m a x i m u s

hey guys,

I can't seem to get rid of my pinging issue, so as per recommendations from the foreman at my stealership as well as the owner of my local indie shop, I'm gonna have to use some octane booster. I used it once in the past and the pinging stopped. of course, I was pretty excited and was set on using it from then on, but I read on some forums that continued use is bad for the engine. anyone have an opinion or experience with that one?

thx.

Ingenieur

if you are using the recommended octane fuel it shouldn't be necessary
find the root cause, ping'ing is not normal


have you fiddled with the car? pull cats, software, etc.

m a x i m u s

it's pinging with the stock ecu, untuned. and I'm only running 91 bc we don't have 93 here in good old California...

Ingenieur

What is the fuel rating inside the gas flap?
Mine is 93 but newer cars are 91

m a x i m u s

mine says 93.

SmittyAMG

Mine says 93 as well but I don't notice any pinging. I did put 92 clear in and it did run smoother, but not sure if that wasn't all in my head.

Ingenieur

Looked at mine again
Doesn't make sense that the min is 93 and it can't be bought

The ratings are euro
98 euro = 93 US
93 euro = 89 US

Can someone verify this?
So 91 is greater than the min of 89 and the engine should run fine
If it knocks there is a problem

Owners manual
Euro avg 96 ron / 86 mon
91 at the pump
So 91 is the rated minimum octane

m a x i m u s

if that's the case, then maybe what people have been referring to as "crappy gas" is the culprit. I've tried various brands, and some seem to be worse than others. and btw, it doesn't ping constantly. it is intermittent (not always under load, either.)

but as for my original question, though, does anyone know if using octane booster is detrimental to the engine?

Tinbucket

I used some octane booster, when I put 89 octane, in by mistake. went to Wally World. they only had two brands. One said Nitromethane. Hooorah some real power here. s akin to diesel andthe main ingredient was kerosense. Kerosene is akin to diesel. They use to start Model A with gas and run them on kerosene when times were tight. Higher compression as in no gas engine likes kerosene. Doesn't do a thing for octane. About as bad as heptane. didn't buy it. Tolulene is what makes race gas smell so good to gear heads. It helps mileage and octane. I don't know what brand of octane booster to use but we hve to watch what we put in our engines. Where are the Chemists?

m a x i m u s

oh, I do love the smell of race gas...

m a x i m u s

im referring to this lucas oil stuff specifically:

http://www.summitracing.com/parts/lu...FU1afgod8VQApQ

whoover

Weird stuff here. I thought all US cars all have 91 octane (that's the US (RON+MON)/2 rating) on the flap because it's the highest available in many states. The manual says 91. I know you can get 93 in Oregon but requiring 93 on Oregon-bought cars would mean you can't drive to California. That makes no sense. What does the owner's manual say for somebody with 93 on the flap?

Also, the knock sensors would prevent pinging with 91 even if the car were mapped for 93. It doesn't make sense that you need octane booster. Something's very wrong.

I wouldn't use US 89 in these engines for very long, btw. The book calls for 91 US.

ruey220

funny you posted this thread. I was just researching what is the best booster, or if boosters are even good.

I started using cheap gas since I got a gas card at a generic fleet station and since I started using it my car pings in the morning. I put racing fuel and it goes away and the car sounds much better. I used chevron gas and it also sounds good. go back to the free company fuel from the fleet and it is back to pinging and knocking in the morning.

zibby43

Do you use "top tier" gas?

Shell V-Power is all I used to use as Shell is a "top tier" provider.

Now, BP is a "top tier" fuel provider so I will use it as well.

I've had great success with both brands. Sunoco is another provider but we don't have that around here.

m a x i m u s

i dont have my car with me, so cant check the manual. as for the knock sensors, the car does have to first knock for the knock sensors to work, so some knocking will happen (like i said, mine is sporadic, not all the time).

anywho, old google found me some answers about octane boosters. apparently, MMT is the ingredient that is harmful to sensors, emission systems, and so on. lucas brand uses MMT. 104+ brand does not, according to their faq's.

m a x i m u s

i use shell, chevron, mobil and 76 (all 91 octanes).

whoover

Actually, knock sensors detect detonation way before it becomes audible. One or two bad combustion events and the timing compensates for it. You should never hear a thing if everything's working.

m a x i m u s

I take it you don't experience any knocking? one more reason NorCal beats SoCal...

zibby43

You're good with all of those. Strange . . .

We have 93 everywhere here. I feel bad for you guys in the People's Republic of Commiefornia.

Here's some reading for you regarding the octane booster (if you haven't already Googled it): http://www.bimmerfest.com/forums/sho...d.php?t=571796

whoover

I always use the cheapest station around, on the theory their gas has the highest turnover and everybody's gas comes from one of the same refineries in the area. I use Rotten Robbie near my home. I've used cheap gas in all my AMGs (C36, C55, C63, S55, S65), regular Mercedes and Porsches, with no problems ever. And no fuel additives ever, except for my old 300SD that would grow algae in the diesel if you didn't use stuff.

And no pinging or knocking ever, except for the diesel, which knocked for a living.

m a x i m u s

maybe it's not ping and it's something rattling? doesn't happen every time, though, which got me thinking it was ping. shop foreman at the stealer heard it and also agreed it was ping. man, who knows.

zibby43

I personally think it's more important to fill up on gas that has the most beneficial detergents (i.e., top tier fuels) to keep everything running clean. It's more of a long-term preventative measure.

But, if you haven't had any problems yet, I suppose it's a moot point.

bhamg

This. Shell, Chevron or Costco in no particular order for me...just proven brands with the highest levels of detergents.

whoover

When does it happen? Under part load at relatively low RPMs? WOT? I've never had any ping, knock or other combustion sound on any MB. My guess is it's something else, but it's hard enough to diagnose an engine sound if you can hear it.

m a x i m u s

tell me about it! well, it only happens at wot, whether that happens at low or high rpms. but like I said, doesn't happen every time.