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New to the air cooled world. I am looking to add a classic 911 to my garage.
Found a promising lead on a 79 SC. IT still has the smog equipment installed. I do not need that nor would the car be subject to any emissions testing,
What is the removal procedure on that? Can you just unbolt it and remove? Any other engine performance considerations that need to be made to compensate for its absence?
My air pump made a "thup-thup-thup" sound that I could hear over the engine, and I hated that. Plus removing it cleans up the engine bay.
If you remove the air pump and bracket, you'll be left with some long studs on the left chain housing cover. You'll either need to replace them with shorter or add some spacers. Removing the check valve in the engine tin will leave a pretty good size hole, so I riveted an aluminum plate over it so it wouldn't compromise engine cooling. The next challenge is removing the plumbing underneath that injects air into each exhaust port. You probably will need to remove the heat exchangers, which has its own set of major challenges to avoid snapping exhaust studs. Then you need threaded plugs (that are readily available) to seal the air injection ports.
I think you would also want to replace the cat with a pre-muffler or straight pipe, since the cat probably isn't doing much now, and without the excess air from the air injection it would do even less.
So now if you have the heat exchangers off, you could consider replacing them with SSI heat exchangers and a 2-in-1-out (or 2-out) muffler to improve performance, but you just added about $2K-$3K to the cost (or more depending on used vs new parts).
Just to add to what Mark said. When I bought my car only the long studs with the spacers were left along with the air injection network underneath.
I was not up to taking the exchangers off so I just cut up the air injection system with my air die grinder with a cutting wheel and the exchangers stayed in place. The air injectors came out pretty easy on my car.
Iceman makes a great point. You can cut the plumbing off with the HE in place. I just didn't want to do that in case our smog laws changed. My air injectors easily unscrewed from the heads as well.
Ice, do you recall what size studs you used when you replaced the long ones? I would like to replace mine; I can't stand the spacer look either.
Iceman makes a great point. You can cut the plumbing off with the HE in place. I just didn't want to do that in case our smog laws changed. My air injectors easily unscrewed from the heads as well.
Ice, do you recall what size studs you used when you replaced the long ones? I would like to replace mine; I can't stand the spacer look either.
Thanks!
Mark
I will check Mark as I think I still have the parts list I used somewhere
M8 by 1.25 by 40mm plain steel
I have in my notes that I should have gone with 50 mm overall length. But I don't remember why I wrote that so I went and checked, sure enough I have a ton more thread in the timing box for the stud to go into. so 50mm overall length would be perfect.
BTT.... what if you just remove the air pump's fan belt temporarily before removing the rest of the smog plumbing... will this adversely affect anything on the cylinders/motor and exhaust?
I replaced all that crap on my 1988 911 cab with RarlyL8 headers with heat, M&K 2 in-2 out muffler and Steve Wong chip and couldn't be happier. Runs better, sounds better and cooler.
What kind of silly question is that. haha OF course I want to improve the performance. Do you have more information you could provide?
Nothing to gain, performance wise, by removing the smog plumbing. But if the smog pump bothers you, then why not remove it and set it aside? Removing the plumbing seems like a lot of work for nothing...a massive waste of time.
Nothing to gain, performance wise, by removing the smog plumbing. But if the smog pump bothers you, then why not remove it and set it aside? Removing the plumbing seems like a lot of work for nothing...a massive waste of time.
a " massive waste of time" for you might be someone elses hobby....
when i got my car just the plumbing underneath remained. i spent an afternoon cleaning it up and plugging the injection ports and it looked all cleaned up when i was done. no piping or injectors.
05-01-2018, 01:51 PM
Smog equipment removal?
