dlambert

The primary purpose of the SAI is to put extra oxygen into the exhaust stream to burn the richer cold start fuel mixture and to jump start the cats. This fix still accomplishes the mission and is not likely to ever fail. Good Job!

roebedo

car-commander, you bring up a good point, which leads me to a couple of questions. 1.) Do all 993's need a top end rebuild a 60, 70, 80, 100K miles? If there no issues, and the car is not consuming oil erratically why would you do it? 2.) I would never let someone tear down my engine and slap it back together for $4K! (my god my darn turbo brakes almost cost me that), and I installed them! My mechanic is not the cheep guy in town, but he's not a rip-off either, they drove the car for hours, to get the computer to reset and didn't charge me for it, but to drop the engine and do it right, well that was on the $8K block, and if it came out to be more I would of been glad to pay it, because he's just that good! He said he would rather not touch the engine, he also said on future cars with the SAI issue, that he would rather spend the 4-5 hours to shoot for a successful flush first, before he would recommend this mod. As far as I can see I think he is on fair playing ground.

roebedo

Andrew - Too funny, and as always its nice to see the humor brought into the thread. Your from my cars home town, she was brought up in LA and Venice Beach, I was lucky she never received a tie die paint job

Amfab

well, Im up near Topanga, so you never know what can happen . . .

maybe someone needs to do a 993 version of this:

roebedo

LOL.... I saw that car in excellence magazine..no? Isn't that some female rock star's car? My first impression was of course why?? Then when I read who the owner was It explained everything. Too funny...

planeguy67

Very kewl mod. I was wondering why Porsche routed the freekin' SAI system through the cam towers and heads instead of running some cheap tubing along the outside. But my understanding is the SAI air had to mix with the exhaust gases fresh out of the cylinder in order to work correctly.

Oh well, if this mod works, great!!! Give the stupid O2 sensors what they want, O2. If and when those tubes get plugged up, they should be a lot cheaper to replace than a top-end overhaul.

cabrio993

Janice Joplin's 356. Love it!

http://www.officialjanis.com/porsche.html

race911

OK, here's the deal on air injection. Look at any 2.7 or early 3.0 car, plus 930's and compare that half-*** external manifold, big *** HP robbing air pump, and nozzles sticking into the exhaust port robbing even more power. Hans und Franz didn't show up hung over one morning and try to slap something together to meet a deadline. I think it's pretty well established we don't drive the cars quite as hard here? Probably works quite well as intended.

Now onto valve guides. I've taken apart 911 engines with as little as 15K factory miles. Remember, before Carrera tensioners A LOT of practically new engines failed. And we, as a matter of course, replaced the guides. I've probably only used 4 head guys in my life (Pete Zimmerman being one, I don't think he posts here.....just on the 911 board), and I've never NOT had it come back that they're out of tolerance. On the flip side, I've pulled apart 200K+ engines that were marching along not burning much oil at all.

Probably the worst oil burners of the bunch came of age when I was pretty much getting out of hard mechanical work--the 3.2's. 60-80K, and some of them were going through a quart every 4-500 miles.

2ndof2

No doubt about it, E is right. If SAI-CEL is the only reason to tear everything apart its not worth the money and this mod is a smart way to go. I'm sure this "mod" could be pulled off the car in no time if necessary and chances are most mechanics doing the smog check see few enough 993s that this likely would be overlooked. I'm all for full disclosure if a sale was involved.

Adrienne

Personally I think that mod is way too obvious. Considering it is illegal and carries severe fines, I would not do that mod or buy a car that had it. But then, I'm the type that won't remove my cats for the same reason. To each his own.

vjd3

I have had my top end done for $3500, as have several Northeast Rennlisters, by a shop in New Hampshire. He does fine work. It's been terrific for 14k miles now and has not used a drop of oil.

Regarding the workaround, if you subscribe to the theory that worn exhaust valve guides are a contributing factor to the SAI system clogging in the first place, and that replacing the guides with the harder phosphorous bronze aftermarket ones is the solution, then it makes sense to do the rebuild as your guides are probably worn anyway. At 58k miles, my exhaust guides were badly worn.

Also, FWIW, having looked into this solution before opting to have my guides replaced, 10 hours of labor seems a bit much to install a couple of bungs into the exhaust and run two air lines from the check valve to there. Maybe the first time it's done, but the shop I discussed it with up here (not the rebuild shop) put it at about half that.

I don't know about liabilities; the law in Massachusetts specifically allows "temporary" repair measures that are true to the overall design of the system, i.e., if the system still functions correctly, it's okay to modify it -- and in this case, since it's supposed to feed extra air to the cats on a cold start to get them hotter quicker, it would still be doing that as long as the air lines are placed before the cats.

YMMV ... I'm glad I had my guides done and don't expect further issues with them, but time will tell.

TheOtherEric

A couple guys have noted that this is somehow true to the original system. But I think Porsche's goal was to have HOT air (not cold air) injected into the cats. This workaround doesn't do that. So AFAIK, this mod does not help emissions and thus runs counter to the intent of the system.

That said, I still like it.

sacman

Is it possible to relocate the SAI valve to a more accessible location for future maintenance/replacement?

pp000830

I always wondered why my car's exhaust system had extra oxygen sensor bunges along its pipes with plugs screwed into them. Now it all makes sense, kind'a like someone at Porsche foresaw problems with the air injector system and pre-installed attachment points for a fix that preserves the integrity and function of the secondary air injection system. Gosh, who would think!

Mr.Woolery

I wonder if this would ever be available as a kit?