2nd Generation Specific 1986-1992 Discussion

Swapping An '91 S5 N/a Motor Into An '86 N/a

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Old 08-25-2005, 12:04 PM
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I bought a 91 parts car that had an awesome engine and a custom exaust for it, but it has been sitting for like 3-4 months, and the battery is dead, If I can get it running, I want to drop it into my 86 n/a.



The engine in my parts car has 130 grand, with 30 - 40 grand since rebuil w/ new apex seals, but its been sitting for like 3-4 months. If I can get it running, I want to drop it in my S4. My 86 S4 has an 87 S4 engine in it right now with about 140 grand on the original apex seals, and it runs pretty good. But about 6 months ago, it got STP fuel injector cleaner run through it. I ran it almost out of gas with the 3 tanks after that happened, but the car hasn't been the same, I am a little short on power and I getting about 15 to 20 mpg. I want to drop in this S5 and then rebuild the S4 for some serious power.



I want to know how simple it is to drop an S5 into an S4 car. I still have the S5 alternator, the S5 computer, and the exaust, that I know I need.What kind of fun can I expect with this swap?



Yeah I know its going to be a pain to swap engines, but I am under the impression that it isnt much more work than the average engine swap. Let me know if I am wrong.



In doing research I have found multiple sources that say the S4 n/a makes 146 whp and the S5 n/a makes 160 whp. PLus the fact that my S5 engine has fairly new apex seals and fewer miles than my S4 engine, so I still think I want to do this swap.



I am looking forward to an extra 15 hp.
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Old 09-01-2005, 11:22 PM
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Originally Posted by The Autoholic' date='Aug 25 2005, 11:04 AM
I want to know how simple it is to drop an S5 into an S4 car. I still have the S5 alternator, the S5 computer, and the exaust, that I know I need.What kind of fun can I expect with this swap?
Forget about all that stuff! You will b using your S4 computer and harness.



You will need to swap the cover plate from your S4 motor onto your S5 motor. The reson for this is the OMP, the S5 uses an electronic OMP. I dont not remember how you need to mount the OMP ROD to the TB on the NA motors. If the TB is in the same position you can swap the linkages out of the S4 TB into the S5 TB or maybe swap TB's. Or come up with any devised plan. If you think this is going to be to much for you then you can just run premix in your gas at a 100:1 ratio.



The TPS's are a little different the S5 TPS can be utalised with a little harness work or you can swap your S4 TPS and mount it to your best judgment, the mount holes are a little off.



You need to use the injectors out of your S4 motor b/c your harness is set for low imp injectors and your S5 motor uses high imp injectors.



Originally Posted by The Autoholic' date='Aug 25 2005, 11:04 AM
In doing research I have found multiple sources that say the S4 n/a makes 146 whp and the S5 n/a makes 160 whp. PLus the fact that my S5 engine has fairly new apex seals and fewer miles than my S4 engine, so I still think I want to do this swap.
How much Horsepower did my car come with from the factory?

86-88 NA = 146 HP @ 6500 RPM w/ 138 Ft/lb @ 3500 RPM

86-88 Turbo = 182 @ 6500 RPM w/ 183 Ft/lb @ 3500 RPM

89-91 NA = 160 HP @ 7000 RPM w/ 140 Ft/lb @ 4000 RPM

89-91 Turbo = 200-202 @ 6500 RPM w/ 196 Ft/lb @ 3500 RPM

Infini IV = 215 @ 6500 RPM w/ 206 Ft/lb @ 3500 RPM



This is due to the S5 rotors being a bit lighter causing a higher redline and a higher compression.
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Old 09-02-2005, 04:59 AM
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Why not yank the ECU out of the S5 as well as pull the complete harness out with it.. stuff it into the S4
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Old 09-02-2005, 03:36 PM
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[quote name='RotorDemon' date='Sep 2 2005, 03:59 AM']Why not yank the ECU out of the S5 as well as pull the complete harness out with it.. stuff it into the S4

[snapback]754494[/snapback]

[/quote]

Cant do it unless you swap your whol dash as well. The electronics are compleatly different!
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Old 09-02-2005, 11:39 PM
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Ok.. well it works for me.. LOL.. Even works in a FB
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Old 09-04-2005, 12:06 AM
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[quote name='RotorDemon' date='Sep 2 2005, 10:39 PM']Ok.. well it works for me.. LOL.. Even works in a FB

[snapback]754743[/snapback]

[/quote]

Yea.....If you say so.
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