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-   -   CIS to Carb conversion (http://forums.pelicanparts.com/porsche-911-technical-forum/878695-cis-carb-conversion.html)

Jhogan0101 08-12-2015 02:38 PM

CIS to Carb conversion
 
(82 SC with cruise control)
From what ive been reading so far looks like a good idea to swap out the oem engine harness from alternator with earlier style for this conversion
Can i remove the computer under the passenger seat?
Is it tied into any other systems?
Any rewiring at the fuse box or elsewhere necessary?
Also whats best fuel pump to use with this conversion?

Bob Kontak 08-12-2015 06:18 PM

The Lambda box talks to throttle switches and temp gauges as well as O2 sensor input.

All that stuff will be gone if you pull the CIS.

Fuel pump pressure is over 50 PSI with CIS/Lambda and about 3-5 psi with carbs.

You need to read a lot before jumping in. We are talking $4k for carbs. High end. Zeniths are said to be wonderful (with the associated work) - maybe $2K and lots of late nights. PMO's are probably the best bet as they are new $$$. Webers are an option and more spendy than Zeniths.

You can just fix your CIS. It' an option.

Joe Bob 08-12-2015 07:35 PM

Your mpg will go down the toilet with little or no increase in performance. The cams and other items will need to be upgraded if you wanna more vroom. Lot's of threads on the subject, do a search.

timmy2 08-12-2015 07:53 PM

For your '82 engine harness everything under the seat goes away and all of the cis wiring in the harness can be deleted as well.
Earlier carb or mfi harnesses are wired differently than the '82 so they would have to be modified.
You would also want to backdate your heat.
I've built a number of conversion harnesses for others as well as given instructions to do it themselves.

Charles Freeborn 08-12-2015 08:34 PM

What Joe Bob sez. In order to fully reap the benefits of carbs you'll have to swap cams & exhaust. Depending on your state, you may not be smog legal either.
Once you're that far in you better get a snorkel... the water is pretty deep.
-C

gordner 08-13-2015 08:14 AM

Ah but the throttle response is way better, they clean up your engine compartment and look fantastic and they sound fabulous. I did CIS to Carbs with my 76 and after dialing it in it I find it way more fun to drive withouth the CIS lag, but if I had to guess I would say no power gain at all.


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