MFI conversion question - which MFI???
 

I have been researching MFI conversions recently and had a question. It seems from what I read that each 911 model had different MFI's (size I think?). Is there any reason when considering a conversion for an SC that you could not use any of the MFI choices, or is there a reason to avoid one or the other? If there is a thread that gives this answer, let me know and I will do more serching... Just have not come across the right info yet, and not smart enough to know any better at this point.

Thanks

It appears you are asking about fuel injector sizes? Are you planning to get rid of CIS and switch to MFI?

I would suggest you search for Tbitz and read up on his mfi setup (megasquirt).

maybe he means the differing space cams

I believe that the general Idea is to match the pump to the Cam you are going to use. IE use a E Cam, find an E pump as the timing of the injections is set to match the valve opening. Apparently most pumps have enough adjustment to be able to be used with a somewhat larger motor, but you might as well start with the biggest you can find, IE a 2.4 or 2.7. But if you are talking about doing a 3.0 I suspect you are going to have to send it away to be rebuilt to 2.7RS or even 3.0 (rare) spec's.

I had read in one of the threads on this here that there was a difference in the E, S, and T setups. It seemed to reference something about sizes, maybe the cams mentioned above. I have zero MFI knowledge presently, but came across a set of the TB's from a T. Price might be right and so I was purely looking at it from a rainy day purchase aspect. Clearly, I need to do much more reading, but was trying to decide if I should go for these and put them on the shelf for awhile until I can learn more and make a better decision down the road...

You will need to do work to any pump you choose for a 3.0. As for what to start with, the throttle bodies and stacks are an issue, particularly for a 3.0. Systems up to and including '71 used magnesium stacks, and '72 and up used plastic. The plastic are a lot lighter, but allow for less modification (enlargement). The mag stacks can be enlarged considerably, and might be the best place to start for a 3.0 system. T stacks would do just fine. '69 stacks have bigger inside diameters than '70 and later, and therefore will save some work. The throttle bodies can be enlarged to the size required, with new throttle plates. Matt Blast at Eurometrix or Henry Schmidt at Supertech are good resources for this work. So, I'd avoid '72 or later T or E components, but other choices should be fine.

Thanks Scott