I've been searching the past hour or so looking for some specific information.

I need to know the physical differences between an S4 and S5 Turbo engine. What would be the most blatantly obdvious give-away, if I was looking at the two side by side?

Pictures would be great!

 

There are many threads about this already, but:

Knock sensor is on front rotor housing on S5's

Taller runners on upper intake manifold

S5's have the electric OMP

No pics unfortunately, but if you look, I'm sure you'll come up on a few.

 

Well, the injectors on the S4 will be square top and the S5 will be oval.

The knock sensor will be located on the center iron in the S4 and I am not sure where on the S5.

The S4 turbo will have a twin scroll system with two diapragm type actuators. THe s5 will only have one actuator.

Hope this helps.

 

No EGR on S5 either.

 

s5
10 fan blades
electric omp
rotor housing knock sensor
uim has "dent" in front most runner
maf
square turbo flange
steel fuel rails
welded pulsation dampener

s4
8 fan blades
mechanical omp
center iron knock sensor
smooth front runner
afm
one bolt recessed
cast aluminum rails
removable pulsation dampener

 

I did search before I posted, so I'm sorry if I wasted your time or precious forum space.

Must be more specific here, I guess.
I'm comparing to blocks side by side. No manifolds, sensors, etc... So far, it seems like the only sure fire way would be the knock sensor's location. The S5 having it's knock sensor in the rotor housing, and the S4 having the sensor in the water jacket. On par so far?

I appreciate anyone willing to apply to what seems like a simple question to me... I just don't know.

 

Yes, s4 knock sensor is in the center iron and the s5 is in the rotor housing.

 

Thanks guys for helping me learn these things.

So, I believe I have some sort of frankenseven here. Correct me if I'm wrong, please.

Knock sensor:



Alluminum coolant neck (this one's a little out of focus):



Electronic oil metering pump (correct part here?):



...then I have a single actuator on my turbo:



...and what I would guess to be an EGR delete on an S4 manifold (I tried to get an in-focus pic, awkward angle I guess):




Can anyone help me sort this out?

I'm asking all these questions because I'm buying a reman block, front cover and flywheel included, but it is an S4. Thinking my engine is an S5, how hard would it be to retrofit to the orginal S4? Thanks

 

Looks like a rebuilt hybrid engine. S5 rotor housings, mechanical omp, aluminum filler neck. Looks like it has a s4 uim too.

How many blades on the fan?

 

Eight blades on the fan... but I ruled this out after reading some posts. It's my understanding now that the S4 manifolds/everything else will bolt up to the S5 block.

How can I identify wich harness is being used, or would this be a problem going back to an S4 block?

UIM?

 

the gap between the leading and trailing plug holes...

s5's on up have a bigger gap... the leading holes were advanced slightly in 89...

hope this helps...

 

It should be using a s4 harness and ecu. Maybe a s5 short block with s4 accessories.

 

Would there be any 'empty' connectors to verify this... maybe something with the EGR?

If this is the case, I should have no troubles going back to an S4 block with the S4 front cover and flywheel (included with the new engine), right?

...this is only to get the car back on the road... I finaggled a Microtech LT-4 along with the car when I bought it.

 

What ecu is in the car, that should tell you s4 or s5. It's under the carpet in the passenger footwell.

 

There's no ECU in the passenger floorboard area.... I have no carpet in the car.

It may be tucked away in that general area, I'll check in a few. Where should the ECU be mounted?

 

It's under that silver kick plate thing towards the front.

 

ECU has bold markings "N332".

...so this must mean I have an S4 Turbo ECM, right?

What problems would this cause knowing the rest of my parts?

 

Yes that is an S4 turbo ecu, it seems like someone took an S5 shortblock and bolted up S4 everything.