Bosch CDI unit. Some Questions...

[86 911]

Well, I got one, a Bosh CDI unit that is . I have gone through 3 Permatunes with my car so far. The P-tune I bought from a pelicanite is the best one out of the 3, so that is going to be my back-up. Anyway, I have a 911 SC and I see that the markings on the back of the Bosch box indicate it is off of an '87 930. My main question is, what is the difference between the CDI boxes made for the 911SC and 911 Turbo?
I'm going to install this Bosch box (from a 930) in my car right now and report back with differences from the P-tune unit.

[86 911]

I just installed the used Bosch unit and took the car for a spin. I was pleasantly surprised. Here are some pros-cons:

PERMATUNE:
Pros:
-Cheap to buy.
-Smaller and easier to install/uninstall.

Cons:
-Takes longer to start up when cold or warm.
-Engine runs rougher.
-Downshifting/acceleration seems rougher.

BOSCH:
Pros:
-Starts right up! Even better than a new car! Hardly no noticible cranking involved during start up since it responds so fast.
-A lot smoother idle/acceleration/decelleration.
-A LOT LIGHTER than the P-tune unit.
- I also noticed a more of a snug fit during installation.

Cons:
-More expensive than P-tune.
- A bit harder to install (not that much room since it's a tad larger).

I was really surprised during start up. It took a split second to start, and when it did start, the Tach needle went up to 3000 RPM, then down to normal idle (~1000 RPM). It was like the engine was eager to start up! Cool! What a great unit!

[86 911]

Oh yeah, and my question still stands:
What is the difference between the Bosch 911SC CDI unit and the 911 Turbo unit?

[jason2guy]

been through three? isnt that a lot? you might want to clean up your ignition grounds and replace your trans ground strap. ive heard a bad ground really burns those parts up. coil too

[86 911]

Oh no, Permatune has a very bad reliability reputation, so I don't think it has to do with the car. I should say that I've encountered 2 faulty ones. The one I have as my back up unit works great, but I don't want to take any chances knowing its a PermaDoom. LOL. If you do a search under my name, you will see where the 1st Permatune unit I had in my car caused it to stall. Good suggestion though. I like you're thinking. Man, Bosh units are great!

[Lorenfb]

"What is the difference between the Bosch 911SC CDI unit and the 911 Turbo unit?"

None! They're the same unit electronically.

Check here ( www.systemsc.com/technical.htm ) under Ignition Systems
for failure/technical info about non-Bosch CDIs.

Check here ( www.systemsc.com/Parts.htm ) for Porsche Bosch ignition
unit part numbers.

[86 911]

Thank you very much Lorenfb. Your website is always very helpful. I'm definatley bookmarking it!