RS2 Competition Turbo

[Ross]

Hi,

I've been trying to find some info about this turbo; seems like quite a rare beast! I'd like to know, what RPM range does it spool at? Same as the RS2 Turbo or a little later?? And when does it run out of steam? I understand it's an RS2 unit with a 2.7" wheel fitted, giving increased flow; does anyone know if it's safe for 400BHP without pushing it to silly boost levels (ie, ideally not above 1.8-2.0 bar).

Any info appreciated; I've researched this turbo a bit and it looks really good but I've not found any ideas of what RPMs it delivers and power expectations. I'm looking into which blower I should get for my 'project 400' (other considerations are K26/27 #8 and 034 kits).

Cheers
Ross

[S2central.net]

I never saw enough proof that an 'RS2 competition' turbo was anything more than some marketing / naming hype by some KKK agents in the US. If you have found some *real* information about the differences from a normal RS2 unit and the fabled 'competition' unit then I'd sure like to know.

My memory of looking info this before was a handful of websites that had various insubstantiated claims.

See what bugs me is that the RS2 was never officially in any form of competition - I'm pretty sure only the S2 was homologated by the FIA for motorsport use in GpN and GpA. The RS2 never was and so why would someone have created an official 'competition' spec turbo. Not suggesting for a minute that you can't modify an RS2 turbo in some way for benefits in certain types of competitive applications - I just have a feelin it was more of an invented sales gimmick by certain resellers or tuners in the states.

Mihnea at MRC is probably best qualified on this forum to clarify this one.

He can also tell you exactly what KKK internals you'll need on a K26/27 for ~400bhp. The #8 hotside body sounds familiar but I couldn't quote you compressor or turbine wheel part numbers !

Paul

[Ross]

OK this is what I dug up - aparrently there never was an "RS2 Competition" turbo; it was actually called the "7200 competition" but was known as the RS2 comp because it basically was an RS2 turbo with the 2.6in compressor wheel replaced with a 2.7in wheel. Oh - some RS2 units were modified with some machining and replacing the compressor wheel with the larger one too. I've been told it makes quite a difference, but would it make an extra 20-30hp? If you don't know too much about it Paul, then I guess it really is a rare one which kinda makes it more appealing to me haha.. as long as it's not rare coz they were sh*te of course

Can't find any figures on this one at all but I do know it exists, it's of course bolt-on which suits my needs

Looks like I'll have to try and get a hold of Mihnea on this one...

cheers
Ross

[S2central.net]

Speak to Mihnea - he will cut through any hype to the facts on this one.

My own personal take is dubious that such a gain of 30bhp can be had with this larger compressor wheel. Even if it is true, like on nearly all things turbo related... A gain somewhere means a loss somewhere else. In this case I would suggest slower spool time, more lag and less torque in the mid range.

There are planty of ways to hit 400bhp with a bigger turbo conversion on the S2. Mihnea can advise which KKK26/27/29 hybrids he has used in the past - as well as a host of Garrett/Turbonetic specials. These are available with K26 #6 or #8 hotside housings for some choices in exhaust manifold (S2, RS2 or Sport). There are other custom special manifolds with Garrett T3/T4 housing brackets.

The choice is yours - I just wouldn't latch onto this '7200 Comp' turbo until you collect some real evidence about its capabilities...

Just my tuppence worth !

Paul

[kwlw]

Speak to Mihnea - he will cut through any hype to the facts on this one.
Paul

You can look at it in photos here:

http://www.bufkinengineering.com/turbo.htm

Sau

[Urquattro20V]

Found some info here, perhaps known to some of you:

http://web.archive.org/web/200303160...ay/000816.html

[dan_b]

You can look at it in photos here:

http://www.bufkinengineering.com/turbo.htm

Sau

if that's some sort of an RS2 turbo, why does it say K24 on the manufacturer's stamp?

[merlin's S4]

if that's some sort of an RS2 turbo, why does it say K24 on the manufacturer's stamp?

I'm pretty sure that all the RS2 housings have k24 stamped on them! Check this out from the s-cars.org site if you've not seen it before:



Is the hybrid K24/K26 turbo the same as the RS2 turbo?

No. The RS2 is all K26 turbo. I've had a couple dozen of RS2 and RS2 Competition turbos apart in the past 6 years. The hot side is based o*n the smallest of the K26 series housings, with a Porsche specified hot side wheel, and the appropriate milling of the housing (which results in a slightly larger downpipe opening). The center section is stock Audi K26 WC, and the cold side is a K24 cold side housing with a K26 cold side wheel. The RS2/Comp both use the larger K26 shaft for the wheels. The RS2 Competition uses a larger cold side wheel and housing, the hot side stays per early RS2. What throws most folks off, is that KKK left the K24 designation in their part numbers o*n the cold side tag.

The actual answer to the years of the K24 cars in the US is up for some discussion. The Audi "claim" is that as of 1989.5 (late MC dual knock MAC-14) Audi switched to the K24 turbo o*n all I5 turbo applications. This switch also "supposedly" came with a revised cam profile, flat flywheel (+ different TOB fork), and 2pc exhaust manifold. IME, 1990 was the ******* year for previous year pieces parts. I've seen 1990's with single pc exhaust, K26 turbos (but all have had the flat flywheel and the revised cam profile).

As of 1991 + intro of the 20vt cars worldwide, all Audi 20vt (I5 o*nly - thought I'd miss that turbo cars except for the RS2, were K24 based turbochargers.

Maximum boost to the K24 is altitude corrected at 16psi. At 3200ft the 1991> stock 20vt cars lowered maximum boost threshold to prevent overspin of the turbo. You guys with modded 20vt computers with K24 turbos should reread that last sentence.

Scott Justusson
QSHIPQ Performance Tuning


--------------------------------------------------------------------------------

What is a RS2 Comp turbo?

Take a RS2 turbo apart, then a "7200 comp" apart, there is a difference. Cold side housing and turbo wheel are different, BTDT. Basically, if you use whatever KKK's numbering system is at the time (I did this back in 94 - at least 2 numbering systems ago), you will find that the cold side wheel is larger o*n the 7200 Competition. The RS2 'Competition' is actually and
ascribed misnomer, as the "RS2 Comp" really doesn't exist. What does exist is the "7200 Competition". Which is EXACTLY how KKK delivered the RS2 hot side housing, RS2 hot side wheel, and RS2 "+1" cold side wheel and housing. KKK also labeled the box it came in "7200 Competition". I know this, cuz I sold about a dozen of them when they were available.

The easiest way to tell the RS2 plane jane from the 7200 Competition is that the plane jane comes with the Audi tag o*n the cold side, the 7200 Comp doesn't come with any tag o*n the cold side. The hot side housing and wheel will carry the same part number, so will the center bearing section (it should they are both K26 derivatives).

There is also another cold side (wheel and housing) that is larger than the 7200 Competition. I currently run 1 of these in my fleet.

Everyone has "opinions" o*n these turbos, and it would appear it's shrouded in grand mystery. I laugh, KKK knew what that hot side was (awesome), and (my guess) KKK was likely restricted in using a Porsche/Audi proprietary "RS2 Turbo". The rules have changed since, because the o*nly way to build a 7200 Comp these days, is to order the RS2 turbo complete, and add larger cold side wheel/housing. Bringing full circle what I did to my first RS2 turbo in
1994.

- original post

Scott Justusson
QSHIPQ Performance Tuning

[Ross]

Thanks for the replies guys... Paul you're right; I'm not gonna commit to this mysterious turbo till I know what it's power/torque capabilities are and what it's RPM range is... if money were no object I'd get it anyway just to see what it was capable of

As it happens, I'll wait till I get ahold of Mihnea and ask his opinion.

Thanks for the links too, some of that was new info; dug up my current knowledge of the thing by searching the audiworld forums. Some new info there but still no detail of the differences between this unit and the RS2 turbo... I'd go for the K26.27 #8 but at £1200 it seems a bit more than I was planning on!

[Fat Audi 80]

If I were doing it, I would tell Minhea what parts I had assembled in my garage waiting to go on the car, let him know what sort of power figures I was looking for, what type of power delivery, i.e. strong midrange or power developed higher up and ask him to spec a turbo for you. In my (admittedly limited) experience, you need the right combination of components and set up not just a great turbo.

MRC will build and set up exactly what you want if you tell them what you want.

HTH

Cheers,

Steve

[Ross]

Hmm, if I call Doug on this one any more I think he'll have my number blocked
I'll see what Mihnea has to say when I get ahold of him, see what my options are!

Unfortunately I know what turbo would fit my needs but it's too expensive - same as what Tom + Doug just sold!! (anyone got one to sell? ) So, until I've saved up enough to buy it, and decide "what the hell only the best will do", I'm kinda looking around for alternatives

I'll keep this thread updated if I find out any more info on the RS2 Comp though, FYI anyone else who has the same question at a later date

[Jon441cc]

Ross, put this on the credit card and you will have it by next week :mischeif:

Duel ball bearing aswell OH GAH!!!!! Get me a towel

[Ross]

Don't tempt me... email from egg informs me my new C/C is activated. No interest until october

I'm trying to persuade myself that buying stuff before i have the money is a bad idea, but then why should I miss out on such an opportunity? Besides, some overtime would ensure that's all paid up in time.. as you can see the angel on my shoulder is losing this battle.

[Jon441cc]

i feel a group buy coming :mischeif:

[Chris M]

What turbo is that, GT30R???

Do it Ross, you know you should listen to the voice of the darkside