pertronix rpm limit

[socalmark]

I'm running a Fiat X1/9 with a 1290cc motor in vintage racing. The current ignition is a Crane XR700 and maxes out at 8500 rpm. Fast tech tells me that is the limit the system can run at. I'm looking for a rpm limit of 9000 rpm. Pertronix tech tells me that their conversion kit will operate to 10000 if the coil has full battery voltage. Does anyone have experience with the pertronix units at this rpm?

[Tuner]

I'm running a Fiat X1/9 with a 1290cc motor in vintage racing. The current ignition is a Crane XR700 and maxes out at 8500 rpm. Fast tech tells me that is the limit the system can run at. I'm looking for a rpm limit of 9000 rpm. Pertronix tech tells me that their conversion kit will operate to 10000 if the coil has full battery voltage. Does anyone have experience with the pertronix units at this rpm?

8500 with your 4 cylinder is 17,000 with a V8. The Crane system will have no problem with that. Pertronix gizmos for 8 cylinders function well up to the 8500 or thereabouts maximum of my distributor machine.

A too large plug gap will limit inductive ignition effective RPM.

.025" plug gap for high RPM with inductive ignition.

Some coils are better than others for high RPM.

Possibly the ignition switch in your vintage car is not as young as it used to be and has some resistance.

You could feed the power to the coil direct from the battery with minimum 12 ga. wire and switch the amplifier power with the ignition switch.

Powering the coil direct is a good plan with some transistor inductive ignition systems, HEI and others, but the tach wire on the negative (points) side of the coil will also be hot all the time.

I think the Crane system will make spark to near twice the RPM than even the Fiat X1/9 is capable of.

[Geoff2]

Don't you mean 8500 with a 4 cyl is 4250 with an 8 cyl?

[Tuner]

Don't you mean 8500 with a 4 cyl is 4250 with an 8 cyl?

perfuddle, you know what I transposed was his 4 cyl would need to turn 17,000 to the V8 8500, or something like that. I need more coffee like a hole in the head. In any case the Crane ignition is nowhere near its RPM limit on an engine with only 4 cylinders.

[Geoff2]

There might be a fault with the Crane unit. If the XR700 maxes out at 8500 rpm with a 4 cyl, it produces the same number of sparks per minute as an 8 cyl at 4250 rpm. They run higher rpms than that with 8 cyl engines.

[Robban 54]

Could it be an advantage to feed the ignition coil directly from the battery even at lower rpm, for example stronger spark?

[mag2555]

If your still running the factory gauge wire from the ignition switch to the coil then at the firing rates ( rpm) your at now your likely exceeding that gauge wires current carrying ability by a good bit .

Wire a amp gauge in your feed wire to the coil and you will see what I mean as the rpm climbs.

[tjs44]

Joe Sherman (RIP)told me he was told 6700 on the Pertronix 1.FWIW

[socalmark]

The car uses a toggle switch for ignition and the coil was wired through a ballast resistor per the crane instructions. I bypassed the resistor with no change in performance. The plugs are gapped at 025. Tech support at Fast told me they don’t build a system that will work for me. Lack of dwell time at that rpm