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High Stall Torque Converter

Posted: Wed Mar 04, 2015 6:06 am
by whitehumh2
So, my rear main seal was leaking and since it is almost an 8 hour job to replace it I decide to take my truck to my Buddies at Eastern Transmission. Since they were in there anyways, I asked them to replace my 12 year old torque converter with the best one available for a truck like mine.
 
Stock my H2 had a torque converter with a stall around 1600-1800rpm. Which may have been good for when my H2 was stock but with all my mods I needed to address it!
 
Our 6.0L LQ4 engines make peak torque of 365 to 380lbs-ft at 4400rpm. The engine torque curve is pretty flat on these engines but there is barely half available at 1600rpm!
 
The normal rule of thumb for choosing a torque converter is that you want it to have a stall about 500rpm below the peak torque of the engine so that it gives the engine a chance to spool up to the power band of the engine before stalling or locking up. This greatly improves overall performance and torque multiplication! That is why most diesel trucks get a torque with a stall of approx 1200rpm...they mostly make peak torque Under 1800rpm.
 
The specs on my new torque converter are as follows;
 
1. Triple disc TCC Clutch to make sure it holds Under heavy loads!
 
2. Based on my estimated engine torque of about 400lbs-ft I was supposed to have a stall of 2300-2500rpm.
 
3. The new converter has a 2:1 torque multiplication
 
 
Testing;
 
So right away many of you may be thinking a high stall torque is dumb, the truck won't move until you get to 2300-2500rpm, but that is completely false! The truck still drives as it did before. I can pull away at low throttle with ease! But where the fun starts is when you mash it...holy crap what a difference!!! My H2 launches like never before and pulls hard through all the gears!
 
I ended up with 2800rpm stall which means that my engine actually has a torque output WELL OVER 450lbs-ft!!!
 
My trials off-road on obstacles at my personal Playground have proven amazing!!! I can literally hold it at 2800rpm and get over or thru most things! The torque is acting like a driveline shock absorber now and I watch the rpm bouncing up and down as the load increases and then stabilizes...truly amazing!
 
I have also noticed about 2l/100km BETTER Fuel Economy, I am Loving it!
 
 
Now, there is one minor issue, the new torque generates a LOT of HEAT when I am off-roading, I already have Amsoil Torque-Drive ATF in my transmission but the tiny OEM transmission oïl cooler is soon to be replaced by the largest transmission oïl cooler that I can fit!!!
 
I am also going to convert from my Mechanical Cooling fan to a Dual electric cooling fan...but those mods will be in another post!!!
 
 
 
SO if you want WAY Better driveability and fuel economy...why not consider a High Stall Torque Converter???? You Will Love It!!!
 
 
Kev

Re: High Stall Torque Converter

Posted: Wed Mar 04, 2015 7:39 am
by Autumn Walker
My transmission is giving me fits - not locking up and slipping... it might be time for rebuild soon and this will be a consideration!

Re: High Stall Torque Converter

Posted: Wed Mar 04, 2015 9:17 am
by whitehumh2
Look Up RAPTOR transmissions made by PATC!!! Truly a well made set-up!

Or Hughes Performance.

Either one are a great improvement over stock but the RAPTOR would be Best!

Re: High Stall Torque Converter

Posted: Wed Mar 04, 2015 10:13 am
by Monk
On a gas engine , generally I've noticed min 1 second drop in 1/4 mile eta time. That's a lot.

I had a 4500 stall on my old pro street car, (400 hp small block Chevy)and I heard those rumours that it won't drive till stall speed is achieved. Not true.

I agree it dove normal on light to light , but once I floored it.......look out , was a screaming beast.

Re: High Stall Torque Converter

Posted: Wed Mar 04, 2015 6:34 pm
by collega
[quote="autumnwalker"]
My transmission is giving me fits - not locking up and slipping... it might be time for rebuild soon and this will be a consideration!
[/quote]
Hello, what is the mileage on your H2 that your transmisson is not good any more?

Re: High Stall Torque Converter

Posted: Thu Mar 05, 2015 8:18 am
by Autumn Walker
[quote="collega"]
Hello, what is the mileage on your H2 that your transmisson is not good any more?
[/quote]
 
I think my truck has hard a hard life (I bought it used) so it's not a good benchmark. It has just over 100,000 kms.