okay i've noticed that all you guys with the single upgrade are lacking the air pump. wtf is the point of this thing?

It pumps air into your main cat, to make it run hotter, thus be more efficient. It only runs at low rpm's, and a clutch shits it off over 3,500. it is pointless to have if you have a MP, but your cat will clog without it.

The original intent of an air pump was the meet emissions standards. The first emissions standards were set by volume, so an air pump helps get around the problem by pumping more clean volume into the exhaust and lowering the pollution ratio per volume.



The 13b is pretty polluting when it's not warmed up, so a pre cat and an air pump were installed to help pass emissions. Had it not been for these the FD wouldn't hav been US legal.



I believe I've heard something about the US FD ECU being tuned differently than the Japenese one to help on this emission problem too. Some speculate that this is where the difference of 20 crank hp comes from between versions. Anyone confirm/deny that?

I thought that the extra HP came from 3 rotors instead of 2 like we have here in the US.

If I get a DP will i have to do anything with the air pump? Or just when you get a mid pipe?

All Factory FD's were 2 rotor, regardless of national market.

the air pump is there to get the converter hot enough to burn all the shizzle in the exhaust at ilde and low speeds. without the air pump the rotary is a. a little too dirty and b wont run at an af mix that the cat needs to work at.



every fd had an air pump from the factory, and every mazda rotary with an emissions system has had and air pump from the factory.

the 20hp difference is partly because the jdm cars have no precat and partly becuase they are in ps instead of sae hp. the airpump is off over 2500rpm so the maps above that are the same



mike

Where did you get that idea?



No. Midpipe only (maybe some high-flow cat's as well).

so are all the guys with single turbo upgrades not running stock MP, or do they just not care?

i thought the 99 spec also had better turbo design

https://www.nopistons.com/forums/pub...IR#>/boink.gif

they bumped the rating from 255 to 280 in 99, thus a better designed turbo system.