Well, my friend is considering sending in his torque converter to a company to modify it.

But hes worried about the daily drivability of it.

It is a 2000 Accord V6 and of course its auto.

Im just wondering if anyone else has this done to their car and how they think about it.

but any information and input is appreciated.

thanks
Vic

 

He'll be fine on the street. They are probably going to raise the stall of the converter slightly. When he drives from a stop, the car will rev a little higher before it moves, causing slighly worse fuel milage. But as long as its not a full race converter he will be fine. However, when you raise the stall on the converter, you build up more temperature in the trans fluid. I highly suggest he get an aftermarket trans cooler. Afterall, those accord V6 trannys are notorious for having problems in stock form. I see anywhere from 2-15 accord V6 auto trannys get replaced under warranty each week.

 

Torque Converter 101: (sorry but I was bored, the part about selecting a converter is very important).

A torque converter ( http://www.levelten.com/images/torque_converter.jpg ) is what you see in the picture. (pretty basic looking from outside).

The case is fill'd with fluid (ATF) and has basically 3 turbines inside: the input turbine which is connect'd to your engine's output shaft, the output turbine which is connect'd to your tranny's input shaft, and a stator turbine between connecting the input/ output turbines to control and direct the fluid flow.

At a certain input rpm the fluid will reach maximum flow through the converter, and there will be hydraulic lockup. (in other word, fluid at max. flow will cause the turbines to lockup... thus transfering the power through the converter to the transmission.) And below this certain input rpm there is slippage cause by poor coupling between the input/ output turbines.

That certain rpm is called the stall speed of the converter (thats also why people sometimes refer to torque converters as stall speed converters).

This property of the torque converter allows it to rev to a engine speed until an rpm were it makes enough power (also called torque multiplication) before it is put under a heavy load. (like it drops the clutch after it revs to whatever rpm the stall speed is at...)

It is cool cause you stage your car by just sitting dead stop, and then you put the petal straight to the floor... the rpms jump/ rev up to the stall speed that your converter is setup for, and then wheels start turning like hell on that stall speed is reach'd (thats when the converter 'locks-up'). If your stall is too high... you will do nothing but blow off the tires when you try and 'flash stall' it like this... too low your car gets off the line like a cow. The best way to insure proper stall speed selection, is by matching to converter to the torque curve of the engine.

Also something more comes into stall speed selection. If the car is for street duty especially.

When cruising your tranny upshifts for economy and such... thus lowering your rpms to the lowest possible level it can. But if you stall speed is above that cruising rpm, you got slippage... which you DO NOT want.

Slippage produces tons of heat... heat is what kills tranny/ converter!

In fact it is also recommend'd as a normal proceedure to add an external tranny cooler (and disconnect the in-radiator unit...). Also recommend'd you run a high-quality sythetic ATF and change it regularly... cause any wear particle's in the ATF fluid can damage/ destroy the converter as it and the fluid travel through the vains of the turbines.

 

Yes I had changed the converter on my old car to a better quality converter, and also had them tweak the valve body, beaf up the reaction plates and beaf up the clutches while I was at it and had it apart.

You dont want slippage though or too much stall obviously so it is a delicate balance... esp. for a street driven car. Too much of a stall will do more bad then good.

I ran a extra external tranny cooler and synthetic atf to help the stress on street driving and had no problems for more than 10k miles.

 

thanks for the info guys

ill show this to my friend and c what he wants to do.

Vic