930 air injection system blowing

[Guest]

I own a 1982 porsche turbo and while looking under the car i noticed that a pipe was missing and exhaust gases were leaking out which I believe comes off the air injection system, could someone please tell me what the air injection system does ?, is it for the turbo system , and also is it a bad thing for these 6 small pipes that run into 1 main pipe to be broken off and blowing into fresh air.

 

[tj930]

It was a just 'dodge' to get through emmisions regulations of the time. (All it did was blow air into the exhaust manifold and 'dilute' the gasses.)

My '79 had had the system removed prior to me purchasing the car. I've heard recently that the pump saps about 5bhp from your engine (much the same as the A/C).

But you'd be getting a "*phat* *phat* *phat*" noise if it had broken off at the manifold - and you'd need to get this 'plumbed' as, for one thing, the exhaust gasses power the turbo []

You can purchase a set of 6 'air-pump plugs' (as they're called) for about £20. (These barrell nuts have an Allen-Key attachment.)

 

[911addict]

Removing this also saves weight.

 

[Guest]

Thank for that I will buy some pump plugs and put them in, did all uk cars have this air injection system then ?, I did not think that the UK was that strict on fuel emissions back in the early 80s, I think the air pump is still fitted at the back of the engine so will take it off if its not doing anything ,are these pumps belt driven from the rear end of the engine.
Also on another note the exhaust on my 930 is looking pretty bad especially the heat exchangers so I'm thinking of fitting a full stainless system, but I don't know weather to go for a full replacement standard stainless one or maybe one that gives the car abit more of a note and BHP too, its all down to the noise. So can anybody please tell me their experiences with fitting these exhausts on their cars,and is there any company who sells the full exhaust system as one package as everywhere I look they only sell each exhaust part separately, thanks again for all your help[]

 

[tj930]

I think the whole world had them. (Other U.S. emmisions changes robbed the 3.3 of 35bhp, making it produce only 265bhp - the same as the previous, R.o.W, 'Decklid', 3.0-litre 930!) But, as I say, there were only a few left-over bits of the system on my car (which I tidied up).

Pretty soon after buying the car, I spent £2000-odd quid getting a standard, stainless-steel system (Heat-Ex's and Rearbox) fitted. This involved a lot of blow-torching of rusty, 25-year-old studs and nuts (so do bear this in mind). Inevitably, some of the studs are going to shear and snap. []

A friend bought a twin-pipe, GHL System. For the rear box, he had to cut a hole in the right-hand side of the rear valence.. Yes, it means the turbo spools up quicker and, yes, it probably makes a few more horsepower (25ish-bhp), but it's too damn loud! (He always adds an expletive when describing it.) And there's resonance inside the cabin, too, and he has to drive around with the window open, so he says. []

The other two well-known, American, 'aftermarket' exhaust systems are B&B ("Billy Boat") and Fabspeed..

But personally, if I were doing it again, I'd go for the modified headers/heat-ex's but I'd keep the standard-style rearbox. (The 930 is loud and angry-sounding enough as it is.) Big-bore exhausts just smack too much of tuned-up Novas, Puntos, Scoobs, Cossies, and Renault 5 Turbos.. And the Porsche has more class! []

If you want more horsepower, the first thing would be the 1-bar wastegate spring, for about £45, and this gives an additional 20-odd bhp. But, inevitably, whilst you're at it, the wastegate will probably need reconditioning (an additional £120 or so).

The next (relatively) simple thing is to go for a K27-7200 turbocharger, an additional 35bhp and far quicker (1,000+rpm) spooling, for about £1,000.

You could also go for a Kokeln intercooler (about £1000).

If you want to do other, bigger mod's, you'll have to do other changes to accomodate them.. (A K27/29 hybrid turbo, for example, could give you around 500bhp but requires fuel-enrichment or a fuel-head modification.)

 

[911addict]

Whilst I do support this site, if you want to look at mods, you need to go to rennlist.com because there is a dedicated 930 forum with owners from all over the world.

 

[sjd]

This thread appears to have now moved to exhaust query.

My experience is that the Scott and Hayward stainless headers work very well and significantly reduce turbo lag. However their rear exhaust box did resonate fo my personal taste..

I have switched to Fabspeed rear box which is a twin outlet system (with the wastegate venting where the original exhaust exits). This is quieter under general driving and a more pleasant note. However, turn on the heat and it sounds like a full blooded racer - if that is your thing then it will put a smile on your face every time.

 

[nathan 1981 930 G50]

All 930's came with the air injection, just like the SC did which also used CIS fuel system.

The air pump is belt driven off the rear of the LH camshaft.

I removed my pump and all the plumbing but my belt was already broken. I think you may have to cut the belt to remove the belt from the car.

I'm happy with my GHL heat exchangers.

Come on over to www.rennlist.com I hang out there too on the 930 turbo forum. Post some pics and introduce yourself.

 

[Guest]

Thanks for your all your replies, I'm going to remove the engine and take off the air compressor as its still fitted on my car and also with the engine out I'm going to remove the old exhaust and air injection system and fit a new stainless headers & exhaust, the bolts look really rusted up and aluminum and steel don't mix to well, so its got to be easier with the engine removed and turned over surely.

 

[nathan 1981 930 G50]

Use a nut splitter to remove the headers/exchangers. If you don't you'll get at least one stud snap off which is no fun. Don't let debris get inside heads when you turn the engine over to work on it, in fact I wouldn't bother. The debris will damage your turbocharger [:'(].