Carbureted M104 possible? - PeachParts Mercedes-Benz Forum

MAG58 · #1 01-18-2010, 10:58 PM

I'm going to man up and say it... Fuel Injection does NOT have absolutely more gross power output than carbies do. In fact there was a Honda drag racer a year or so back that ran Webers on his NA car instead of injection as he found it produced MORE horsepower. EFI has the advantage of being continuously variable and adapt much more easily to changing weather than carbs. You could get carbs to run as well as efi, you'd also have to dyno tune your car every day before you drove it. Why do modern cars get more power you ask? Well because of 02 sensors and Knock sensors. Modern computer controlled cars that run efi and spark can push advance and fuel tables much closer to the ragged edge between max performance and detonation since the computer is keeping check on the works. The only way you can do that with carbies is with a knock amp and a dyno. Most people don't just have that sittin' around in their garage.

However, EFI cannot atomize fuel as well due to the location of the injector sitting literally on the intake port. Unless you're running injectors at the top of the air-horns (think F1), you will still get fuel falling out of atomization and a puddling effect on the intake port. In fact, most EFi systems acknowledge this and compensate for it. Compared to injector-on-port efi, webers have, and as far as I can tell, will continue to atomize fuel better.

Do carbs suck? no. They have their place.

The M104.980 3.0L engine already has a dizzy on the exhaust cam as well as an aluminium intake manifold. You could run MegaJolt (the spark only side of MegaSquirt EFI) triggering off the flexplate as normal through the dizzy or even through a wasted spark (you could probably run the cam with it too), and you could cut the alloy manifold and weld on some side-draft flanges. Et viola! A carbie M104 with a sweet sweet Weber carb sound on the top end.

wolf_walker · #2 01-18-2010, 11:12 PM

Direct injection gassers fixed the atomization bit.

MAG58 · #3 01-19-2010, 12:17 AM

Quote:

Originally Posted by wolf_walker

Direct injection gassers fixed the atomization bit.

True, but at the current it is heinously expensive to modify or gain performance out of the current crop of Gasoline DI engines outside the realm of stock parts.

They also do have a rev limit currently iirc they can't just go static or fire through multiple strokes.

wolf_walker · #4 01-19-2010, 11:46 PM

Quote:

Originally Posted by MAG58

True, but at the current it is heinously expensive to modify or gain performance out of the current crop of Gasoline DI engines outside the realm of stock parts.

They also do have a rev limit currently iirc they can't just go static or fire through multiple strokes.

Give em time. Same was said about EFI a few years back, look at it now, people build em on the kitchen table.
I like carbs too, I've had lots, I have a couple now, they are still piss poor
for daily use more often than not compared to EFI.
Or even MFI/K-Jet.

To the OP, I vote diesel if it's an option. Screw gas and it's assorted BS.

MAG58 · #5 01-19-2010, 11:56 PM

Quote:

Originally Posted by wolf_walker

Give em time. Same was said about EFI a few years back, look at it now, people build em on the kitchen table.
I like carbs too, I've had lots, I have a couple now, they are still piss poor
for daily use more often than not compared to EFI.
Or even MFI/K-Jet.

To the OP, I vote diesel if it's an option. Screw gas and it's assorted BS.

I'm not sure about that. DI Gas is pretty much like Common Rail Diesel with more headaches and spark control. Those peizeo injectors aren't cheap and I don't see them getting that way. The control modules maybe, but there's a substantial amount of work to make them.

I agree here, if the option is there, go common rail diesel, of if you just don't like the modern technology of electricity, go for an OM603 or just any non CR diesel. Hell could freeze over and three apocalypses could come and it would still be rattling along.

locry · #6 01-18-2010, 11:17 PM

Quote:

Originally Posted by MAG58

The M104.980 3.0L engine already has a dizzy on the exhaust cam as well as an aluminium intake manifold. You could run MegaJolt (the spark only side of MegaSquirt EFI) triggering off the flexplate as normal through the dizzy or even through a wasted spark (you could probably run the cam with it too), and you could cut the alloy manifold and weld on some side-draft flanges. Et viola! A carbie M104 with a sweet sweet Weber carb sound on the top end.

hmmmmmm... will do research on this thanks bro!!!!

RBYCC · #7 01-19-2010, 11:26 AM

Quote:

Originally Posted by MAG58

I'm going to man up and say it... Fuel Injection does NOT have absolutely more gross power output than carbies do. In fact there was a Honda drag racer a year or so back that ran Webers on his NA car instead of injection as he found it produced MORE horsepower.

If you intend to use Webers then the best setup would be three 45DCOE's.
For racing they are great, but street not so good...no chokes and without a flame box they tend to catch fire on starting.
Not the easiest to synchronize.
Lived with this setup for many years on a 4.0L I-6 Aston Martin Vantage engine.

MAG58 · #8 01-19-2010, 08:07 PM

Quote:

Originally Posted by RBYCC

If you intend to use Webers then the best setup would be three 45DCOE's.
For racing they are great, but street not so good...no chokes and without a flame box they tend to catch fire on starting.
Not the easiest to synchronize.
Lived with this setup for many years on a 4.0L I-6 Aston Martin Vantage engine.

I've ran one on my mini and a pair on my datsun. They have a choke, just not as one would think. IF you want the traditional flapper choke, mikuni 44PHH's give you that with more streetability and 99% the power