on my 73 911t i have modified the motor with 2.7 rs pistons, intake ports ported out to 35mm, and some oil system updates. everything else is stock, incleding the stock 2.4 cis injection system. I had some hessitation problems and did some tests and found out my throttle valve for the control pressure is bad.(i found this using the bosch gague and the correct procedure). what i want to know is if i should just replace it. or should i install the vacuum controlled warm up regulator, and toss the old one and the throttle valve. any help would be appreciated (unless you think I should just install webers)

Thanks

 

If you want real power & throttle response, then carbs or EFI is THE only way to go.

IMHO, CIS on an engine like yours is an unhappy marriage for what you are trying to do.

Webers (in perfect condition) or PMO's are VERY reliable if they are installed, setup, and adjusted correctly.

 

the cis on my car works great, it is my daily driver so putting carbs on is not an option. i think there are more ways to get performance out of this car without just dumping fuel into it. what I want out of the car is somewhat good fuel economy, and performance with a lot of torque on the bottom end. does any one out there know the ins and outs of what i can do to modify the cis fuel injection. can I put the vacuum controled warm up regulator on my set up, or should I put the throttle valve on.
thanks

 

My suggestion is that if you like, and wish to retain the CIS, then be happy with what you have.

You really cannot do anything else worthwhile as the CIS is THE limitation here.

The only other suggestion I would have for folks who like the CIS system would be to install a larger version of these things. A 3.2 CIS motor (made from an SC) is very durable and those run quite well.

 

hey,

thanks, that is what I was looking for. I guess if i want to do something no one has tried, i have to try different stuff.

When did I do this?

thanks

 

FWIW, many people have tried almost everything with CIS engines and I know I have several hundred hours of dyno time trying different things with them.

I would only caution you not to waste too much money looking for "the Grail".