pj 90 gxl

I know there have been alot of post about this in the past but It will not let me do a search since s4 and s5 only have two letters...anyway...I have a s4 parts car and have a s5 with a blown motor. I was wondering if anyone could point me to any write up or post about doing the swap...any help would be greatly apreciated.

Thanks
Noel

hypntyz7

I saw this the first time and was just gonna let it slide off the front page, but, its back from the dead

I have seen many a person try this swap. It doesnt work very well, but you car will run I guess.

Basically there are enough differences between the 2 to make the swap difficult for the average person. A few off the top of my head:

1) compression on your s5 motor is 9.7:1, comp. on the s4 motor is 9.4 ; the s5 ecu you'll still be using will think it is still running the 9.7 motor, and idle/power issues will occur. That, and it'll just be a bit weaker.

2) the s5 intake needs to be used, but wont fit onto the s4 block as it is. There is a chunk of metal on the block that needs to get trimmed off for it to even fit.

3) the s5 motor has no egr, and the s4 does. Fitting the s5 intake(hugs the block) onto the s4 block (with the egr sticking up) means you'll have to remove and block off the egr to fit it.

4) the "port air" passages on the s4 and s5 block are different; you wont be able to pass emissions.

5) the front cover must be changed to accomodate the s5's electronic OMP.

6) remember to keep the s4 flywheel on the s4 block, as well as the s4 front counterweight.

7) you need to use all the s5 ecu, wiring, electronics, manifolds, and hoses.

8) most used s4 motors are weak as hell, more so than an equivalent mileage s5 motor. They began to change the way they made/coated rotor housings in 89, and those engines (when you can find em) tend to be in better shape than an s4.

pj 90 gxl

Would it be easier to swap the complete wiring harness along with the engine into the 90gxl since I have both cars?

hypntyz7

no, the s4 wiring, ecu, and injection are incompatible with your 90 model car. remember that the computer not only plugs into the engine wiring harness, but also the vehicle dash wiring harness; since the plug styles are different from s4 and s5, this means you have to use the s5 ecu, the s5 wiring harness, and the s5 electronics.

pj 90 gxl

I understand that and what i was trying to ask is would it be easier to change the engine and dash wiring harness and use the s4 ecu

hypntyz7

thsi involves changing every wire in the car. if you wish to do so, then you'll wind up with an s4 engine/electronics and s5 body.

Any s5 specific stuff would no longer work, such as electric seatbelts, the stock anti-flood feature (floor gas pedal) etc.

see what you get into when you start trying to mix and match stuff between series? it starts off as an innocent engine swap and grows to become a frame-up restoration/monster...

pj 90 gxl

yeah i see what it leads to...thank you for all your help

FourtyOunce

iTrader: (15)

its really not as hard as you make it to be. i did it to my s5 daily driver.

pj 90 gxl

which did you do and can you give me any advice on doing mine?

hypntyz7

No, it's not, but Im trying to save the man some headaches here. You do all this work and modifying **** only to wind up with a semi-poor running vehicle, when you could have done it the right way to begin with and come out way ahead.

Just think how he's gonna react when he puts this engine in and it doesnt run for dammit and he realizes he could have put a few hundred into it and done the job right in the same amount of time/work?

pj 90 gxl

Let me ask you this...do you think I would be able to trade the s4 motor for a s5 motor or be able to sell the s4 motor and buy an s5 motor with out it costing much more then what I am looking at doing?

FourtyOunce

iTrader: (15)

your right, it can be a bunch of headaches, but if done properly, it can run good.

casio

hypntyz7 - you make me not want to buy the s4 turbo 2 i'm looking at. i dont know the year, i just know its an s4 with just under 92,000miles and driven mostly by senior citizens. so whats the haps.

hypntyz7

IF you can provce that s4 motor runs well in its current body, you can document this and sell it to someone needing an s4 na motor for $300-600. I can do a full rebuild if your 90 motor for $1100 plus shipping each way, so you're in it for what, 600 bucks? For a rebuild? How can you go wrong that way? You can part out the rest of the s4 car you have (if you work hard at it) to cover that much easy...

Why not? so long as youre not hoping to make a s5 car int a turbo with it, it'll be just fine left alone.

pj 90 gxl

that would work if my rotor housing wer not cracked and my engine could be rebuilt

casio

i wouldn't mind having a better engine in it, which is what you make the s5 sound like. but a great condition s5 turbo2 with less than 92,000miles isnt easy to come across, so i may take the s4. unless you have one on hand....? *bats eyelashes*

hypntyz7

the $1100 quote I gave you assumes that Ill have to replace a rotor and housing (with used ones) during the rebuild. Any motor can be rebuilt...

nonameo

I have s5 rotor housings in my s4 engine.... or so the company that rebuilt it told me. Is this a bad combo?

hypntyz7

It's actually a good combo. s5 housings seem to hold up better than s4 ones. For instance, a rebuild with used s4 housings might reach a peak compression of 115psi. A rebuild with used s5 housings might go up to 120+. Now, with new housings, it doesnt matter, new is new, theyre just as good. But, over time, old ones, that's what Im talking about.

nonameo

ok, so housings have nothing to do with compression ratio... I hope my engine lasts a good while. this is good.

EDIT: they also put 3mm seals in there... not sure that was a good idea though. they put them in as a standard thing on turbo motors.

Makenzie71

where are you gonna get a "good" running S5 engine for a few hundred? I need to find this place.

This is a question about budget. I did it and it worked fine. If you were seeking performance then you'd be able to afford to do it right...if you're having to rig something up then you should be looking for performance.

Anyway...First thing you'll have to do is remove the EGR and other emmisions related equipment (you won't be able to pass emmisions anyway so why try). The only vac lines you need are the ones to your brakes and to your fuel rail. The fuel rail can tie directly into the TB. The EGR on the stock S4 block must be removed and a plate made to block it off (be sure to use a good gasket).

Also, you to pull the electronic metering pump and front cover off of the S5 and install in on the S4 block. The only way around this is to use pre-mix...which is quite effective. If you intend to premix then either seal off the lines from the oil pump somehow or...preferred method...make a block-off plate where the oil pump goes. Also, remove the oil injectors and put in bolds and lock washers (make sure they're about the same length as the threads on the oil injectors).

The S4 block will line up with the S5 tranny no problem...but as stated, use the S4 wheel, it's just better for the engine. Install the block alone...only leave the exhaust manifold on it, you need to do this one piece at a time.

After you install the short block go ahead and run two good grounds from the block to the frame. Once this far you need to pay attnetion to the S4 intake manifold. With the removal of all other emmisions gear you can now remove the 6-port sleeves and actuators...you'll need more block-off plates and gaskets. After you have that now useless stuff removed from the intake manifold you can install it on the block...again, strong enphasis on gaskets.

Now the ports going into the block are different between the S4 and 5...but the ports leading to the rest of the intake are the same...which means the S4 intake manifold will bolt to the rest of the S5 intake. With the intake manifold on block off the vacuum ports exposed. Now install the vacuum web if you want...you could just run 1/4" neoprene fuel line wherever you want it...cause the fuel line is all that's needed. don't install any of the sensors that attach to the web...when it comes to those connectors you can just leave em alone but your car will throw codes at you...you can get around it by cutting the clips off and installing a little resiter to connect the leads...then wrap them carefully.

Also make sure you install the S5 pulsation damper and fule rail...they're a bt sturdier than S4 dampers. Also use the S5 injectors.

Next install the lower intake runners and the expansion chamber. Then the TB...block off all vac lines to the TB except one for the fuel rail and the ones that go to the brakes.

Everything else is as a normal engine install would go...I think I might have left some stuff out though...not certain.