torque converter

[3400-95-Modified]

All automatic automotive transmissions have torque converters. A "stall converter" is usually what an aftermarket torque converter is refered to as (one that doesn't operate at stock stall speed).

Not true really... Every converter is essentailly a stall converter... its just the stall speed and the efficency of the coverter that differs depending on stock, or performance.

Someone asked about stall speeds on Bnet and I posted this.

http://www.hardtail.com/techtips/selectingconverter.html

[pocket-rocket]

What I meant was most people don't really call it a stall converter if it's stock despite all of them being a stall converter. They usually (in my experience) call them a stall converter if a non stock stall speed is used.

[3400-95-Modified]

What I meant was most people don't really call it a stall converter if it's stock despite all of them being a stall converter. They usually (in my experience) call them a stall converter if a non stock stall speed is used.

Yes this is true and I agree with you, but it's one of those terms thats used incorrectly, thats all I was stating.

[pocket-rocket]

Yes this is true and I agree with you, but it's one of those terms thats used incorrectly, thats all I was stating.

Gotcha

[anonymous48420]

go to the junk yard. get a converter off a 3800 sumwhere round a 98ish. i yanked on off the 3800 i was puttin in my friends car cause he had his old one and the jy engine we bought had 1. its a 2100 rpm converter. i can load it to about 2500 rpm's when i launch and it made my car drive so much better. very much worth it. even picked up a few mpg's in the city.

[3400-95-Modified]

For a stock engine thats a better converter yes. I have a 2095 in my daily car as well. My original was a 1650.

[Rootie524]

yeah and thats just it..my engine isnt stock so ill probably need a custom made one. and thank you for that very informative post fiero.. it helped me better understand the importance. im still at a deciding point between a built 4t45e with a bitchin torque converter or a 5spd swap.

but now im alittle bit more interested in "torque shock"..i hope that wont become an issue for me. i tend to worry about things like that..

[86FieroSEv6]

For most of our street iron it mainly beats up on the mounts. Once you start to get over 200 ft.lb.s of torque there are other considerations involved. One of these being the driveshaft/s and associated connections a.k.a. u-joints and yokes for rear wheel drive and the inboard joint trunnion and housing on front wheel drive. As long as the mechanicals hold out, torque shock then becomes a concern for the suspension and tires to keep it under control so that traction is not upset during your launch as well as during high powered shifts farther down track. Nothing pisses me off more than to leave the light like John Force and then break traction and drop a second during a shift.

[Rootie524]

so i should be fine with my engine in the bu producing what i hope soon to be 220hp to the wheels.. and after that even more with a turbo. will it be a issue for me.. i only care if it will be an issue for the engine. suspension and stuff can be fixed. i just dont want hard work and money going to waste.

[robertisaar]

i'm not really sure if a 4T45 can handle sending 220WHP without issues...

[3400-95-Modified]

Build it right, send things out to get hardened if possible, and send things off for cryogenic treatment... I'm sure it will last a little while after all that work... LOL

There was someone putting down 220WHP before in a malibu, but I'm not sure if that was a 5-speed conversion or not. Ben had his dyno slip up before to show what a certain cam and proper porting work could produce.

[86FieroSEv6]

Preperation is everything. Do a mild blueprint on everything, reduce the tolerance stack to as near zero as possible. Use high quality fasteners everywhere you can. Make certain the person you farm out machine work to is familiar with the requirements set forth by the manufacturers of the components you choose. Check, double check, triple check . . . then double check your triple check. Right now I am working on a '95 Roush stage III that gets hammered on regularly by one of the most retired white males in America and he shows it no mercy. The reason it has survived is because of the process attitude that I mentioned at the beginning of this little diatribe. I am certain I can get an Amen from the guys on this. The pros got to be pros by blowing up a lot of parts so you don't have to. Listen to them and take their advice. The 440T4 when properly prepared can take an awful lot of abuse. The 125 can too. I believe I remember reading an article about building the 125 for power in Hot Rod magazine.

[Rootie524]

ok so just a little side bar. if i start my car up and go to put it in gear and the RPMs DROP down to almost stalling then go back up to normal (and sometimes it actually does stall..but rarely) is that the sign that i need a new torque converter with a different stall speed?

[pocket-rocket]

I would say that's an issue somewhere else. Maybe you should go back to where you had it tuned and have them bump up your idle speed since you have a cam in there. They should do it for free since they tuned your car not to long ago but who knows if they will go that far to keep a customer happy.

[86FieroSEv6]

While a converter change may help a bit with the gear engagement idle sag, I tend to agree that tune and adjustment should be addressed first. Ideally, the idle shouldn't sag and the difference in converter will mainly be noticed as greatly reduced driveline shock when placing the car in gear. The reason for this is that on the street with a near stock engine you wouldn't be using a converter with a high enough stall to eliminate the idle drop from engaging drive/low. Double check that your minimum idle air rate is properly adjusted, badly adjusted throttles drive me crazy. Also check that you are using the correct OEM PCV valve. Wrong PCV valves have ruined idle maps for as long as I can remember and aftermarket PCV valves are notoriously miscalibrated.