let's say one has a box of electroinckery driving a Ford EDIS and one wanted to implement a rev limiter.

Is there are recommended way of doing this? i.e. does one trun off all sparks to the engine when it hits the specified RPM?

or is there a better way of doing it that stesses the engine less for example cut off every 3 spark thus slowing the engine down less than the afroementioned method. (soft limiting)

Does not cutting off all sparks at high RPM result in the exhaust and instake systems being filled with unbrunt mixture (oh, engine is fuelled via carbs) that will explode in specatacular style once engine is firing again? The "soft" spark kill will reduce that.

So what is commonly done?

I wouldn't turn off all sparks.
Or rather I'd have two rev limits. Somewhat like a soft cut and a hard cut. Soft cut = missing out some sparks, hard cut = stop all sparks.

You can, of course, also cut power to the fuel pump as a simple way of having a rev limit, though I wouldn't want to do that on it's own.

If you cut out some sparks you'll run rich. If you had a fuel cut on it's own you'll run lean at full throttle and likely under load If you cut fuel pump supply at the same time as doing the "soft cut" alternate firing you'ld probably get a nice reduction in revs without blowing a piston......

Megajolt has a built-in rev limiter that retards the ignition timing to 0 degrees. This has the effect of robbing the engine of most of its power. Works quite well.

You can also get an add-on board that interferes with the plug firing - rather like your original question

ooooh, changing the timing, didn't think of that! nice.

So how did the rev limiter in points distributors work? Kill all sparks?

My old Honda VFR750 had a mint way. It cut the spark to two cylinders and left the other tow running... stopped the revs dead at the red line and sent a nice huge flame and bang out the exhaust on each cylinder stroke

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Originally posted by 02GF74
ooooh, changing the timing, didn't think of that! nice.

So how did the rev limiter in points distributors work? Kill all sparks?

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Originally posted by David Jenkins
Megajolt has a built-in rev limiter that retards the ignition timing to 0 degrees. This has the effect of robbing the engine of most of its power. Works quite well.

You can also get an add-on board that interferes with the plug firing - rather like your original question

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Rescued attachment images.jpg

A Lotus Cortina I once drove had that switch in the rotor, usually killed the ignition just as the rear end stepped out, lots of fun.
Don't kill all the cylinders at once, Ford tried that with Crown Victoria Police vehicles, threw you into the seatbelts, near tore you head off. The next year they went to soft setting, retarded spark, alternet cylinders.

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Originally posted by 02GF74
ooooh, changing the timing, didn't think of that! nice.

So how did the rev limiter in points distributors work? Kill all sparks?

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Omex make a adjustable limiter you splice in with 3 wires.
Has option for hard and soft cut.
Had one on one of my swift gti's, worked very well about £80

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Originally posted by rusty nuts

Some old Lucas and Bosch distributors used a centrifugal rev limiter that was in effect a rotor arm with a spring loaded contact that shorted the HT circuit to earth when limit was reached. Or at least that was the theory , don't think they were too reliable??

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Originally posted by goaty
Omex make a adjustable limiter you splice in with 3 wires.
Has option for hard and soft cut.
Had one on one of my swift gti's, worked very well about £80

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quote:

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Originally posted by 02GF74

quote:

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Originally posted by goaty
Omex make a adjustable limiter you splice in with 3 wires.
Has option for hard and soft cut.
Had one on one of my swift gti's, worked very well about £80

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£ 80 !!???

I had to pinch myself in case I had posted on wealthy arab sheik gold plated diamond encrusted cateringvan forum?!?!?!

You are having a laugh. I will be making my own megajolt for less than a tenner a

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Originally posted by MikeRJ

If you can make something as well built and packaged as the Omex for a tenner I'll be mightily impressed.

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