What is CIS??

[sean m]

Sorry guys.....I'm still a newby. What is CIS conversion???? I've seen it in several posts, done the search, still don't know what it is.

I've got a 77 911s, 2.7. Just recently put in the 11 blade fan and what a huge difference in temperature that made! I've seen an air box in Vertex and Pelican that said is for the CIS conversion.

I'm still lost. What is it and is it something I need to do?

Thanks for helping out.

Sean

[Oh Haha]

CIS=Continuous Injection System
In simple terms it means fuel is constantly flowing metered by a valve or meter. It works very well versus carburetors as there is less tuning needed.
Do a search here on CIS and read more info than you can process.

You should have CIS on your 77. It was standard starting in 74. You should get some books on 911's so you can learn as you upgrade/make repairs. 101 Projects for your Porsche 911 is an excellent source of info. A Bentley repair manual is vital to maintaining these cars, if you do the work yourself. Heck, you can understand what your wrench is telling by learning more. Hope this helps and welcome aboard.

[c911s]

to pick a point - actually CIS started in 73.5 911's.....

[Oh Haha]

Bite me.

[74-911]

this should help with your CIS questions:

http://members.rennlist.com/jimwms/CIS/CIShome.html

Jack

[randywebb]

I'm lost on the conversion part -- maybe some mentioned converting away from CIS to carbs?

[FenderGuy]

Originally posted by Oh Haha
CIS=Continuous Injection System

Sorry you are wrong it is" Continuous Income Spending” ask me how I know

[al lkosmal]

Cranial/rectal Inversion Syndrome

[LakeCleElum]

Originally posted by c911s
to pick a point - actually CIS started in 73.5 911's.....

Thank you!!!!!!

[allaircooled]

I couldn't find anything about a 'CIS conversion' air box on their site. Maybe post a pic of what you are looking at so we have a better understanding of what it is.

[sean m]

Here is the air box. Anyone installed this? Is the sound different?

[allaircooled]

I believe it's just for aesthetics, no real improvement on anything. I could be wrong and if I am someone will correct me.

[jmohn]

Originally posted by allaircooled
I believe it's just for aesthetics, no real improvement on anything. I could be wrong and if I am someone will correct me.

From a number of people who have done this (or something similar) no performance increase, just noisier.

Jerry M
'78 SC

[Paulporsche]

A good source for CIS (and other) info is the Bentley Manual for the SC, which covers cars from 78-83. Your system is very similar to that for a 78.

There is also quite a bit of info on this site on this. There are exploded system diagrams in the tech section. There are also numerous entries on various component problems and solutions.
If you search the names of the various components, you will see what I mean.

Most common start/warmup/run faults seem to come from an out of spec or bad WUR (warmup regulator). These can be cleaned, adjusted, made to be more easily adjusted, or replaced.

Oher common maladies arise from a malfunctioning AAR and/or AAV (auxiliary air regulator and valve) or often a bad Decel (eration) valve.

Vacuum leaks and bad or out of adjustment points also contribute to possible run problems.

An out of spec mixture can cause start and run problems. This mixture should be adjusted to compensate for the ambient temp changes that can occur in the fall and spring.

Many members have purchased a CIS fuel pressure gauge to check their fuel and control pressures, which are critical to achieve proper functioning of the system.

You should search first, then post any questions or problems you are having.

Good luck and enjoy the "mysteries" of your car.

[sammyg2]

That cover will make you go faster by making your wallet lighter.

[Kelly Bell]

CIS = Constantly In the Shop..............

[azasadny]

Constant Irritation Syndrome...

[azasadny]

Cannot Increase Speed

[ChrisBennet]

Complicate Icky System

[Dan in Pasadena]

Originally posted by Oh Haha
Bite me.

Not often I laugh out loud at a thread response. Hilarious Wayne. Perfectly understated, I almost sprayed coffee out my nose!

Sean, that "conversion" IS just a bling thing. Doesn't do a thing to make your car run better. Not that I am entirely against aesthetic stuff...I've done plenty of it to my car. Better to spend the $$ you would have spent on that on (as everyone has said) Wayne's 101 Project book or a Bentley Manual. A MUCH better use of some extra cash if you own a 911.

P.S. SOmeone should post "The Ultimate Acronym Thread" here. These CIS acronyms are hilarious. Cranio-rectal Inversion System is too, too funny.