1st Generation Specific (1979-1985) 1979-1985 Discussion including performance modifications and technical support sections

over-rev buzzer

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Old 04-24-02, 08:53 PM
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over-rev buzzer

I do not believe that my overrev buzzer is working, as I have passed redline more than a few times and never heard a thing (other than a screaming team of angry hornets under the hood ). Is there a way to check/adjust it?
Old 04-24-02, 09:01 PM
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out of curiosity, why would you even want it to work..
i think that it is bloody annoying, and i am glad that mine is dissconected.

besides, you have a rev limiter. that is enough
Old 04-24-02, 09:10 PM
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Do all first gens have a rev limiter? Does this mean that I can ride out each gear to the end? What about revving out in neutral?
Old 04-24-02, 09:18 PM
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you can but there is no reason to.. a stock ported, or even streetported engine will stop making power way before that... plus, at those hi rpms, you risk engine damage.
Old 04-24-02, 09:20 PM
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My '80 had no buzzer. The '85 does... but it's pointless to rev the engine that high. There is no rev limiter unless you add one.
Old 04-24-02, 09:26 PM
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I was wondering what the hell he was talking about...
Old 04-24-02, 10:41 PM
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my 85 has no buzzer, when is it supposed to come on, i've never taken it over 7000rpm
Old 04-24-02, 11:03 PM
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peejay , i have had my car bumping off of a revlimiter before when i did not have a tac. it is set redicusly high though, like 9k
Old 04-24-02, 11:04 PM
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if that was on your '79 then it was probably the points bouncing
Old 04-24-02, 11:04 PM
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Humm, My buzzer comes at 7K. But it's not a over-rev buzzer it's more like a "now we are having fun: buzzer!"
Old 04-24-02, 11:08 PM
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peejay: 80 dizzy on my 78 engine
Old 04-24-02, 11:16 PM
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No carby RX-7 ever came with a rev limiter.
Old 04-24-02, 11:25 PM
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hmm.. well i donot know what it was then, but it sure felt like one..
oh well. not like i intentionally bring i up to 9k anyways, so it is not of importance..
Old 04-25-02, 12:58 AM
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My overrev buzzer changes when it comes on slightly when the temperature changes hot resistors have more resistance. You can swap out resistors for the overrev buzzer to make it come on at a different time. Or you can even make it into a light.
Old 04-25-02, 01:28 AM
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http://www.monmouth.com/%7Erothe/overrev.html
there ya go
Old 04-25-02, 07:07 AM
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I've wired a remote external potentiometer in place of the stock circuit board model, and removed the buzzer from the board. The wires are temporarily snaked down the console to the shift lever. For now, the old buzzer is rewired to them, and I can control at what RPMs it goes off; Down to about 3200.

I did this to eventually hook it up to a relay and my electric exhaust dump. But it could run a buzzer or shift light...oil slick dump, smoke screen, flame thrower. Whatever!

(In my opininion, shift lights are for idiots; And furthermore, could only work to your advantage if the RPMs at which the light turned on was optimised (different) for each gear.
I think you only find them in cars where the driver has too many things to focus on that he can't really be 'one' with the car...Like rallying where the co-driver is screaming a constant blurry of instructions to him.)

I now think it would be far easier to just get a "bolt-on" tach unit and a simple programmable computer to run accessories in this mannor with any sort of accuracy and consistancy.
(I.E., It seemed like a real neat idea at the time, but it does'nt work all that great!)

[And no, I'm not "seeing the light" of computer control.
I refuse to be sucked into the "fulie vortex"!
Dive in, maybe. But not sucked in!
-Just so you know, mar3!]
Old 04-25-02, 09:03 AM
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Actually, I detest smart boxes. They've ruined traditional drag racing with those idiotic Dedenbears that control accelerator trim, start the nitrous, and then pull back throttle at the end of the run to cut the index time...stupid...oh, yeah, RX-7's never came with a factory stock rev-limiter. That was your apex seals bouncing off the sides of the chamber slowing rotational speed...just rying to stay on the subject of the thread...
Old 04-25-02, 09:10 AM
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WTF???? You totally lost me
Old 04-25-02, 11:15 AM
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Sterling, I see one advantage to shift lights. Okay, maybe two. The first advantage (the primary one) is when you're still using the lazy, inaccurate factory tach, or if you don't even HAVE a tach. (I've seen people wire shift lights in to, say, the fasten seatbelts dummy light... very sleeperish)

The other reason i can think of is if you have one of those huge 5" tachs with a WHITE face and BLACK letters, and you're racing at night or with the sun behind you and you can't read the tach if your life depended on it
Old 04-25-02, 12:50 PM
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Are pretty much all aftermarket tachs accurate? Or only the well known brands? I'm considering getting one cause i dont want to overrev the motor, although most of them look ridiculous.
Old 04-25-02, 01:03 PM
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Originally posted by theNeanderthol
Are pretty much all aftermarket tachs accurate? Or only the well known brands? I'm considering getting one cause i dont want to overrev the motor, although most of them look ridiculous.
Time for a new thread...
Old 04-25-02, 05:45 PM
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WHat if your engine is too loud to hear that silly overrev buzzer? Even before I had a loud car, I hated it, so I took and removed the little long screw in the back of the cluster which closes the circut. Just got too annoying with the mildport and now the bridgy would be even worse.
Old 04-25-02, 06:05 PM
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Ya know, there is another potentiometer on the tach circuit board, and I'm willing to bet it's for proper calibration of the tachometer. It will be very interesting to find out if that is so. It's the only thing I can think it's for.
Also, there's the circuit planning on the board...My 82 has the circuit map, but many of the components are missing. The 85 board has them all in place.
Among the missing components is the over-rev buzzer pot. This means that at least for the 82s, and probably earlier, the buzzer is not adjustable.
Yet the other pot is there.

If you can recalibrate it so it's right, why get another tach?
Old 04-25-02, 06:59 PM
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Sterling, you'd be amazed at how inaccurate the stock gauges are.

Do a search for "soul assassin full bridge video" and watch the video. There are about three or four different sites hosting it. About halfway through the video, the camera focuses on the aftermarket tach. It's accurately reading the engine RPM as the engine braps and bounces between about 1400 and 1600 RPM. Then it shows the factory tach. It's reading a rock solid 1500rpm.

The factory gauges are buffered so that they don't move very quickly... people in general don't like to see gauges moving and jittering with every little change. The tach, even if statically calibrated to perfection, will read inaccurately under acceleration because it reacts too slowly. That's what racing gauges are for.

It also explains why in 1st gear the buzzer goes off at an indicated 6500rpm, but in 2nd gear it's an indicated 6800 and in 3rd it's an indicated 7200. The buzzer is going off at the same RPM each time, but the tach lags behind. As mentioned before, the tach also reads too high, so at some point of acceleration the lag and the misadjustment cancel each other out, but frankly it hurts my head trying to reconcile two fudge factors like that


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