JZX100 V's MX83 auto Q's

[jzk25]

Go over to JZX100 forums and you should find an auto. People often convert from manual to auto because the auto cars are a lot cheaper to buy. The auto has a slip joint extension housing so is not a big PITA to fit either. You'll have to fit a speedo drive to it though, the casting is there from memory, just needs drilling out.

[CrUZida]

Errr, am I reading this correctly?
You are planning on running the original Cressida auto behind a 1JZ?
And you are expecting it to last more than a few months?

[TTMX83]

Sure, have a mate running one behind a TT 1J. Just has a shift kit in it. Two years now and counting. It's only 3rd gear that is weaker on the Cressida one right? Either way it's not happening now. By the time I got it up and running properly, I'd be better off buying my old JZX83 back...

Cheers Brad.

[Nilezy]

http://wiki.jzx100.com/index.php?title=VVTi

The turbo on a VVT spools faster because it is smaller. Therefore it runs out faster and the turbine falls off it faster

1. VVTi 1J turbos (CT15B) are not smaller than twin turbo 1J turbos (CT12A)
CT15B
Impeller 46/65mm
Turbine wheel 60/48mm
CT12A
Impeller 37/54mm
Turbine wheel 52/42mm

2. The turbine doesn't fall off faster, the CT15B is a more efficient turbo than the CT12A. Of course if you increase boost pressure, the ceramic wheel doesn't like to overspeed so will be damaged. Look at Diagram 6 when comparing both CT12A's against the CT15B

The head ports are tiny, this also helps it spool faster but chokes the top end. This is just how it is, the engine is built to deliver a flat torque curve and boost low in the rev range and the pay off is limited topend when compared to the other JZ turbo engines.

The head ports are not smaller, look at diagram 13, the exhaust ports are shaped better in the VVTi head when compared to the earlier 1J heads:
"The shape of the exhaust ports, combined with making them smoother increases exhaust flow efficiency"

Smaller ports don't increase exhaust flow.........

I would not recommend running a standard A340 behind a VVTi 1J motor.
The older 1J does not produce the nearly 400nm of peak torque in the same part of the rev range as the VVTi 1J. 80% of peak torque is produced at 1800rpm from a VVTi 1J

This alone would be enough to damage a standard A340. The torque convertor and the clutches in the A341 behind a VVTi 1J are way more heavy duty than the standard A340, the torque convertor steel thickness is greater and the A341 uses kevlar clutches and uses the Type IV fluid for that reason.

[TTMX83]

PS: I know the MX83 auto isn't the strongest thing compared to the auto the engine comes with. But thats not the question

Read the first post?

Cheers Brad.

OH, an Simons MX83 auto is still fine behind the TT 1JZ..... Although I guess that isn't proof enough