90 S4 Fuel Rail Question
03-11-2010, 10:53 PM
#1
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90 S4 Fuel Rail Question
I thought I read here on the forum that after a certain model year, the rubber bushings between the fuel rails and the intake were done away with...????
When I did the disassembly, there was nothing there, just the studs, but....was there supposed to be bushings in there?
PET shows them, but I'm really not convinced.
Observations would be greatly appreciated.
TIA
When I did the disassembly, there was nothing there, just the studs, but....was there supposed to be bushings in there?
PET shows them, but I'm really not convinced.
Observations would be greatly appreciated.
TIA
03-11-2010, 11:05 PM
#2
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No rubbers between the intake and fuel rails in '90.
03-12-2010, 12:39 PM
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Tom, you must have your GTS intake finished up! I saw you driving on Lamar this morning. Nice to see you up and running again!
On later cars does the fuel rail bolt directly to the intake? I had rubbers on my '87 but they are currently shot.
On later cars does the fuel rail bolt directly to the intake? I had rubbers on my '87 but they are currently shot.
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03-12-2010, 08:56 PM
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You should use rubbers for safe BWAAAAAAAAAAAAAAA
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Does it have the "Do It Yourself" manual transmission, or the superior "Fully Equipped by Porsche" Automatic Transmission?
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03-12-2010, 09:00 PM
#10
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Intake rubbers are early '87. After early-'87 is just the studs.
03-12-2010, 09:08 PM
#11
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IIRR fuel rails are different for rubber version. They were changed in early '87 MY but PET was never updated. It shows 931 rubbers for '95 MY GTS.
03-12-2010, 09:44 PM
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Erkka is correct. You cannot mix and match fuel rails between "rubber" intakes and "studly" intakes.
Also, the _exact_ type of bonded rubber buffer is critical. There are many different versions across the various Porsche models that differ in the thickness of the rubber and length of stud on either side. Stud length is unimportant, but, too thick rubber on a "rubber" intake will cause the injector seals to sit proud of the intake's injector ports. This will cause an intake leak, lean running, and failure to pass emissions due to high NOx.
EDIT: FYI and IIRC, the rubbers for the airbox standoffs are the correct rubber thickness but not the same stud length as the original fuel rail/intake rubbers. But, they work just fine in the rail/intake position.
Also, the _exact_ type of bonded rubber buffer is critical. There are many different versions across the various Porsche models that differ in the thickness of the rubber and length of stud on either side. Stud length is unimportant, but, too thick rubber on a "rubber" intake will cause the injector seals to sit proud of the intake's injector ports. This will cause an intake leak, lean running, and failure to pass emissions due to high NOx.
EDIT: FYI and IIRC, the rubbers for the airbox standoffs are the correct rubber thickness but not the same stud length as the original fuel rail/intake rubbers. But, they work just fine in the rail/intake position.
03-12-2010, 11:31 PM
#13
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This will help for everyone to easily tell the difference between the early and late style fuel rails.
As you can see in the photo early version has "squared" mounting tabs/ears and the late style has "rounded" mounting tabs/ears.
Sorry for the fuzzy pic.
As you can see in the photo early version has "squared" mounting tabs/ears and the late style has "rounded" mounting tabs/ears.
Sorry for the fuzzy pic.
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