Emissions. W124 E320 failing NOx - PeachParts Mercedes-Benz Forum

JohnM. · #1 05-03-2010, 09:13 PM

Quote:

Originally Posted by bsmuwk

Are you still using regular grade fuel?
It may not be you, but somebody somewhere with a name similar said something about your use of 87 octane on a road trip without any problems and your continued use of regular grade fuel.

Just saying, maybe the use of regular fuel over an extended period of time does have it's side effects. Food for thought is all. Would be interesting to see if that were the case.

That's true. Continual running of low grade gasoline is not good for the engine. Nowhere in the manual does it say that 87 octane is OK. It's not because Mercedes is trying to stick it to ya, these engines REQUIRE premium gasoline. Conversely, running 91 in your Honda when it only requires 87 is just as retarded.

Even though there is a knock protection system on these cars, there can still be detonation you are NOT hearing, causing engine damage!

neanderthal · #2 05-04-2010, 04:14 AM

That is/ was me, but I don't see how using regular gas regularly would affect NOx significantly. The difference in flame speed between premium and regular is micro milliseconds. The slightly slower burn of premium makes for a more "complete" burn and keeps combustion pressure on the piston for a fraction of a second longer, ergo more power.

To whit, I have only been using premium for at least a month and driving far more aggressively than the typical hypermiler driving I do. Going from circa 400 miles per tank to ~ 300 while paying more for that gas is a bitter pill to swallow. I have intended to get it done several times but I am only finally free this weekend. We will see if premium fuel makes a difference.

neanderthal · #3 05-04-2010, 04:16 AM

Quote:

Originally Posted by JohnM.

That's true. Continual running of low grade gasoline is not good for the engine. Nowhere in the manual does it say that 87 octane is OK. It's not because Mercedes is trying to stick it to ya, these engines REQUIRE premium gasoline. Conversely, running 91 in your Honda when it only requires 87 is just as retarded.

Even though there is a knock protection system on these cars, there can still be detonation you are NOT hearing, causing engine damage!

If there is a knock, the sensors should pick up on it and pull the timing, That is their function.