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]

A problem with carbs and MFI is that a lot of unatomized fuel ends up in the crankcase over the miles. 3000 mile oil changes become a requirement.
Also, the cheapest decent throttle bodies are motorcycle... 1999 to 2000 GSX-R 750 or 1000 depending on the size you want. Triumph ITBs require a manifold. I did this on a 3.2 back in 2012 with megasquirt (which I'll never use again).

[horizontally-opposed]

A problem with carbs and MFI is that a lot of unatomized fuel ends up in the crankcase over the miles. 3000 mile oil changes become a requirement.
Also, the cheapest decent throttle bodies are motorcycle... 1999 to 2000 GSX-R 750 or 1000 depending on the size you want. Triumph ITBs require a manifold. I did this on a 3.2 back in 2012 with megasquirt (which I'll never use again).

You've touched on a couple of the things that put carbs or MFI ahead of most options for a small flat six—development and support, both in the short term and the long term. Right now, of the aftermarket stuff, what is likely to still be around with parts and support in the long run? There are some very attractive custom ITB and EFI products for old Porsches out there, but it seems we have several developers vying for a slice of a fairly small pie and I wonder what living with the products in the long arc will be like. Thinking of race cars that require the upkeep of a 386 or 486 laptop to run in 2020. You hope for the best, but if it stops running 12-17 years from now?

Suzuki GSX-R750 ITBs are actually pretty interesting, as I suspect those will be supported for a very long time with new parts and still possible to look for used parts if you're in a pinch. Manifolds and other machined parts to adapt them are, so long as they're well made, unlikely to be problematic (and can be replicated down the road if need be). So a Suzuki setup might match or even beat PMOs in that regard.

Which gets back to the brain/software/etc. All of the EFI setups are going to offer superior performance over carbs (and MFI), I am just thinking about those "un-sexy" factors like reliability, fixability, support, etc. in the long term. Don't have a position on it yet, but very much appreciate the conversation going on here.

[jd74914]

I did this on a 3.2 back in 2012 with megasquirt (which I'll never use again).

Which gets back to the brain/software/etc. All of the EFI setups are going to offer superior performance over carbs (and MFI), I am just thinking about those "un-sexy" factors like reliability, fixability, support, etc. in the long term. Don't have a position on it yet, but very much appreciate the conversation going on here.

As much as DIY people online like to say, Megasquirt is not really a 20+ year kind of thing. It’s really just not hardened, and IMO many of the control strategies are rather lacking, as is some of the hardware signal processing. I think most people who are really pro MS haven’t use high end stuff (think Motec, Life, etc) which is constructed with much stouter hardware and will last for decades. I’d be shocked to hear about something like a Life F88 which has failed even over 20 years. The computer insolence part is certainly a real issue. MS is nice here because the under community forced it to be up to date. That said, in general the guys carrying around a 486 have hardware which is now 30+ years old. It’s surprising they’d really ever have to touch it after so many years of tuning. Chances are if you do with an established ECU company, you’ll have hardware support for a long time.

I’m not a high AEM fan, even with the Infinity (probably pick just about everyone else in the high end market over them), but the Rasant package looks really clean.