something other than........... Options

[karmanbuilt]

This topic has probably been asked before, but.........can MFI mechanical fuel injection throttle bodies be setup on the 14, instead of running EFI?? Saw PMOs MFI for the 911, soooo.............

[jhadler]

ghuff...

Dude, chill. The question was asked about MFI...

What exactly do you think MFI is? MFI is a system that was used on late 60's and early 70's Porsche and BMW models, as well as others (I think there was an MFI Vette if I recall). It is Mechanical Fuel Injection. There is no MAP sensor, to MAF sensor or otherwise. It is a metered, mechanical fuel pump that is connected -directly- to the throttle. This means careful tuning needs to be done to an MFI car as there is nothing more than the state of the tune to meter the A/F ratio. I have driven some MFI cars, and the throttle response is unlike anything else I've ever driven (and I've driven quite a lot of different cars, both in stock trim, and race trim).

A very well tuned MFI system is a joy to drive. But they're hard to tune that well.

I'm sure someone has already said this, but CIS is -not- MFI. CIS uses an airflow metering plate that is connected to the fuel pump.

EFI is great, it can be tuned to compensate for a vast array of different configurations and conditions. It is inherently more flexible of a design than MFI, but is limited in the sense that it usually requires measurement of the air in the manifold, either by vacuum (MAP), or air flow (MAF). These sensors can sometimes be fooled by uneven pulses in the intake manifold due to large amounts of overlap in the cam(s). There are some simple EFI systems that are based solely on rpm and throttle position, but they lack the flexibility of the EFI, or the immediate throttle response of the MFI.

Ghuff, you seem to be tooting your horn pretty loud about turbo and vtec cars, cool. I like turbo cars, and I like EFI for turbo cars because it's flexible enough to allow for all sorts of reconfigurations and varying boost levels.

But this topic started asking about MFI, and MFI is a very particular and unique beast.

To the original poster - yes MFI could be done. On a four, I'd say a reconfiguration of the MFI off a BMW 2002 tii would be one way to do it. Custom throttles would be needed, probably modified aftermarket ITB's.

And by the way ghuff, this board is really here to talk about 40 year old sports cars that we enjoy. It's not everyone's favorite thing, but it's ours. If you think the Hondas and VW's are superior, you may be right. They certainly have 30 to 40 years more engineering behind them. But it doesn't change how we feel about our cars. Don't like 'em? That's okay, there are a lot of cars out there I don't like either. But here, we try to keep the focus on 914's and related cars...

-Josh2