6l80/90

[SPDMETL]

Is anyone making a standalone controller for these yet? Seems like this trans would open up new options in rearend gears and other things

[Nothingface5384]

I'd also like to know cause i'd definatly get someone to fab up a bellhousing adapter to fit behind a BOP motor!
unlike an AA80E 8 speed auto this trans can be builtup to handle major torque

[SPDMETL]

Everything I've read about these makes it sound like this is the latter-day T-400

[laguna4efi]

We are currently working on a standalone controller for these transmissions but they're not as ideal as most people think unfortunately. This trans won't live very long without some type of torque management and the biggest drawback is the size. It is significantly larger than the 4L80E trans, especially if you look at the centerline of the output shaft to the bottom of the pan. It may cause issues with tunnel clearance but also driveline angle more than anything. By the time you raise the trans enough to get ground clearance the driveline angle is pretty extreme. I could be wrong or there could be a version that I haven't seen but the ones we've been working with aren't very rodder friendly.

[SPDMETL]

Thanks for the answer. I've seen in GMHTP where People are putting fairly impressive power through these. Is the 6L90 bigger?

[Hambone!]

We are currently working on a standalone controller for these transmissions but they're not as ideal as most people think unfortunately. This trans won't live very long without some type of torque management and the biggest drawback is the size. It is significantly larger than the 4L80E trans, especially if you look at the centerline of the output shaft to the bottom of the pan. It may cause issues with tunnel clearance but also driveline angle more than anything. By the time you raise the trans enough to get ground clearance the driveline angle is pretty extreme. I could be wrong or there could be a version that I haven't seen but the ones we've been working with aren't very rodder friendly.

I just have to ask how far along you've come with this. The reason is, that as far as I know, in order to use this trans, a drive by wire throttle is required. That, coupled with an RPM limitation of a drum cage that can come apart and its size have stopped me from using the one I've got. Also, isn't this more suited for a vehicle making less than 600HP or so?

[Poorhousenext]

Thanks for the answer. I've seen in GMHTP where People are putting fairly impressive power through these. Is the 6L90 bigger?

The 6L90E is a little longer and beefier.

Both transmission in stock form do not last long, and lack of knowledgable tuners with any knowledge of how to tune them to last are few and far between. Standard tuning practices used on 4A don't work.

Both transmissions have pan to ground clearance issue when installed in older cars, and you'll want to look into a GTO 6L80 pan for the 6L80 to get a little more ground clearance. 6L90E does not have a shallow pan, so most modify the GTO 6L80 pan when installing one. Most likely you want be slamming your car with one.

Gear ratio wise, you can see 6L's are designed for gas mileage first and performance second, it has the best close ratio gearing in GM's automatic catagory. You can see GM changed the gear ratios to try and keep them from downshifting/hunting gears so much. No 1:1 gear, so choose your rear gear ratio carefully, are you'll find you top speed limited in 4th gear compared to an A4 or Manual. Also need to gear to weight of car, as GM did with the G8 Pontiac, 3.27 with A6, 3.70 with manual, and in all the mag test the A6 was 0.2th quicker in the 1/4 mile.

Early 6L80/90 ratio's thru 2010 = 4.03, 2.36, 1.53, 1.15, 0.85 & 0.67.
Late 6L80/90 ratio's 2011 & up = 4.0, 2.4, 1.5, 1.2, 0.90, & 0.70

6L80/90
4.03
2.36 -- 58.56% (high) RPM Retention 41.44% RPM DROP
1.53 -- 64.83% (high) RPM Retention 35.17% RPM DROP
1.15 -- 75.16% (high) RPM Retention 24.84% RPM DROP
0.852 -- 74.09% (high) RPM Retention 25.91% RPM DROP












Now I'll throw in the other A6 transmission you might want to look at. Want beat the 6L80 in 60' foot time, but does beat it in 0-60 mph. The 6L's 1st to 2nd RPM drop is the reason for that. They are almost dead even in 1/4 time when modeled. It's TCI's 6X close ratio 6 speed transmission. Hold 850 HP as shipped and 1000-1200 with modifications by TCI.

Gear ratio's: 2.93, 2.23, 1.57, 1.18, 1.00, 0.75. 6X's 2nd - 5th gear ratio's are almost identical to a 4 or 5 speed close ratio manual transmission 1st - 4th gears, but with it's 2.93 1st gear gets you off the line better. Even a 3.54 rear gear will give you a 4.19 4th gear ratio for the strip. Better trans if you are going to try and autocross car due to it gear ratio's.

Also easier to install in most cars since it's 4L80 based and aftermarket supports them, where with the 6L80/90E you are on your own, for the most part.

TCI 6X (4L80E based)
2.93
2.23 -- 76.10% (high) RPM Retention -- 23.90% RPM DROP
1.57 -- 70.40% (high) RPM Retention -- 29.60% RPM DROP
1.18 -- 75.16% (high) RPM Retention -- 24.84% RPM DROP
1.00 -- 84.745% (high) RPM Retention -- 15.255% RPM DROP
0.75 -- 75.00% (high) RPM Retention -- 25.00% RPM DROP

My 6L80E car.



My TCI 6X car.



For best source of information on 6L80/90, you might want to go to LS1TECH site and search in both Automatic Forum and Conversions & Hybrids Forum.

[laguna4efi]

We've been bench testing it for quite some time now. Our driveability test vehicle is almost finished and we'll move on to that stage soon. We've put an LS2 and 6T75E transaxle into a Fiero GT chassis. Should make the testing fun and interesting. I would agree with Jere on many of his points above. TCI does make a 6 speed out of a 4L80E and it is a much better choice than the 6L transmission family. Others are coming out with 6 speeds also and the more there are the better they all get as development always goes. Bowler has been testing with us on a version of a 6 speed 4L80E with great results as well as Hughes is rumored to enter the 6 speed market very soon also and they've made a tail housing that has a gear driven speedo drive to make using your factory speedometer much easier. It's available now in their 4L80E transmissions. There are some great things happening in the transmission world and we'll all benefit from them in the long run with better fuel mileage and much better driveability.

[SPDMETL]

I did find this while poking around the 454 LSX crate engines

http://www.mastmotorsports.com/2010/...w.php?cat=M-90 Components&id=44