The V8 Owners Forum -

Quick query.
I'm upgrading a 4.0 gems RV8 Landrover 90.
Changing the chassis, so everything is accessible and will be moved across at some point, so I'm upgrading, refreshing and rebuilding other bits too.

It's going to get a nicely tuned 4.6 top hat probably with a 270 or 275 cam.
Ported heads and large valves.

Current trans is the standard 4hp22.

I am considering upgrade to 4hp24 for longevity
(Either going compushift or a rebuilt trans with the hydro mech valve block)

Is it worth it?
I did run this engine spec on a RRC which had a 4hp22, and although I had no problems, it didn't always feel completely solid.

Any advice gratefully received.

Thanks,

Mike.

I don't know how you change one into the other. However, I do know that the 4HP24 is longer because the pump is thicker. This will affect mountings and propshafts.....

Chris.

Yup, the 24 is 18mm longer, but you can fit it in by elongating the engine and trans mounting holes a bit, and a bit is taken up by the prop.

Otherwise, they are interchangeable ( mechanically ).

The electronics on the 24 are another story though...

Ashcroft transmissions would know, but whether they'd tell you is another story!

Chris.

Think I've read the 4HP22 can be upgraded to handle more torque. Which might be an easier route. The standard box is good to 380 NM if it helps.

Yeah, ashcroft reccomend a 24 or a modded 22.
I'm just wondering how close I'm going to get to breaking a 22...

I have a 4.6 with a Piper 270 on twin 2" SU's (about 250BHP). I have a 4HP22 (fully mechanical version). No issues yet......

Chris.

Mm that sounds nice ...
What's the torque like on that setup?

In my current layout, it feels quite flat in top gear at 2250 to 2700 rpm.
At 2800 it's coming on song, and pulling really well at 3000 ( about 90 mph)

Yes, if I floor it, it'll rev up in third and go like a train, but it feels boggy low down in lockup top.

Bored 3.9, 50229 camshaft, ported heads edelbrock carb and manifold, megajolt and 75 shot of nos and a standard jag zf4hp22 box holding up fine

Captainbeaky wrote:Mm that sounds nice ...
What's the torque like on that setup?

In my current layout, it feels quite flat in top gear at 2250 to 2700 rpm.
At 2800 it's coming on song, and pulling really well at 3000 ( about 90 mph)

Yes, if I floor it, it'll rev up in third and go like a train, but it feels boggy low down in lockup top.

Not as torquey as the Torquemax cam I had before, but more than adequate. And it keeps pulling around to the upshift point, whereas the Torquemax seemed to be running out of puff a bit. I certainly wouldn't describe it as 'flat' anywhere!

Chris.

Ok, thanks for that, looks like I'll stick with the -22 for now, and save a bit of cash.

Now, what else can I spend the cash on?
( no - don't answer, you will only give me ideas....)

Captainbeaky wrote:Mm that sounds nice ...
What's the torque like on that setup?

In my current layout, it feels quite flat in top gear at 2250 to 2700 rpm.
At 2800 it's coming on song, and pulling really well at 3000 ( about 90 mph)

Yes, if I floor it, it'll rev up in third and go like a train, but it feels boggy low down in lockup top.

Are you sure it's not a tune problem? Have you got a wideband O2 so know what the mixture is actually doing where it feels 'boggy'?

My bog standard Vitesse unit always felt very 'flat' at low revs but flew on full throttle at over 3000 or so. Fitting a Megasquirt made it also pull like a train at low revs - it was running far too weak with the standard set-up other than at full throttle.

When I fitted the megajolt to mine it transformed the bottom end torque of the engine, probably the biggest single boost it was given

JSF55 wrote:When I fitted the megajolt to mine it transformed the bottom end torque of the engine, probably the biggest single boost it was given

Yes - I've looked at a standard flapper with a wideband O2 sensor and it ran very weak indeed at low throttle openings/low revs. Only went rich enough on full throttle.

Yup, mixture is fine, if anything, on the rich side.
Ignition is fine.