My S2 Coupe refurb/ upgrade projects

[tomwood_uk]

Hi guys,

After finally managing to find myself a small unit to rent, I have recently decided to bite the bullet and begin work on my ABY coupe. Ive been meaning to start a thread on here sooner - just haven't had the time. Although I'm not new to working on cars, I have a back-log of questions and queries that have cropped as I've began to get stuck in! I'd really appreciate it if some of you more experienced guys wouldn't mind shedding some light

History;

The car is completely standard, other than some KW V1's, RS4 replica wheels and a S/S cat back exhaust. It has covered just over 100k.

One of the main reasons I've decided to undergo a refurb on the car was due to a large amount of slop in the drivetrain. There was also a considerable amount of rumbling/ resonance being transferred through the floor into the car. To cut a long story short, it appears than the transmission mounts had failed, transferring a lot of the engine vibrations though the subframe and into the body of the car. This coupled with signs of wear visible on the rest of the drivetrain bushes resulted in action being taken. I plan to refurbish the drivetrain, upgrade the brakes, increase engine power (hopefully circa 400 CHP), and tackle bodywork and interior. I know this amount of work will take time, effort and a considerable amount of money

So far;

To date: the engine, gearbox and subframe have been removed. Engine and gearbox split, engine stripped down and examined. The cylinder head and block are now at the machine shop awaiting refurbishment.

Questions

The cylinder head is cracked in numerous places - between the valves and spark plug threads. I'm aware that some people have re-used heads like this without repair however some of these cracks appear to have climbed quite fair up the spark plug holes. Consequently I'd like to address this problem. A rough estimate from the machine shop to have the head welded is at least a few hundred pounds. Would using a modified 7A head be the best option? I have close connections to an engineering company which may be able to carry out the conversion free of charge.

Should I get the gearbox refurbished? I had planned to, but as I'm unfamiliar with the Quattro's gearbox I'm unsure; where to take it, what to have done, common problems and how much to pay.

Should I switch to single mass flywheel, If so which one, which clutch should I use and where to take the engine to be balanced in the Midlands? Upon disassembling the engine I noticed a considerable amount of "play" in the flywheel assy. I observed play equivalent to 5 teeth on the ring gear. This slop could be taken up by hand while the flywheel was still bolted to the engine.



I'll leave the questions there for now. I have used the forums search function but admittedly haven't had chance to get really stuck in. Pictures are below, and thanks in advance for any contribution!

[jade]

20vt heads are prone to cracking, but your looks to be one of the whose I have seen, I would recommend replacing it either with a modified 7A or sourcing a good ABY or AAN head, not so easy

[jade]

Should I switch to single mass flywheel, If so which one, which clutch should I use and where to take the engine to be balanced in the Midlands? Upon disassembling the engine I noticed a considerable amount of "play" in the flywheel assy. I observed play equivalent to 5 teeth on the ring gear. This slop could be taken up by hand while the flywheel was still bolted to the engine.

Play in the flywheel ? there no play in that

[tomwood_uk]

Yea the gearbox side of the flywheel will move independently of the engine side, by hand.

[diesel des]

Those dual mass units do move about a bit. I'm not sure what the maximum permitted movement is, sorry. There is a fella on here that sells a clutch conversion, complete with new flywheel, clutch etc to go solid and bin the dual mass unit. May have some chatter noises once converted, but in my opinion worth it to do away with a failure point.

That head does look bad. Go 7a and get it converted and rebuilt with your valves or better.

As for gearbox, is it noisy or crunching gears? If not leave well alone. Bits are very expensive.... if it ain't broke, don't fix it.

Good luck, des.

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[tomwood_uk]

Those dual mass units do move about a bit. I'm not sure what the maximum permitted movement is, sorry. There is a fella on here that sells a clutch conversion, complete with new flywheel, clutch etc to go solid and bin the dual mass unit. May have some chatter noises once converted, but in my opinion worth it to do away with a failure point.

That head does look bad. Go 7a and get it converted and rebuilt with your valves or better.

As for gearbox, is it noisy or crunching gears? If not leave well alone. Bits are very expensive.... if it ain't broke, don't fix it.

Good luck, des.

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Cheers Des. Ive been thinking the same thing about the gearbox.

Ive been doing a bit of research about the flywheel, and it seems that the should be movement in it but not as much and it shouldn't move as freely. Its also a very heavy bit of kit!

[diesel des]

Yep, as soon as you start chasing power a single mass unit becomes even more attractive.

What's your plan engine wise.

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[Greg_S]

As has already been mentioned with the single mass you loose a little bit of give and refinement on the clutch, but engine does rev more freely with the single mass (SM) flywheel.

[tomwood_uk]

Cheers guys.

Regarding the dual mass flywheel; the drive and gear change wasn't very refined before, so I'm sure I wont be disappointed.

In terms of engine I'm still undecided on a few things. I don't want a race car. I'm aiming for a smooth, reliable and very usable amount of power. Initial thoughts are; stock bottom end (rebuilt, most likely using ARP hardware) 7A cams, Garrett GTX series turbo, custom inlet + exhaust manifolds (reversed), custom crossmember/ intercooler and pipework, custom exhaust system, new injectors to suite and possibly a coil upgrade. As mentioned above I have access to some real top-quality fabricators/ TIG welders so I plan to make full use of this. I know a lot of people switch to forged conrods at around the 400bhp mark, and I'm still undecided on this.

My real dilemma regards engine management. It appears that getting the stock ecu remapped is gonna be a real PITA. I'm also not fond of generic chip tuning as Ive had disastrous experiences in the past (2x melted Polo G40 turbo engines!). Having said that there seems to be some really well respected tuners on this forum that are a dab-hand with Motronic, so perhaps they could shed some light? Standalone management is appealing at the minute, as once its installed It'd be much easier to further develop the engine in the future. What do you guys think?

[diesel des]

Well for 400 hp stick with stock cams. The 7a cams just give less bottom end and little little more top end due to restricted turbo for only 400hp. I say only, but you know what I mean. To be honest, a rs2 setup would get you 375bhp, and is straight forward. When you run Garrett turbos (I do) you need to make up oil and water lines, downpipes etc. I'm on stock rods etc on a gtx2867r and it's a nice car to drive, and would easily make your power goal. Food for thought.

Prj, Dimitri is probably the man to map it on motronic. If you are building and balancing the engine, get a set of rods. For 400 quid it's not a lot for the insurance it buys. And it's a pain and expensive to change later.

Jp at jnl racing is your man for balancing too. He is also good for stuff like rods.

Cheers des

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[tomwood_uk]

Well for 400 hp stick with stock cams. The 7a cams just give less bottom end and little little more top end due to restricted turbo for only 400hp. I say only, but you know what I mean. To be honest, a rs2 setup would get you 375bhp, and is straight forward. When you run Garrett turbos (I do) you need to make up oil and water lines, downpipes etc. I'm on stock rods etc on a gtx2867r and it's a nice car to drive, and would easily make your power goal. Food for thought.

Prj, Dimitri is probably the man to map it on motronic. If you are building and balancing the engine, get a set of rods. For 400 quid it's not a lot for the insurance it buys. And it's a pain and expensive to change later.

Jp at jnl racing is your man for balancing too. He is also good for stuff like rods.

Cheers des

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Cheers Des, food for thought indeed.

I had considered an RS2 setup. However it appears that it's not a cheap option, and I'd like to use a new turbo and other components to enable further development in the future.

Are you still running Bosch management Des?

[diesel des]

no I went with vems as I like tweaking. Motronic is still worth keeping if you can get a good mapper...

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[tomwood_uk]

Quick update guys. Managed to get hold of an uncracked AAN cylinder head today, many thanks to 'Chez' on here for sorting me out!



Gonna take it into the engine shop tomorrow to get in refurbed. Just a quick question; are the valves in the AAN the same as the ABY? I rather not swap the valves over if they're the same (sodium filled etc).

[diesel des]

Yep, same valves.

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[tomwood_uk]

Yep, same valves.

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Cheers Des.