I am putting a S5 Turbo motor into an S4 turbo car. They say its not worth it and some call it dumb but its what I had to work with. So Im out tearing the S4 down to the block and getting all the neccesary electronics off to swap over to the S5. But now I need a little more specific help. I have the harness off and ready to lay onto the S5 but the S5 has different vacuum line routes on the manifold. I havent found a thread on the specifics of doing this... So I havent torn the S5 down yet. Does anyone have any advice or know where the thread is? And before a bunch of people say search before I ask, I did. I just found a few threads saying generic things like use the S4 electronics and S5 manifolds but, yea thats alot to fill in the blanks... I'd appreciate some guidance. THANKS!

 

Swapping na S5 turbo motor into an S4 turbo car isnt stupid. The s5 motor is better. If you cant afford to go stand alone the easiest way is to use the s5 short block and swap everything over from the s4 long block. All of this has been covered in here so do some searching and learn the diffrences. Thats the smart thing.

 

there is many ways to skin the cat,,
some will fit the s4 timing cover and turbo and drain and TB to the s5 block to get around the premix/ EOMP issue
some will also swap the nest over,, some will delete it,, some will hybridise it


my advice is to keep the new engine as intact as possible,, you don't necessarily have to convert the engine to s4 turbo, drain, timing cover, TB and manifolds

there still may be some issues you may need to get creative for
IE
the dash coolant sender on the s5 block cannot be exchanged for the different thread s4 unit
IE
s5 boost control solenoid will be inoperative
IE
the new motor may lack thermo switch sender on the back of the water pump
( if the old engine was auto and the new one not )

IE
you may choose to fit the solenoid rack from the s4 to the s5 engine
( if you desire as it is not essential in some places )
if you use the s5 turbo ( and turbo manifold ) you can leave the twin scroll solenoid disconnected


OK-


if the car has a injector ballast resister,, bridge it
the injectors and the sensors provided on the engine block ( not nest solenoids ) will work with the s4 ecu now the ballast resister is bridged

hook up the s5 narrow range tps to the s4 ecu
use an aftermarket EOMP controller to run the s5 EOMP ( avail from aus )
use either a spare MAP sensor or the unused wide range TPS to command it

-this is a smarter solution to premixing
allowing you to use the s5 engine intact
and way cheaper and less risky than paying someone to swap the timing covers and water pumps and TB to s4 parts -

 

When I bought the car the previous owner had put in a S5 turbo and a 3 in down pipe Racing Beat system so I have two S5 turbos, ( one from the car and one from the S5 motor I purchased ) one is out being rebuilt.

My car was manual and the new set up going in is also manual so the thermo switch sender isnt going to be an issue - correct me if I am wrong here.

As far as the dash coolant sender goes, does this mean my dash gauge wont work?

I have the S4 stripped down and all the parts set aside but if I am going to use my EOMP then all I need is the harness that I took off? and of course buy the EOMP controller..

 

pretty much
if you have early s4 car you need to bridge the ballast resister that drove the low ohm injectors of early s4s

the vac nest swap which should share common vacuum pickups between the series
+ a few more to retain the s5 secondary air purge system
and thus will not be too hard to nut out
the routing diagram for your car may well be on the under bonnet sticker,, if not various versions are floating here and on the net


i don't think the dash sender will scale the same, though i never checked
if it does not , then your option may be to tap the s4 one to the back of the water pump and elongate the wires
i do know you cant just swap the sender,, the thread is different on the s5 block

eomp controller from aus only requires the wiring pigtail that runs from the pump to the the water pump thermo neck
you cut the connectors there

the shipped pigtail requires you to buy some 7 core trailer light wiring and some cheap spade plug connectors to complete bay part of the loom
you can choose to run it from the spare wide TPS or from another map sensor and they are not that much harder than some stereo head units to connect up
IE
5 meters of 7 core trailer bundle , two 3 pin , one 6 pin spade plug connectors
[ substitute one 3 pin connector for a 4 pin unit if choosing a MAP sensor instead of TPS ]

 

Im doing the same thing as OP except s4 na. From reading the faq on Rotory Resurection it looks like that if you have all of the electronics from the s5 engine all you need in the in-dash harness from an s5 car to bolt up.

I know that everybody says to just swap the s4 stuff over but that kinda defeats the purpose, when you thinking long term horsepower goals. Id rather not have to then upgrade to s5 rotors and such to make the horsepower I want.

 

I couldnt find a S5 TII in MN to gut the car for the harness, plus that bad boy is very long, as is it goes to the back of the car long... So while I am deleting the rats nest on my S5 turbo motor I will be okay with swapping over the required S4 turbo parts. But it looks like I will have to keep the air pump intact to run the other ports properly on the S5.

Does anyone have a link to a thread on deleting the rats nest? I have PM'd a few people but they havent gotten back to me yet.

 

The harness doesnt have to be from a tII just the same series.

Deleting the rats nest should be intuitive. I did it for my s4 na. Buy the block of plates, some gasket paper, and a pack of nipples and pull it all out. It isnt complicated its mostly just making sure there are no vacuum leaks.