Increasing the stall speed is not rediculous depending on the application. A lot of drag racers use a high stall speed converter so that when they launch the car, it is already in the power band or at least closer to it. This becomes even more effective when the motor is running very aggressive cams where low engine speed operation is weak. Go to a Drag Race(Especially those with a lot of old V-8 domestics) and you'll probably see a few. You can usually tell who they are when the engine is revved up on the line and you can see the drivewheels load up while the linelock is holding the car there. These cars tend to look like they were never stopped as soon as they take off.

The mod is usually not very streetable especially if overdone and will waste fuel since less power will get to the ground under cruising conditions.

 

Since the factory stall speed is already between 2600 and 2900 I don't see haow "raising" it to 2700 is aany kind of mod at all.

Mark

 

Yes. I believe that was the point being made. It seems likely the placebo effect has had more of an influence on the car's performance than anything else. I look forward to Q45Tech's next post on the subject.

'03 G35s 5AT, Garnet Fire/Willow
Staggered 18" SSR GT1/Bridgestone PP S03
Eibach Springs/Sways, Stillen 2-pc BBK
Stillen Intake & SS Cat-Back Dual Exhaust

 

I have a coupe and I can tell you the stall speed stock was NOT 2600 to 2900. It was more like 2200 tops.
You can debate all you want, I know that this mod has really made a significant performance difference for my car.

 

I sent my torque converter to Edge racing converters .They raised the stall and reworked it to work alot better . you will not need a cooler unless your running hot or you track the car. Its the best mod for the money for a AT5

Couldnt afford it when young...gonna play when Im old

 

Interesting that stock convertors can be modified to increase stall speed. I didn't know this was possible. If you floor it from a standing start do you get a lot of wheel spin? Did they modify or replace the stator and fins? I'm surprised that an oil cooler wasn't recommended to compensate for the extra heat in the transmission. 1/4 mile times will be drastically reduced if these cars could launch harder. I had an ArtCarr unit in my old Chevelle and the difference before and after was like night and day. This is great news for us 5AT folks !!

The King of El Sereno

 

thank you booger for stepping up. I couldn't send mine to Edge racing because of the downtime, so I had it done locally.
I guess we have some people here who think Japan reinvented the wheel or something. A torque converter is a torque converter, it works the same no matter who made it, and can be modified by skilled transmission shops.
For those 5AT owners looking for a little extra pop, without spending a ton of money, this is the mod you want.
I have been checking the tranny often since I had the mod done and everything is just fine. I don't race and I drive the car everyday, and so far the gas milage has not changed at all.

 

You said it, for an automatic tranny car, a stall converter is the way to go. I used to be big into the camaro/firebird LS1 scene, having owned two, and I can tell you that people were dropping .6-.8 tenths off their quarter times by adding a stall and slicks. They were also running considerably faster than the 6 speeds with similar mods. Just the facts. But remember that in going with a high stall, you'll also need a set of tires to back it up and get the power to the ground. Throwing rubber doesn't do anything for acceleration

 

this isn't an LS1

shift kit + pi stallion 2800tq converter made my mustang funner to drive, but certanly didn't know a second off the 1/4mile time.

 

I believe the stall for the 5AT coupe is at 1800. I guess the next real question is whom is selling new new torque converters w/ a higher stall? I think SPC but anyone else?

 

OK -

I have a 3200-3400 stall converter in my car, along with 3.92 gears and a Quaife 2.0 diff, and a custom Japanese 5AT.

The car is a monster - especially with the TC and the gears!!! The stock TC is a 2800 - at least on the 05+ it is, and I don't know about the earlier years.

ACT Performance is a SoCal Co that rebuilds the stock converter and makes it 3200-3400 for about $450. Mine happens to be a ProTorque, as I wanted other heavy duty parts inside, rather than just adjusting the stock one.

On the note of trans cooler - you have to have one once you raise the stall - or you'll burn it up quickly.

My car is driven every day - about 26,000 miles a year. My mileage went down about 2 MPG once the converter was put in.

If I had to do it all over again...NOTHING would be different here.

Rick

 

Many don't understand that the stall rpm is just a function of the applied torque at that rpm. Raise the torque [say with a axial*supercharger] and the stall rpms go higher.

* Radials SC don't make much boost at 2800 [say 0.5 psi] so that should be 4% more torque or about 50-75 rpm increase.


Important to measure ATF temp and decide upon an upgraded heat exchanger, as in Summer you can fry things going up a long incline at espressway speeds.

Hopefully these TC mods will last 100k and not reduce the durability of the 5AT units.

 

Please tell more !!! What comprises a custom Japanese 5AT? Where did you get it?

 

It's part of an R&D project - you'll hear more the first 1/2 of 2008...

SUNDEVILJAY has been for a ride - ask him how the trans felt...

Rick

 

^^^i'm still waiting for you to swap that out with mine!! i told you straight up for the chrome dampers...fair is fair...

Now back to reality, it was amazing how well his car shifts. I have the same supercharger on mine and his car feels completely different. No jerking at all when shifting in manumatic. It is sooo smooth. Very impressive