Being a newby to the 993 and after reading a lot about the valve, wouldn't it be a good idea to consistently use 93 gas with techron in it or am I missing something?

Chuck

 

Chuck, it's a completely separate system from the engine but its issues are a byproduct of worn valves and valve guides (inevitable on 993s). I'm pretty sure running Techron in your gas mixture would not prevent oil from getting through into the cylinders and burning off. What happens is the soot/carbon gets sucked up into the SAI system passages from the heat exchanger chambers on startup to a point where it clogs the system and trips your CEL. The only true fix is a top end service where new (stronger/better) valves are installed. Or, if you are still quite a ways from a top end job, you can maintain this system by clearing out the passages and swapping the valve every 10-15K miles..

 

Bruce 7,
In your previous change of the check valve, did you use anti-seize on the threads; and if so, was the valve much easier to remove the 2nd time around?

 

In his most recent post, it states he did use it and it helped a lot.

 

Chuck I think yours is a 95, in which case you are exempt from SAI CEL's you get to ignore SAI threads( or read them for entertainment value), go directly to go and collect $200. Congrats

But you don't get the neck snapping power of the varioram set up either.

 

Thanks, JB. I knew the CEL wasn't an issue with the '95, but I didn't realize the SAI was a total non-issue. Nice to know.

The 991 PDK SC is faster, but the 993 has nice power. The last old one I owned was a '74 and that one was truly a snail.

Chuck

 

There is no sealing ring listed, so I assume the threads are a tapered pipe thread on the check valve?

 

From Bruce's update...

The thds are NOT sealing/tapered pipe thds; and while I'm not sure what type of sealing ring Bruce used, I used an alum crush washer for sealing purposes.

The SAI system is still employed in the 95, however, the OBD I was not coded for the SAI feedback to throw a CEL.

The SAI system acts as a bellows for quick heating of the cat. If the system fails due to clogging, the cat still heats, albeit slower. IMHO, it was senseless of Porsche to employ the feedback in 96 via the OBD II iteration, but I think we can all thank the EPA for mandating of the OBD II.

As I understand things, the 95-98 Pcars, can be in a perfect state of tune and running fine with the SAI ports clogged solid.

 

Re the sealing ring, the 993, 986, and 996 all use the same SAI valve. However while the PET for the 986 and 996 show the sealing ring, the 993 PET does not. The air distribution housing that the SAI valve screws into for the 986 and 996 is a 996 part number so must be different from what is in the 993. Bottom line - is the sealing ring necessary for the 993 or only for the 986 and 996?

 

When I removed the original factory-installed SAI valve on my '96 C4 I found a sealing ring. I replaced the sealing ring along with the valve.

Also, FWIW, the PET is not known to be 100% accurate.

 

Same here

 

Thanks. Replacing the SAI valve is on my to-do list and I will also replace the ring.

 

The SAI replacement DIY is no longer on the P-Car.com site, altho there are many other useful ones there. You would need to buy the DVD from Pelican Parts.

I had my SAI valve replaced at 42K miles, and it was a corroded mess inside. Planning on doing it again soon as I am at ~65K miles. Just need to get the crowfoot, as I am now in DIY mode. Just passed smog again with flying colors, numbers even lower than 2 years ago.

 

It looks like it is still there (or back again)... http://p-car.com/diy/sai/1/sai.htm

 

The DIY written up in this very thread is far easier to follow than the pcar one...just saying.

The Pelican SAI kit is good because it also comes with a screw on air compressor hose connection for cleaning out the passages along with a very high quality SnapOn crow's foot that's modified. Will make future SAI services a breeze!