Can I Swap An AL4 With A 4HP20?

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16K
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Can I Swap An AL4 With A 4HP20?

Post by 16K »

I have a Citroen C5 2.0 Petrol with an AL4 however knowing it is a very limited box, plus its woes, I was wondering if a 4HP20 is a straight swap? I have located a box with 58,000 confirmed miles from a crashed C5 2.2 HDI and was really tempted to pick it up.

Any suggestions?
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Re: Can I Swap An AL4 With A 4HP20?

Post by xantia_v6 »

16K wrote:
Any suggestions?
Turn around slowly and walk away...

There is no way that it is practical to fit a 4HP20 to an engine that it wasn't designed for. The transmission ECU needs to talk to the engine ECU, the stability ECU and others, and it would immediately detect that it was in the wrong place and go into likmp mode.

The gear ratios from a 2.2 would be wrong for your engine anyway.
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Re: Can I Swap An AL4 With A 4HP20?

Post by 16K »

I see, is it not possible to take the ECU from the V6 petrol or to have someone flash the existing one?

I am some what frustrated, I was hoping to increase the engines power to over 180bhp + that’s why I was contemplating a more robust autobox. I spoke with a few Peugeot tuners and the prices were very reasonable, seen as this engine is heavily used in the Peugeot tuning scene (notably the GTI.)

If not, is there ANYTHING that can be done to the AL4 to make it more reliable? The amount of woes this box has is unbelievable. I know this all sounds very bizarro to everyone here, but it is impossible to find someone to buy my car at a reasonable price, and worst yet it is even more improbable to find a car that I want at a reasonable price. Where else can you find a 20,000 mile car fully loaded to the teath with every option from the factoy selected?
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Re: Can I Swap An AL4 With A 4HP20?

Post by GiveMeABreak »

It may be a great spec'd car, but the Diesels are more popular and more economical than the Petrol C5s. They are cheaper to tax by at least £100 a year and the in some cases the parts for the petrol engines can be difficult to obtain (we don't know your year or model), such as the HPi fuel pumps. I'm sure it's a great car though - but some people will decide on the fuel type first then the manufacturer and model. :)

Just looking on Autotrader out of interest as of posting - there are 327 Diesel C5s for sale and 27 Petrol C5s (of any year), and if narrowing this down to the later C5 X7 from 2008 on, there are 243 C5s of which only 3.3% (8) are Petrol v 97% (235) Diesels for sale, which may partly explain why you are having a harder problem selling it if this is typical across the market.
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Re: Can I Swap An AL4 With A 4HP20?

Post by 16K »

The vehicle is a 53/2004 non-HPI standard EW10 engine.

I am aware of all the diesels for sale but the reasonable mileage/age ones start from over £5,000 but that is not the reason I am doing this.

I already have a brand new LPG kit waiting to be installed, but first wanted to mod the engine before doing so however this gearbox is going to be the life of me now that I know its the AL4. It has totally messed up everything I had already planned.

I was going to have a 180bhp+ petrol luxobarge that does equivalent to 60mpg on the motorway. :D My plan is to keep this car for another 3-5 years as of last month most of my journeys have become dual carriage/motorway.

All the advice I can get is appreciated.
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Re: Can I Swap An AL4 With A 4HP20?

Post by teuski »

Swap a HDi engine in there ;)

The AL4 is much more civilized when attached to a diesel engine. Probably the best ride I've had was a '98 Xantia 1.9TD with an AL4. Almost 500 000km when i sold it and the box was just fine :)
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Re: Can I Swap An AL4 With A 4HP20?

Post by Carsten S »

Also, the automatic gearbox controller is optimised to your engine, so gearchange characteristics, etc. will fit nice.

When you NA tune an engine the power typically comes at a higher rpms, i think it would be somewhat weird to drive with an automaticbox.
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Re: Can I Swap An AL4 With A 4HP20?

Post by Mandrake »

16K wrote:I see, is it not possible to take the ECU from the V6 petrol or to have someone flash the existing one?
You can't use the ECU from a Petrol 4HP20 on a Diesel 4HP20 as the final drive ratio will be different. This will confuse the ECU and put it into limp mode. (See a recent thread on this exact problem with a donor gearbox with the wrong final drive ratio)

Your gearbox model swap idea is basically impossible, for multiple reasons both mechanical and electrical. I wouldn't waste any more time thinking about it.

By the way, I don't think the 4HP20 is a particularly good gearbox. Yes it has much higher torque capacity but after having owned two Xantia V6's the autobox is the weakest part of the car for sure, and even at 70k miles they can start to get a bit cranky, and outright failure just past 100k isn't that uncommon. (Had it happen to me at 112K - just after the car was sold for parts!)
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