Hi guys,
I am looking into maybe getting a torque converter for my setup. I am looking for some suggestions on what stall speed I should be looking to get. I read about peak torque and at what rpms it hits, and per my dyno sheet its about 4K, and then read that one can move that around to 600-1000 rpms from the peak number. This setup would see a few visits a year at the track and it is my daily driver, so it would need to be streetable. I was thinking from 2400-3000? My mods are below in my sig.

Thanks

 

You won't be happy with a stall from 2400-3000 because your stock converter will do that.

What you need is a well built converter that stalls in the 3200 or so range. No lower and not too much higher since you are positive displacement on the power adder.

Darrin

 

I disagree.
I run a 2400 and it's perfect!
I used to run a 2600 and it sucked on the street.

Phil

 

With a 4R100 in an older truck that may be the case. But, with his newer truck and a 4R75W transmission, not so much.

Also a WHOLE lot of this comes down to who manufactures the torque converter and how they determine stall. What I am talking about is a true stall speed as would be seen if tested in the vehicle on a transbrake. I have had part in a bunch of these and that is how I came to my conclusion on stall speed choice.

For informational purposes and maybe some good discussion, why would you suggest a stall lower than what a stock converter will stall on his truck? That's a whole lot of money to spend to not change the stall speed in my opinion.

Darrin

 

I was only basing it on my truck. So if theres a difference,I wasn't aware of it.

The 2600 stall I had was with my 4r70w and was a PI converter.

When I went with the BTS 4r100 . 2400 was what was recommended buy the builder and he said ,most of the Lightning guys run the 2400 stall.
Oh,and it's a PI converter too.

The way it feels now, you don't even notice it in daily driving.
With the 2600 stall,you could really feel it lock and unlock wile driving it normally.
I didn't like it and it was hard on the MPG too.

Phil

 

You may not be happy on the street with a 3200+ stall on a blown 2004-2008. It'll take a lot of data logging and tune changes to get it to even be "acceptable" on the street, especially since SCT does not offer all the torque converter controls needed for that year truck in the calibration (the values are all dummy 78, 2C, etc. values). You'll end up with a ton of up/down RPM swings in 3rd and 4th gears on inclines at light throttle and it takes a log of tune tweaks to work around most (but not all) of that. You'll also end up with converter flashing when downshifting at certain speeds from 3rd to 2nd, which only results in a power pause when what you want instead is immediate power. The only way around it is as much TC lockup as possible (meaning.... spending extra to get something with a lot of locking surface area) and radical changes to the shift patterns.

If you plan to stick mainly to the track, have the tuning software and skills to handle the calibration changes your self, or deep pockets to pay someone else to spend a lot of time on it, go for it.

 

Yeah, I figured it was either a PI or an Edge that you were talking about. I still think that if you call PI and ask them that they will tell you that stock stall is 1800rpm and that isn't the case anymore. We put a transbrake to a PI "3000 rpm stall" for a 4R70W and got more than 3800 out of it if that tells you anything.

I guarantee you that I can hook him up with a 3500 that will drive as nice as your "2400".

Also, the OP had his truck tuned by Troyer. Mike T is definitely familiar with the products I am talking about.

For reference, the factory stall on his truck is rated at a minimum of 2404 and a max of 2842 on a completely stock engine. With the extra torque he has with that blowe it's going to push a good amount past that already and I wouldn't want to back him down performance wise with a lower stall converter.

Darrin

 

I will again refer you to Troyer on the product I am talking about him using. This one is a recent addition to the mix and doesn't have the issues you speak of. Mike can/will fill you in on how happy he is with them if you ask him.
He was amazed and even called to take the time to tell me all about it.

Darrin

 

Thanks for the great info guys, it is much appreciated.

 

I've got a PI converter with low miles for sale if your interested. Cheap compared to new.