Perma-Tune CDI

356911930 · 356911930's Garage

I was thinking of buying a Perma-Tune CDI for my 1976 930 3.0L. It would just be a spare for testing and emergencies. I wanted to know if these are "plug and play" or do they require any adapters?

Thanks,

Rahl

full quack · 03-28-2020, 03:39 PM

Plug-n-play, but not up to the quality of the Porsche unit, good for a spare.

My '84 had a brand new Perma-tune in it when I bought it, lasted 5 years, then left me stranded. put in a rebuilt factory unit and is {presumably} still running to this day 9+ years later.

Mark

Tremelune · 01-24-2022, 07:23 PM

I've read a lot about the unreliability of Perma-Tune boxes, but some of them date back to the 70s...Blue ones are good and silver ones are bad, and they're both ancient.

What's the story with the Gen 5 suckers with USB/Bluetooth interfaces that are in stock-looking boxes? They are a different beast entirely and I'm curious to hear of anyone's experience.

I have one of these 6-pin modules (model 911SC903) lying around, and I was thinking of putting it in my 3-pin 2.2L engine to hopefully improve the consistency of the timing at higher RPM.

David · David's Garage

I'm a fan of M&W CDI's so I'm surprised more 911 owners don't use them.

Not cheap but you get what you pay for.

Garen · Garen's Garage

The OEM Bosch unit failed in mine, and the replacement Perma-Tune did as well, in the span of about 4 years. I switched to the MSD 6AL and had no issues, and the unit was half the cost of the Perma-Tune, plus it provided an adjustable rev limiter. I did mount the unit in the passenger compartment, so maybe taking it out of the harsh environment of the engine bay had something to do with the longevity. If you go with the 6AL, pair it up with an MSD coil (the one that is not liquid filled, so you can run it upside-down in the stock location). I don't think the stock coil plays nice with the MSD.

Tremelune · 01-26-2022, 08:49 AM

Was that permatune one of the 2012+ versions that look like stock CDI on the outside?

Garen · Garen's Garage

Quote:

Originally Posted by Tremelune

Was that permatune one of the 2012+ versions that look like stock CDI on the outside?

No, mine was older than that. The Perma-Tune / Bosch CDI episodes all happened around 2005-2009-ish. Don't remember exact dates.

Speedy Squirrel · Speedy Squirrel's Garage

Go with an aftermarket MSD or Mallory. They are digital now (MSD 6AL2). More reliable than ever, plus a decent rev limiter. We can help you will plugin and playin it.