Thread: ZF 5HP24 into a P38 possible ?

No, but I like your thinking.

Anything is possible as long as your wallet is open! I would assume an ecu swap would be in order...

Keithy

Why?

The effective torque band in the P38 comes in around 2500 rpm which is bordering on the max open road speed limit in 4th (ZF4HP24)... below this it is 'lethargic' to say the least around 90-105kmh in top gear especially on a gentle uphill grade...

A 5sp box with a reasonably close ratio 4th gear would enable it to cruise up long grades at sensible rpm around 2800 rpm (= not revving the guts out in 2nd/3rd as it does now)...

(Tired of being left in the dust of pesky turbo diesel Jap wannabees on long gradients )

An alternative is to somehow improve the torque in the 1700-2500rpm range. I did wonder about a supercharger but a 5sp box seemed a better proposition. I'm not looking for a rubber burner... just need to improve the tractibility of the existing setup if I can...

I have looked at the feasibility of a TD2.7V6 transplant and retaining the 4Hp24 as per the Simtek/Bodylogic offering from the UK, but the local availability of suitably priced donor engines plus the emerging incidence of catastrophic engine failures due to bearing problems in the early TDV6s makes the whole exercise a bit "iffy" to say the least...

Hence the thought about a 5sp box.

EDIT: having lived with a GMH LS1 for 9 trouble free years ...my son has it now... I am sure that a LS2 with a slightly different cam profile to reduce the rpm needed for max torque would be ideal!

It wouldn't be worth the expense

Anyhow, you can switch the BeCM to manual, you'd also need to control any 5 speed

I searched the ratios for the 5hp24 box and all the magic is in the lower ratios. 5th gear is slightly 'lower" than 4th gear on the 4hp24 (0.8:1 vs 0.78:1) and the lower gears are considerably lower than the intermadiate gears on the 4sp box. 4th gear in the 5sp box is 1:1, the same as 3rd gear in the 4sp.

Back to "square 1"....
cheers

So it would only really be of benefit if you had a taller diff ratio in the diffs or larger tyres (33's as an example)...

Perhaps more financially viable if teamed with an engine transplant also!

The P38 is the new classic, I wouldn't be surprised to see some heavily modified versions hitting the road over the coming years...

Keithy

Hmmm, got me thinking... I run 33's with 4.1 diff ratios and my speedo is still out by around 10% on the 4.0 Hard Rangie. At 110kph it is doing around 2600rpm.

So the 5HP might be more useful off-road and working up through the gears but no real value for highway cruising?