badblackgs

iTrader: (1)

The thought crossed my mind about instead of buying a higher stall aftermarket torque converter to achieve more takeoff, just swapping in a gs300 torque converter into a gs430 a650e tranny. I had a 02 gs300 in the shop this morning so I did a brake test to see the stall speed and it seems to be about 2200 rpms before tires started breaking loose. Its my thoughts that lexus would have used a slightly higher stall speed on the gs300 to help with the off the line performance from the factory. When I did the stall test in my 02 gs430 it seemed to be about 1800 rpms. Was wondering if anyone has gone down this road before.

DaveGS4

iTrader: (2)

I don't know about any OEM difference in stall, but the GS300 has 3.9x gearing vs 3.23 in the GS4 to help the off line performance.

angus

iTrader: (4)

True the diff ratio is different - but the stall speed is not effected by the diff.

I really wonder if the stall speed is different - it would seem to make sense though since the motor has a different torque curve.

The thing is, unless you got lots of traction, higher stall speed won't help you much, my car can blaze the tires from a dead stop as it is.

I wonder how it'll change the feel going 400rpm up?

RamAirRckt

I was poindering this myself, I did a converter swap with my old 4.0 3.27 Ford Aerostar with one from our dead 3.0L blown headgasket Aerostar that has 3.73's. The 4.0L van ran GREAT with the 3L converter over the stock 4L converter, it was wonderfully smooth at low rpms and let the convert flash really well when you step on it. Only issue you would see is it you had a heavy load (trailer) or on a steep hill or in soft mud and try to take off you'd feel the rpms climb like you were slipping, but it was just the convert stalling. It really was a great swap.

So having had done that in the past, I am pondering getting a GS300 converter and toss it in my GS400 and see how it wakes it up.. Sure it could kill some mpg, but only when the convert isn't locked, as long as the convert locks up as normal, mpg should be largely no change.

I have a converter shop about a mile from the house, if not less that will build any converter custom, so let me know if anyone is interested....

But I'm on the lookout for a 2JZ stock converter just for fun.

GS400V8

iTrader: (4)

The GS300 converter is different and will not fit in the GS4X0 models' transmissions

The GS300 does have a slightly higher stall and shorter rear end because it makes a lot less torque in the bottom RPMs

RamAirRckt

What is different? the trans is the same, so that part shouldn't be an issue. The flexplate side must be different.

I'll see if I can get one of each. Heck, even a IS300 converter might be better? Lighter car convert in heavier car means more stall.

GS400V8

iTrader: (4)

The bell housing which houses the TC that fits the I6 engines is different. The starter is in a different location as well and these all make it a different shape. The I6 converters are also dual clutch not single. And the transmissions are both called A650Es but thats where similarities end, as the A340 guys found too. The I6/V8 valve bodys are different, There are beefed up internals in the V8 models, as well as different bell housings and torque converters. It would be a waste of time to try it, many have tried so before.

RamAirRckt

Interesting, quick look on car-part.com shows

98-00 GS400 uses same trans
98-00 GS300 user same trans
98-00 LS400 uses same trans
01-03 LS use the same trans
01-05 GS/SC users same
01-05 IS300 uses the same.
But oddly, NONE are mixed, a 98 GS4 can't use a 99 LS or GS3 trans, etc. It seems restricted to platform only.

So I guess the only way to go higher stall on the GS is get the converted in to the shop....

thanks GS400V8!

GS400V8

iTrader: (4)

No problem! I sent a stock TC into Precision Torque Converter in Kennedale, TX and thet did a great job. I asked for around 3000RPM and I feel like it is perfect with the 3.77 gears