Engine Conversion on a b6 cabriolet.


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Dec 19, 2007
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hi there guys, i have got a audi a4 cabriolet 3.0 sport MULTITRONIC. I am interested in doing an engine conversion and swapping the 3.0litre lump for a 2.0T FSI out of a donor a4 cabriolet (facelift).
How hard would this conversion be? both are front wheel drive, but as mine has a multitronic gearbox, what do i need to look out for in particular in the donor vehicle?

thanks :)
Why would you want to do that unless your engine is beyond repair and the other one is free! devalue your car and a lot of hastle for no reward. CHOP IT IN FOR A 1.8T.
Why would you want to do that unless your engine is beyond repair and the other one is free! devalue your car and a lot of hastle for no reward. CHOP IT IN FOR A 1.8T.

i agree y would want to go through all that hassle for a slower car unless your engine f**cked
maybe its not such a good idea then lol, reason why i considered the 2.0T was its tuning opportunities such as miltek exhausts, intake, remaps and so on.

im not sure if u guys are aware but im in the middle of performing a b7 rs4 facelift onto my b6 cabriolet, im still locating all the parts and i am nearly there.

would you recommend going for a full conversion and stick in the rs4 4.2 v8 lump, so that the car look as good as it performs? i have a mate who has a lot of links in the salvage industry so he will most probably be able to locate a donor rs4 vehicle with only body damage but no chassis,engine, suspension damage?

whats your ideas on sticking in the big v8 lump? is it possible?

I'm sure we were chatting a good few months ago about the b7 facelift. hows that going then? I am still considering it in the spring.

As far as i know need everything from the front end, and the wings are ok on a cabriolet (they are the same), am i correct? they say the wings are different but only on a saloon.?

Also, parts like the headlights, bumper, slam panel, grille... are they the same on a saloon as on the cabriolet?

if you already have a 3.0litre petrol and your doing an rs4, then thats fine, just tune that up, why bother changing engine. Mine is a diesel so i don't want to do rs4, just a b7 facelift.
Slower car if he fitted a 2.0T I dont think so.

Just a remap would be way quicker than 3.0 but the thing that would say not to do it is the cost, that would be the reason not to do it as I'm sure it would be cheaper to just buy a 2.0T
I'd seriously consider selling the car you have and buying a 2.0T, especially if your about to start major body mods.

Not only will you end up with cheaper insurance (engine conversions ARE difficult to insure), you'll also end up with a better resale value and it will probably cost you less in the long run, ESPECIALLY if your planning on paying someone else to do the conversion.

Not sure on the RS4 engine, but the B6 S4 is a V8, so you'd be able to use all the mounts etc from it. Your multitronic box will probably snap in half with that engine sat on the end of it though, so again, you'd be better selling up and buying an S4.

Do you NEED the Multitronic box, and can you do the conversion work yourself?
thanks for the replies guys.

dillon884 - im still locating all the parts before i can start the work because its my everday car so its not worth doing it bit by bit if u catch my drift, im waiting to get hold of all the parts and then get the work done in one go. hows ur conversion going mate?

docurley - u understand where im coming from with the 2.0T idea, its more of a tuneable engine than the 3.0 and a lot of power can be achieved in very little time and at a reasonable cost, especially the remap

aragorn - ermm to be honest i dont really need the multitronic, but i was considering swapping my a4 for a mates cabriolet which is a 3.0 manual as he wants an auto, he cant be bothered driving a manual but he drives like a grandad anyway lol
would the mounts not be a problem as i could shift all the parts such as the mounts and so on from the donor rs4? whatever part is needed will be available from the donor rs4 so if the standard part is not sufficient then the donors part will be used? i wont be doing the conversion myself but i have a lot of mates with bodyshops, some who are mechanics so the work will be done by them
what do you reckon mate?
I was just looking on Autotrader... b6 cabriolets fetch over 8k... and i've seen decent b7 cabriolets start from about 13k.... 5k difference between the two..

I don't know how much the whole conversion will cost, including facelift and engine... but would it be worthwhile just buying the b7 with the engine you want and replacing the front bumper with a rs4? That way you will have the rear conversion done aswell (even though its only the lights).

PLUS u'll have a newer car

and i'm sure it would be a lot less hassle!! What do you think?
yeah them prices sound about right tbh. well the thing is, the reason why is that i can get all the work done quite cheap as i have a few mates with bodyshops so the only hassle is getting hold of the full list of parts, which i am in the process of doing still, but iv been told that aslong as i can get hold of the parts at a good price , the total for parts and labour will be less than £5000, which is pretty good going i think.

the reason why i asked about the engine conversion is that for that amount of work, will it be worthwile putting in the rs4 lump, ecu and so on, for an extra couple to a few thousand pounds?
if you get the manual base car, the swap gets much simpler.

The RS4 (or S4) mounts should fit your chassis just fine.

The V8 would even bolt streight up to the manual gearbox you already have.

Not sure how RS4 would compare to S4 in terms of how difficult the conversion would be. The S4 is a conventional 40v V8, whereas the RS4 is a FSi engine, and i'm pretty sure the FSi fuel pumps etc are a bit odd.

S4 V8 shouldnt be too difficult a swap though.
hi aragorn, as u say the manual base car will make it much easier, which is why im in the process of looking for a manual a4 convertible, but its either between the 1.8T or the 3.0 incase i dont go through with the conversion but i still be adding all the rs4 exterior and interior parts :)

i see where ur coming with the fsi injection to the rs4, what must be done in order for it to operate as a normal rs4? what parts in particular or in general must be changed ?

cheers buddy
I've no idea on the specifics, but for example i've read the FSi fuel pumps dont have a return, and they use some kinda PWM modulation to control the fuel pressure. Whereas your 3.0/1.8T will have a normal feed/return system with a pressure regulator on the fuel rail.

Its not going to be impossible, its just a whole extra level of complexity.

If your going to add the RS4 interior and exterior, and the engine... why not just buy an RS4 in the first place?
iv got hold of a company who are willing to do the whole engine conversion, so now its just a matter of gathering a list of parts off the company and then sourcing the parts.

the reason why i dont want to buy an rs4, is one i want to do a little project and secondly i can source the parts really cheap, as i have a few friends who are in the salvage iindustry and motor trade.

i will let u guys know how i get on :D

thanks for all ur help guys, much appreciated ;)