most like be a slip yoke style handled by 1320 or DSS. Not sure yet, and the crossmember I will figure out as I go.

The engine will also receive an ATI Super Dampner and it'll come out for a short time because I need to address some pesky ass oil leaks.

Anyways I will be posting pictures of everything that happens during the swap. It may be after the turn of the year due to another project that is getting finished up, but I'm so excited about this I couldn't contain myself any longer.

Cheers!

[IDRIVEAG8GT]

Forgot to mention, that after finishing the project I will be posting up the tune as well for everyone's viewing pleasure.

[rocket69GTP]

Interested in seeing this as it would be another good auto option for a G8.

[gr8lover]

Good luck with it---- should be an easy mod!!!

I put a prototype 6L90 in my car back a bunch a years ago..... (actually 1st 6L90 made in Toledo...hand built by me and my crew... ). i did it just for fitment purposes and had to return it back to the plant cause it had to be scrapped... .... fit real good and no issues in my tunnel or anything....

good luck and I am sure you will enjoy it..

[Slizzo]

I think the case length is an inch or few longer on the 6L90E, so you'll probably need a custom driveshaft.

Otherwise, will be great to hear and see progress on this!

[G8GT721]

Hope this works out for you, is the 6L90 that much stronger? The 1000ftlb is not listed/stated on century's site


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[IDRIVEAG8GT]

Good luck with it---- should be an easy mod!!!

I put a prototype 6L90 in my car back a bunch a years ago..... (actually 1st 6L90 made in Toledo...hand built by me and my crew... ). i did it just for fitment purposes and had to return it back to the plant cause it had to be scrapped... .... fit real good and no issues in my tunnel or anything....

good luck and I am sure you will enjoy it..

Right, you originally got me started on this as I read your thread from awhile back. No one has actually completed the swap on a G8 yet, but there has been one on a Camaro

I really really didn't want to lose any features so I figured this would be the best way to go. And thank you for your info in the past. Put my mind at ease a little when I was trying to justify clearances in my head. I'm sorry to hear that. I always wondered what happened to that thread and/or why you went with a different transmission.

[IDRIVEAG8GT]

I think the case length is an inch or few longer on the 6L90E, so you'll probably need a custom driveshaft.

Otherwise, will be great to hear and see progress on this!

Correct, which is no sweat at all.

Hope this works out for you, is the 6L90 that much stronger? The 1000ftlb is not listed/stated on century's site


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Not only have a few stock 6L90's taken CTS-V's into the low 10's with good tuning, they shift faster, and run cooler. This one is the highest level 6L90 build Century offers. They usually say that a transmission will handle 1200 horsepower or something like that, but I don't care for ratings done that way. It's initial torque that breaks parts and LMR states this trans will hold over 1000 lb/ft of input torque, as do the guys at Century. I had to call to get that information though.

What made the happiest was the warranty.

[matts88yj]

Can't wait to see this come together! Going to be following this closely since a 408-418 with two snails are finding their way under the hood.

[IDRIVEAG8GT]

One of these days..... One of these days Matt. I just want a single Borg Warner S500X with a 4" downpipe out the hood. lmao.