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930 Air Pump


GregAx

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Hi,

 

In the attempt of returning the 930 back to factory the PO had removed the air pump. I am after the air pump an related parts to complete the setup.

 

The car still retains the spider tubing and air injectors.

 

Any help would be great.

 

Thanks Greg. 

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Hi,

 

In the attempt of returning the 930 back to factory the PO had removed the air pump. I am after the air pump an related parts to complete the setup.

 

The car still retains the spider tubing and air injectors.

 

Any help would be great.

 

Thanks Greg. 

I'm all for restoring a car back to original spec. but this has me stumped.   Smog pump adds weight, uses engine power to drive it, and worst of all creates a false reading of the air/fuel mixtures and efficiency by diluting the exhaust gases.  Why do you want to put a smog pump back on?  Am I missing something?

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I'm all for restoring a car back to original spec. but this has me stumped.   Smog pump adds weight, uses engine power to drive it, and worst of all creates a false reading of the air/fuel mixtures and efficiency by diluting the exhaust gases.  Why do you want to put a smog pump back on?  Am I missing something?

 

Now where I have I seen this discussion before? :D

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I'm all for restoring a car back to original spec. but this has me stumped.   Smog pump adds weight, uses engine power to drive it, and worst of all creates a false reading of the air/fuel mixtures and efficiency by diluting the exhaust gases.  Why do you want to put a smog pump back on?  Am I missing something?

 

Stumped why? you answered it in your first statement (to bring the car back to original spec). Most of it's all there anyway.

 

Also there have been numerous discussions on the effects of removing the air pump and most people do when they are going down the path of modding the car.

 

From my research there are several posts on Pelican which prove that Hanz Mezger the genius behind the turbo wrote a whitepaper on the effects of the air pump on a turbo with the standard equipment and the results speak for themselves. Full boost comes on at 2500rpm rather than 3000rpm which is what I am seeing without the pump.

 

Graph is on the bottom of the post below.

 

http://forums.pelicanparts.com/porsche-911-technical-forum/748938-air-pump-76-930-a.html

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Am I missing something?

Yes!

For me Harvs nothing symbolises an unmolested car more than having a functional air pump!

In reality they are harmless: don't weigh much, negligible power to run - feels like the pulley isn't actually connected to anything, in fact Porsche say it's 231hp air pump or not - and don't do anything else offensive at all. I agree, 20 years ago I would have dismantled it but I've become content and accepting in my old age.

So you could say I'm almost proud of my air pump.....

Retroairrearcondenser_zpsc129797c.jpg

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Stumped why? you answered it in your first statement (to bring the car back to original spec). Most of it's all there anyway.

 

Also there have been numerous discussions on the effects of removing the air pump and most people do when they are going down the path of modding the car.

 

From my research there are several posts on Pelican which prove that Hanz Mezger the genius behind the turbo wrote a whitepaper on the effects of the air pump on a turbo with the standard equipment and the results speak for themselves. Full boost comes on at 2500rpm rather than 3000rpm which is what I am seeing without the pump.

 

Graph is on the bottom of the post below.

 

http://forums.pelicanparts.com/porsche-911-technical-forum/748938-air-pump-76-930-a.html

I suppose there are two issues here.  Yes, I did answer my own question on originality.  Herr Mezger answers my second question.  Air pumps actually do something positive on a turbo car.  Now I know.  Thanks.

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  • 3 weeks later...

Yes!For me Harvs nothing symbolises an unmolested car more than having a functional air pump!In reality they are harmless: don't weigh much, negligible power to run - feels like the pulley isn't actually connected to anything, in fact Porsche say it's 231hp air pump or not - and don't do anything else offensive at all. I agree, 20 years ago I would have dismantled it but I've become content and accepting in my old age.So you could say I'm almost proud of my air pump.....Retroairrearcondenser_zpsc129797c.jpg

I didn't know that 3.2s had air pumps? I thought the motronic took care of all of that?

Incidentally, my car, as a 81 California delivered, has no air pump from stock because it has a catalytic converter and O2 sensor and the air pump wasn't part of the setup. I believe this is different to ROW cars.

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HOLD ON! HOLD ON! ........

Am I sensing a turnaround on how we feel about Smog Pumps?

FlatSix ....... I never thought I'd see those words typed from your keyboard!

Where's Russ? QUICK ....... someone tell him to read this thread! ...... along with half the other members from PFA ......

SMOG PUMPS FOREVER!!!!!  B)   :)   :lol:

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Did you miss the bit where it spools up your turbo at 2500RPM not 3000RPM?

 

there's no excuse on an N/A engine, it's just using power for no benefit - sorry :(

 

but yours looks nice

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Yeah, no turbo, no pump. I stand by my previous comments!

I concur :)

If it ain't contributing to power output, or it doesn't pass the bling test, then it's got to go!

Turbo OK

N/A No Way

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I didn't know that 3.2s had air pumps? I thought the motronic took care of all of that?

Incidentally, my car, as a 81 California delivered, has no air pump from stock because it has a catalytic converter and O2 sensor and the air pump wasn't part of the setup. I believe this is different to ROW cars.

Coastr,

I could just answer that only the '85 model year of the C3.2's had air pumps but there would be no context!

The '84 Australian delivered cars had the 170kw ROW 930.20 engines except for the fitment of an activated carbon canister to better control hydrocarbon emissions to meet ADR's of that time. So as you say, no air pump.

The '85 Australian delivered cars had the 930.26 engines that was also used in Sweden and Switzerland. Identical to the 930.20 engines but with an air pump fitted. Still 170kw as the air pump allowed the newer ADR's to satisfied without detuning the engine.

The '86 cars got the detuned 152kw 930.21 engines with lower compression ratio (9.5:1) to suit the low octane unleaded that was mandated that year, catalytic converter and retarded Motronic. No air pump now required as the converter now did that job and the cleaning up of a few other emissions at the same time.

With the broader introduction of 96 RON fuel, the 930.25 engine was introduced in '87 that had a retuned Motronic that restored some of the previous glory but still the lower compression ratio. (160kw)

So like Dreamr says, no shame with having the air pump!

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there's no excuse on an N/A engine, it's just using power for no benefit - sorry :(

Russ,

I think you have to put it in the context of 1985. Porsche had to choose between adding an air pump OR reducing the compression ratio, mixture strength and retarding the ignition timing to meet the Australian Design Rule emission limits. Both approaches can achieve the required hydrocarbon and carbon monoxide reductions but one approach also guarantees drivability and power reductions.

 

So really air pumps can be a benefit...... ;)

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I'll amend what I said, there's no excuse now for having an air pump/smog pump. unless you're chasing originality to the nth degree. (and/or own a turbo that you haven't made any other modifications to)

 

but each to their own, if we all liked the same thing it'd be boring

 

although i'm still going to have a go at people i see with smog pumps on their cars :P

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The question is still unanswered , and posting a 1970s graph pertaining to the pre catalytic converter , primitive-turbo era 930 does not prove anything. $24 would allow some analysis http://papers.sae.org/780718/

 

The only proof would be a dyno , and even then you need someone who understands the results.

 

I'll keep an open mind on this.

The air pumps really do shift minimal air and on the 928 at least , only really work when the engine is cold (rich , need to reduce emissions). 

 

Keep the posts coming!

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gax , what year is your 930?

Potentially (on the later turbos) the air pump only works for ~60 seconds after startup from cold , the a valve reroutes the air into the cat. Thereafter the pump is a dead weight and even steals a few hp, not that you'd notice in a 930.

A parts diagram for your 930 would help.

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