Correct MFI Setup for '71

I’m trying to restore my ’71 911E back to MFI. When I purchased the car, it had carburetors, so I’m afraid my car may be a bit of a Frankenstein. Looking at the PET parts catalog, it appears that there may be a difference between the MFI set up for a ’71 vs ’72 on. First of all, my left engine tin has only one nipple to connect a hose. I see that there is another possible piece that has two. Secondly my air box does not have the Air Regulator. So, what is correct for a MFI setup for a ’71? Finally, does anyone have any pictures they can share of their setup. Any advice is greatly appreciated.

Regards,

Chris

Here is basic pictures of air stacks between 70-71 and 72-73. Amber shroud is 70 system without top air horns with metal stacks and red shroud is 73 system with plastic stacks that includes air horns in the stack.

Your first diagram is correct for 1971 MFI, and the second diagram is for 1972/73 MFI(parts 14-17 in diagram 2 were added in 72/73); and the air stacks were metal in 1971 and then changed to plastic in 1972/73. I hope you already have the MFI parts(pump, linkages, stacks, injectors, throttle bodies) because it's very expensive

Thanks for the input and pictures. I didn't have the MFI system. A friend had the set and yes...it was very expensive.

Chris

So a quick follow up. According to Savagejayj, there was a change in the air box from 1971 to 1972. So when it comes to the heat exchanger, I understand where two of the outlets go but I’m unclear if the other two are used in in my case.

Thanks Chris

The secondary heat exchanger on the pictured exhaust for 72-73, was for the intake pre-heater system numbered 14-15-16-17. Not applicable for 70-71.

This is all simply answered with there is a 2.2 system and a 2.4 system both are significantly different. For a 71 you need to look up 2.2 only. Your air cleaner box would be plastic but with a plastic long snorkel pointing towards the oil tank. All MFI need a heat stove hose up to the injection pump thermostat - all have the left side sheet metal with the small metal connecting tube for the thermostat heat.

2.2 has no hole in tin over muffler.

2.4 has a hole on the right side for emissions hot air duct. 2.4 also has the heat exchanger with extra exchanger for emissions.

One of my builds 2.2S in the Orange car and a 2.4E on the ground for comparison.

Thanks!

Chris