Outer Limits 4x4 Board

Breaking away from the Disco thread.

Aquarangie wrote:Even the P38A 4.0's have the 22 box in them as well as the S2 Disco V8 and td5's (4.6's have the 4HP24 fitted), so they are virually identical and I can't see why the 97 onwards would be atronger, maybe you know something I don't about the ZF's (doesn't surprise me with LR )

Trav (or anybody), what is the difference between the 4HP22 as fitted to the TD5 and the 4HP24 as fitted to the 4.6V8? I've got a TD5 with a 170kw/520Nm upgrade and I'm sure the auto is going to pop itself. IF it does happen, then perhaps the 4HP24 is a better alternative???

http://www.outerlimits4x4.com/PHP_Modules/phpBB2/viewtopic.php?t=37518&highlight=zf

Philip A wrote:Just on the subject of ZFs and big engines.
I looked up the maximum torque rqatings for the various ZFs.
The 4HP 22 fitted to 3.9 rangies etc has about if I recall 280 ft Lbs
The 4 HP 24 from the 4.6 has a max torque rating of 370Ft Lbs
A gen 111 has a max torque output of 385 ft lbs
Apparently you can upgrade the 4HP 22 by putting clutches etc out of 4HP 24.

BUT a 3.9 ZF will not last very long behind a Gen111

Regards Philip A

Thanks fellas.
In essence, the 4HP 22 is rated to 380Nm, and the 4HP 24 is rated to 500Nm

Philip A wrote:
BUT a 3.9 ZF will not last very long behind a Gen111

Regards Philip A

I think HSVRangie might beg to differ.

Hey its not me saying what the max torques are, its ZF. Do you think they say it for fun???
Or do you think land Rover put the 4HP24 behind a 4.6 because they wanted a more expensive transmission??
IF you use the power a 4HP22 will not last taking more torque than it is designed for..
I would love it not to be, as it makes a Gen111 just that more unaffordable.
Someone I know who has a 5 litre built by Bruce Davis , says that Bruce knows someone in Melbourne who can build a 4HP22 to take Gen111 power, for $7000. There is an intermediate build using 4HP24 clutches for $3500-4000 which this bloke bought.

Regards Philip A

I really don't know how the guts of the autos are made or what the bits do, but if the 4HP22 is modified using the 4HP24 upgraded bits (clutches?), then will the 4HP22 then be able to deal with the same torque that the 4HP24 can? Does that effectively make it a 4HP24?

Having a look at Ashcroft's site I found this:

If you are running a high performance engine it is possible to upgrade the internals of the 4HP22 to the 4HP24, please note the box will be 15mm longer due to the thicker pump assembly

So I guess its not just clutches and is effectivly an HP24.

I'm starting to think about an auto conversion now as once I've had my engine tuned up I should be pushing out something in the region of 500Nm I also need to work out what else I want to do to it....

So far mine is behaving OK.

I have no doubt it will die eventually.

But at the moment it is behaving perfectlty.

I'm pushing almost 250 KW through it and have 485 NM.
aprox 400 NM at 1200 rpm.

Michael.

Yeah HSV I guess thatis what anyone would do. I do not know whether something goes BANG or just the clutches give up. My guess is that the clutches give up. One day you will do a full throttle take off and on the 1-2 change she will just flare. BUt if you drive slowly without using max torque it may last a long time, but why have a 5litre then?

The 4HP24 is fully computer controlled, no kick down cable etc. Obviously it has a bigger pump for higher line pressures.

Seeing we are on ZFs, anyone know if a Jag kickdown cable is longer than a 3.9 one. I am currently putting a Thor manifold on the 3.9 and the kickdown cable is one of teh major glitches. and what a job to change. Valve chest out job.
Reagrd s Philip A

Philip A wrote:The 4HP24 is fully computer controlled, no kick down cable etc. Obviously it has a bigger pump for higher line pressures.

I didn't know that, I though the EH boxes were the electonic ones.

I have been told you can change KD cable from out side the box carefully.

I thought the HP 24 was manual at first then went to electronic at later date.

Michael.
P/S doesent get treated gently

See this site
http://www.d-k-automatics.freeserve.co. ... .htm#rover
The Rover 4.6 always was electronic.
regards Philip A

...kickdown cable is one of teh major glitches. and what a job to change. Valve chest out job.

I have been told you can change KD cable from out side the box carefully.

You can change the KD cable with only needing to pull the oil pan off. Quite easy just takes a little delicacy with a screw driver to position the cable. I did this once.

That's good to know. I have asked Jag Rover Spares about a Jag Kickdown cable, so hopefully they will tell me if there is a longer one available.
Its still a pain to drop the sump, with having to drop the exhaust , but better than removing the valve chest. Imagine dropping it and all the little balls and springs flying all over the floor.
Maybe I can set up a bellcrank and shaft and use the current cable with another short cable to the throttle spindle which doesn't yet exist..Maybe a Hobby shop is the go.
Boy the drama little things cause.
Regards Philip A

When I did my conversion:

I extended the Std RR cable.
Had a custom cable made up for the ext, wanted to keep the stock cable.

Michael.

Michael,
How did you do the extension? The only way I can think of is to have a bell crank,ie a wheel mounted in a bearing with one cable connected to one side and one on the other with mounts for the outer.. i went to Hobbyco looking for Model car or plane stuff but nothing suitable.
Regards Philip A

Philip,
Will Post pic tonight

Michael.

Thanks in anticipation
Philip A

ZF kick down joiner


Cable to engine


Michael.

Thanks Michael,
That looks a good system. Now all I have to do is get the ratio right, and figure out how to mount it to the motronic spindle.
Regards Philip A

Im assuming by the Ashcroft website that the ZF4HP24EH is 15mm longer than the ZF4HP22EH. Do you know if they are a direct swap over apart from this?

Slunnie wrote:Im assuming by the Ashcroft website that the ZF4HP24EH is 15mm longer than the ZF4HP22EH. Do you know if they are a direct swap over apart from this?

the box we build using the 4HP24 is made as a straight swap for the 22 apart from the additional 15mm length (from the thicker pump body) and you will need to make either new oil cooler nipples or adapt them as they go from 16mm to 18mm thread. The earlier 24's used a larger torque converter, if you want to stick with the stock converter you will need to make sure you find the correct type of 24 as the donor, ie the later 4.6 one or the Disco II 4.6 one (this might be US spec only), if you use the right box anyone familier with building ZF's can do this,

Thanks for this Ashtrans. Do you know if the ZF4HP22EH from the D2 that is rebuilt using the upgrades from the D2/P38a ZF4HP24EH able to carry the same amount of power and torque as the proper ZF4HP24 or the ZF4HP24EH? It doesn't seem to take a lot with this motor already to bring on the temp warning light. Also do you know what the differences in lengths are for the standard ZF4HP22EH and the ZF4HP24EH and if they are a bolt up and plug in on the TD5 despite coming of the V8? Thanks for this tech.

Slunnie wrote:Thanks for this Ashtrans. Do you know if the ZF4HP22EH from the D2 that is rebuilt using the upgrades from the D2/P38a ZF4HP24EH able to carry the same amount of power and torque as the proper ZF4HP24 or the ZF4HP24EH? It doesn't seem to take a lot with this motor already to bring on the temp warning light. Also do you know what the differences in lengths are for the standard ZF4HP22EH and the ZF4HP24EH and if they are a bolt up and plug in on the TD5 despite coming of the V8? Thanks for this tech.

physically the 4HP22/24 hybrid will be the same strength as the 4HP24EH but when the EH is used in the P38/disco II the engine power is reduced by the ECU's during the shift, I guess this is for smoothness and box longlevity, if used in a TD5 Disco you can keep the electronic control and just build in the 24 parts, length will be plus 15mm and you will need to mod the oil pipes,

If you are finding the oil light is coming on a lot I would suggest fitting an additional cooler, the oil temp is proportional to the box life,

Excellent, thanks so much for this info Ashtrans! Your worth your weight inb gold!