Where did my rev limiter go?
 

I just bought the car for a grand so problems are no suprise, but I found this beculiar. I didn't notice this when I test drove the car, but I didn't really max it out, but any ways while I was showing my friends what a rotary sounds like (I was parked and just reving) I floored the gas and immediatley burried the tach, it was stuck at 8 but the motor was still speeding up, and somewhare past 8k rpms (my guess would be between 9-10k rpms) the motor started to belch blue smoke. I wasn't trying to wreak my motor, all this happened within 2-3 seconds and I assumed my rev limiter worked, also my shift alarm doesn't work. Any body have this problem before?

There are no rev limiters on carbed 1st gens, that's why there is a buzzer.

Yeap the rev limiter is the boom when you get it up to high.


Hope you did not hurt the motor.

The buzzer is standard on all rotaries whether they have a rev limiter or not.

Im not even sure where the limiter is on my S5 engine,I dont think Ive ever hit it, and I know Ive pulled 8K clean rpms on a couple pulls.Must be a bit higher up.
The smoke was likely from the abrupt let off of the throttle at those high RPMS.There is a lot of pumping going on in the engine,and when you slam the throttle plates shut at those speeds,the rotors are now trying to suck air from the next easiest source....usually from the crankcase,through worn oil seals.The vacuum draws oil into the chambers and creates the heavy blue smoke.If the engine still runs well,its probably OK,but definately dont exceed 8K RPMS regularly,or ever for that matter.

i hit around 8200 on my 12a and never heard a buzzer, maybe its bad or disconnected for some reason

Oil pump start pumping air in when it's over 8k, doesn't it?

The buzzers are unreliable,but they usually go off right before the factory redline (6500 RPM)

The oilpump probably does cavitate at some preset speed.But typically,most race engines run the stock pump,so its probably pretty high up there.Some internal mods can be done,likely to quell cavitation and increase output.
Oil foaming will cause air bubbles to get into the oil pickup and lower oil pressure and raise oil temps.Thats wht we run baffle plates.Running with low oil levels and doing lots of cornering will also allow air into the pump pickup....always bad.

I had a similar thing happen when I first got my car, it still runs fine to this day, so you shouldn't worry too much. Yeah, good luck with the car.

A rev limiter requires there to be a computer controlling at least your fuel or your spark.

In a first gen 7 a carburetor controls the fuel, and a distributor controls the spark. No computers.

Not very complicated. No limiter, just a buzzer which kicks in when common sense fails.

You shouldn't assume a car even has a rev limiter, let alone assuming that anything on a 20+ yr old car works as originally advertised.

Remember, assume makes an ass of u and me. Which is why I'm being an ass about it ;)

Jon

and yeah, you're an ass. :bigthumb:

As far as I know, only the 3rd gen rx-7's had rev limiters. But I could be wrong.

The second gens cut fuel to the rear rotor for a rev limiter. I don't remember what rpm it happens at, but it is noticeable. It has put me forward in the seat before on my 87 NA.

To the thread starter, check your oil for metal glitters when you change it. If you hit that high of an rpm, you stand a chance of spinning a bearing.

I just changed my oil no glitter, chunks, or any thing weird just very black neglected oil. She still smokes a bit when I first start her up after sitting for a day or longer, but now I mind the rev's and there hasen't been a trace of blue smoke. I think I got away with it, but now I alot more careful.

Let's hope so, the oil glitter won't show up this soon so check the next oil change too. If you get industrious the rev buzzer is attached to the back of the tach. I would check to see if the low coolant buzzer is working too. While the engine is running, unplug the single wire at the top, center, of the radiator. Treat it gently, they get brittle.

you need to change your oil. 3k per change max.

The tachometer over rev buzzer circuits do go bad. They have a few potentiometers on them, standard variable resistors of the day. Stuff gets wet, dusty over twenty years, and they fail to work.
I wired mine from the circuit board to a remote potentiometer. "Dial-a-rev". ;) It helps when I test carbs for jetting and want to only shift at "X" RPMs.