turning a 4.4L to 4.6L
 

Since there is such a big HP difference between 4.4L and 4.6L I ask the forum now what parts must be exchanged in order for this to happen?

There is more to it than just swapping a few parts. I think other's have said you're better off super charging it.

In short:

Remove your current 4.4 X5 from driveway.

Clean driveway.

Install replacement 4.6 X5 into driveway. Torque to 44ft lbs.


In all seriousness, at least pistons, cams, and transmission upgrades; not even considering any exterior modifications to look the part.

If not too concerned about the unique 4.6L parts/appearance, just get an '04 - '06 4.4L. The HP difference is less so, ~25HP or so...

Engine, transmission, DME, EGS, stiffening plate (has cooling duct), front and rear differentials.

That's the big stuff, anyhow

I'm not concerned with the outward appearance; mainly just the engine and upgrading the performance to what the 4.6 offers. I have a 4.4L apart now and am thinking about boring it out, sleeving it to get it to 4.6L but what else would I need aside from new software? Would the transmission not be able to handle the extra power? Dinah sells a S/C kit that brings hp to 412, which is impressive.

The Dinan S/C kit would be less invasive than an engine overhaul, and a better bang for the buck. They've tested the 4.4i kit like any other Dinan product, the transmission will be ok to deal with the torque.

How far apart is the 4.4 motor?

Down to the block. The heads are on the bench.

Eh, maybe give VAC a call. They do some pretty gnarly head work.

I'm looking into a number of options so we'll see what happens. I want to try to achieve something most wouldn't tackle and since it's not like my daily driver is waiting to go back together, time is on my side with this project.

VAC is definitely top notch. I've toured the shop with a friend that has a 740il with the 4.4 thats been bored out etc. etc. and has a supercharger strapped on it as well. It is more fun to drive than I could ever imagine. When I got back in my car (stock 4.4 with the sport diff 3:14) it felt like I was in grandmas station wagon.

Im a fan of the 4.6 (340hp) and 4.8 (355hp) too. :thumbup: I'm painting my X5 now and planning on selling it to step into a 4.6 - Dropping it off tomorrow for the paint job - getting excited!:D

Nice!! Well post some pics once it's newly painted. I'll check the VAC website.

Cheers

A guy did this in his E39 540 about 5-8 years ago. I believe that he had to keep his stock heads and was able only to use the 4.6 block.

He had a few little things (as you might expect) to work out, but he said it pulled like a freight train. I'll have to find the link to his story.

That would be great if you could find it. THanks

Here ya go:

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