How much power does the smog pump take? Is it worth removing it? If so, what is the proper way to remove it from an LG4? Thanks!

------------------
1986 IROC LG4 "Bone Stock" (for now)

 

I'm not sure it really takes away any power. The gain will be little if you remove it. It really just takes some of the drag off the engine, because there is one less thing to spin. Just take off the pump and all the hoses that connect to it. Its really not too hard.



------------------
350 TPI
Flowmaster Cat-Back exhaust
Performance Chip (am trying to find out which one)
Modified MAF
Smog equipment removed

 

Did you have to use a different belt when removing the AIR pump?

 

If you have a serpentine belt, theres 2 options:
You can use a different belt and reroute it, theres a tech article on this site.
There is now an idler pulley available to take the place of the smog pump, then you can just use your old belt.

I have heard of people gutting the pump, but personally I wouldnt do that, I would just take it off so it can be reused later if necessary.

 

An '86 LG4 has its own belt for the pump.

As for effect on performance, I took the belt off mine one Friday afternoon before heading to the track. I keep track of the stats on each run, and the difference was ... zero.

A couple of weeks later I decided to put the belt back on. Only problem - the pump is now frozen.

Emissions test coming up in August. Good thing that LB9 engine had the pump on it...

The proper way to remove it is to take everything that attaches to it off, from the belt to the manifolds, and plug anything left open in the process (exhaust manifold ports, vacuum lines, etc.).

------------------
82 Berlinetta, orig V-6 car, now w/86 LG4/TH700R. 2.93 limited slip. Cat-back from '91 GTA, Accel HEI SuperCoil. AMSOIL syn lubes bumper-to-bumper. Daily driver, work-in-progress (LG4 w/LB9 block, ZZ3 cam and intake, WP 305 heads ported & polished, TBD headers & hi-flow cat).
57 Bel Air, my 1st car. 0.030 over 396, Weiand Action+, Edelbrock 1901 Q-Jet, Jacobs Omnipack, 1-3/4" headers, TH400 w/TCI Sat Night Special conv & shift kit, 3.08 10-bolt, AMSOIL syn lubes bumper-to-bumper. Best 15.1 @ 5800' Bandimere. Daily driver while Camaro was being put together.

 

If it isn't really a loss of power and all it does is take up space, I guess I will just leave it on. At least until I build my 350 for it. From what I understand, all it does is pump clean air into the exhaust to dilute the pollutants that are in it so it winds up being less parts per million. Isn't that cheating since the same amount of pollutants are still going into the air. Why can't they just tune it better from the factory?

------------------
1986 IROC LG4 "Bone Stock" (for now)

 

That isn't what it does. It helps the cat burn up the extra hydrocarbons. It pumps hot gases from the manifolds to the cat, or maybe it's the other way? well it does something like that.

------------------
1989 Pontiac Firebird Formula LO3 Auto
-180 degree stat
-Hooker Cat-Back
*****Possible summer '01 mods*****
Open Element, Auburn Posi, Keyless Entry, wonder Bar off the IROC, 4th gen seats, T/A tail lights

1985 Camaro IROC-Z LB9 Auto
http://www.geocities.com/krt80/

 

In a nutshell, Wiggy is right.

------------------
1989 IROC-Z 5.7L

 

The smog pump is part of the Air Injection Reaction System. It doesn't pump hot gases, but it pumps fresh air into the exhaust not to dilute, but to help burn off emmissions.
http://people.ucsc.edu/~kbrandt/mustang/smog.shtml

 

Thanks for the info. Great website too from Keith5.

------------------
1986 IROC LG4 "Bone Stock" (for now)

 

AIR started before catalytic convertors, so it's not strictly tied to cat function. But, like others are saying, the purpose is to increase the O2 content to enhance burning of any remaining unburnt hydrocarbons.

 

Yeah all the air pump does is puts fresh air into the exhaust or cat (depends on what year you have)to help burn Hydrocarbons. Also it only does this at idle, Its bypassed at higher speeds. On my old V-6 firebird when it was working my emissions test had almost zero CO2 and had zero hydrocarbons. Later the check valve failed and I went through many rubber hoses not realizing what it was. I looked at the pump and it had a big hole burnt in the side as well which caused it not to work. The next test it still passed but the CO2 and Hydro where higher. If you remove it, hey its one lest pully to turn!! Anything thats engine driven is horsepower taken away, althought in this case its not much, just a couple.... 5 at best.

 

The pump itself doesn't cause much drag, but each exhaust port has a steel tube, about 2" in length and the diameter of a pencil sticking into it and getting in the way of the exhaust coming out.

Just remove the AIR manifold and, using a drill bit (1/4" ?), remove each of those tubes and put the AIR manifold back on. That way, the smog pump can still do its job and the exhaust can come out of the cylinders a little easier.

[This message has been edited by jrr (edited January 27, 2001).]

 

How do you tell if the pump isn't functioning properly?

------------------
1986 IROC LG4 "Bone Stock" (for now)