shiznizzletech

I was wondering if I could get some elaboration on this air pump on my 88 RX-7 NA. I know it does something like oxidize the unburnt fuel for a more environmentally friendly exhaust, correct??

Now I also would like to know if I can remove it?? We do not have an emission regulation here in Florida, since I believe everything just drifts out to sea. Would there be any adverse effects?? Such as ruining the car??

I have also noticed my car smells quite rich when it runs and can this pump be used to maybe lean out the air/fuel mix?? Or are there any other ways to lean out the mixture or make it run a little less rich??

As always, any information would be great! Thanks!

RotaryRocket88

iTrader: (7)

Smog pumps/air pumps add oxygen to the exhaust prior to the cats to be reduce HC, CO and NOx. Adding oxygen promotes production of H2O, CO2 & N2.

Info on catalytic converters: http://en.wikipedia.org/wiki/Catalytic_converter

If you remove the air pump, you need to remove the cats too. If this is an NA car, removing exhaust restriction will also make it difficult for the aux. port actuators to function. There are solutions such as RPM switch activation (with an air pump) and relocating the pickup tube for the actuators.

The air pump does not connect to the intake. It pumps air into the exhaust. There is only a mixture adjustment for idle, but it should not be played with unless idle is rough. If the car still has cats and an air pump, the exhaust should not smell much at all.

shiznizzletech

I am glad I waited to play with these parts. Are the aux. port actuators the 5th and 6th that open when the throttle pressure is high?? I have been looking at an aftermarket set of headers, would those would replace the exhaust pipes where the cats are located?? Just a ballpark estimate of how difficult it is to create a RPM activation for the actuators??

Thanks for not letting me ruin my car just yet. Cheers!

RobbyWally

iTrader: (2)

For details on where the air from the air pump goes, check the Factory Service Manual (FSM) section called 'Secondary Air Injection Control System' starting on page 4A-38. Briefly, the output of the air pump goes to the air control valve which directs the air to four differnt places depending on rpm, throttle position, coolant temp, etc. As RR88 said, the main purpose is to add air to the exhaust stream - directly at the ports and in the middle of the main cat. [The FSM is available for download from foxed.ca and other sites.]

If your exhaust smells when idling (after the engine and exhaust system are fully warmed up), something is misadjusted or not working (pretty helpful, huh!). The most basic things are pretty easy to check and repair / adjust: no missing or leaking vacuum hoses, no leaks in the intake path (after the air flow meter), correct operation and adjustment of the throttle position sensor and correct idle speed / mixture.

I can't provide any advice about removing the air pump or other emission controls. Both of my 88 verts still have all the original non-CA emissions systems...and pass the CA smog check easily.

RotaryRocket88

iTrader: (7)

Some people call the aux. ports "5th/6th ports". The actuators open with 2 psi of exhaust pressure, which corresponds to approx. 3800+ RPM and 0 manifold pressure.

A header replaces the stock exhaust manifold & precats. Some (Racing Beat) will also require another piece (presilencer) to replace the main cat due to length. RB's downpipes and headers are all meant to be used with their presilencers, which are 3" longer than the OEM main cat.

RPM switch writeup: https://www.rx7club.com/2nd-generation-specific-1986-1992-17/activating-aux-ports-vdi-rpm-switches-907824/

RobbyWally

iTrader: (2)

The aux port (so-called 5th and 6th ports) actuators are operated by back pressure in the exhaust system as mentioned by RR88. Some of that back pressure probably comes from the air pump, since it is pumping air into the exhaust.