eyecandy

iTrader: (19)

I wanted to know if any one can help me out.. A friend of mine has a 90 RX7 and when he got the car it had all the emissions stuff taken off, and he finally got a new high flow cat. But the there is a problem, he is missing a few sensors that cuts off the air flow to the cat after it is warmed up.

Now basically my question is, is it harmful for the cat if you do not have the air pump connected to it? Will it cause the cat to clogg or not work? From my understanding of the air pump is that it is used to help warm up the cat to working conditon so it takes the impurities out, also to open up the extra ports. But on my friends car the ports are tied open so the pump serves no purpose there(iguess).

I am almost postive while i was talking to some ppl a long while ago that you do not need the air pump to run the cat..but i may have been mistaken...

Sorry if some of this was alittle confusing.. and any help would be greatly appreciated!

J-Rat

iTrader: (2)

the air pump supplies fresh air to the cat to aid in the catylist. The cat will not last long without the Air pump.\\

Jarrett

benny_rx_blanco

That cat is gonna heat up like a cherry......LOL

eyecandy

iTrader: (19)

Thanks for the replies!

Well from what my friend told me was that the air pump shuts off after it warms up.. does that mean that it stays on all the time? Cause that is what i orginally thought..hmm not sure now.. I am just all confused now what the air pump really does/how long does it saty on etc.. All i am postive about is that it help keep the exhaust clean..

Now when you say it is gonna heat up like a cherry is that without the air pump?

J-Rat

iTrader: (2)

THe air pump is always on (hard to shut off a belt driven one). Depending on RPMs and driving conditions, the ACV routes the air from the air pump to various areas of the motor (split air, port air, etc.) Its called the "secondary air" system. HAILERS is the forum god on this system. Basically, under hard driving, the pump air is directed to the cat. This aids in the catalyst and I guess cooling (wasnt aware of that one).


Jarrett

Actually, I think the air is routed depending on RPMs only.

Scott 89t2

the air pump is there to pump air into the cat. which then burns which causes heat so the cat works better.

no airpump = LESS heat = higher emissions.

I run a cat with no other emmisssions stuff just fine. but you will need the other stuff to pass a test.

J-Rat

iTrader: (2)

Thats what I thought...

Icemark

Hey remember if it is a NA the 90 RX-7 needs the air pump to activate the 5th/6th ports and VDI, so besides for emissions reasons it would be bad to remove the air pump on a 89-91 NA. If he did he would loose all sorts of high end or low end power (depending on 5th/6th port and VDI location).

Stews'7

Thanks for replying people. From what the shop told me whn they smogged it. They just hooked the air pump directly to the cat, and go it to pass once. Now the belt has been removed. ive been driving it around for a few days, and it hasnt seemed to be clogging though. They people i took the car to have it worked on dont know there *** from there head when it comes to rotarys. The guys sad hes seen only 5 of em in 25 years. Now if i reinstall the ACV would that ilimnate my prob of the cat being over heated. I didnt think the air pump would stop rather just have the air rerouted. Would the ACV be all that i really need ot fix the prob? Cuz the 6 ports are wired open as with the VDI. Yesterday eyecandy and I installed my HKS exhuast, but now its acting how it did when it the straight pipe was on. When I come up to a light its will stall. Or if it idles it does so at 500RPM and is very lumpy. I think it may have to do with intallng the exhuast and not having enough back pressure. If anyone can help im very gratiful Thanks!!

Icemark

(shakes head about 5th/6th ports and VDI wired open)...

I am curious why you/he disconnected the air pump and wired the VDI and 5th/6th ports open... did you want to loose HP and torque at low RPM? if you were just trying to remove the air pump for weight reduction you also removed low end torque (which is really the last thing you want for anything but high speed driving).

Anyway, the air pump is needed to help keep the cat from overheating. The closer to the car being tuned correctly will extend the life of the cat. Without the air pump, the cat will fail much earlier than otherwise would happen. The ACV controls the amount of air and operational feed for the Cat based on the O2. It also helps prevent backfire on lift throttle situations.

rotaryrex7

3rd gens air pump has a clutch that cuts it off above 3000 rpm, 2nd gens don't have a clutch and they run all the time.