RE: A/C and Air pump performance hits

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RE: A/C and Air pump performance hits

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Corvette Forum >> Corvette Models >> Corvette C3 Forum >> RE: A/C and Air pump performance hits

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RE: A/C and Air pump performance hits - 7/7/2007 9:18:38 PM

cwb

Posts: 1508
Joined: 5/13/2007
From: eastern NC
Status: offline

quote:

ORIGINAL: 78buckshot

Hey cwb, 73shark is describing the steel nipples that carry the A.I.R. air deeper into the exhaust manifold, their aimed at the port in the head to maximize the oxidation process of the gases. The stainless steel injector manifold mates to the exhaust manifold with inverted flare fittings and seats the flare to another short nipple inside the cast iron exhaust manifold. This is about as well as I can describe it.

Yup. I've seen this plumbing before, but didn't know what it was.

So they won't dispel heat if there's no flow???

So put on an underdrive wheel in the pump? Keep some flow, save power...

_____________________________

Don''t know nuthin''; ain''t never got paid for wrenchin''...
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(in reply to 78buckshot)

Post #: 11

RE: A/C and Air pump performance hits - 7/7/2007 9:25:54 PM

cwb

Posts: 1508
Joined: 5/13/2007
From: eastern NC
Status: offline

quote:

ORIGINAL: C3 Starship

I believe that you'll find that the air pump draws from the filtered air from your air cleaner, not push air in. (this line is inside your filtered area) Although a hose from your air cleaner does draw air from your valve cover, through the pcv valve in the valve cover, to burn internal engine gasses. (this line is outside your filtered area)

Why would the AIR pump need filtered air to go into the exhaust plumbing?

Yes, the other line would need filtering, to go into the crankcase, for Positive Crankcase Ventilation, but the other?

_____________________________

Don''t know nuthin''; ain''t never got paid for wrenchin''...
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(in reply to C3 Starship)

Post #: 12

RE: A/C and Air pump performance hits - 7/7/2007 9:47:43 PM

73shark

Posts: 1097
Joined: 4/18/2006
Status: offline

quote:

ORIGINAL: 78buckshot

Hey cwb, 73shark is describing the steel nipples that carry the A.I.R. air deeper into the exhaust manifold, their aimed at the port in the head to maximize the oxidation process of the gases. The stainless steel injector manifold mates to the exhaust manifold with inverted flare fittings and seats the flare to another short nipple inside the cast iron exhaust manifold. This is about as well as I can describe it.

Thanks 78buckshot! Couldn't have said it better.

_____________________________

So many toys, so little time

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Post #: 13

RE: A/C and Air pump performance hits - 7/8/2007 4:03:15 AM

78buckshot

Posts: 654
Joined: 1/28/2007
From: Michigan
Status: offline

Looks like we all agree on the A.I.R. and it's operation, if you disable the pump your not going to see one bit of performance improvement, if it were mine I would leave all of the emission controls on and concentrate on getting it back to stock so that you can diagnose it better. The other option I would consider given the somewhat poor performance history of the twin TBI would be to gut the factory EFI and go with either an after-market injection system or carbueration, this way you wouldn't have any interference or need of the emmision controls.

(in reply to 73shark)

Post #: 14

RE: A/C and Air pump performance hits - 7/8/2007 9:19:09 AM

C3 Starship

Posts: 4761
Joined: 7/25/2006
Status: offline

quote:

ORIGINAL: cwb

quote:

ORIGINAL: C3 Starship

I believe that you'll find that the air pump draws from the filtered air from your air cleaner, not push air in. (this line is inside your filtered area) Although a hose from your air cleaner does draw air from your valve cover, through the pcv valve in the valve cover, to burn internal engine gasses. (this line is outside your filtered area)

Why would the AIR pump need filtered air to go into the exhaust plumbing?

Yes, the other line would need filtering, to go into the crankcase, for Positive Crankcase Ventilation, but the other?

I think you missed it...
The filtered air is to protect the pump, that draws air from the filtered side of the air cleaner, the line from the pvc valve draws air from the crank case, to burn gasses from the inside of the engine. This air is filtered, to keep particulates out of the intake system.

_____________________________

1980 L-82 Fastback (forward too)
Mono composite front and rear.
Full adjust ride height and
response.
400+ hp, 454, M-22, 3.07

http://i121.photobucket.com/albums/o225/C3Starship/Patch.jpg

2007 H. D. Sportster, XL 883 EFI

(in reply to cwb)

Post #: 15

RE: A/C and Air pump performance hits - 7/8/2007 9:27:05 AM

Batmobile

Posts: 31
Joined: 7/4/2007
Status: offline

I would have sworn that air was blowing out of the tube from the air pump to the unfiltered area of the air cleaner assembly.

What gives?

(in reply to cwb)

Post #: 16

RE: A/C and Air pump performance hits - 7/8/2007 11:51:30 AM

C3 Starship

Posts: 4761
Joined: 7/25/2006
Status: offline

O.K., I'm goin' to back up.....
The Air Injection Pump, with an integral filter, compresses the air and injects it through the air manifolds and tubes into the exhaust system in the area of the exhaust valves. The fresh air helps burn the unburned portion of the exhaust gases in the exhaust system, thus minimizing exhaust contaminations.
A check valve prevents exhaust gases from entering and damaging the air injection pump, as back flow can occur even under normal operating conditions. So, IMO, you should not have air blowing into the air cleaner from the smog, or air pump.
I took this direct from my manual. I'll detail more, if you feel it will help.

_____________________________

1980 L-82 Fastback (forward too)
Mono composite front and rear.
Full adjust ride height and
response.
400+ hp, 454, M-22, 3.07

http://i121.photobucket.com/albums/o225/C3Starship/Patch.jpg

2007 H. D. Sportster, XL 883 EFI

(in reply to Batmobile)

Post #: 17

RE: A/C and Air pump performance hits - 7/8/2007 6:41:41 PM

73shark

Posts: 1097
Joined: 4/18/2006
Status: offline

There is also a vacuum controlled dump valve that dumps most of the air under high vacuum conditions like closed throttle. This prevents exhaust backfiring. There's a muffler on the back of the AIR pump that is the dump exhaust. Maybe that's the air he's referring to.

_____________________________

So many toys, so little time

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Post #: 18

RE: A/C and Air pump performance hits - 7/8/2007 9:08:35 PM

Batmobile

Posts: 31
Joined: 7/4/2007
Status: offline

How does the air pump not affect the air/fuel ratio the O2 sensor is measuring? The volume and oxygen content would change with environment, rpm and pump wear. Therefore, the emissions system could not expect (subtract) a constant or linear adder of oxygen resulting from the pump.

(in reply to 73shark)

Post #: 19

RE: A/C and Air pump performance hits - 7/9/2007 3:13:41 AM

78buckshot

Posts: 654
Joined: 1/28/2007
From: Michigan
Status: offline

That's a real good question Batmobile, something that I don't have the answer for. As a test, you could pull the belt off and run the car on a city/highway test loop and see if the computer has any complaints.

(in reply to Batmobile)

Post #: 20