Torque converter advice.

[tarik1985]

Hey guys,

Thanks in advance for any advice you can offer.

Since I swapped my 2010 camaro ss l99 (daily driver) engine for a crate engine with the GM hot cam ([https://paceperformance.com/LS3-Crat...-19435100.html)) (the stock engine blew up). I've been experiencing some weird symptoms. At stop lights, the RPMs surge, especially with the AC or heat on. Worse, on the highway with the AC cranked, the car stumbles and almost stalls or chokes.

Iwas told the GM hot cam in the new engine, along with my bolt-on upgrades (LT headers, CAI, Borla ATAK cut-back exhaust), is overloading the stock torque converter and I should upgrade it as well.

So, here are my questions:

GM recommends a stall speed between 2400-2800 RPM. Is that enough, or should I go for a 3200-3400 RPM stall converter?

Should I upgrade the gear as well?

The car was tuned after the engine swap, but I don't know the original stall setting. Will I need a retune after upgrading the converter?


Thank you,

[ss camaro-monte]

Hot cam is NOT a big cam. I am sure a 2800 is enough but I would personally do 3200 or higher. Most on here who have stall speeds that are aftermarket start at 3600. Depends on what you want. More performance or do you still want stock driving style characteristics? You will notice even a 2800 stall.

As for a tune after a new stall. Yes I would think you need a transmission tune afterwards. Not necessarily anything done to the motor side but definitely the transmission after a stall increase imo.

As for gear. Do you care about increased rpm on highway? If not 3.73-3.91. Even a 3.45 helps a little but I have a 3200 stall and 3.73s and that is considered a mild stall and gears by many on this forum. 3600 stall and 3.91s is the hot ticket for a street/strip setup that doesn't do a ton of long distance highway driving.

[1JEWLDSSRS]

Originally Posted by ss camaro-monte

Hot cam is NOT a big cam. I am sure a 2800 is enough but I would personally do 3200 or higher. Most on here who have stall speeds that are aftermarket start at 3600. Depends on what you want. More performance or do you still want stock driving style characteristics? You will notice even a 2800 stall.

As for a tune after a new stall. Yes I would think you need a transmission tune afterwards. Not necessarily anything done to the motor side but definitely the transmission after a stall increase imo.

As for gear. Do you care about increased rpm on highway? If not 3.73-3.91. Even a 3.45 helps a little but I have a 3200 stall and 3.73s and that is considered a mild stall and gears by many on this forum. 3600 stall and 3.91s is the hot ticket for a street/strip setup that doesn't do a ton of long distance highway driving.

Agreed with the above. That cam is not a big cam by any means. But I gotta say on the stall you might want to go bigger than 2800. Reason I saying that is "most" aftermarket cams recommend a 3200 or higher, some may state only a 2800 or higher is fine. When we did my build my builder installed a 3200 in my car. Yes you WILL notice any higher stall converter over a stock one. I sure did. But after about 2 years with that one it just wasn't enough converter for where my power band was, and it was holding the car back, so after some research and questions I went with a 4500, man what a huge difference, AND my tuner has it tune where I still have great street driving manners. What I'm trying to say is, don't go too small with it as you might not like it, and want more, and they are NOT cheap!! I watched a vid on YT where one of the converter manufacturers swapped out the stock converter on a bone stock SS Camaro for a 3200 and picked up half a second on the cars ET. That's some noticeable gains from just a converter. Plus you will need a trans cooler to keep it all cool. As for a rear gear swap, I was going to do that too, but decided NOT to because I cruise on the interstate sometimes to go to shows, and just didn't want to turn the extra RPM's. But I di have to say, even the 3200 stall I have was good enough for me, at the time. But I'm really pleased with the 4500 I have now. Just my experiences. Good luck. Oh, almost forgot, yes you will have to have the trans re-tuned for a converter change, the shift points will have to be re-set for part throttle driving AND WOT pulls, and possibly the line pressures..

[morepowerjoe]

Yeah on the tune side of things they will have to change the converter apply pressures and like the others stated change the shift points and change where the converter locks up. I will tell you this, I would not lock up any high stall converter in any gear below 5th. The reason I say this is because it will make your car buck like a horse when your basically less then like 1600 rpm. I have a 3600 stall and I don't even lock mine up until 6th gear and at 55 mph just because of the drivability problems with locking it up earlier but you might get away with it locking up a little earlier because your cam is a lot smaller then mine.