My S2 tuning project

[Hesky]

If you want to secure the future plans take the engine apart and fit proper conrods and steel type head gasket and new bottom end bearings and perhaps piston rings. The std pistons will do the job for you beyond the 400 mark.

I really like that suggestion, i think i can budget for a set of forge rods at the time of the rebuild as I can get a set for a very reasonable price but forge pistons are going to set me back about £750. It may never be necessary to get pistons as I don’t plan to exceed 400bhp 600nm. If the standard s2 pistons are good for 400+bhp that works out very nicely indeed!
I was planning to get a copper headgasket for the rebuild, but would it b best to stick with a multi layer steel job?

[Greg_S]

Its not the pistons that are the problem but the conrods since they cant take the torque as well above 400hp and 600nm. Would be interesting to see how you get on with head gaskets.

Greg

[audiman]

Yep, i was the one told that Motronic is no good past 400bhp!! Well we proved this to be ********. My car is closer to 500 and is still using std ECU setup!! Of course with some custom chips

80k miles is fine for the engine, but its better to be safe than sorry, i guess. I was running 370bhp on my engine before i did the rebuild at 156k miles Only reason for doing it then was because it started to burn a lot of oil.

With an RS2 turbo you will push past the 330bhp mark with ease IMO. Will make it a fast car then.

[audiman]

Dont drop compression ratio too low if you want off boost driving!! Mine is 8.6:1 and its very slow when off boost. But then all that changes when it gets to nearly 4k rpm

[AAH!]

Hi Hesky

My set up does seem to work very well indeed. It was done with the exception of the Bosch Motorsport fuelpump about six years ago, but it was only when Mihnea did a custom map that it all came together and the reel power and torque became apparent and useable throughtout the range.

The MD147 26/27 Hybrid Turbo (from Turbo Dynamics) does spool up a little later than the stock RS2 Turbo, at about 3600rpm opposed to 2500rpm and when combined with the 7A cams makes the bottom end feel a touch more sluggish/laggy than a stock RS2. It is still very quick but once it gets going its unbelievably fast and just keeps pulling. You can get good bottom end performance but it does involve keeping the revs up and driving in a slightly "enthusiastic" style You also have to think a little way in advance to allow for the less than imediate throttle response at lower revs.

IIRC Mihnea isn't a great fan of the MD147 26/27 Turbo and although good, he feels that the stock RS2 turbo is more appropriate and better suited to our cars as it was designed for the engine and spools up quicker.

Having said all that I would not change my set up, I have got very used to planning ahead to allow for spool up and I would miss the top end acceleration and I can always switch into "enthusiastic mode" when I want to get the car to move switly of the mark. Untill they develop a Turbo that does it all, I stay where I am.

At the recent Rolling Road meet the car acheived 377ft/lb @ 3750rpm and 361bhp @ 6293rpm.The plot suggests that there was some heat soak at about 5700rpm which looks like it capped the bhp earlier than it should. We will have to wait and see if Tom C is correct in his guess of 390bhp when we get it on a RR with good cooling (It would be nice if he is).

Good luck with your project....Angus

ps As Lee suggested the car is still very useable around town and you could even call it sedate, depending on your right foot. The only thing that gives the game away are the various noises from the DV, exhaust and K&N and also the lousy fuel consumption - 15-18mpg-ish.

[Audi_CQ]

Dont drop compression ratio too low if you want off boost driving!! Mine is 8.6:1 and its very slow when off boost. But then all that changes when it gets to nearly 4k rpm

Don't think you will feel much difference with 8:1 compared with 9:1. A dyno will tell, but the changes is small. I think there are other reasons then CR that creates your off boost "problems" I've also got ~8.5 CR, but better performance below 4000 then a 7A. At 4000 the fun begins
Would have been fun to have the 600nm at 3k that the RS2 setup can create, but wouldn't trade it for my current setup

[audiman]

I also see that Javad is selling some thick headgaskets for a bargain 135 dollars. That should drop mine to 7.7:1!!!!! Crank up the advance!

[Hesky]

80k miles is fine for the engine, but its better to be safe than sorry, i guess. I was running 370bhp on my engine before i did the rebuild at 156k miles Only reason for doing it then was because it started to burn a lot of oil.

audiman, that’s just testament to the quality and build of this turbo motor, thanks for putting it into perspective. I'm hooked on the idea of upgraded eagle rods now anyway, better safe than sorry!

Dont drop compression ratio too low if you want off boost driving!! Mine is 8.6:1 and its very slow when off boost. But then all that changes when it gets to nearly 4k rpm

I was thinking of dropping the compression to that exact level, maybe I should leave it stock compression as I'm not going to be running excessive boost, just replace the old gasket with a steel or copper one.

Thanks Angus for your help, I bet nearly 400ft/lb would pack a series punch! As soon as I finish the engine rebuild I will start making some decision about the turbo.

[audiman]

I think mine may be worse do to a large turbo and tubular exhaust manifold, thats the impression i get from others with similar setups.

[Hesky]

Speaking of tubular exhaust manifold's I've been keeping an eye on the 034EFI forum following the development of Javads pre production em. Especially interested in the 3" stainless downpipe he is developing also.

http://www.motorgeek.com/phpBB2/viewtopic.php?t=3241

It uses a T3 flange so a completely different turbo arrangement is required, but so far results look damn good. think he’s at 600BHP now!!

Anyone got any Comments on the design?

Hesky