I'm curious about your plans. Sounds like an interesting idea.

1. Will the TT's 6 speed transmission and the rest of the drivetrain work okay, or will you need to replace any of that?

2. Are there any different ventilation/cooling concerns?

3. Aren't these engines designed to be mounted (very) differently?

4. Can you just order an S4 engine as a mere mortal? How are you going to get one? And if you can buy the engine, what else will you need to buy to get the job done?

5. Who do you get to do this job? A custom shop? An ultra-mechanic? A tuner shop?

I'm interested to hear your entire set of comments and plans about this, even if it's not really something you've fully researched yet.

Wow, ok, so i guess I'm curious also. I've worked on both cars and couldnt even imagine tackling a project such as this. All i can say is good luck and hope someone out there is really good with a b.f. hammer.

Jason Dale
Lamborghini technician
Exotic Imports
SLC, Utah

Engine transplants
Abt put a VW v-6 into the TT and it works so well they are going into limited production.
MTM have put two engines into a TT front and rear.
So yes the 2.7 turbo could be made to fit but it may not be the best choice at this time

If I chose to go the S4 route I'd probably be better off converting the TT into a rear wheel drive car. Logistics on such a project are only daunting when looked at before starting such projects. Once you're into them and "time" is not an issue they are encountered/handled as a hobby. No different than building an R/C balsa aircraft from scratch. The components are heavier but the task is no more complicated. Also helps to have my own 17"x42" lathe with Pro-Trak digital readout and 3-axis Sharp mill with a Pro-Trak also. Oxy/atc setup mig/tig and heliarc and a plasma cutter and pneumatic. Simply a matter of when I want to dedicate myself to this committment. And lets face it, it is but a committment, nothing more. About the only thing I can't/won't do in-house is final body work/painting.

Procurement of an engine is easy. Audi will take my money for a new engine if I chose to approach it that way as will VW. But history indicates I will do better in a junkyard purchasing a low mileage engine/tranny from a recent "totalled" car.

Essentially you pull the existing engine/tranny and start with ancillary components. Engine mounts are first. Got to figure a way to get the new engine in and on a perch for taking all required measurements. Ideally with as few of its components removed as possible. Then figure what must be done to get any/all components that are removed in that process back on. After that comes "mating-up"... matching final drives, exhaust, cooling, etc. Next is getting belt-driven components back on and fabricating new mounts/brackets. Oil pan configurations are always a problem in conversions such as this. They never fit. Basically cut off their flange where they mate to the block and have it welded to a new one fabricated with appropriate baffling/design and a new oil pick-up made. Sometimes dry sumps facilitate this, other times not. Cooling is typically not a problem as capacities can be increased by having a thicker (not larger) radiator core made. Maybe a 4 rod or a 5 rod radiator. Same H/W, just thicker, perhaps with inlet/outlet relocated. While much of the prepatory work is done the engine/heads are at a shop having work done that will increase power potential. Definately porting/polishing and probably titanium rods/forged pistons and lower compression ratios. O-ring the heads to block or solid copper head gaskets for higher boost and intake/exhaust ports matched to each other. New ceramic/bearing'd turbos. Once all necessary under-hood cutting is done, new plates fabricated and welded in place. Flat ones are cake. Contoured ones or ones with convex/concave contours are rolled out on an "English wheel" then welded into place.

I've made all this sound so easy and matter-of-fact. Truth is, there will be problems and dilemmas encountered. But they'll be solved. Its no more complex than a thousand piece jigsaw puzzle... just heavier pieces. The electronics scare me as I dont have a clue how to approach that. I'm mechanical but not any kind of electronic/electrical whiz. I will allow someone else to do that for me. This isnt an altogether "easy" project but its not an impossible one either. Most things like this are very intimidating before you start, but if you allow it that alone will keep you from tackling it. If you dont think about it too much and just jump into it headlong all problems are addressed and solved one at a time, as they arise. Wasnt it Confucious who said "even a journey of a thousand miles begins with a first step." Could be a one year project or two or even three. But hey... everyones gotta be somewhere doin' something. I put a chevrolet 350 LT-1 in a Ferrari 375 GTB Daytona once with only handtools and a LOT of rotary grinder work when I was 24, a time when I could LEAST afford to be doing such things. I think I can get a 350HP V6 in a TT today... nay... I KNOW I can. And in a way that is tasteful, professional and if you opened the hood and looked it would appear it rolled off the line that way.

Just a matter of time...

I guess there's not large enough overhangs either front or rear on a TT to fit the S4 engine with the tranny towards the center of the car with the AWD intact. Because of that you figured it should be possible to fit it in the front, but further back than with the forward axle take-offs in the correct position, so it would have to be RWD only. But it should also fit well in the back of the TT, with the tranny to the rear, using the original front axle take-offs for the rear wheels? You have to make a "return gear" to replace the center diff, but that would be easy, wouldn't it? :-))

No irony intended here, just respect for your skills coupled with amusement over such an ambitious project!

I would have no prob building a tubular frame engine mount, but from that point on I'd be pioneering something I've never done before. Just the dozens of in-and-out fitment/alignment tests with a cherry-picker thru the hatch instead of straight in/out from a hoist already has me cringing. And I have no facilities in my garage to do it from under the car a la NSX. But now that I think about it, the entire NSX engine/tranny/FD would be an excellent choice from a "minimal work" standpoint to slip into the TT normally aspirated. Hmmmmm Marius... maybe you've started something here. Would definately be a RWD config but who cares with 50/50 W/D +or- a smidge? And I know where theres one of those in a junkyard right now with 2100 miles on it and $9k would buy everything I'd need. Yowza, wouldnt the purists hate me for that one!!! 300 N/A HP/375 ft lbs and 8,500 rpms IS intriguing. 20"x12" wide BBS wheels and 3" metal flares on the rear with Boxster ducts jus ahead of the rear fenders for induction? And zero
tranny "notchiness" ever again. There ARE definate pluses. Maybe "MissLed" (my black FWD TT) wont go away when the 225 shows. Ok guys... come'n get me. I GOTTA stop smokin this stuff first thing outta bed on Saturdays.