W124 Fuel Type

[g8crasher]

jameslhm, this is for you.

Page 128 of the W124 Mercedes Benz manual states to use Premium Unleaded fuel of 95 RON/85 MON minimum OR Leaded Premium Fuel of 98 RON/88 MON.

I hope this puts any doubt you have to rest otherwise you will have to take your argument to Daimler Benz's technical team.

[Guest jameslhm]

bro i noe i try 95 but gt issue i tried 95 for 2 to 3 month , when chnage to 98 car become better still looking the reason behind it

[Guest alumetal]

95 RON will do.

[g8crasher]

bro i noe i try 95 but gt issue i tried 95 for 2 to 3 month , when chnage to 98 car become better still looking the reason behind it

Can you be more specific about what it is that is bothering you when you pump 95 vs 98 ?

What strange noises do you hear ?

In what way is the car better ?

You need someone to adjust your ignition timing ?

Are you using the correct spark plugs ?

Look at it logically -

1. M102.962 engines are not high compression engines.

2. Our 8V cars are not equipped with knock sensors to take advantage of the higher octane in the fuel.

You have previously mentioned your car dies off when you engage reverse gear sometimes. If there is some co-relation between pumping 95RON fuel as opposed to 98RON fuel and that problem we'd like to hear it.

I guess what I'm trying to say here is to look at things objectively and work out the problem. FFS stop your guessing games and send it to a mechanic.

Good luck in finding your solution.

[Guest colrc]

Does it generally mean that a higher compression engine runs better on higher octane levels?

[Guest jameslhm]

is it bcause i ever patch ,y ebgine head b4????

[g8crasher]

Does it generally mean that a higher compression engine runs better on higher octane levels?

Rather, a high compression engine requires a high octane fuel because it combusts slower than lower octane fuel. If you feed 92RON fuel in an engine designed for 98RON, you run the risk of detonating your engine. Detonation happens when the air/fuel mixture burns too quickly and is ignited by means other than the spark plug ignition causing excessive pressure and heat build up .

[Guest angela]

Rather, a high compression engine requires a high octane fuel because it combusts slower than lower octane fuel. If you feed 92RON fuel in an engine designed for 98RON, you run the risk of detonating your engine. Detonation happens when the air/fuel mixture burns too quickly and is ignited by means other than the spark plug ignition causing excessive pressure and heat build up .

i wonder if that is the reason of people saying there is a "knocking" sound if they pump lower fuel grade?

[g8crasher]

is it bcause i ever patch ,y ebgine head b4?

Maybe possible. It depends on the extent of the damage prior to you fixing it up. Only the person who patched your head will know how bad the cracks were. Likely that the previous owner didn't take good care of the car like you have tried.

[keltanky]

if scare, go change to head la, should be around the range of $400+

[Guest jameslhm]

but the funny part is even b4 i patch my egine head whenever i pump 95 same issue until i change to 98after a while den my engine head gt problem.......

[Guest jameslhm]

if scare, go change to head la, should be around the range of $400+

where to find?????

[g8crasher]

Rather, a high compression engine requires a high octane fuel because it combusts slower than lower octane fuel. If you feed 92RON fuel in an engine designed for 98RON, you run the risk of detonating your engine. Detonation happens when the air/fuel mixture burns too quickly and is ignited by means other than the spark plug ignition causing excessive pressure and heat build up .

i wonder if that is the reason of people saying there is a "knocking" sound if they pump lower fuel grade?

Yes Willy. Pinging, knocking are one and the same. Different people hear different things. :la: Higher RON rating does not mean higher quality fuel. In fact, the energy for a given volume of 98RON fuel vs 95RON is less!

[Guest colrc]

What if we tune up our ECU? Need to use higher RON?

[g8crasher]

What if we tune up our ECU? Need to use higher RON?

It all depends on how aggressive the mapping will be with the new ECU. There are a few different stages involved in modification. Stage 1 usually involves a simple chip upgrade or additional piggyback ECU. In this stage, a slightly more aggressive map is introduced to obtain more HP and torque from the factory setup.

Even if you increase the boost pressure of your turbo/compressor significantly, the ECU can still be tuned to within 98RON tolerances.

[Guest starnite]

HI all, how do they tune the CO? I understand we are using ECU, and not caburettor, so is it still possible to tune it? Is there a meter the mechanic use? or just using his ears and nose?

[Guest colrc]

I am using RON95. If my ECU is remapped, does it mean that I have to upgrade to 98? or can I remain in 95 with increased boost from my supercharger? :pray:

[g8crasher]

I am using RON95. If my ECU is remapped, does it mean that I have to upgrade to 98? or can I remain in 95 with increased boost from my supercharger?

Perhaps you could shed some light on the ECU you are using or plan on using ? As mentioned previously it really depends on how aggressively mapped it is. Generally if you do an "improvement over stock" ECU upgrade which touts a better throttle response, fuel efficiency(crazy as it sounds) etc, chances are it will still be okay on 95RON.

Anything more than "improvement over stock" is usually geared towards significantly higher power output and involves a whole suite of upgrades such as intercooler and fuel delivery system upgrades. In this case, 98RON will be highly recommended.

[Guest Mike]

Yo hi again everyone... haha i m back... James just stick to ur 98 cos ur cylinder head is skimmed by quite an amount. and the EZL dial setting is set at S. if u wanna use 95 den u can just change the setting on ur EZL dial got it?

[g8crasher]

Thank God for yr answer mike. I have more info in 1 post from you than 10 conversations I have with James haha no offence James. Case closed

[Guest Mike]

haha dun mention that bro... sumtime u just got to be a bit harsh and firm.

[Guest jameslhm]

jus wan to noe more as why i cant use 95

[Guest Mike]

gd... noe u noe... u shld be glad that leon is providing so much info for u

[Guest jameslhm]

i am gald that there is lots of pple to seek help thanks

[Guest Mike]

yea... thumbs up.