InchUp

iTrader: (2)

The idea behind a low stall speed is to give the driver the torque he or she wants at a lower RPM to get the vehicle moving with less engine revs. The result of a lower RPM stall speed is to limit heat due to slippage and provide a more firm feeling to the vehicle's characteristics, giving the driver some form of predictability of when the tires will start moving with a given amount of throttle. In a lifted truck with tall tires, gearing the axles and/or transfer case is important, no doubt. If a driver chooses not to re-gear after up-sizing in tires, then he or she would want a lower stall speed in their converter to produce the engine's torque at a lower RPM. The engine's torque sent to the tranny wont be as much as a higher stall converter, but the torque will be sent earlier. Get what I'm saying?

It's no secret that a converter with a high stall speed will sit and multiply the engine's torque in greater amounts than a stock converter's speed, but that's not what a lifted truck driver wants, or at least shouldn't. One would be willing to give up net torque multiplication in exchange for a converter that gives them the torque earlier, if the goal is improved daily driver manners, fuel efficiency and better predictability of the engine. Tall tires already put extra heat into the tranny, a converter with a higher stall speed would only make it worse.

InchUp

iTrader: (2)

And to the comment of lock up and what my salesman is telling me; the lower stall speed will allow my truck to maintain lockup through harsher conditions. For example, say I'm cruising along in my big truck on the flat highway and I come up to a steep highway incline. A stock converter would unlock at this point and either rev the engine a tad higher in the same gear to maintain cruising speed, or downshift to ask the tranny for more torque multiplication by dropping into 3rd. Since my converter will be at lockup at a lower RPM, I'll already be making enough torque to cruise along at a low chugging speed and I wont need to downshift to maintain speed because of the efficiency brought about a lower stall speed converter. Granted there wont be as much PEAK torque made, but I'll have all my engine's power at a much earlier RPM because of it, meaning less or no slippage at cruising speed. My converter was also furnace brazed, which my salesman assured me that I would see a decrease in turbulence of the transmission fluid inside the converter, resulting in an increase in efficiency and lower heat transfer which means more power to the wheels and more peace of mind knowing my two transmission coolers don't have to work as hard.

Atomic

iTrader: (42)

You know when the converter is locked up its 1:1 with no slippage right? Your current TC is unlocking because your engine isnt making enough power to maintain speed, and your pcm is telling it to unlock to raise the rpms and make more power. Your engine doesnt care what torque converter is behind it, it will only produce X amount of power at Y rpm and Z map. When your not making enough, it downshifts.

If you tell your converter to stay locked the whole time then your going to be running your engine harder than otherwise (assuming you would need more power in the case of climbing a hill or something).

Decrease in trans fluid turbulence to make more power, eh? Do you have one of those tornados in your intake too?

03z-71

the guy i was talking about with it for sale is on this site and I didn't even know!! LOL

It is for sale in the GM section! He said it kicks in at about 2400 RPM...

InchUp

iTrader: (2)

Define 'harder'. Yes the motor will need more throttle to maintain speed with a given load and set RPM. Will that be 'harder' than downshifting to 3rd and increasing wear and fuel consumption by revving the motor higher? I think not.
You'd love it if I did have a tornado gadget so you could feel better with having a lesser torque converter that puts more heat into your trans fluid because it's not as efficient. I didn't say it makes more power. I said it's more efficient, which is different. Furnace brazing is a very common practice amongst top dollar converters and when you have a goal of a certain fuel efficiency like I do, which was set long before the V8 build even began, every little bit counts towards that goal.

MPFD

iTrader: (5)

I think you've just proven to everyone that you don't know what your talking about.

Won't more throttle make engine's efficiency suffer.

I understand that you being an S10 driver have probably gone through a few transmission because of the torque converter unlocking and getting the fluid hot. (I saw more S10's 4l60e replacments when I worked for GM service then all other makes put together.) But with a V8 you will be making plenty of power and you converter issues will be history.

InchUp

iTrader: (2)

It's a good thing you're not paid to think.

MPFD

iTrader: (5)

Actually I'm paid to train dealership technicians. But I'm done trying to help you.

joehawkz71

iTrader: (2)

mine......01 z71 6" susp lift, 3" body lift, 35's and 4.56's, yank 2600 and im running a TR220 cam and i think its just a bit too much for my set-up...not enought tq down low.. but it pulls hard as hell up top!!

its a lifted truck you cant expect it to be super fast as well! (( well depends but thats a different story))

stock48

iTrader: (16)

The cam would work ok in your truck but it really is on the to big side.

The stock cam is a dog, you would pick up power across the whole RPM range with a ISKY 206/206, .553''/.553'' 110*(with headers) or 206/212, 112*(if not going to run headers).