[JokerJangles560SEL]

everyone around knows how gas prices are bad, and only going to get worse as summer comes around. but premium gas for a 560SEL? is it just a moral thing that you would only want to put the good stuff in the best cars or does it really have a huge effect on the engine?

stupid question i know but ive been wondering that for a long time..i dont want to go cheap and ruin my baby

 

[jdc1244]

I’ve been running 87 in my 300 SE for at least a year w/o any problems. The US Market spec engines don’t need it, IMO. Yes, I know the OM says to use premium and you’ve got the sticker on the dash – but I believe that was due to a purity issue rather than an octane issue.

During the 80’s and earlier many refiners added fillers to low octane gasoline; this was fine for the most part for carbed engines but the fillers would solidify as gums and resins on the injector nozzles of FI engines causing performance issues. As FI cars became more prevalent refineries stopped using the fillers. For at least the past 15 years or more 87 and 89 octane fuels have been clean. 'Modern' 87 octane also contains additives and cleaners when earlier they were found only in high octane fuels.

In any event the issue’s moot for me – as noted the car runs fine and I simply can’t afford 91 octane prices, particularly when they go up.

 

[srf25]

MB engineers knew that Americans would probably not use premium gas, and installed a chip in the US spec cars to compensate for it. If you do want to continue to use premium, you can remove the chip, and pick up a few more HP. Either way, your car will be okay using 87 octane, I would suggest however, using a good gasoline. Chevron, Exxon, Shell are all good gases, avoid cheap gas without cleaners. Good Luck!
Sheldon :thumbsup:

 

[JokerJangles560SEL]

thanks alot...thats a huge weight off my shoulders knowing that i dont HAVE to use it lol.

 

[DOM47]

I need more info on that chip. Where is it and how do I remove? I needs my HP!!!!

 

[Chadahar]

It is in Gen II cars only and it is found in the bundle of wires inboard side of the fuse box on a W126. If you remove the chip check your timing so it's not to advanced. if it's too far advanced it'll ping(and you won't hear it) and it'll damage the car.

 

[DOM47]

I'll for sure have a look at that tomorrow. I always run the premium (Shell) so if there is a chip costing me HP then it has to go.

Thanks!!!!

 

[srf25]

I need more info on that chip. Where is it and how do I remove? I needs my HP!!!!

DOM
Here is a pic of the chip/resistor:
Good Luck!

 

[DOM47]

AWESOME!!!!!!!!

BTW: This forum is the best thing since sliced bread.

 

[srf25]

Just pull the resistor/chip out, and store in your glove box. I would put some black tape over the plug to keep dirt and trash from getting in there. Viola, more horse power. Cheers!
Sheldon

 

[900$sel]

what do you mean about the ping, how would you check the timing?

 

[DOM47]

I pulled mine after Googling the PN. Some interesting conversations pro and con but I decided to give it a try. I'm gonna run it this way a couple of days to see if it helps.

Mine looked like it had been removed before.

 

[900$sel]

yeah mine to looked like it had been removed before and even had electrical tape around the connection to prevent water getting in. You will have to let me know how it worked.

 

[Dr.Grillz]

yeah mine to looked like it had been removed before and even had electrical tape around the connection to prevent water getting in. You will have to let me know how it worked.

All of them have electric tape wrapped around

 

[Chadahar]

Jono said in an earlier post to be sure and check the timing so as not to damage the engine. Check ir with a timing light.

 

[DOM47]

Holy speed demon Batman. My car seemed fast before but this is amazing. I just made a fun run this morning and was smiling ear-to-ear. SWEET. Left a smart-a%$ Lexus IN THE DUST!!!!!!!!!!!

Timing is OK but I will keep a close eye on things.

OK guys, where is my next free power increase for this beast?

 

[900$sel]

the car manual says use high grade, but iv heard that back then premium was only 89 and not 91. The new high grade gas is too rich for the old cars and can mess with them.

 

[PAS]

I need more info on that chip. Where is it and how do I remove? I needs my HP!!!!

I took mine out and didn't notice any difference, it also didn't ping with 87 until it started getting hot down here. I put the resistor back in. I was told the HP increase is due to timing change that is only different up to 2500 rpm. in other words over 2500 rpm the resistor makes no difference.