j9fd3s

you could always use it to open your 6 ports



mike

dcrasta

you could always use it to open your 6 ports



mike [/quote]

Its very useful to open the 5th and 6th port .. Actually works great for that. I just make a small hole in the hose coming from the air pump and add a dual sided barb to connect the Aux port actuators to it. Hooked all the hoses back up (its actually good for your cats to have that fresh air pumping through.)

FDNT

I know this is a really old thread but just had to add this... because so many people over there (I'm in Japan) seem to wreck their engines and say rotaries are unreliable because they don't really know what everything is there for....

The air pump is not just there for emissions. The air pump (on an FD at least) pumps metered air into the exhaust manifold in order to thin out the hydrocarbons (unburned gas/carbon) and accelerate the exhaust going out from its thermal expansion (not combustion mind you, thats why its metered so it doesnt explode in the ex. manifold and blow it apart), mainly at low RPM ranges when the combustion efficiency is low and you've got more unburned gas and carbon. Its just how rotaries work, they don't burn efficiently at low RPM. If you remove or stop the air pump without removing the cat or while having a small diameter restrictive exhaust system, it will:

1. Eventually clog the catalyzer and/or cause it to heat up and cause detonation inside it which will crack the honeycomb of the cat(which is more likely and so it wont clog in this case lol) and make it totally useless
2. If you use the engine alot in traffic; ie low rpm ranges, no airpump /restrictive exhaust will cause more carbon buildup in your engine because you are not thinning it out and ejecting it out of the ex. manifold as much. The rotors will rake the carbon back into the engine if you don't rev high to push it all out - you always need to rev high in order to keep your engine from fouling the plugs with the excess carbon/causing carbon build up on the rotors/seals. Thats why removing the air pump is best left to track only cars or if you live somewhere with no traffic.
3. Lose a bit of low end torque for some power gain+ for not having to turn the air pump on the belt.

If you get rid of the air pump or stop it you pretty much need to take out the cat or it will eventually heat up and crack, which happens more than clogging I believe. Even if you have a big diameter free exhaust/no cat you will also need to drive the car differently; drive it at high rpm alot to prevent the plugs from fouling up; good for race cars, Not practical if you use your car in any traffic, because it will foul the plugs easier and lose a bit of low torque.

If you only drive on highways and the track, by all means pull it out, but just be aware of the above. And people who have plug fouling issues/unstable low rpm/idle with their FDs often removed their air pump, or if they have a working air pump have a clogged up ACV that meters the air in this system, or the check valve going into the cat. Which can lead again to a blown engine from the excess carbon.
I've never fouled plugs on my SA or the FD (light tunedw/full exhuast/sport cat/intake/power fc) in the 26 years I've owned it.

You have to realize Mazda engineers put years of thought into balancing the engine for everyday use.... if you mod it to be a track car you have to treat it like a race car ...break it down and inspect it after every run etc. Removing stuff will make the engine operate differently, and also require the user drive the car differently... or they will eventually have fouled plugs, detonation from the carbon = lose compression and blow the engine.

sweerek

Old but still useful. Spot on about balancing....

Other issues without the air pump (that can be found in books and many threads):

• the water pump pulley & belt have too little contact. Over-tightening the belt to compensate destroys the bearings.
• Per Chiltons the air pump cools the exhaust flow at the injector (and then obviously heats it in the header / pipe as the fresh O2 reacts with hot, unburned fuel). An aside, this can result in glowing red headers meaning a tune-up is needed to make the exhaust a bit less rich.)
• With newer cars, the O2 sensor & computer are thrown off, and the car doesn't understand how it should react. On carbs, it is a similar but an analog balancing act
• Reactors and cats definitely need oxygen to work and airflow so as not to overheat. The air pump provides both. Rotaries run richer than pistons, meaning cat's get a heavy-duty work-out even when optimally tuned
• Even if the reactor / cats are all deleted, there is still value in keeping the air pump