S2 project, goal: sub 11sec

[zlobo]

Let me see if i got this right, what you're recommending, basically is to drop the standard S2 engine and gearbox, and use 2.5l diesel block and crank, plus the pre-1887 Quattro 'box?

- what about the remainder of the transmission, this box will bolt straight on...?
- what cylinder head, conrods and pistons do i use?
- other engine accessories, they fit right on the block?

Is the standard 3B engine + gearbox that bad, in terms that it can't handle that sort of power, or is the alternative that much better? I was, honestly, thinking of avoiding a lot of "chemistry" and just max-out the standard S2 hardware, so is this necessary for 600+ or just wise or recommended, or what?

The ur s4 gearbox they say is the strongest 5 speed 91-93.

i have frends that uses the stock gearbox and they ave around 6xxhp but some say that they wont hold.. by the way i use nira to.

[S2central.net]

This is interesting... Lets take the big stuff one thing at a time...

1 - Any S2 is essentially a good starting point for your aims

2 - The 3B engine came essentially shares the same internal components as the later ABY and RS2 (ADU) engine so it too is a good base to start from. However, there are some weak points to think about - such as the distributor and single coil approach. It left the factory with a paper head gasket and lower spec crank bearings than later cars. It also has a pretty small intercooler, injectors that max out around 320bhp and a fuel pump with little headroom for big power

3 - You'll know that bolting on a bigger turbo gets you so far, but bigger changes are necessary if you wish for say 600bhp. Things such as bigger/better -

EM, IM, IC, injectors, pump(s), lighter/uprated conrods (and pistons if you wish)
Lighter flywheel, uprated clutch... Lightened/balanced bottom end
Many good vendors of rods & pistons are mentioned here already.

4 - The 3B head is essentially the same as other 20V I5 engines - actually its derived from the 16V 1781cc Golf GTi - thats where 2226cc comes from amongst other things. Higher lift camshafts such as from the 7A, RS2 or special custom jobs will be needed for your target. The head will benefit from a good port & polish job - aim for high polish on exhaust side only. That 3B head will need some machine work to accept the camshaft (hall effect) position sensor that is needed for distributorless operation (unless you keep a stripped down dissy just for that - but then your camshaft choice needs to drive it)

5 - The gearbox on 3B S2 is the weakest point of the car - its the same 01A family as non-turbo engines. The 6-speed 01E fitted to ABY and RS2 is stronger, and you might find even stronger 01E quattro boxes from modern diesel engines needing coolers and such. BUT the strongest boxes are the oldest ones - the 016 family... and in particular the ones that came before Torsen. These old boxes have the capability to lock BOTH the centre differential and the rear differential. The oldest 016 quattro boxes did this with cables, whilst the next generation used vacuum actuators. When Torsen was invented only vacuum control for locking the rear diff was retained. ALL of these bolt straight up.

Without going for a stroker to 2.5L your limit on a GT35R is gonna be something like 500-550bhp unless you get into nitrous and other non-linear stuff.

Lots of people have built solid dependable & rapid cars from a 3B base using GT30R and stronger rods for safety with RS2 bearings, RS2 EM.IM.IC pump & injectors to ~450bhp without breaking the bank.

Theres also some crazy Norwegians running ~1000bhp with monster turbos running with exotic internals and funky fuel.

[206]

Now we're getting somewhere with this

1. the idea was, basically, to retain the standard block, crank and head, all other parts would be replaced and uprated - IC will be custom made, injectors increased to match the power, coils replaced for sequential ignition, head gasket and bearings from RS2, 2x044 fuel pumps should do fine as well. That's the route i was thinking about.

I've got no illusions that just bolting on a bigger turbo will get me anywhere interesting - ALL has to be changed to match, that part i know. What i don't know is car specific data, such as gearbox specs, which is the best, any special mods to be made apart from the plug-in stuff such as the conrods, pistons, etc, i hope it's bit clearer now...

Exactly the point you made on gearbox advice part, that's the car-specific data i need. Still, i'm REALLY an Audi virgin here, so excuse the dumb question now and then So, what would be the exact Audi models carrying those badass 016 'boxes? Quattros, 80, 90...? Do i need to find the box only, or the diffs as well, any problems in connecting all these different diff/box.driveshaft combinations together? Any need to go and replace the diffs with non-standard items for e.g. Quaife?

550bhp? Not interesting, done that already So, a bit more then. Nitrous will be present as well

[terrybullwon]

[QUOTE=S2central.net;309478]

Without going for a stroker to 2.5L your limit on a GT35R is gonna be something like 500-550bhp unless you get into nitrous and other non-linear stuff.
QUOTE]

Disagree, look at the compressor map again.

Hells racings S2 achived 525hp @ the wheels

[terrybullwon]

Btw sorry for the out burst :-)

[206]

Don't be sorry about anything if it makes things clearer or helps in any way, fire away

OK, let's say i go for the GT35R in both 2.2 and 2.5 configurations, what do you thinks the difference in power would be, provided everything else that's been changed remains more-or-less comparable? 550bhp on 2.2, and ... how much on a 2.5?

BMW from the pics runs a GT35R hybrid on 2,3l, btw...

[Jamo]

The spreadsheet is a little conservative on torque and bhp figures.

A GT30R will do 500-550 bhp in a stroker configuration which has been proven on the dyno's by 034 and Aronmatic2

Then Pallers2 and Aronmatic2 both had over 600 bhp on a 2.5 stroker engine and Prosty had 600 bhp on a 2.2 engine with the G35/40.

End of the day there's a difference between theory and reality, the Garrett maps are very conservative in relation to real life data.

[206]

All things considered, i'd rather go for the 2.2 as the foundation than the stroker, so i guess it'll be that then. After all, the difference in power is just a question of a turbo, more or less...

[Jamo]

All things considered, i'd rather go for the 2.2 as the foundation than the stroker, so i guess it'll be that then. After all, the difference in power is just a question of a turbo, more or less...

Depends on what you mean by power, bhp or torque?

bhp will be the same just the range of power will be earlier in stroker than 2.2 block.

2.2 crank can rev higher, if your into VTEC racing.

Torque is where the stroker will out do 2.2 crank.

Personally if I was in your shoes, I'd use the 2.2 block and the 92.8 crank from 034.

This way you can use the OEM length 144mm rods ( so any standard S2 uprated rods from Pauter, Scat etc ) but you'd need short pistons.

Now that would be the daddy

[206]

Now that's interesting, please elaborate further

[Jamo]

Now that's interesting, please elaborate further

http://www.motorgeek.com/phpBB2/viewtopic.php?t=4966

Or see flat on my backs project

Also search for Pisobikers posts on stroker engines http://www.s2forum.com/forum/showthread.php?t=4910

[206]

Will look into it, definitely...

Now, about that transmission confusion i still have...

[S2central.net]

LOOK at the spreadsheet - there are three calculations for estimating power. The summary results take an average of those, and there is quite a big range. The spreadsheet tool is just a guide and I've always erred on side of caution with regards things like VE, CE & IE woithout real hard data.

I didn't optimise for GT35R compressor map by the way - did this in a hurry - so yeah maybe more beans left in the tin.

[206]

The ur s4 gearbox they say is the strongest 5 speed 91-93.

i have frends that uses the stock gearbox and they ave around 6xxhp but some say that they wont hold.. by the way i use nira to.

Would the '93 S4 be a better base, then?

[206]

...did i just upset a whole lot of people by mentioning the S4, so nobody replies...?