Rotor Reaction

anyone use rev limiter on 12a with distributor??
how to wire up a rev limiter??

fatboy7

My foot usually works pretty good

Honestly I don't think it would be worth it. You can over-rev a rotary to an extent without damage, so as long as you aren't trying to blow it up, it really dosen't need a rev limiter.

peejay

You can overrev a rotary to an extent *with* damage, too. Hell you can even do it if you *have* a rev limiter.

I had a 6AL on the leading ignition, stock as a rock trailing ignition. It would limit OK at part throttle like when doing a burnout or when missing a shift, which really is all one needs a limiter for if one has a brain. What it will NOT work for is being a doofus and driving at WOT in 2nd gear and holding the tach pinned while you show your co-worker "See, look, pegged!".

Not that is only with modified. With stock engine and exhaust, leaving the trailing alone still allowed me to set the limiter ay 7,000 and it would actually *hold* at 7000, even if you brick the throttle in Neutral. (Which I've done one time trying to clear a flooded engine)

So what to set the limiter to.... bad things happen to the stock apex seals, stock stationary gears, stock rotor gears, stock bearings, and stock tension bolts, all nicely coincidentally at around 8500. So don't ever go over 8500.

You don't want to maintain revs over 6200 (stock apex seals) for any significant length of time, either, for what it's worth. The apex seals start to chatter at 6200, causing more rapid seal wear and the rotor housings to get chattermarks around the bottom curve. Should be just fine accelerating through. It's kinda *interesting* how the 12A cars are geared so that top speed is around just under 6000 in 5th, no? And the more powerful GSL-SE's have a taller 5th gear, and I don't have my numbers handy but I bet that coincides to just under 6000rpm at top speed also. Mazda didn't want people bolting the throttle to the firewall for minutes at a time with the engine in an unhappy RPM range, so they geared accordingly.

wagondriver69

Yes, because according to your avatar you always follow these guidelines..

Rotor Reaction

according to the way i drive, i really need some limiter which can hold the rev at some where.

i just kill a 280,000km standard 12a, so now i am getting a new laaaaaaaaaaaaaaaaarge street port engine buit. and i don't want it die to soon@@

anyone using two 6al?? or one 6al with another rev limiter to work with standard trailing ingnition??

peejay,
if my right foot doesn't have any problem, one 6al can do the job?!

peejay

doppelposten

peejay

One 6al can do the job. If you only use the limiter for safety in shifting or burnouts, not for a speed limiter like say at an autocross or a road course (or being a moron on the highway) where you would be faster if you bounce off the limiter instead of upshifting and then having to downshift right away.

It's a safety net but don't trust it.

The avatar... well, normally I'd shift at 8k. (Limiter was 8400) The stock tach stops at 8200. I missed 3rd and the video camera sees all...

I think I need a new avatar, though. Every time I see it I miss my '80.

mar3

iTrader: (8)

Here's a thought and I'm basing this on real experience when an ignitor fails...

When the lead fails, you've got some serious problems. When the trailing fails, you lose your tach and a lot of power, but you can limp it home to replace the ignitor.

So why not rev limit the trailing side first by 200 rpm or so before the lead hits the limiter?

peejay

You could do that. Actually, that's exactly what I would *like* to do.

MSD 6AL is only $30 more than the regular 6A. Or looked at another way, it's only 20% more. A stand-alone rev limiter is what, $50-60?

I think I might have a simple cheap rev limiter circuit for the trailing if you have a MSD already: Drive tach off of the MSD tach signal (male spade connection on MSD box), recalibrate the redline buzzer to come on just before the rev limit, and use the buzzer to operate a normally-closed relay mounted inline with the wires going between the trailing pickup and ignitor. Done and done.

Two notes on this as-yet-untested idea: Calibrating the shift buzzer should be a snap to ge it where you want it: Just disable trailing ignition, adjust it up to it doesn't come on, adjust it down gradually until it comes on right before the car hits rev limiter. (You *will* know when you hit limiter... ever hear a turbocharged rally car with anti-lag? Sounds just like that)

Second note: It would seem like a good idea to cut power to the trailing coil instead of cutting signal between pickup and ignitor. Until you remember how coils work: They recieve power, and then when the power is cut, the collapsing field in the coil induces a voltage in the secndary windings. So cut power to the coil and it will fire, in all probability when you do not want it to! (This is my line of thinking, anyway...)

Rotor Reaction

getting confused@@

my thought: use two 6al, set trailing limit at 7400 and leading limit at 7600?!

peejay

a big street port will be peaky and 7400 would be right in the middle of the meat of the powerband and when you shift you'd fall below the powerband. Generally with a SP the meat of the powerband is above 5500-6000 or so. You'll still have decent power below that, don't get me wrong, but you won't be ideal. (My SP had a noticeable kick in the *** at 5500, would spin the tires in the dry from a roll at that RPM when conditions were right, and it wasn't *quite* as big as it culd have been.. and it was sorta optimized for low end too) Go to my website htp://www.angelfire.com/oh5/izzmus and download the "oops" video and watch/listen to how the engine comes alive at that RPM...

With the stock gearing, really, for best results you'd want to wind it right out to the limits of the engine (just below 8500) because in the lower gears anyway the revs drop down to 4800-5000 after a shift, regardless of what the laggy stock tach claims. I was only shifting at 8k because my carb setup was too small.

Rotor Reaction

nm~~ about where to set the limit, still have to wait until i get the engine

but one or two 6al??