Is there a way to add a rev limiter?

[JP911]

I will be autocrossing my car and doing the occasional track day and I would like to have a rev limiter, but my car is kind of a ba$tard and I'm not sure if there's a way to add one on. The chassis is a 74, the engine is SC with CIS, and the distributor is a 964 unit modified by Rennsport for mechanical advance. So, I can't use the rev limiting rotor and the car doesn't have the fuel cutoff switch that an SC would have. Is there a way to limit the revs or should I just install a shift light and pay closer attention to the tach?

[Porschekid962]

What type of ignition are you running with your dual plug? The msd boxes have rpm "pills" that you simply plug in and cut igntition at a certain rpm. If your running stock CDI's I have no idea what you could do but I am sure there is a way to limit them.

Best of luck

[Steve@Rennsport]

If it were me, I'd install an MSD 6AL, MSD High Vibration coil and use the very nice "soft-touch" rev limiter that these have.

Shift lights is always a good idea but a real rev limiter helps keep you honest when afflicted by the "red mist",....

[JP911]

I've got stock 6-pin CDI boxes and I'd like to stick with them. Guess I'll have to go with the shift light.

[aturboman]

I have found a stand alone rev limiter in the aftermarket that is designed to work with CD ignitions and is completely adjustible. I have not yet tested it but I can give you the info if you want.

[JP911]

Are you referring to the CraneCams rev limiter? I was reading up on that but wasn't sure if it could be made to work with a twin-plug setup.

[johnsjmc]

In this case you should be able to add the US style SC fuel cut relay. I believe it runs off a signal from the tach.

[aturboman]

It is not made by crane cams its Jacobs Electronics ( don't know who owns them) but it is specifically for CDI ignitions.

[911SCfanatic]

Originally posted by johnsjmc
In this case you should be able to add the US style SC fuel cut relay. I believe it runs off a signal from the tach.

Tell me more. What information do you have on this mod. Is it adjustable (for example, by using a particular resistor)?

[aturboman]

If you are referring to the Jacobs set-up I mentioned I can get you the exact model if you wish. It is a small add on box (radar detector size) that wires in very easily. You can select any desired RPM cut out by just turning a knob on the front on the unit. As I mentioned earlier I have not used it yet as my project is still being finished but I did buy and install the units.

[johnsjmc]

The US style rev limiter relay 911.617.136.00 is wired to the fuel pump relay and uses a tach signal to interupt fuel at 7000 rpm I do,nt know if a resister could be used to change it. It is standard equip in any US delivery SC ( behind the dash) . See the recent thread by ecm911.