For flat sixes: Webers v MFI v EFI, Ecologically speaking… Options

[horizontally-opposed]

Currently have a 2.2E/S with Webers. It runs well and makes good power, having been tuned on the dyno and further dialed in since then, but I have discovered I'm just not a carburetor person. Fuel economy isn't good enough for the size of engine/car, and the emissions bother me—both in terms of the smells in my garage and while driving the car. And yes, we've been totally spoiled by low emissions cars.

What I'm curious about, for anyone who has lived with carbs and MFI: Is MFI noticeably cleaner and/or more efficient than carbs?

Or is EFI the way to go? I'm in no hurry on this, but curious for the experiences of others. Yes, Motronic, but I actually like the 2.2 engine.

Thanks! (IMG:style_emoticons/default/beerchug.gif)

[roblav1]

I've got the same cams as Mark in my Carrera 3.0 engine and decided to run 46 PMO. I've spent enough time on this car already and the PMOs, all new and properly jetted, will provide me a good induction solution at minimal effort. And why spend money and time on old 40IDA3C that will need rebuilt and rejetted when for a bit more money you can get the brand new PMO setup?

[Mark Henry]

I've got the same cams as Mark in my Carrera 3.0 engine and decided to run 46 PMO. I've spent enough time on this car already and the PMOs, all new and properly jetted, will provide me a good induction solution at minimal effort. And why spend money and time on old 40IDA3C that will need rebuilt and rejetted when for a bit more money you can get the brand new PMO setup?

Ben already has the weber carbs, as long as the throttle shafts are good and he doesn't care about the MPG they can be made to run just as smooth as FI.
My webers for a twin plug 3.0 have 34mm venturis, 155 main jets, F3 emulsion tubes, 180 air correction, 55 idle, tuned with a WB meter and runs a solid 12.7 AFR throughout the RPMs. Paul Abbott confirmed this was about perfect AFR. I'd suggest the same set-up but your main jets may be a bit smaller.

But this is where the bulk of the fuel mileage penalty happens, the FI can lean out the AFR at cruise, where as the carb is locked into the jet sizes.

[roblav1]

I've got the same cams as Mark in my Carrera 3.0 engine and decided to run 46 PMO. I've spent enough time on this car already and the PMOs, all new and properly jetted, will provide me a good induction solution at minimal effort. And why spend money and time on old 40IDA3C that will need rebuilt and rejetted when for a bit more money you can get the brand new PMO setup?

Ben already has the weber carbs, as long as the throttle shafts are good and he doesn't care about the MPG they can be made to run just as smooth as FI.
My webers for a twin plug 3.0 have 34mm venturis, 155 main jets, F3 emulsion tubes, 180 air correction, 55 idle, tuned with a WB meter and runs a solid 12.7 AFR throughout the RPMs. Paul Abbott confirmed this was about perfect AFR. I'd suggest the same set-up but your main jets may be a bit smaller.

But this is where the bulk of the fuel mileage penalty happens, the FI can lean out the AFR at cruise, where as the carb is locked into the jet sizes.

Here's the going in PMO 46 setup:
Vents 38
Mains 155
Air Correction 185
Idle 55
Idle airs 130
E tubes F16

We're not that far off. With my larger vents, looks like I may be a little leaner at higher rpm. Engine has the larger 3.0 intake ports, running 9.5 compression single plug. I timed the cams per spec, but given the cam sprocket pin placement, they are very slightly retarded.

I'd be real happy with your AFRs!