Coalman

I've read several posts of timing being advanced for 93 octane with significant performance improvements. My MB dealer claims he never heard of being able to make this change. How does one go about making this change?

I never use anything but 93 octane anyway and would love to get free improvement in performance.

chiromikey

i'm quite sure it's done with the star diagnostic machine at your dealer. iirc, there are 3 settings for 85, 89, 93...or something similar. if it hasn't been altered, you should already be at 93 on aren't going to get any gains.

if your dealer has never heard of it you probably don't want to be taking your car to him anymore.

dragonAMG

Where do you guys live to only have 93 octance available? The highest we have in Vegas is 91oct.

Jakpro1

Hey Dragon,

Wonder if our modded ECU's are already set to 93 setting??

Any idea?

dragonAMG

Cory told me that the Kleemann ECU is adaptive and has several different octane settings. Depending on the octane we run 91 - 104 (or something like that) it automatically tries to choose the closest setting? Thats why he said we can run 100oct and the ecu will adjust after 40-50miles. Whether or not that's true... who knows, but that is what I was told.

Coalman

Thanks for responses.

lupidus

St Louis has 93 at a lot of facilities.. 91 is common too of course..

jangy

Can anyone confirm if star can do it? I've never heard of a car that can remap to any gas octane, OEM or K. I had heard that you could have it advanced by about 6 degrees, which would help me avoid the dreaded ECU mod needed to get the most of new pulleys, headers, etc.

jangy

By the way, stock setting is for 89 octane. i heard, but don't know for fact that the recent ecu flash retarded the timing to accomodate 87, since people were having issues with the winter gas.

blackbenzz

93 octane is available at every gas station in the MD/DC/VA area. Sunoco used to offer 94 octane a while back but not anymore.

chiromikey

winter gas, summer gas...i haven't got a decent tank full of gas since 76 quit selling leaded on the street.

E.fifty.5

there are two kinds of fuel settings with star diagnose:

1. Ingnition from base to 93 octain. "car will feel stronger"
2. mixture from base to slightly enrched. "car will feel smoother"

personally i wouldnt come close to playing with it if i have an ECU upgrade, on stock, the car will feel stronger and smoother. i lost 60 HP with this setting because my upgraded ECU program is already set for fuel.

PEACE

newton22

For the first 4 years my car was bought, it used 91 octane in Cali. After moving to Texas, we only have 93 as premium here. So I would too be interested in this tune (if it exists at all).

ima55r2

This is what Kleemann said:

https://mbworld.org/forums/showpost....37&postcount=7

stevebez

Euro spec E55 say premium (95 RON) minimum and recommend super 98 (RON). I think this is partially the reason for the slight power spec diff between US 469hp and Euro 476hp specs.

Recently BP in UK they started selling 102 octane form selected stations .. at around $4 per liter!!!!!

Anyhow I am going to try this 102 out and see if there is any seat of the pants effect at all... only really been using 97/98 since new.

Got qtr tank of mixed 98/95 in so will try run this out before I get some of the 102.

Grumpy666

There is no power difference between the US and Euro cars. The 476 HP is actually Metric Horsepower, which is equivalent to 98.6 % of SAE horsepower (469 / 0.986 = 476).

stevebez

Now thats a mystery I am very happy has been solved!!!! Often wondered about this.

350 kw - aint that easier !??

stevebez

Well put in the 102 ... filled 'er up with just on a qtr tank of 95/98 left... so I guess I am at around ~100 mark - although not sure this type of averaging works with RON ratings. (?)

Anyhow car pulls fine .. hard to say I felt any difference other than the car sounding different... more rumble and smoother ... but it could all be 100% placebo who knows ... also only done a few miles and ecu has not had a chance to addapt yet - but will see how it goes next weekend. Will also note any changes on a cold start.

BTW this stuff is really too expensive for everyday use ... I can barely justify the 3/4 tank for this experiment... at £2.46 ($4.67) per litre its insane, and I am really bumbed I did not have a completely empty tank to start with.

Not sure a 150% premium is worth the 4 octane improvement over Shell Optimax 98... but we shall see.

Grumpy666

Yeah, I noticed that my car always runs a little smoother right after I wash it.

Make sure you drive it hard with the new mixture - this will cause the ECU to extract the most performance available with the higher octane mix. And yes, simple averaging works with your mixing method.

E55 RUSS

What if we have bad 95 here and eveen worster 98 (95 boosted to 98) here ???

All MB dealer say use 95 cause with 98 Sparks plug will die quicker and etc...

Used 98 then switched to 95 and now back to 98 again...confused

stevebez

Shell Optimax is best to use in UK from my experience

E55 RUSS

I know but I am not in UK anymore...

stevebez

Dont you get Optimax there ?

Finnish C32

Thats BS 98 is ALWAYS better choice than 95. I live in Finland and at last Shell got V-Power (99.7octane) to Finland and i dont use anything else anymore.

MB AMG

I'm just wondering if it's bad to use an octane higher than necessary? Just like using 93 octane instead of 91.