I have seem people mix leaded race fuel with their unleaded fuel at the track. Is this safe? Has anyone bought unleaded race fuel? What octane? I see 111 octane leaded race fuel here in S.D ..Input please from guys whom have tried and bought please.

 

Dont mix leaded and unleaded race fuel. You want unleaded fuel. If you use leaded it will kill your cats and O2 sensors. I've bought several different grades of unleaded race gas.

 

How can I find out who sells race fuel around my area ?
I tried almost every single gas station around here, but no luck

 

Torco - http://torco.com/content/view/74/26/
VP- http://www.vpracingfuels.com/index2.html#

 

100 oct unleaded is all you need anything higher and the ecu won't even notice. 100 unleaded is usually pretty easy to find. i use sunoco or 76 blue are excellent brands of gas. most stations near a race track will have race gas or a wholesaler will have it. you just need to ask around. or start calling wholesalers.

 

You will at the best, not gain any power, and at worse lose power running 100 octane or above in your 63.

Here's a rule of thumb - you want to run THE LEAST amount of octane possible before detonation/preignition. Too much octane is a bad thing. More octane doesn't make horsepower.

-m

 

If you're in the Newport Beach area there is a 76 off the 73 that has 100 octane. There's also another 76 near Santa Monica with race fuel. I want to say it's off Pico but not sure.

 

Yup, ran straight 103 and the car just HATED it. Even let ECU adapt etc and the car just couldn't handle it.

Oh, and running leaded will just COOK those CATS. Call the dealer and ask um how much those pups are to replace. $$$$$$$$$$$$$$$$$$$$$$$$$

 

Maybe you should own a 63 to make statements like that. Juice said many months ago that he was mixing 100 oct unleaded race gas with 91 oct.
My personal experience is that you do feel and notice an increase of power.
Maybe Mr M should look at the compression ratio before he speaks

 

I absolutely agree with the above statements regarding more octane not equating to more power...however!

...quality brand race fuels are typically better fuel to start with which DOES make more power. i've seen vp fuels make 5% more power on a dyno even though the ecu maps were not adjusted for it and left at 93 octane.

 

You sure about that Marcus???? Agree with the too much statement though.

Hot Rod Octane Shootout..Oldie but goodie

 

use unleaded 100 and mix with your 91 to get to 93.


There are a few probs that are California specific. Much debate but the bottom line is the car is rated MINIMUM 93 octane , we do not have 93 octane here so your only choice to get the correct octane is a mix. My car out traps with the mix vs without it. On 91 109-110 trap is likely on 93 111-113. Car likes the 93-100, running straight 100 is fine too but its 8.49/gallon.

In other states 93 is common and this could be why the cars in the East run better than the cars in California. The higher you go over 100 the less you need to get your mix to 93. I just go by experience and my trap speed increased after I started the 100/91 blend. This N/A motor needs quality fuel and it loves 100 IMHO

 

Ok ladies, allow me to clarify.

First off - if anyone is going to argue with me with a butt-dyno, or the car "feels" faster - that is NOT a credible way of measuring power gains - period. I don't know why this 63 guys keep insisting on "it feels faster" with these mods - take it to the track or the dyno, and prove it. I have done it with the E55, which with forced induction is in a much better position than a naturally aspirated car to take advantage of 100 octane. It made on extra power.

Jackpro - OCTANE does not make more horsepower, per se. OCTANE prevents detonation, which allows a car to run a more aggressive tune. When you have an ECU that can adapt to the extra octane, it makes more power by running more aggresive mapping, not because of the fuel itself. Our ECUs do not have that flexibility. I've run 100 octane at the track and I know it doesn't make the car faster. The car also has trouble starting because the ECU does not like the slower burning fuel.

There are MANY cars that instantly make more HP with higher octane fuel - this is NOT because the octane makes more HP, it's because the car's ECU is equipped with mapping and sensors that allow it to progressively run more aggressively until it detects it can no longer do so. In my experience this was primarily done with knock sensors.

If everyone reads the article Jackpro provided - the difference between 91 octane, and 100 octane, with the same tune, was a drop in TQ and a +1hp difference - negligible. The go on to draw some other conclusions that I disagree with and simply do not find applicable to our modern day EFI engines and ECUs.

Do not waste your money on high octane fuel with stock or stock-ish late model AMG cars. Running 100 in a 63 is a joke, no offense to you 63 guys. I've built and been around a LOT of high-hp cars - German, Japanese, and American. This is coming from real world experience, not a butt-dyno.

-m

 

if your TUNE is for 100 octane it can make a difference ... especially for the FI motors.

 

This comming from someone that thinks when a motor is broken in it doesn't produce more HP or Torque..

 

Bluemax,

I'm glad I provide such great comedic relief for you. I obviously don't know what I'm talking about, and you are in a position to criticize me - so you tell me - do you have evidence of a factory car gaining significant horsepower after being delivered to it's owner? Or is that another "it feels faster" assumption on your end?

Even further - what is your experience with cars and engines? What have you built that makes my experience seem so pale and insignificant in comparison? Please, let me bask in your knowledge.

-m

 

The 63 LOVES 100, LOVES it, how do I know?

I have several hundred timeslips, and the higher trap speeds are attained using 100. Im sure 93 works well but it is NOT AVAILABLE here. Improvement of 2 plus MPH in traps is NO JOKE.

Your 55 in Southern Cali on our 91 would get whooped pretty badly by a 63 on 100....

You can not "over octane" an engine regardless of what others might say.
But yeah the ECU programming will be necessary after 100 octane, you can tune the ECU for 100+ or 93. Our ECU's are programmed for 93 so there is a problem when 93 is not available.

 

Juice my friend, how are you? It's unfortunate that so much of this 55 vs 63 stuff winds up being between us, given we both are big AMG guys. It looks like we're just always unfortunately going to butt heads.

Your statement would have been possible with my '03, but not my '05. I have been blessed with a pretty strong '05 - and honestly while the 2 octane hurts, it would not hurt me into the traps you mention. I have had my '03 on the dyno with 100 and 93 octane, no difference.

I'd really like for you to lay out your slips and make a case for your argument. Do you know what kind of timing the car runs, have you looked at logs, dynos, etc to prove the car LOVES 100 octane -or are you just speculating on the hundreds of timeslips? I have time slips from Z06s that vary 4mph all day just because of different temperatures, headwinds, whatever. If you want credibiity in saying the 63 loves 100 octane, proof would be at the same day at the track, you did a 91 and a 100 octane run, and the slips clearly show that you picked up significant MPH on the 100 run. Maybe you have this proof?

-m

 

Juice,

See now you are going to lose significant credibility. You can absolutely over-octane very easily. You don't want to listen to me, here's what a quick google search netted me:

http://theserviceadvisor.com/octane.htm

http://www.chevron.com/products/prod...rmance/pg3.asp

http://en.wikipedia.org/wiki/Octane_rating

But you are right Juice - don't listen to ANYONE but you. Everyone else is downright stupid or crazy!!!

 

While I agree with the above comment the new unleaded race fuels are starting to change that somewhat. The vp unleaded 103 and 109 are oxygenated fuels which tend to have a slight affect on your afr's which in turn can yield slight increases in power with-out a timing change.

 

rflow,

oxygenation is not octane. I specifically said octane does not make more horsepower, and this is true. Two 93 octane fuels can absolutely have different power levels, but not because of the octane, because of the quality of the fuel. A different octane level may also be achieved as a byproduct of the chemical composition of the fuel.

If Juice wanted to argue that it is possible for a significantly higher quality fuel to make more power than a poor quality fuel... we'd be holding hands and doing the cha-cha-cha.

-m

 

Hey man, sorry for the shot accross the bow...

Yeah I have same day slips , same track.

Ill post em up for you.

Hard to capture a "real world" diff on a dyno...No way to measure "trap speed" on a dyno. also remember you have 93 available we only can use 91 or mix 91/100 or run straight 100.. I have only done the mix.

This is two different CLS 63's running against eachother.
car 141 has a 100/91 mix and outrapped car 142 3-5 mph all night long until we added 100 octane to the car, guess what?

Almost identical numbers, car suddenly "woke up"

I would love to say my CLS 63 was just faster but it was simply FUEL. On my own car it is not as dramatic 1-2 mph higher trap but hell Im 100% convinced it helps the car in the 1/4 mile and overall efficiency.

[IMG][/IMG]

 

Ok Juice! Now we have a good discussion!

What MIX are you running - IE, how many gallons of 91 and 100? Your theory of 91 to 93 may be sound - and it makes sense that MB would not provide two levels of tune for 91 and 93, rather it will BACK down the original maps if it sees the car doesn't like the 91. I think another interesting comparison for you 63 guys would be to see what 93 vs 95 nets?

There may be a middle ground here in this discussion, my original arguement was that 100 doesn't net over 93 in our cars, but I actually will agree that 91 to 93 may show some improvement given it doesn't make sense technically/financially for MB to have a 91 only map. This is NOT because of the octane though! This is because the car has the room in it's factory tune to run more aggressively on 93. I do not think you will see gains in 93 vs 95-100 though, our E55s do not.

-m

 

Juice,

I think we now have a legitimate theory here, and I would actually like to help you prove it. If we can agree that you CAN have too much octane, octane does NOT make horsepower, and that 100 octane for a car that's designed for 93 will NOT do you any good unless the ECU can take advantage of it (which ours can NOT) - we can move on to address your theory.

93 octane is pretty much the "world's premium" in an (R+M)/2 rating. Sometimes there's 94, and sometimes there's 91. It makes sense that even though our ECUs don't have the ability from the factory to take advantage of octane ratings above this - almost ALL ECUs (including ours) will turn down the tune to deal with ****ty fuel. This theory would apply to running 87 or 89 and then throwing in 93 as well. Obviously, there has to be a way to protect the engine in the case of ****ty or improper octane fuel.

So I will support the notion that a 63 with 93 will make more power than a 63 with 91, I however will not agree that octane above 93 will show any performance gain against a straight 93 car.

How's that rub ya?

-m

 

Ok yeah we just mis-understand.

Im simply trying to get to 93!! The 5 gallons was added to appx 1/3 of a tank of 91. Octane was likely a smidge higher than 93. I agree there is likely no difference between 93 and 100. We do not have both available so its not possible to test. I think 100 straight would be similar to the mix I use. Next time I go to the track I will fill up completely with 100 and run that..

Sorry for the confusion, i just want to get to the minimum rating.