Carbureted M104 possible? - PeachParts Mercedes-Benz Forum

locry · #1 01-18-2010, 08:52 PM

If one absolutely HAD TO... can an M104 be made to work with a carb? I can have an intake fabricated no problems there... what i want to know is where to get the spark. where can i attach a conventional coil/distributor? can the current coils be made to fire without the computer? what can control the retard/advance aside from the computer if i were to possibly use the current coil setup?... i'm thinking a conventional distributor/coil and a centrifugal or vacuum advance system is the simplest way to go... only problem is where to mount it. what do you guys think?

no... restoring to the original systems/getting a new engine/junking the car is NOT an option.

btw... i'm not enirely familiar with the m104 yet... i'm a 603 guy. not even sure if the m104 has a distributor... i dislike computer controlled mechanicals.

Oracle12345 · #2 01-18-2010, 08:56 PM

carburteurs suck, theres a reason why cars have gone to electronic fuel injection because its 100x better in terms of fuel management

locry · #3 01-18-2010, 09:09 PM

there's also a reason why i need to eliminate all circuitry.

so is it possible... and yes... carbs do suck... it's primarily how they operate. hehe...

pretend there's a zombie apocalypse, you have a w140 getaway car, but the electronics are fried... you have about 2 weeks left of rations. you have all the materials to fab an intake, all the carbs you need and a 6 cylinder distributor and coil etc etc...

junkyard wars meets 28 days later type of deal

mpolli · #4 01-18-2010, 10:22 PM

Of course it can be done. But it will definitely be easier to fix the old system. But I am guessing you are trying to do it the hardest possible way, since you have lots of time on your hands.

wolf_walker · #5 01-18-2010, 10:27 PM

Quote:

Originally Posted by locry

pretend there's a zombie apocalypse, you have a w140 getaway car, but the electronics are fried... you have about 2 weeks left of rations. you have all the materials to fab an intake, all the carbs you need and a 6 cylinder distributor and coil etc etc...

junkyard wars meets 28 days later type of deal

This is why the Germans gave us VW Rabbit diesels.

pawoSD · #6 01-18-2010, 10:43 PM

Why on earth would you convert an injection car to a carb?

MAG58 · #7 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 · #8 01-18-2010, 11:12 PM

Direct injection gassers fixed the atomization bit.

locry · #9 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!!!!

MAG58 · #10 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.

RBYCC · #11 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.