2.4 CIS Rebuild Options
 

Looking for some advice on rebuild options for a '73-1/2 2.4 CIS engine. The car has been cosmetically changed to look more like a 74+ 911 so I'm not concerned with staying OEM with the engine, I'd just like more performance than the 140 HP the 2.4 CIS delivers. The engine options in "How to Rebuild and Modify your Porsche 911 Engine" don't address modifications to the 2.4 CIS engine and from what else I read, PMO carburetors and aftermarket Fuel Injection kits (ie- megasquirt) don't exist either for the 2.4 CIS. Any recommendations or personal experiences with 2.4 CIS modifications would be appreciated.....


http://forums.pelicanparts.com/uploa...1237416052.jpg

That is one of the nicest short nose conversions I have seen.

You are actually incorrect in your research. PMOs are brain dead easy to add and the TBitz EFI system can be adapted just fine to a CIS 2.4T. 40mm PMOs will do the trick just fine, but TBitz is by far the coolest. Here's an even more involved conversion than yours - a 72T w/ MFI converted to Bitz EFI using CIS runners:

http://www.bitzracing.com/gallery/James_72_911T_2_4.html

Instructions so you can get knee deep:
http://www.bitzracing.com/docs/CIS_to_EFI_manual.pdf

The answer to your specific question:

-Will the kit work for a 2.4L engine?
The problem with the 2.4L engine is that the CIS injectors are
mounted directly into the intake head. The CIS to EFI bungs
which are key to the conversion will not fit in the heads. They
are designed to fit in the intake manifold. One fellow is trying to
do the conversion on a 2.4L by making an adapter plate to fit
between the 2.4L heads and use a later year intake manifold
that has the injectors on the intake runners. Have a look here to
see if your intake is the correct type.

Making spacers (or having them made) is easy and not very expensive - there are vendors already selling them for MFI, so you can just order them with CIS injector bungs. They look something like this:
http://www.bitzracing.com/sitebuilde...ed-450x600.jpg

I also believe you could source later runners and just block of your injector ports in the heads with properly sizerd bolts. They are cheap.