swap questions - s4 motor in s5
01-01-05, 09:54 PM
#1
swap questions - s4 motor in s5
i have a 87 5spd and a 91 auto
the 91 engine is dead... coolant seal and the car refuses to start (water inside?)
what i want to do is put the s4 engine and transmission into the s5
from what i have read, everyone says that i need to swap the ecu/harness
but what if i rip the s4 into a shortblock (do you guys call it that?) and bolt all the s5 parts in it? that way, the only difference would be the rotating assembly, and i could give the s5 shortblock the rebuild that it deserves... will i run into any problems if i do that?
and when i swap the car into a manual, anyone know where i could buy the bracket? i am not that great at making things...
think that seems to be all? i can take all the necessary part from the s4 for the s5...
the 91 engine is dead... coolant seal and the car refuses to start (water inside?)
what i want to do is put the s4 engine and transmission into the s5
from what i have read, everyone says that i need to swap the ecu/harness
but what if i rip the s4 into a shortblock (do you guys call it that?) and bolt all the s5 parts in it? that way, the only difference would be the rotating assembly, and i could give the s5 shortblock the rebuild that it deserves... will i run into any problems if i do that?
and when i swap the car into a manual, anyone know where i could buy the bracket? i am not that great at making things...
think that seems to be all? i can take all the necessary part from the s4 for the s5...
01-01-05, 10:00 PM
#2
i'll blow YOUR valve off
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think thats covered in the FAQ... but that won't work because the 89 has an electrical OMP and s4 has a mechanical OMP... plus other things too... like TPS... etc...
01-02-05, 02:30 AM
#5
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Yep it's doable. I have the same swap. It works well, I had a bit of difficulty working the bugs out. I'll post links to my threads about this since I've typed it up many times.
There is a writup in the thread here that was posted by me. I found it very useful but not entirely applicable. Basicly block off the split air port on the LIM with JB Weld and remove the EGR valve and replace it with a blockoff plate which is available from Racing Beat. I have no idle issues and the car runs strong like this. You'll feel a dropoff in power at 7500 rpm without exhaust modifications. As far as passing emissions, I was successful after replacing the 15 year old catalytic converters. Now I run no cats, Hi flow aftermarket mufflers (can't remember what brand) and a CAI. Oh yeah, I also used the S5 front cover and the S5 MOP.
https://www.rx7club.com/2nd-generation-specific-1986-1992-17/omfg-s5-car-s4-engine-311548/
http://homepage.mac.com/carldavis/intake.html
There is a writup in the thread here that was posted by me. I found it very useful but not entirely applicable. Basicly block off the split air port on the LIM with JB Weld and remove the EGR valve and replace it with a blockoff plate which is available from Racing Beat. I have no idle issues and the car runs strong like this. You'll feel a dropoff in power at 7500 rpm without exhaust modifications. As far as passing emissions, I was successful after replacing the 15 year old catalytic converters. Now I run no cats, Hi flow aftermarket mufflers (can't remember what brand) and a CAI. Oh yeah, I also used the S5 front cover and the S5 MOP.
https://www.rx7club.com/2nd-generation-specific-1986-1992-17/omfg-s5-car-s4-engine-311548/
http://homepage.mac.com/carldavis/intake.html
Last edited by inflatablepets; 01-02-05 at 02:43 AM.
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01-03-05, 06:48 PM
#8
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Well, I was saying you need to transfer the front cover from the old "Blown" engine and install it on the good "S4" engine. There will be a small O-ring on one of the oil passages that needs to be transferred as well. It is small and easy to overlook. When you remove the front pulley/eccentric shaft bolt, make sure the engine is flywheel side down as you don't want the bearing stack in the engine to shift. You'll have to take it apart to fully understand what I'm talking about. The reason you need to change the front cover is that the S4 engine has a mechanical MOP (metering oil pump) whereas the S5 engine has an electric MOP. You cannot de-activate the S5 MOP as it will put the engine ECU into running in limp mode. Hope this helps you. I'll post this in the forum as well.
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