oldgixxer

Contemplating using 5 gallons at the track this friday.I know too much octane will actually cause an engine to make less power.
So my question is this: Does the 11.3:1c.r. of a bone stock E63 warrant the use of 100 octane fuel in order to make a bit more power or is it a waste?
Thanx..

BMWEATR

I'd do it just so i could smell that sweet smell of high octane gas!!!!

It wouldn't hurt, but gains??????? maybe a little.

rarfinancial

Depending on the type of race fuel. I know that with most fuels the octane is not motor octane. 100 octane would be around 97 motor octane. Also there are other thing within the fuel that you must also consider. If your car has the stock tune then as you know 93 octane is what MBZ recommends . Look up VP racing fuel they have a website with loads of info. IMO I don't think that 100 octane will rob power. Good luck with your search.

Marcus Frost

We just had this discussion - running pure 100 is a waste. It's not question if the motor could benefit, it's if the tuning can benefit - and the stock tunes on the AMG cars are only for a max of 93-94 octane. MAYBE with a proper tune to take advantage of 100, you'd see some gain, but not on a stock ECU. Anything above 93/94 will not make a difference.

-m

jangy

I've tried it on track days and it definitely makes the butt wiggle a bit more (my butt that is). There is a place in Ramona that sells VP Racing fuels.

jangy

I disagree. Is 100 octane overkill? Probably mostly, but not in all of the fuel map spots. Obviously, this is a thing we need to test.
The E55 runs pretty pig rich as it is. By adding octane, you are FORCING the ECU to compensate what little timing it can. Be sure to do an ECU reset when you test it. Also, try it on an almost empty car. I promise you will practically feel it coming through the veins.

Edit: Absolutely, an ECU tune + 100Octane is the daddy, but then you can't run 91.

rarfinancial

I would say that 100 octane = around 97 motor octane. So a mix of 91 pump gas = 89 and 100 race = 97 would be a great combination. The trick is what mixture. Do your homework

mche55!

wont do anything stock ecu

juicee63

Bring some with you , do some runs without then add 5 gallons and do some runs see if you trap higher. evem though you have added some weight I think the fuel will open up your top end. Do it so we can get some data!!

Like the champ needs 100 0ctane , LOL whooooosh

Marcus Frost

Jangy,

I've dyno'd and run at the strip with 100 octane in the tank, giving plenty of time to adapt. The ECU was never tuned for 100 octane and unlike other boosted applications AMG did not leave the tuning open-ended to allow it to take advantage of extra octane. You know that you can't rely on a butt-dyno for this kind of thing.

I don't understand how you are correlating A/F ratio with added timing. The ECU isn't forced into anything, you can run a 93 timing/fuel map with 100 octane, it just won't run that well. In my testing I have seen that instead of leaving timing maps somewhat open ended, they have a ceiling. That prevents the ECU from taking advantage of the extra octane, and will actually theoretically hurt performance because without that extra timing - you are going to lose power with higher octane. Higher octane is harder to burn, so without the room to compensate for that characteristic, it will negatively impact performance.

Your car may run better on 100 than 91, that I cannot really speak about, but my car ran worse (startup and throttle response) on 100 than it does on good 93. You guys have some really, really ****ty fuel in CA so it may not just be the octane rating itself of 100 that helps, but also the actual chemical composition of the fuel that helps your car run better.

The moral of the story is, 91 octane is the anti-Christ.

-m

oldgixxer

I was considering using VP Fuels Streetblaze 100 unleaded,(96 motor octane)..

The fuel filler door on the E63 says 91 octane,in N.Y. here we have 93octane&a few Sunoco's have the 94Ultra.
I guess I will just stick to the pump gas.I have a 55g drum of C12,along with 6 or 7 5gallon pails of MRX01,U4&MR9 that I run in the bikes but they are all leaded so I can't even mix a bit in the tank.

I'll just take the spare out&all the extra weight&see where that puts me at the track

JamE55

Stock ECU + Race Fuel = Waste
Custom mapped ECU + Race Fuel = Not a waste

MB_Forever

The fuel filler door on all the 63s I've seen says minimum 93 octane ???

Can you please double check and let me know? I'd be interesting if some cars are tuned for 91 and others for 93

oldgixxer

I would go&check but the car is at the dealer today for the squeeky brakes(3rd time)I will have it back tomorrow.I'm almost 100% positive,and here is a link direct from M-B:
http://www.mbusa.com/models/features...E63&class=08_E

MB_Forever

I know that on mbusa.com the website states 91 minimum, and in fact, on almost all websites and online documentation I've read, it stated 91 minimum. But I think that these websites are built from default templates, and then edited for each car's specifics. As a result, it is so easy to make a mistake on them.

I went to my local mercedes dealer and I opened the fuel tank door of over 10 non-amg models, and found that it said minimum 91. I also checked at least 4 AMG models (all 2007+ 63 engines) and saw minimum 93.

My car, juicee's car, rarfinancial, etc... all say 93. That's why I was surprised when you said 91

jangy

Keep in mind that we only have 91 octane in Cali. So, if I run 91 octane and then put in 100, I may see gains IF the ECU compensates at all. That is where my point about the higher octain causing advanced timing. I do not know where you got your info from, but adjusting (although minor) for varying fuel octane / quality by advancing or retarding the timing is exactly one of the functions of the ECU.
Do me a favor. You said you dyno'd with and without, etc. Post your A/Fs and see what the difference is. IF the dyno runs both show similar A/Fs, then that is some indication that the ECU IS INDEED adjusting for the more volatile fuel. The ONLY way to modulate is by timing.

jangy

I hate all the additives to the Cali gas. It was first just for winter and now year round.

sack5000

Mine says 93.

Jon2007E63P30

By the way. I stopped by Laguna Seca to watch a small track event. They have Sunoco Racing Fuel, both 91 and 100 octain. $6.00/gallon. Just insert your credit card. Based on the discussions here I passed, but just wanted those in the area to know where to get it.

oldgixxer

I can pretty much guarantee mine says 93.I hand washed it yesterday&dried out the fuel-fill area&noticed it said 93.


Just be careful the Sunoco is not leaded,as most of their race fuels are

rarfinancial

So it would be fair to say that YES racing fuel is better. Not just for the octane but it's made better. They sell 87,89,91 Also. If we are tuned for 93 then a 100 with 91 mix will improve performance. As I stated earlier, I had a very long talk with VP and one of thier suppliers, they gave lots of info. Do some runs with 91 then add the 100 see what happens Again the trick is in the mix, do your homework thats the fun of it.

jangy

It is the mix. Most people go 70:30 between it and 91. VP is the way to go and not having the additives alone will help.

Oh crap, where is a VP dealer near Fontana?

juicee63

I just do not understand...

How is it that your fuel door says 91 octane where 93 is available and mine says 93 where only 91 is avail? WTF, :-)

EDIT: Ok i read the thread LOL, all 63's say 93?


So a mix 100 plus 91 is best to achieve 93 unless you have 93 at the pump , then 93 is likely best. see what happens adding 100 to 93 , I am real interested in this as are many folks on this site

jangy

I would monitor the A/Fs for a guide.