C280driv3r

I apologize if this has been discussed before but it seems so counter-intuitive.

MDMercedesGuy

The C250 and C350 are both direct injected. The C300 is an older engine that is not direct injected.

C280driv3r

Is that the same technology they use in the 335i?

Does it mean it will be as unreliable as the N54/N55 engines used in those cars?

jimmythegreek

for a few mpg most of us want the most HP. The new DI engines are over 300 hp for a 350, the same reason most of us would take a C63 no matter the mpg if it was affordable.....

2012c350

There is nothing inherently wrong/unreliable about DI. Like any technology, the issue is how it's implemented. No one knows that yet (aside from the MB insiders it appears.)

cswang

There were no issues with the n54/55. Problem was with the fuel pump.

C280driv3r

Does the c350 engine feature a fuel pump?

Glyn M Ruck

Huh ???

Cy3

Almost all cars do...its used to get gas out of the tank and into the engine. Without it you would only have gravity which would be hard to rely on with a car that goes,stops,turns, etc.

Sportstick

No....

1) There is a fuel pump, as on all cars, but it is not part of the engine.
2) It is not "featured", but is just one of thousands of parts...sort of ordinary.

FraKctured

This outta be good...

220S

I assume what he meant to ask was whether they have high pressure fuel pumps. The HPFP is an integral part of direct injection systems.

HPFPs are failing on the DI motors with BMW and Porsche (Bosch is the vendor.) I'm sure Daimler has done a lot of testing given the widely known problems with BMW, but some of the speculation has been that failures are connected to the fuel found in the USA. Mercedes diesels have used high pressure fuel systems for a long time but the fuel is totally different. Who knows yet if there will be issues with these new motors.

kevink2

The C350 has a taller final drive, for less rpms at the same speed, for any one gear selected, vs the C300 or C250.

3.07 C250
3.07 C300
2.82 C350 -> 9% taller

I recall the transmission ratios were all the same for the 7 speed atx.

.

qaz393

revised transmission too. 7g-tronic PLUS

kevink2

What was upgraded? any links?

Thanx

kevink2

I believe there is a low pressure supply pump in the tank, feeding a high pressure pump, that is driven off the camshaft, and would be considered part of the engine.

.

Glyn M Ruck

Indeed! & amplifier injectors as I understand it.

Glyn M Ruck

Kevin.

The Sales pitch:

7G-TRONIC PLUS 7-speed automatic transmission

The new consumption/efficiency-optimised 7G-TRONIC PLUS automatic transmission includes a DIRECT SELECT lever on the steering column as standard (except the CLS 63 AMG). The seven forward gears of 7G-TRONIC PLUS allow for a larger ratio spread between lowest and highest gears and still ensure smaller intervals from gear to gear. This guarantees optimum engine speed at all times, lower fuel consumption and virtually imperceptible gearshifts.

For quick bursts of speed, multiple downshifting allows the 7G-TRONIC PLUS to skip gears when changing down.

See pdf - The real deal

Glyn M Ruck

Oh! & Kevin!!

New 236.15 transmission fluid imminent - In fact already required. I will post Sticky with pdf.