I have a M103 powered 300e with CIS-E and am looking to get maximum performance out of an MFI system even if modified instead of just going MS3 and EFI. I have a two barrel carburetor I made an adapter plate for to run my original intake on my 1989 300TE with just the air meter and fuel distributor removed. It still retains factory ignition and distributor and runs quite well just a little rich.

I was curious if anyone has ever tried to eliminate the air flow meter and instead replace it with a mechanical barrel valve style regulator to the throttle linkage like of an older style MFI system. The barrel valve is usually hooked to a distribution block which has the lines going to the fuel injectors and the barrel valve just controls the return to the fuel tank which relieves pressure in turn control injector flow and the air fuel ratio at the given throttle input. The old system were basically on/ off systems but with proper bypassing people have adapted them for street use. With this theoretically you would be able to run ITB’s as long as linkage still references barrel valve or maintain the factory manifold with a similar setup. These systems were constant flow such as CIS-E so you could probably even try to run the distribution block to factory Bosch injectors. I am just trying to ping this idea out there to see if anyone else thinks it would be possible to run such a fuel system with a larger cam and modified ignition curve. I’d really like to pull the maximum amount of power out of my M103 without going EFI or forced induction.

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Mercmob Car Club Milwaukee

Seeing you can not post links- google FrankenCIS

Mm:

In the systems which you seem to have in mind, those made by such companies as Hilborn and Kinsler, the engine driven fuel pump is of a positive displacement design, and is the principal component in determining the shape of the fuel curve.
The OEM electric pump does not fulfill the engine speed-linked flow requirement.

I don't think any changes to the induction system will result in a meaningful amount of increased power. It's the equivalent of installing a bigger carburetor on a vintage engine, and it usually didn't make much difference, but could result in a nightmare trying to tune it to work well across the full rev and load range.

The best way to get more top end power is to massage the head.

Those old constant flow mechanical FI systems like Hilborn were very crude. Fuel metering was based on throttle position and pump speed. They worked fine at WOT, high revs once you got the bypass "pill" right, but they couldn't account for VE changes over the full rev range at both WOT and part throttle, so they don't work very well over the speed and load range required for a road engine.

I think you're opening up a real can of worms for yourself. Pull the head, pocket port it and port match to the inlet and exhaust manifolds. If you still want to go further you can probably still find a stroker crank and pistons to make it a 3.2 liter.

Duke