6l90 ZL1 Converter in a 6l80 truck? anyone done it?
 

One of my buddies picked up a 14' Chevy SS and he's in the midst of gathering parts for a blower/cam setup. Anyways, he was telling me that it's apparently popular to swap a ZL1 converter into those cars for a slightly higher stall speed over the original converter.

I did a little bit of research and couldn't find any info about someone swapping one of these into a truck. My trans is about to get pulled and rebuilt in the next few weeks and I've got a line on one of these converters for next to nothing brand new. all I do is tow, really not interested in dropping $900 on a circle D thats going to hold up to that. If the ZL1 converter is something that would be an upgrade and stay alive under some towing (approx 5500lbs boat and trailer) I think I'm going to jump on doing it.

I'm way out of the loop on modding these days.

You would be better off installing a CTSV converter. Very strong from factory.

The CTS-V and ZL-1 have the same converter. So the same question applies. Just looking for a concrete answer if there is anything to gain.

I've been looking at the same thing. The ZL1 converter is a 6-bolt, a new flexplate (which Yank has) would be a good idea.
Zl1 converter - Pontiac G8 Forum: G8 Forums - G8Board.com

That's the best thread I've found on it. I don't see why it wouldn't work with any 6L80.
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Extending that thought, I'm looking into to the 2014 C7 vette converter. It looks like it stalls a bit higher..2,500. Trying to find out if it will work with the regular 6L80 trans. Pricing is similiar as the Zl1.. about $350 with a $100 core charge.

I'm not terribly concerned about the flex plate. I don't see why three bolts over 6 is going to make a difference when that is what's used OEM on the truck.

the c7 converter information is a bit interesting though. I'll have to do some digging tonight after work.

The OE GM LSA 300mm is a nice setup with the twin disk. It has a little looser stator, ballpark stall range is 2000 - depending on weight and torque of course. We can modify the OE 300mm to bring the stall closer to 2500. 3 vs 6 bolts is an interesting debate. We have a lot of 3 lug converters running well over 1000HP. But there are several flexplate options that will allow you to use all 6 bolts.

C7 converter will not fit, they use a completely different bolt circle and converter pilot. But you guys are correct, it is close to a 258mm setup - ballpark 2500 stall.

Chris

Cool! I'll hit you guys up to modify one for me.

What's the cost on modifying the OE converter Chris? Do you keep them stocked and allow someone to ship back a core?

My interest is in something super budget with very mild change in drivability. I can get an brand new LSA converter for $265+100 core charge. That seems hard to beat to me, for even marginal gains.

Posting a quick update here. I rebuilt a trans for myself this past week and installed it today, along with the 6l90 torque converter. It bolts right up and you only use three of the six pads on the converter. Drives like stock (my truck is 100% stock for now) and it brake stalls a bit higher. I can foot brake it to 2200ish RPM.

I put a cts v converter in my 2010 sierra today. All was well but after about 100 miles of driving, I developed a whining noise. Trucks drives,shifts and locks up perfectly. Guess I'll be doing some noise diagnosis tomorrow.