With Pertronix do I need Bosch CDI??

[Dirtrocks]

Hi there, I've read a lot of great articles on Pelican on how the Pertronix wires into the system with the CDI; however, when I got this 70 911T, it already had Pertronix installed, but without the Bosch CDI being used.

The car runs well up to 4,000 rpm, but cuts out and falls apart after 4,000 rpm. Could sure use some direction or ideas on this one! Do I need the Bosch CDI with Pertronix? Any other suggestions on why at 4,000 rpm everything goes south?

Thanks Greg

[cdrik915]

Many issues with Pertronix.

Some fails when temp' is hight , others when RPM is hight........

Mine for example. (2.4 E MFI)

But when that works , it's a great product.

[ruf-porsche]

That Pertronix acts as a CDI for that year 911. That year 911 came only with just a coil and points ignition system. I remember installing a Pertronix in my Lotus.

As for the cut out at 4000 rpm have you looked at the distributor cap for arc tracing? Have you replaced the rotor?

[mskala]

That Pertronix acts as a CDI for that year 911. That year 911 came only with just a coil and points ignition system.

Wrong and wrong.

Pertronix is only a points replacement, it doesn't care about the rest of the system.
You have 2 choices; with or without CDI. But, the coil is a different coil with CDI than
without. Don't mix and match.

[Dirtrocks]

Mskala,

So if I go without the Bosch CDI, do I use the 0.5 ohm coil or the 3 ohm coil?

Thanks for the help! Greg

[Bob Ashlock]

Only use the Bosch 3 Ohm coil with the Pertronix.

[Nostril Cheese]

As Bob said, use the 3 Ohm Bosch coil

Your running problem is the Flame Thrower coil.