V8 S4 engine conversion

[RichMk3]

Has anybody ever done a V8 S4 engine conversion to a 2.0T B7?

I have a V8 itch that needs scratching and have been saving for a while to buy an S4 convertible, and then got thinking about buying an engine, rebuilding it, and stuffing it into the Avant...

A few questions I have are...

Will the DMF, clutch and manual 6 speed box bolt upto the V8? Is the clutch the same on the V8/2.0t?

What exactly would I need to get from an S4 aside from the obvious?


Thanks,

Rich.

 

[Darren92]

Brakes, suspension wiring, ecu and so on.

It’s not worth it. Just tune the life out of your 2.0T.

 

[RichMk3]

It's not about tuning, I want the V8. Brakes and suspension are sorted. I know it would be more cost effective to sell it and just buy an S4, but again, I don't want to do that either...

So, does anybody know what would be needed from a donor S4?

 

[Darren92]

Absolutely bonkers.

 

[RichMk3]

Thanks for your input Darren, very helpful

 

[kev-s]

Your probably better off buying a rear ended or side swiped S4 as there is bound to be lots of bits that will be needed

Also you can break whats left of the S4 to recoup some of the cost

 

[RichMk3]

That's exactly what I'm trying to weigh up, I've found a very good engine that's complete apart from the ECU, and it's only done 47k with paperwork to back it up.

Agreed it would be better to have a donor car..

People think I'm mad for wanting to do this, rather than just buy an S4, but it does have its benefits. The tax is cheaper than an S4 and my insurance is cheaper for an engine transplant rather than an S4.

Also I know my car is mechanically sound, and if I rebuild the V8 and do the chain before I install it, I know everything is good...

 

[DieselJake]

Does your 2.0t have quattro? I know you say suspension is sorted on yours but the heavier lump will no doubt need different springs for the front if not more. In terms of clutch/gearbox you might get away with it but I'd etleast swap for a more heavy duty clutch if the gearbox lines up. All in all I like your idea and have had similar myself before just have to weigh up whether it's worth doing rather than swapping especially if yours is running good now, I often think of tax and insurance too but surely they don't warrant the labour and parts. What I'm trying to say is the performance (taking into consideration power to weight, etc) of my 1.9tdi (yes the eco engine, I don't even have a 2.0t or better!) is not all that far off an S4, yes it's cost allot and realistically I should have just bought an S4 but I just think if yours is sorted as it is why not pour some money into a highly tunable engine or save some cash back so if anything is up with an S4 you like then you can get it how you want.

 

[petetheprop]

Like said above you'd probably be better off buying a whole donor vehicle.
Dvla will need some proof of ownership of the engine when you update the v5. plus once changed on your V5 the tax will also change, not sure but given the amount of changes you may even need an IVA and end up with a Q plate or other age related plate (Google dvla radically altered vehicle - you may have enough points from the original car so that you're OK).
Not 100% on any of this but I think. ..The clutch is not the same as the 2.0 not sure about the gearbox but I suspect not, the rear diff isn't the same. I'd guess shafts are the same, rear brakes are different. Exhaust is different but you get away with it from the mid sections back. Engine mounts, air con rads, main rads auxiliary rads and oil cooler are also different. air intake is different. Obviously exhaust manifolds and pre and post cats are different. Fuel system is different as the v8 is not fsi it has no return line. Front brakes are different and front suspension is different (S4 is ~200kg heavier at the front). Then you've got all the other bits that most S4 had carbon trim power seats and mirrors, recaros etc etc. Engine loom and front end loom will all be different, ecu. I'm guessing that the body ecu is all fine and with some vcds programming you could get it to work with the new engine ecu.
A lot of work given the current price of S4s, can get b6 versions and face-lift for sub 5k. If you are going to do it Why not go for the rs4 engine instead just as much work but up to 80bhp more as a start.

 

[ajax1976]

I get what the others are saying but sometimes you've got to throw logic out the window and do your own thing, if you really feel attached to your existing car I say go for it. Unless you've got buckets of cash to throw at it I do agree a donor car is the way to go, your cash will go quickly on mounts, looms and smaller crappy bits etc. Personally I wouldn't bother trying to mate it to your existing box, clutches are cheap enough to stick a new one in it and use the donor box as well. Use the donor cars looms, ecu and clocks etc and it should be hard to get running and if you're struggling there are plenty of guys around that are great at coding the ecus etc.

I had the itch and I've almost finished scratching it in my old coupe. Spent a bomb, physically and mentally pushed me beyond limits, would I do it again, hell yeah, that first time of hearing it run more than made up for all the pain.

 

[Charlie Farley]

fully agree with above , sometimes it is just something that one has to do...….sod the cost and the work involved , its a personal thing....
something that everyone should try at least once....
I do it a fair bit with tractors...fitting way bigger diesel engines in to small compacts....mad but worth it....

What is the lump you have slid in there....

 

[DieselJake]

I know this is a boring thing to say but another thing you have to think about is this will turn into a car for life... I've often considered selling up (just for a change) but I'll never get what the car's worth and anything in the same league which I would swap to costs allot more... I know at this moment everyone probably thinks they want their car for life but car enthusiasts always have eyes on alternatives... owned mine 7 or so years and within this time I've bought/sold two other car's, a motorbike and moved three times so yeah it really has to become something you will never get rid of as you won't get back what you pay... you could also potentially kill a good car... I'm not saying don't do it as it totally sounds like something I would be tempted to do but just think of all options.

Oh and let's not even consider what could happen in the event of an incident... this is why I will strongly consider something I won't/can't mod as my next car (... probably still will but I'll try not to haha).

 

[RichMk3]

Thanks all for taking the time to reply, very much appreciated

AJ, that coupe is looking like a beast!

This will not be the first engine conversion I've done, but admittedly will be the first on a "modern" car where electronics play a much bigger part than just the machanicals.