I am restoring an SA22 I bought new. My intent is to make it as close to original as I can. But I live in CO which requires emission checks and I'd like to improve the gas mileage for daily driving.

My understanding is that the TR cars have to run very rich which kills the mileage. Will replacing the TR with a CAT allow me to lean out the carb for better mileage while still passing emissions for the year.

(I know I'm not supposed to alter the original emissions system but the idiots at the emissions station won't know the difference.)

Herb

 

The fuel economy difference is minimal in practice. At any rate, altering the emissions system is illegal, even if you are making the car cleaner.

 

i've had both systems, and for me the SA actually got slightly better mileage than the FB cars did. not really sure why, although the gas we have now is leaner than the gas we had when these things were new.

the second, and more important part, is that the air injection system is different between the two cars. some how you would need to plum the air pump air into the exhaust ports, Mazda used a passage in the engine...

 

come to FL and run open exhaust. LOL

 

Is your thermal reactor cracked or damaged? If not just use it and make sure the smog stuff is
setup right. The SA (80s for sure) has special logic builtin to the ignition to disable the rear rotor
and/or richen/lean the mixture based on speed/temp/vacuum. It all works well when its
maintained.

 

The feds said the 1979-80 got 15city/26hwy where the 83 - 85 12a is listed as 19city/29hwy. I have been told that is because of the TR having to run very rich to work properly. Can anyone address?

Herb

 

Any clues on how to set it up correctly? I've had the whole thing apart. I tried not to change settings on the bird's nest but?????

Herb

 

I saw a steady 20mpg on my SA when it was all stock. 24mpg when street ported.

I saw as high as 33mpg but normally 27mpg with my FB... which was running on my SA's carburetor

 

The FSM gives you all the details about how to maintain, test, and tune the setup for the factory
specs. If you have ahd it from new, you may just need to clean things and replace leaking vacuum lines and be good to go. Likely not many adjustments needed.