s4-rs4 heads?

2.7 V6 30v biturbo - 251bhp
2.7 V6 30v biturbo - 261bhp
Dippy
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Post by Dippy » Mon Jan 17, 2005 1:11 pm

Mihnea,

Are you familiar with the AZB engine that I have? If it is even easier to swap in an RS4 engine into my car, then if and when it comes to needing turbo work done, I might seriously investigate an RS4 engine transplant instead of a turbo upgrade.
2001 Silver S4 Avant
AmD remap, APR R1 DVs, APR bipipe, Full Miltek exhaust
H&R coilovers, AWE DTS, Porsche front brakes, Short-shifter, 18" RS4 replicas
Defi-HUD boost gauge / turbo-timer (with afterrun pump modification), Phatbox

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S2tuner
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Post by S2tuner » Mon Jan 17, 2005 1:24 pm

Dippy,

Yes, I do know the AZB engine. AFAIK the AZR engine is a straight swap in your car, and the ECU is as well, as it has 4 lambda sensors and everything else should be the same as with your original AZB engine code. A complete AZR transplant makes mapping the ECU and troubleshooting lots easier than just "throwing" the RS4 parts at the AZB engine. IMHO/IME, an S4 engine with RS4 turbos can't produce much more than 410-420 crank HP, whereas a complete RS4 engine could go as high as 490-500-ish with FMICs and a complete free-flowing exhaust system+appropriate mapping.

It all comes down to the amount of air that the engine can flow, and an AZB/AGB engine can't flow as much as an RS4, mainly because of the head ports and intake cams differences. I don't know how much the RS4 IM is accounted for but I'd guess it also makes a difference in the amount of air that the engine flows.

One thing you have to remember here guys is: boost alone makes no power. Air flow and efficient boost levels can produce lots of power instead, but fuelling and ignition advance also play a big role in this.

Example of what I'm saying? An S4 with RS4 turbos, ICs, injectors, MAF, exhaust, etc etc running 1.5 Bar boost at 6000 RPM will produce 420-ish HP. An RS4 running a free-flow exhaust and 1.5 Bar boost at 6000 RPM will produce approximately 470HP, possibly even more. The engines have the same capacity, the only thing that's different is the baseline engine airflow, which depends on volumetric efficiency, which means how much the air actually goes into the engine.


HTH,

Mihnea

S4RS4
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Post by S4RS4 » Mon Jan 17, 2005 8:49 pm

Dippy wrote:Mihnea,

Are you familiar with the AZB engine that I have? If it is even easier to swap in an RS4 engine into my car, then if and when it comes to needing turbo work done, I might seriously investigate an RS4 engine transplant instead of a turbo upgrade.
Dippy,

That was exactly the thoughts I had and when an engine came available, I jumped at it. Your problem will be gettinng hold of a genuine one. I have never seen one for sale in the UK before or since. I did have problems getting it to make big power on the early ECU. Ended up fitting MoTeC ECU for this and "future tuning" reasons!

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S2tuner
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Post by S2tuner » Mon Jan 17, 2005 8:56 pm

S4RS4: The early ECU has some specific issues, that can always be worked out IMHO and IME. Going for a MoTeC sounds IMHO like a huge headache and a great lack of security features (knock sensors among a few other things)...

HTH,

mihnea
S4RS4 wrote:
Dippy wrote:Mihnea,

Are you familiar with the AZB engine that I have? If it is even easier to swap in an RS4 engine into my car, then if and when it comes to needing turbo work done, I might seriously investigate an RS4 engine transplant instead of a turbo upgrade.
Dippy,

That was exactly the thoughts I had and when an engine came available, I jumped at it. Your problem will be gettinng hold of a genuine one. I have never seen one for sale in the UK before or since. I did have problems getting it to make big power on the early ECU. Ended up fitting MoTeC ECU for this and "future tuning" reasons!

S4RS4
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Post by S4RS4 » Mon Jan 17, 2005 9:01 pm

KayGee wrote:Do you mean the RS4 ECU doesn't physically fit or is wired differently?

Since no one seems to have K04 or RS4 map for the earlier ECU (551c) I was planning on doing an RS4 ECU swap myself.

Any help greatly appreciated!!
I have a 551C ECU programmed for the RS4 spec S4 that I am selling. I also have the MAF, injectors, air box, K04 turbos, clutch, oil cooler, Stratmosphere DV's etc. PM me if interested.

Dippy
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Post by Dippy » Wed Jan 19, 2005 1:52 pm

It's not really in my game plan, I just wanted to know in case my circumstances change.

Of course I am no stranger to buying goods and services from mainland Europe such as Germany, so if I wanted to source an RS4 engine, that's where I would start...
2001 Silver S4 Avant
AmD remap, APR R1 DVs, APR bipipe, Full Miltek exhaust
H&R coilovers, AWE DTS, Porsche front brakes, Short-shifter, 18" RS4 replicas
Defi-HUD boost gauge / turbo-timer (with afterrun pump modification), Phatbox

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