transplant S4 turbo into S5 chassis

[rotarymike]

It's been so long since I've messed with this, I'd like a second pair of eyes to see what I'm missing.

I know I need to:
swap front cover
swap OMP
swap engine harness (& ECU)
swap injectors
swap alternator (different plug and higher amps anyway)

what else am I missing?

This is to put an engine configured for an S4 chassis into an S5 chassis with as few hacks as possible.

Engine is a mostly S4 block with S5 turbo and manifolds. I have the front cover and OMP, and can get the harness reasonably. Injectors are proving a bitch to find for less than $400/set.

Mike

[Pete_89T2]

Looks like you got it covered, the only other things I can suggest are:

1. Do you have and S4 TB, with associated linkage to the OMP? S5 TB lacks the linkage mechanism.
2. You didn't say if you have an S4 or S5 radiator. If it's the latter, you may need to get creative with the upper & lower hoses to drop an S4 block in there. Also may have some issues getting the fan shroud to fit right.
3. Oil feed & oil return lines for the turbo - not sure if there are any S4/S5 differences that could impact putting an S5 turbo on an S4 block.

If you're looking for a set of stock S5 injectors, I have a set for sale. PM me if interested, but it looks like you need S4 injectors since you're swapping in the S4 harness & ECU (different connectors).

[djmtsu]

You don't need to swap the alternator. The power harness is separate from the engine harness.

Otherwise, that is just about it. Other than the MAF, Boost sensor, TPS that are specific to the harness/ECU you are using.

[rotarymike]

Pete, it's a block set up for the S4 going into an S5 chassis. So, I will be adding the electrical OMP, and need to switch to high-impedance (89+) oval-connector injectors. PM me if you have a set of these - I'd be willing to trade for my S4 550cc injectors.

Good call on the boost sensor. I would have missed that. And I can hack the S4 MAF into working, since I can't seem to find an S5 T2 MAF/airbox assembly.
I do have a couple different TPS from several different cars, so it will just be a matter of trying to fit the dual-throw S5 on the existing S4, or seeing if I have a S5 throttle body in the parts bin.

[RETed]

Moving to 2G section...


-Ted

[Pete_89T2]

Pete, it's a block set up for the S4 going into an S5 chassis. So, I will be adding the electrical OMP, and need to switch to high-impedance (89+) oval-connector injectors. PM me if you have a set of these - I'd be willing to trade for my S4 550cc injectors.

Mike, see link below for my original for sale ad on the FIs, they are the right type for you. They never sold, so they should be somewhere in my garage - just need to find them. Will look tonight and PM you when I do.

http://www.rotarycarclub.com/rotary_forum/showthread.php?t=13935

[RETed]

Some options...

Electrical OMP:
Keep the S5 harness already installed.
Plug the E-OMP into the harness just to fool the stock ECU.
The S4 mechanical OMP is just going to operate normally, since it has nothing to do with the stock ECU.
No need to mess with a messy front oil cover swap.

Boost sensor:
You just need to repin the plug, since the only difference between S4 versus S4 boost sensor is a +12VDC reference.
The other three wires are +5VDC, signal (back to stock ECU), and ground.

Fuel injectors:
You can run the low-impedence fuel injectors just by swapping plugs - easy to find EV1 / Bosch type and installing resistors on each channel.

Alternator:
Only difference here is I think the lug on the main power wire to battery?

Main engine harness:
This is where is gets tricky, since it doesn't plug in with the dash crossover harness.
This is where you gotta repin or just brute splice the wires to make everything work.
This is basically just to get the instrument cluster working (i.e. oil pressure, boost) and wipers to work.

As for the turbo, the S5 has a longer "adapter" pipe on the front from the oil pipe drain from turbo to the front oil cover.
Else, the positioning is identical, although it looks physically different - due to the turbo clocking.


-Ted

[rotarymike]

Before I get into specific replies, let me summarize a little better what I'm actually doing.

I have an S4ish turbo drivetrain in an 88 vert chassis. Running and sorted out, more or less.

The car sat for 3 years of grad school. When I started messing with it again, I noticed it had basically rusted in half along the rockers and other areas - as in, no trunk floor or footwell left.

So I picked up a 90 vert in great physical shape but a tired engine. Has the bonus of new paint, new top, new leather, and being all one color, unlike my 88. I'm in the process of swapping the drivetrain in the S4 to the S5 so I can get rid of the S4 chassis. Already swapped rear subframe and suspension, starting to work on dropping the front subframe with engine/trans/suspension. Since I have the winter to play with it, I thought I'd do the drop-in properly (well, as properly as I can afford) instead of a hack. I'm tired of hacks, in general, although I see their usefulness.

On to replies and further queries.


Electrical OMP:
Keep the S5 harness already installed.
Plug the E-OMP into the harness just to fool the stock ECU.
The S4 mechanical OMP is just going to operate normally, since it has nothing to do with the stock ECU.
No need to mess with a messy front oil cover swap.



I would like to change the front cover mostly because at one point, I had blocked the oil galley to the OMP, and tapped into the boss on the front to feed 2-stroke to the OMP. Even with all the return holes capped/plugged, the tolerance between the OMP shaft and the housing is great enough that the 2stroke leaks down over a day or so into the oil pan. If I try this again, I'll machine the OMP, I think.
Otherwise, simplify, simplify. When I pull the engine out of the S4, it's easy enough to pop it on the stand and do the swap. I'll be draining the oil and coolant anyway (sat for 3 years) and taking off most of the ancillaries for the harness swap.


Boost sensor:
You just need to repin the plug, since the only difference between S4 versus S4 boost sensor is a +12VDC reference.
The other three wires are +5VDC, signal (back to stock ECU), and ground.

Fuel injectors:
You can run the low-impedence fuel injectors just by swapping plugs - easy to find EV1 / Bosch type and installing resistors on each channel.


Is the S5 like the S4, in that the boost sensor is a different range for the NA and T2? Also, I may have a proper S5 boost sensor (N370?) in my spares bin.

For the injectors, I thought it would be a good time to put in some cleaned injectors, since I had to take the UIM off to swap the engine harness anyway.


Alternator:
Only difference here is I think the lug on the main power wire to battery?


The 2-wire plug is a totally different shape. Big oval instead of T-shape.


Main engine harness:
This is where is gets tricky, since it doesn't plug in with the dash crossover harness.
This is where you gotta repin or just brute splice the wires to make everything work.
This is basically just to get the instrument cluster working (i.e. oil pressure, boost) and wipers to work.


replacing the S4 harness with a decent S5 engine harness, so it should all plug in. I'm not worried about boost, I actually use a NA cluster and separate boost gauge. I remember getting the S4 turbo to work in the S4 convertible chassis took some rewiring - the 'vert chassis was an Auto so some wires were absent or in other places. I think I had to rewire the alternator completely (sense wires, not power wire). But the S5 harness I'm trading for is completely stock and looks mostly good.


As for the turbo, the S5 has a longer "adapter" pipe on the front from the oil pipe drain from turbo to the front oil cover.
Else, the positioning is identical, although it looks physically different - due to the turbo clocking.


So I need an S5 lower oil return pipe to use the S5 front cover. I can't remember off the top of my head what pipes I had laying around when I put the S5 turbo on, but everything fit more or less without too much 'splaining.
If necessary, I can make that from scratch if I have to.

Thanks Ted!

[RETed]

Is the S5 like the S4, in that the boost sensor is a different range for the NA and T2? Also, I may have a proper S5 boost sensor (N370?) in my spares bin.
All non-turbo FC pressure sensors are 1-bar type = -15psi (well, vacuum) to 0 ATM.
All turbo FC boost sensors are 2-bar type = -15psi to +15psi.
So all the turbo FC boost sensors are calibrated the same.

Unfortunately, non-turbo FC versus turbo FC are caibrated differently.


The 2-wire plug is a totally different shape. Big oval instead of T-shape.
Oops, sorry about that.
We all run FD alternators (who runs S4 alternators these days? :) ) which have the same plug as the S5 alternators do.


replacing the S4 harness with a decent S5 engine harness, so it should all plug in. I'm not worried about boost, I actually use a NA cluster and separate boost gauge. I remember getting the S4 turbo to work in the S4 convertible chassis took some rewiring - the 'vert chassis was an Auto so some wires were absent or in other places. I think I had to rewire the alternator completely (sense wires, not power wire). But the S5 harness I'm trading for is completely stock and looks mostly good.
Side note, you can use a non-turbo S5 wiring harness to make this work (with the S5 engine).
There are a couple differences - VDI, 6-port versus boost control - but almost all of the other pins are the same.
It'll all plug into an N370 - S5 turbo FC - stock ECU.


So I need an S5 lower oil return pipe to use the S5 front cover. I can't remember off the top of my head what pipes I had laying around when I put the S5 turbo on, but everything fit more or less without too much 'splaining.
If necessary, I can make that from scratch if I have to.
I'm pretty sure the only difference was that intermediate pipe.
Double check the flanges - the S5 uses an offset flange at one point I think.


-Ted