Rev Limiter (123 Ignition) Options

[Not_A_Six]

The positive reviews here have me looking hard at a 123Ignition dizzy replacement on my '73 2.0 w/ stock D-Jet.

But, the version they offer for the 914 that's compatible w/ D-Jet (123\PORSCHE-4-R-V-IE) has a fixed 8000 rpm rev limiter.

The thought of my motor turning to shrapnel at 8000 rpm is a just tad bit worrisome. (IMG:style_emoticons/default/icon8.gif)

Ed at 123 Ignition said that the OEM rev-limiting rotor won't work in their dizzy, and suggested an aftermarket stand-alone rev limiter. But, I'm not too enthusiastic about adding an extra box at additional expense, just to limit revs.

Has anyone here used the 123Iginition w/ D-Jet? What did you do to limit rpm? Anyone just run without a rev limiter?

Thanks.

[Mark Henry]

You want no more than a 6K redline and never use a limiter as a shift indicator.
Depends on the cam but torque drops of at 5400 rpm with most cams, some hotter street cams it's about 5600.

[Not_A_Six]

You want no more than a 6K redline and never use a limiter as a shift indicator.
Depends on the cam but torque drops of at 5400 rpm with most cams, some hotter street cams it's about 5600.

Thanks. I was more concerned with somebody over-revving the engine accidentally and thought the rev limiter would be a valuable (essential?) safety valve.

I do know how to drive, after all. (IMG:style_emoticons/default/wink.gif)

[VaccaRabite]

Thanks. I was more concerned with somebody over-revving the engine accidentally and thought the rev limiter would be a valuable (essential?) safety valve.

I do know how to drive, after all. (IMG:style_emoticons/default/wink.gif)

How would you accidentally rev past 6K?
A rev limiter won't save the engine from a money shift (typically 5th to 2nd) since that is a mechanical over-rev and not caused by the gas pedal.

Only way I see this as possible is racing the car (AX or track) and not paying attention to the sounds your car is making.

Zach

[Mark Henry]

Thanks. I was more concerned with somebody over-revving the engine accidentally and thought the rev limiter would be a valuable (essential?) safety valve.

I do know how to drive, after all. (IMG:style_emoticons/default/wink.gif)

How would you accidentally rev past 6K?
A rev limiter won't save the engine from a money shift (typically 5th to 2nd) since that is a mechanical over-rev and not caused by the gas pedal.

Only way I see this as possible is racing the car (AX or track) and not paying attention to the sounds your car is making.

Zach

Never say never, with a high performance balanced engine it's a lot easier than you think.
I hit my rev limiter a couple times on my 2600cc T4 bug this last season. I haven't hit it yet on my new 3.0 /6 but I came pretty damn close. I wouldn't drive a performance engine without one.

Mr. Hyde's engine, a 2.3 (80x96mm) balanced with healthy breathing from 44mm webers and a tangerine 1-7/8" header, he had one of the cable linkage carbs stick WOT and it went BOOM. Pete from RD has a vid of the mishap, it only took a second before it granaded.
Mike was so bummed he sold me the car, in his case a rev limiter would have likely saved the engine.

On a stock or stock-ish engine you are much less likely to ever hit a rev limiter, as the engine just can't breath enough to get one into trouble.