Hi guys, I've been reading the posts and have come across a lot of discussions about the aftermarket torque converters.

Can someone please explain the Benefits?

Drawbacks for a daily driver?

thanks guys.

 

the afermarket one has a much higher stall speed at 2800rpm, meaning that the engine will rev to 2800rpm before the tranny fully engages, that will provide more power and also more responsive system imho.

there isn't much drawback. there are a lot more heat build up, so you want to have tranny cooler for sure. and i suppose if you do a lot of very low rpm driving for whatever reason, you might get more tranny slippage than normal?

but for most people, this is a great mod

 

so in laymans terms what this does is act as if i have a manual transmission and leaving it in a lower gear during acceleration, ie inhibiting the automatic transmission from shifting into a higher gear as usual?

 

wait wait i get it. so the enine revs til around 2800 then the transmission kicks in. so its like having a manual tranny, at stand still, in first gear, reving it to 2800 then releasing the clutch?

 

response to post #3

Ah no.

With the higher stall speed your transmission does not start to engage untill the engine reaches a higher rpm. There is no noticeable lag, at least to me, but the car does seem to launch harder. Since the torque converter does not lfully engage untill higer rpm's are achieved your are at a place in your engines power band where you are creating more power when it does fully engage. This creates better responsiveness.

 

Hey you snuck a post in there while I was responding, your second response is closer too what is happening.

 

and you dont get to 2800 rpm before the tc kicks in and you start moving. You actually start movng under 1K rpm almost stock as I noted. But with a TC you are not fully engaged untill around 2800 meaning there is some slippage at the TC prior to 2800. What this means is that hte input shaft to the TC may spin lets say 3 times but the output shaft will only spin twice prior to 2800 rpm. (those numbers are just for an example)

 

Stall speed and in fact converters in general take some time to understand. The TC (torque converter) is more or less the clutch for an automatic. Unlike a manual clutch the TC actually acts like a variable speed gearbox until it reaches its "stall" speed. At which point is more or less does nothing but connect the engine and tranny.

So, from idle to stall speed the TC actually multiplies the engine torque before it goes into the tranny. The highest multiplication occurs at the lowest RPM. As you aproach stall speed the multiplication is reduced. This occurs seamlessly.

The design of the TC determines how much it will multiply the torque and at what speed it will stall at. Stall speed is DEFINITELY dependent on engine torque output. The stronger the engine the higher the stall will be with NO other changes to the TC.

This is just a basic description and anyone curious should read more.

In operation, with a stock converter, you can feel a slight pull at idle with the tranny in gear. This is the TC transmitting some power to the tranny but slipping basically 100%. Take your foot off the gas and the car will creep forward, again, TC transmits some power but slightly less slip. Ease onto the throttle and the car will pick up speed and the TC will slip less and less until it basically stops slipping. Now if you install a quality higher stall TC your car will operate very similar at low power. It will move and drive very similar with a light throttle BUT when you accelerate hard it will slip more and multiply torque more than a stock TC up to its stall of around 2800rpm. This both allows the engine to rev faster, send more torque to the tranny, and reach a higher RPM before the torque multiplication stops and the slipping stops. This makes the car have MUCH more available power and torque than the stock TC up to the stall speed after which power is basically the same as stock.

Drawbacks include a loss of gas mileage and a "loose" feeling below stall speed under MODERATE power use. i.e. medium acceleration from 2000rpm.

 

Good explanation John!
For more complete understanding of how TCs work -with some great pics and diagrams- check this out:
http://auto.howstuffworks.com/torque-converter.htm
Driveability is affected very little if at all. Performance is dramatically improved due to better matching of the engine's torque characteristics with the TC stall speed (and changed torque multiplication effect). One of the most effective performance mods for not only our cars, but most auto trans. cars IMO...

 

what a great explanation, thanks.

So what happens when i'm slowing down to go into a turn? when i accelerate through the turn am i gonna experience any hesitation?

From what you have described, at idle i will have a bit more forward force without any pressure on the gas pedal than i would with the stock converter.

so when i go WOT at stand still am i going to get a whiplash motion like a bad transmission slipping into gear? or is it going to be smooth transition as the tranny is engaged.

thanks guys all input is greatly appreciated!!

 

Rather than ask all the questions, you're in car land (CA) so go find one of the many GS owners who have one installed and have them take you for a ride. That would be the best way to find out.

And no, there's no jerking or whiplash or anything, it's very smooth, in fact shifting is smoother with the upgraded TC than stock and the car is more responsive in all situations. This is the biggest performance no-brainer upgrade for the GS4 ever.

 

sme here paul, no brainer mod for me, it's just great.

 

Have to agree-in fact if you (Kaine) are anywhere in So. Cal. I would be more than happy to "demonstrate" the benefits of the TC!

 

Hello all,
I have been putting off this TC installation for awhile now, and I gues I better jump in feet first. The questions are:

1. Where can I get one? I guess that Carson Toyota has them, right?

2. How much are they?

3. How hard to install? I will be doing my 90,000 mile service soon, so I might as well do this while I am working on major projects. I would love to give it a shot installing it myself.

Any hints would be appreciated.

GSEREP1

 

any 430's w/torque converter here?