How much power/torque can a ZF 4 speed auto take

mr_s · Post by **mr_s** » Tue Mar 27, 2007 8:56 am

I've got a 3.5 Rangie on LPG, and was wondering how much power/torque the ZF 4 speed auto box (and the LT230 transfer box for that matter!) can reliably take...

I'm toying with the idea of an engine swap for a non RV8 unit, as to get big torque, I want big capacity and it's cheaper to start with a bigger engine IMO!

Cheers, Martin

ChrisJC · Post by **ChrisJC** » Tue Mar 27, 2007 10:25 am

It's measured as a torque, it's around 330 or 350. But I can't remember if the units are Nm or lbft!

The 4HP24 can be build to be a mechanical box like the RR 'HP22, but is stronger. The only difference is that it's a touch longer.

I'll check the spec. sheet tomorrow.

Chris.

mr_s · Post by **mr_s** » Tue Apr 10, 2007 7:19 pm

Hi Chris, did you manage to find out if the 330-350 were NM or Ft Lbs?

Cheers for the help, as ever

Eliot · Post by **Eliot** » Wed Apr 11, 2007 6:00 am

and i wouldn't worry about the LT230 - i'm putting at least 400ft-lb and BHP through mine and it seems happy.

ChrisJC · Post by **ChrisJC** » Wed Apr 11, 2007 6:59 am

Well reminded - thanks!

My German isn't great, so I can't remember the translation, but here is the spec sheet:

http://www.cowdery.org.uk/downloads/4hp22-spec.pdf

Also the exploded diagram from JP Automatic Transmissions:

http://www.cowdery.org.uk/downloads/ZF- ... iagram.pdf

Chris.

alex · Post by **alex** » Wed Apr 11, 2007 7:26 pm

I Thought the 4hp22 meant 220nm torque
and the 4hp24 meant 240nm torque.
I read the 3.9 already stretches it as standard, but I think it can handle lots more just need to take a close look at the oil temperature and keep it cool.
Ashcrofts are quite helpfull and can build a mix of 22 and 24 to work manually.

alex · Post by **alex** » Wed Apr 11, 2007 7:28 pm

you might want to be looking at the diffs and halfshafts aswell depending on how heavy your right foot is

Eliot · Post by **Eliot** » Wed Apr 11, 2007 8:20 pm

i'm running 4 pin diffs and 24 spline half shafts at the back and ashcroft half shafts at the front - no problems so far - but i do try to avoid hard launches and spinning the wheels.