Citroen XM Forum

Hi John, thanks for that info, it was only a supposition on my part with regard to space. The torque difference between the V6 and the DK is less than 20mN and i know the HP20 has a max rating of 330mN, well above the ratings of either engine, i have no data for the HP18, but as others have posted on this topic assume it will be in the same range, it was after all fitted to American spec 911's and 944's.
robertm

I wonder how the 4HP20 would cope with the 2.5 lump. It would be a car I would be very interested in driving if such a thing were ever to be made. The 2.5s supple nature minimises the need for a lot of gear changes anyway, and the economy is bad enough as it is, without an auto box making it worse!

The biggest problem I saw with fitting the HP20 was programming the gearbox ECU after the gear ratios were physically modified.
All the XM gearboxes are hung from the same type and position of engine mount.
The XM chassis is common to all models that side so any box will fit any XM.
On the other side the 2.5 has a 30mm reinforced inset into the main chassis rail.
The inset is just a bit wider than the engine.
So for my conversions the 2.5 engine had to stay in the 2.5 shell while the manual box went in the V6 in the original chassis.
The pedal boxes need to swap between the cars.
Some of the smaller bits I had obtained are now buried deep in a corner of the unit.
It was just the stored V6's that had to go.

There are rumors that surface occasionally that there were 2.5 auto prototypes built.
With suggestions that the selected autobox failed to survive the test track.
All I can confirm is that chipped manual 2.5's had a reputation for short clutch life.

John

xmexclusive wrote:The biggest problem I saw with fitting the HP20 was programming the gearbox ECU after the gear ratios were physically modified.

Indeed John, the HP20 ECU gets very upset indeed if it doesn't see the right input and output speeds so if you go altering ratios then this will happen and the ECU will believe there is an excessive amount of slip and throw it's toys and initiate emergency third..

There may be a solution. The Pug 406 V6 with the 2.2HDi engine was used with an HP20. I know because I have the remains of a 2.2HDi HP20 'box here as a spares donor. Sadly no ECU though... So, perhaps if you really want a 2.5 Auto this would be the HP20 to choose?

Hi Jim

Missed the 2.2Hdi auto as a donor option.
Have added that to my list of ECU's to obtain if I see one going spare.
For the V6 manual option I had obtained a ML5 box from a 406 coupe.
Do not suppose you have a naff ECU for a V6 HP20 for me to pull to bits.

John

xmexclusive wrote: Do not suppose you have a naff ECU for a V6 HP20 for me to pull to bits.

I do indeed John It's from a 406 V6.

PM me your address and I'll pop it in the post to you...

Hi Jim

That is good.
Do not waste your money on postage, there is no urgency.
I will collect some time convenient to us both.
I have to visit Automec before long.

John

No worries John, it's here with your name on it. Give me a buzz next time you're near here and I'll come out to meet you or you can come here and enjoy a cuppa...

Supposedly sold on the 26th October but its RE-LISTED for sale again !

Did someone get cold feet ?

If so and are forum member, was there a issue/problem with the vehicle ?



XMX

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It has 3 previous owners that makes 4 over 15 years and only 100k giving 6.5k a year between them an avergae of 25k each. Either two or three owners didn't have it very long or perhaps the mileage had been adijusted downwards at some point in the past?