Does anyone know the flywheel diameter of a N/A 2nd gen 13 B? When I mean flywheel diameter, I mean a circle sweeping around the outside of the starter teeth.

Also, does the '87 13B N/A have a rev limiter? Who makes some good aftermarket rev limiters....link?

And, does the same motor have a knock sensor? If not, what's involved with getting one installed?


Thanks,

Tom

 

Don't know on the flywheel... I'll have to look it up.

There is no rev limiter in the 86-88 13B, however there is a buzzer that sounds at redline. From personal expericance you can take it past redline and up into the 8k range, and you will notice that the power curve drops quickly. Aftermarket (as below) can have issues as many aftermarket rev limiters can be difficult to set up due to how the rotary works. Your best is using the trailing coils test lead and the aftermarket rev limiter set for a 6 cyl setting.

There is no knock sensor either. The motor was tuned for 86 octane gas so mazda didn't figure that it would need one. You might be able to retrofit one from a 89-91 in, but you would need to re-wire the car car and replace the harness and ECU. It would not be at all cost effective. Most aftermarket knock sensors do not work well on rotaries as they can be easily confused by the three fires per cycle per rotor.

Frankly I don't see the need for either on a 86-88 N/A rotary and I think you'll just add extra complexity to the car for something that you should seldom need if the car is tuned correctly.

 

I do want a rev limiter. How would a 6 cylinder rev limiter be setup? You would sense just one spark plug wire...but I'm interested in how the module would cut the motor out. Would it do random sparking like the MSD modules? What would you recommend for a rev limiter?

As for the knock sensor....what would be the max boost I could run before this becomes an issue in regards to knocking? I do plan on turbo or supercharging the motor...but am nervous of what the limits are.

 

And the answer is.....11 and three quarters for a 13B non turbo and 12 and five eighths for a turbo. Both 87 models. Not measuring in meters today, sorry. All measurements plus and minus one eighth. Used a yo-yo.

 

The spot I mentioned is for the rev limiter pickup, that wire will work like a single coil for a 6 cyl car. Most rev limiters need to be set by the expected number of cylinders. You would want to interrupt either the main power to the leading coil or rear injectors depending on what you really want to do with the car (race vs girlfriend proof).

Again I wouldn't. Maybe the Accelle or Jacobs limiter if I had too... but I think human interface (I/E your hearing a buzzer and deciding yourself if you need to back off) is better