Opinions on the 6l80

[spacepirate]

Hey guys,

I've been talking to Travis, daytonayellaz, and he was suggesting the 6l80/LS3 combo for my 68. I live in LA and the stop and go traffic sucks so I like the idea of the auto however I want to see what you guys opinions are?



Thanks

[srh3trinity]

I have it in my g8 and I like it a lot. I have a sport shift mode for when I want to keep the car in a certain rpm range for fun or to hear the exhaust. I hear a nice tune will firm the shifts up nicely. I am staying stock for now.

[alocker]

There are a few issues that need to be addressed. The overall size not only requires tunnel surgery, but the pan is also lower in relation to the centerline. Also the output shaft does not use a regular yoke like older styles.

[1989GTA]

There are a few issues that need to be addressed. The overall size not only requires tunnel surgery, but the pan is also lower in relation to the centerline. Also the output shaft does not use a regular yoke like older styles.

As to the output yoke mine uses the same one as used on the 4L80. There are different versions of the 6L80 depending on the application. I think the ones from the pickup trucks use the standard yokes. You can convert the tail shaft to one that uses the standard yoke but that is more money. I would like for the right version to save a few bucks. Yes you will have to raise the tranmission tunnel. Yes it will hang lower with standard pan however there are pans available the are shorter in height.

[spacepirate]

Thanks for the input guys. I understand the tunnel surgery and yoke swap will be needed but I do have some concerns about the trans pan hanging low. How low are we talking here? Is it lower than the oil pan?

[SShep71]

A 6l80 doesnt hang as low as a 6L90. The pan hangs low, but since you are going to have to do the surgery on your trans tunnel any way the hang down of the pan wont matter much because you are raising the transmission accordingly. Also raising the motor/trans helps to eliminate the problems that pans were having with the crossmember and steering components.

[spacepirate]

Oh good to know.

[Poorhousenext]

It would be a good idea for you to join LS1tech and do a little research in both Automatic and Conversions and Hybrid. Good info there. Corvette fourm C6 section will give you and understanding of trans limits when abused also.

If you plan on abusing trans, you need to send it to one of about 3 builders with experience and know how to beef it up prior to installing. The rebuidlers are just getting a handle on how to make a 6L80 or 90 hold up.

Also there is down side to using a shorter pan even the G8 one. Fluid starvation under hard accleration plus lack of cooling ability.

Take a good look at the gearing also. First gear is granny gear, 2nd gear is another 1st gear too. You get two overdrive gears, but no 1 to 1 gear. Reason for 2 OD gears is trans kick out of 6th and downshift into 5th like my Korean car on hills here in SE US. You will need to research rear gear ratio to use. Remember 4th is 1.15 to 1 so a 3.27 will = 3.70 or a 3.08 a 3.54. Start going below one of those may give you great low rpm cruising in 6th but you could find top end suffering. Even the C6 Corvettes suffer from that with their high ratio stock rear end. The 2 low gears and no 1:1 will make car feel quick, but you blow through 1st and 2nd real quick too.

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
0.85 -- 74.09% (high) RPM Retention 25.91% RPM DROP
0.67 -- 78.72% (high) RPM Retention 21.28% RPM DROP (note: Gearing may have changed to 0.70 on later models trans Vs original per GM performance website.

Good trans for everday driver. Well built and 3.42 rear end and right motor 9 second light weight car. 3.42 X 1.15 = 3.93

If you want to know what gear trans is in, your options are limited. One vender here says they will have working indicator soon. Other than that best thing I've seen is gage set being Sold by Speartech. Indicator is built into speedo.


http://www.youtube.com/watch?v=2gaE6syO854

By the way I have one in my 66 corvette. I don't abuse the trans as it's stock and engine is 505 HP at crank. I have tap up and tap down shifting but no gear indicator so it a cruiser only.

[1989GTA]

This is from a post on Yellowbullet. I found it interesting. This is a L99 car with the 6L80 still being used. Also look at the modification list. Some of you may have already seen the thread.

"Congrats to friend Ryan Stevens on running 10.87@124 last night at No Problem Raceway. Props to Chris @ Circle D for the converter!

Mods:
Longtubes
Custom X pipe
Slicks
Skinnies
Some weight reduction
Mast Cam
GM 3.91 gears
Circle D 4000 stall
Tune
Cold air
Underdrive

He drove from AR to LA and is driving back.

I think the 5th gen is pretty damn good. Hopefully we'll have some videos."

And one more from the same thread.

"Thanks Phil! On the 93 octane tune, 492/447. I will carry some E85 when I go back, it currently makes 503/455 on E85, but the e85 is impossible to find in LA so I just ran the good ole 93!"

Looks like the 6L80 can do the job. I have not seen a car faster with the same mods.

[spacepirate]

Thank you guys!

[SShep71]

You will need to have a tune done for your trans. The shift times and line pressures are controlled electronically. Just taking a 6l80/90 and running it without the proper ajdustments are what is causing failures. The results of a good trans and engine tune with the appropriate converter are bringing in great results.

[Steve Chryssos]

An excellent transmission with real engine braking and quick shifts. Go drive a new A6 vette, then envision it shifting a bit quicker if tuned. They dumb them down a bit from the factory.

Some pointers:
-Choose your harness builder carefully. Some have been sniffing way too many solder fumes. Our customers are having great success with Howell and John Leonard at Modern Vintage Systems. Talk to your prospective harness builder before you commit to a transmission and TCM. There are some important guidelines to matching ECM and TCM regarding make model and year.
http://modernvintagesystems.blogspot.com/
http://howellefi.com/

-If you want TAPShift, the Corvette scheme is more adaptable than the Caddy/Camaro scheme at this time.

-Regarding gear position, I have a customer in CA testing the Dakota Digital BIM-01-1 CAN Bus interface along with their VHX gauges.
http://www.dakotadigital.com/index.c...rod/prd752.htm

-Our Shrifter Six™ Paddle Shifter includes a sub harness that sends the correct TAP UP /TAP DN voltage. There are many in service already, so don't let anyone tell you it can't work. It is, after all, just a fancy looking two channel momentary switch. From Modern Vintage....
http://modernvintagesystems.blogspot...e-shifter.html