rgoodrich

Does anybody have experience with the Plasma Drive Ignition retailed by Perma Tune?
Dallas Eurocars, a Porsche restorer usues them and swears by them. Anyone else?
Robert
81 911 SC Fabspeed headers and exhaust

Ed Hughes

As I replied on Pelican, this is "snakeoil" on a par with the Vortex. Anything that needs to include "we can supply a whitepaper to back up our claims" is suspect at best. If this was the hot ticket for Porsches, there would be many testimonials here and on Pelican due to the amount of DIYers and guys looking to get every ounce of power out of their flat 6.

I'm not slamming Dallas Eurocars-I've met the owner-but they are not a Porsce restorer in the classic sense. I'd almost consider them a quasi-tuner or "rodder" as long as the modifications are bolt-on.

rgoodrich

Ed,
I see we cross paths. Great minds think alike!
Do you know anyone who has actually used the system? Performance and fuel economy are secondary benefits for me. I'm really trying to get rid of the ignition noise in my stereo. My mechanic likes PermaTune, and this Plasmatronics seemed like a step up. You think Hype?
Robert

Ed Hughes

No experience, other than seeing the "latest breakthrough technology in the automobile world" however many times in the past few decades. I've never seen anyone on the 911 forums admit to using this system.

It seems that there are other ways to deal with noise in a stereo: suppressor, new wires, etc.

theiceman

put a filter on your stereo .. it is basically a small transformer and a cap ... any car stereo shop can do it at a tiny fraction of an ignition system.. now we are getting down to the real issue ...noise on the line ..

User 4221

Can you describe the stereo setup in your car?

I ask because engine whine is typically ground related. There may be a cheaper method to fixing the issue like cleaning all ground points on the car or grounding all audio electronics at the same point, etc.

Lorenfb

"My mechanic likes PermaTune, and this Plasmatronics seemed like a step up."

Take the insights from Ed and others, i.e. don't waste your money on hyped
product promos. First, the PermaTune ignition is the least reliable ignition
unit for pre-911 3.2s. The OEM Bosch 911SC CDI is very reliable and rarely
if ever fails, which is not the case for PermaTunes. Besides, the ignition
output from the Bosch unit is more than adequate for spark energy and
voltage. Also, the PermaTune requires more peak currents which can cause
more power input noise.

On the issue of noise, Ed and the others are again correct in suggesting that
you focus on the two types of your noise source, i.e. radiated (via the
antenna input, e.g. spark plug wires), and/or the power source (via the +12
or the ground (which is affected by radiated noise). Additionally, noise
can enter via the speaker wires or via a booster amp. I've seen junk alternator
regulators causing radio noise too.

Bottom line: Isolate the source and then determine the corrective action.

rusnak

yes I agree. Check your grounds. Each component should have a ground, and isolate (make sure there is adequate distance) between the signal (head unit to amp) and speaker (amp to speaker) cables. The two should be separated, like city water and high voltage power lines.

rgoodrich

Guys,
Thanks for your input; your points are well made. I've found a shop in town that deals with auto electrics via computer oscilliscope testing. The owner has an 80 SC, and thinks he can find the problem easily. We'll find out tomorrow. I'll let you know what happens.

rgoodrich

Update. Every wire in stereo and ignition system tested. Grounds tested. Noise is coming from CDI. Different CDI tried. Now the decision is which aftermarket box to use.
Opinions?

User 4221

Good luck. Please let us know if this fixes your issue.

rgoodrich

Further update: New shop moved grounds and eliminated background hiss! We'll see how the rest goes.

theiceman

yeay i was gonna say .. there are tonnes of us with CDI that have no hiss so getting aftermarket as Loren Pointed out would be doing yourself a disservice ... glad your on the right track now .... if you insist on replacing i would be more tham happy to buy your CDI that doesn't work for a small fraction to keep as a spare

User 4221

Yep, that usually does it. There are many ground points in these cars and they oxidize or build up an impedance over time. This results in a "ground loop" and manifests itself in the audible range.

Glad to see they are employing fundamentals in solving your issue. Throwing parts at an unknown root cause rarely fixes anything.