I have a 1993 S4 2.2 turbo running the MTM chip. I want to go for a bigger turbo to overcome the boost starvation above 5500 rpm. Should I keep the KKK24 and just change the compressor side to a KKK26 or KKK27 or go for something completely different. Cost is an issue and the modded KKK would mean no interface problems. Also will the standard management system be able to control the boost sufficiently to ensure that it doesn't detonate untill I can afford the management upgrade.

Any thoughts....

Leon

Check Chris's S2 project at http://cardomain.com/id/audis2nut . He is going for the kkk27 comp side and a kkk26 hot side, not finished yet, also going aftermarket management.

L8r

Albie
91 500 Turbo

leon , choose the turbo carefully as many people are disappointed when using the 26 or 27 hybrids when not matched properly to the ecu.
I suggest do a search on the S2 Forum on the results others have had with KKK26 or 27 hybrids. The RS2 turbo boosts from about 2800rpm but the KKK26/27 normally only boost from 3500rpm and may not give as much power.

BTDT! (Been There Done That)

You have many options of varying cost If you look at the discussions on www.s2forum.com the preferred upgrade route is the RS2 (KKK K24 7200) turbo. It uses a K26 #6 hot side with a K24 compressor housing but has a K26 wheel fitted to it! It is good for 380 hp and is a very easy upgrade. For 380 hp you would need a good exhaust (3"), RS2 EM, RS2 or 7A cams, RS2 IM, RS2 injectors and a good remap. With just the RS2 turbo and a remap you can get to 300hp.

The RS2 turbo bolts on to your EM and the water and oil feeds fit directly. It costs R18000 from Audi or you can buy the exact same brand new turbo from the KKK agent, Turbo Exchange, for (wait for it) R10,000! I sold mine to a urS6 owner and it took him an afternoon to fit it. BTW I sold it for R5000 but since there are only 15 RS2's in the country I doubt you will find a second hand one locally. Maybe overseas?

The next step up is to go for a roller bearing turbo. I replaced my RS2 turbo with a hybrid setup. The turbine housing is a K26 #6 (same as RS2) but the compressor housing and CHRA are Turbonetics T04E (46 trim) roller bearing. It should have much less lag than the RS2 but is good for 420 hp. The turbine housing will be a straight fit but the oil and water feeds are different - Geoff Mortimer is currently busy sorting that out for me. The price of the turbo is about the same as a new KKK but it is more effort.

The mother of all turbos will be a double roller bearing Garrett GT turbo. You would need to get a KKK K26 #8 turbine housing (used in the Porsche 944 Turbo S aka 952) and then you can use the GT30R compressor housing and CHRA. It will spool up even quicker than the single roller bearing turbo (full boost below 3000 rpm) but will cost about R15000.

Email me at gandalf@audiclubsa.org.za if you want to go the roller bearing route. I can put you in touch with the right people.

Also owning 1993 S4, I thought my penny's worth may assist. Running at the coast we have no lack of boost at over 5500 RPM. Situation may be totally differnt at altitude.

In fact it revs cleanly and extremely fast right thru to the rev limiter. It is so fast it still catches me occassionaly, but normally change 7500 RPM. (normal ...when sending it.)

Maybe the problem is not the turbo but something else. Running too lean? We get nothing less than 14lts \100 at the coast. On a long trip it may drop to 13 or 12.5 if one is very carefull.

We also have a problem when it is very hot. Feels like no boost or massive retarding of timimg. Switch car off and restart and it flies again. Very strange!!

Good Luck with the solution.

Regards
Ryss
Cape Town
S4 (AAN)
A4 1.8
90 Q

I agree Ryss - I have seen so many 2.2 5 cyl turbos with boost leaks. I think it is important to make sure the car is running optimally given the current configuration. An chipped AAN with a good exhaust should produce 280 hp (209kw). Before concidering a turbo upgrade ensure that the car is running perfectly. A bigger turbo can be like a band-aid for a poor performing car - it makes the car faster but the undelying problem is still there! ... and you get more lag

And if that don't work for ya....