S2 project, goal: sub 11sec

[206]

Oh great...more things to play with...

On the logging/instrument side, i've got that covered when i get to that, i always overdo that part

Ok, say i get a hold of on RS2 gearbox, and use that. Now, we're talking about lockable centre diff, and lockable rear...standard S2 or this RS2 'box has neither. So i'd have to get a hold of another box with option to lock the centre/rear diff, or...?

[206]

Correction, the S2 has Torsen at the middle, and manually locking rear, as far as i could understand, but the rear can't stay locked above certain speed...

So, with an RS2 box, i leave the cente as is and do...what with the rear?

AAAAA!

[S2central.net]

01E / RS2 has lockable rear diff - so does S2 - even with the 01A box on 3B.

Actually the rear diff on your 3B donor car is coded AYV - that is same on 01E S2.

The Avant/Sedan cars have different rear diff packaging cos of rear suspension layout. I would be pretty confident that your lockable AYV diff is same internals as RS2 item.

The AYV diff and RS2 box are both 4.11 ratio - thats a good thing huh...

http://www.s2central.net/specifications_main.html

[S2central.net]

There is a simple electrical mod to fool the rear diff lock controller if you wish it to stay locked above factory recommended speed. Great for launches or going sideways

[S2central.net]

Oh and just confirmed... RS2 uses AZE rear diff which is same as on ordinary S2 Avant - so yeah the AVY diff you have is good enough I reckon.

There are stronger 01E boxes than the RS2 item (CRB) which also have oil coolers, used on big diesels but you need to check ratios carefully for your needs.

[206]

THANK you very much for clearing some of that up How you guys "navigate" among all these combinations, i'll never know...doing that with a single gearbox and diff is not easy enough, but you have three here...

I think i'll go for the RS2 item, as i have one for sale close by, in mint condition for stupid money as the owner probably has no idea what he has.

As for the Quaife ATB diff breaking - if Audiman broke that one, that would be one of the two cases that ever happened with a Quaife, as they are IMMENSELY strong. OK, i get the point in using a solid-lock diff at the rear, traction is probably a bit better, but it's also a bit more uncontrollable...anyway, i've got something to think about there as well.

No thoughts on the dry sump?

As for the valve oversize, i don't think that oversizing the valves will give a significant increase in power for all the work involved, so that it pays off to bother with that - 0.05 bar of extra boost would probably do the same thing. I've toyed with radial valve seat grinding and oversized valves on the previous project - not worth the extra bother on a turbo car...N/A, maybe, but here...nope.

BTW, if i use any of the exhaust manifolds you guys recommended, does anybody have any idea what would be the biggest ball-bearing Garrett that would fit without significant modifications under the hood - by that i mean banging out some metal to make space, or something...GT30R should fit, GT35/40 not so sure, any bigger than that...?

[S2central.net]

Just to clarify the rear diff thing... I wasn't talking about an ATB style diff that was destroyed on a 600bhp car. That guy was running a TORSEN rear diff - this was uniquely fitted to the Audi V8. Some guys run this rear (NOT lockable remember) to give the car less understeer tendency and more fun in the corners.

I have one, but not fitted it yet - picking up a spare diff casing soon to build into it. I'm running less than 300bhp with maybe 400-450 in the future so I wont be generating the monster torque that has the potential to break the rear diff.

I totally agree with you on the valve sizing - much easier / cheaper ways to get the extra oomf that marginally bigger valves will provide.

As to the dry sump - a few have done that here - it is brilliant and race proven etc etc but its all about time and money. The oil pump, pickup and baffles on the S2 engine are well up to the job for your 600bhp target - as long is its healthy of course.

Paul

[S2central.net]

Oh on the turbo and EM question...

There are some companies like Turbonetics, Applied Trubo Dynamics and 034 who can supply hybrid variants of the GT30/35/40R turbos that can work on the RS2 EM or SQ EM.

From memory the hotside on the RS2 EM (too small for your needs) is a KKK#6 flange whilst the bigger SQ (SPort Quattro) EM has KKK#8.

Some of the hybrid turbo options can let you keep the KKK centre section for simplest oil and water plumbing but the benefit of the roller bearing is better for you.

Talking of exhausts and thinking about bodywork - make consideration for the simplest / legal exhaust you can get away with for a street machine. Also think about a direct output from the wastegate (perhaps) thru a silencer - then you can be...
"The Loud of the Rings" - get it !!!!!!!

[S2central.net]

Finally (for now) - don't forget likes of Wagner tuning who can supply you with a monster EM that should accomodate GT30/35/40 with ease. Carsten Wagner is a member on here - you'll be wanting one of his inlet manifolds as well BTW

[206]

I figured that the standard oil system is enough for 600-ish BHP, but what i want is a system that will have extra capacity, as i learned the hard way that having an oil system that supplies "enough" is not always good enough. What i want is "more than enough and then some". You can never ever have an oil supply that's too good. Second, standard oil supply WILL have problems with high G's at some point, all road car wet sump systems do. Dry sump won't. There are some gains to performance as well, miniscule as they might be, and dry sump is a little bit easier to integrate into engine prelube and turbo oil recirculation system (after shutdown) that i plan to make as well.

Ball bearing turbos are the only option here, and that GT40 does sound nice already OK, i know about the spoolup time, nothing a bit of nitrous won't sure

[G60Rallye]

Well, take your pick

http://www.quaife.co.uk/shop_manufac...cfm/manu_id/94

Yes but theres no ATB rear diff on there, except for the A4. Perhaps the A4 rear diff would fit into an UR Quattro or S2?

The other thing that worries me is if you do get 2 ATB diffs its going to be stressing the gearbox a whole lot more, as it wont be able to unload the power through any spinning wheels, unless it gets all 4 spinning!

Its a good thread this.

[206]

Well, i guess the standard OE diffs will have to hold, then.

[206]

Would the RS2-spec driveshafts hold up to this power level?

[206]

...and the propshafts as well, standard, or better spec aftermarket? I've used a carbon propshaft on the BMW, any need to go that far?

This inability to delete your own posts is kind of stupid...

[VladaS2]

Welcome to the forum, I live in Belgrade as well and drive a RS2-ed 3B, not so fast as you'd like maybe high 12 on 402, but have a lot of experience with it.

Ako ti nesto treba ili zelis da se provozas javi se.

Pozdrav!