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Why? What would be the benefit?
The computer/electronic complexities would be great.
The 8L90 and even the 6L80E come out of vehicles that use CAN (Car Area Network) to communicate between the BCM (Body Control Module), the ECM (Engine Control Module) and the TCM (Transmission Control Module) built into the transmission case, and all the other computers and sensors in modern cars. CAN is like the Ethernet cables that connect the computers in your house or office. The simple PCM in a Gen 4 cannot connect to a CAN bus.
You might want to talk with GM Engineering about all the sensors it uses just to tell it when to shift. From talking with them two weeks ago in Bowling Green it even uses data from Air Bag sensor. Now this is one used in the Corvette. I'm guessing the others model GM cars and trucks using it would require about all the same sensor data.
If size of the 6L80 or 6L90 was a problem for you installing one of them, the 8L's will be about the same.
I'm sure someone will do it. I might if I could get hold of a wrecked 2015 C7 Vette with good intact Torque Tube so trans mounts to rear end.
The gain is in it's gear ratios, both for performance and fuel mileage.
When you shift to 3rd with your A4 with it's 1:1 ratio with a 3.55 rear gear ratio you are at a disavantage against my 6X with a 4th gear ratio of 1.18. 3.55 X 1.18 = 4.19 ratio.
I am writing here hoping to turn this thread into a sticky on the 8l90 transmission. I have read a number of propaganda articles on the trans on a number of websites. Not a lot of confirmed details out there. I hope the following information is factual, but this is what I have found and I hope it is good information.
1. The dimensions of the unit will be the same as the 6l80. Not sure what this means.
a. Will the input and output shafts be at the same level as the 6l80.
b. Will be able to use some GM equipment on the market from the 6l80 (shallow pans, output shaft covers, etc.).
2. Per the articles, there should be an external controller for this unit. I hope this holds. Opens the door to a lot of options.
3. The Corvette mileage should be up 5 percent. This should be close to 29 mpg. Not sure how much the VVT and DOD is helping or is it all the transmission. The LT4 articles say this engine will have VVT and DOD.
4. The gear ratio spacing is a lot better. I hope over time they can improve on this or have added some flexibility.
5. The unit is to weigh about 5 to 10 lbs less than the 6l90, depending on options.
6. If you want paddle shifters, here you go.
Above, a reference was made to CAN BUS. Just say CAN Bus is my friend. Not sure if it was a negative or positive comment. May have been just a comment. The trans will run on the CAN Bus??? This is good. I hope they don’t sneak in a non-standard Low speed Bus connection like the 6l90. The internal controllers of the 6l90 also made it hard to interface and use with various engine options and other 3rd party ECU with CAN Bus.
I hope someone has started a thread on the LT4 engine and the new ECU that will be used on the Corvette. I have not looked, but will another day. These devices should be included as a sticky as well. These devices represent a milestone in GM’s plans. These products will not be 100% backwards compatible. I am hoping it will be begin a more open future for GM. I think this GM’s move to become more competitive in the racing world, Super V8’s is also pushing thei change. All the car companies want to be leaders in the racing world the play in. Not sure how this plays for Nascar or Indy. Could change some levels of drag racing.
A more open CAN Bus address plan from GM on their products would aide in integrating with other manufacturer products. Many companies publish this info on their products. Products like traction control, launch control, ABS brakes, VTT, DOD, power control modules could be added to your project. Lots of fun toys out there. I digress. My Electrical Engineering background is showing through.
I am about a year from beginning my 73 Camaro project. I have had the car since March 28, 1980. A daily driver with 185,000 years (just one bent push rod). Dated my wife in it. I will need to finish a 1951 Ford Truck project with my sun before I can begin. Current plans are for a LSA/6l90 setup. Plan to use VVT. Would like to DOD, but GM did not do a good job on the Trucks. 70,000 miles and an engine failure is not real good. Close to going with the 8l90. I have a year. I hope they do better on the new LT4 engine. The new LT4 propaganda sites say it should have both VTT and DOD. We will see.
09-06-2014, 08:40 PM
8L90E into 4th Gen? 
Any retrofit kits out there? 
