Race Gas
Thread Starter
Newbie
Joined: Jul 2002
Posts: 21
Likes: 0
From: Phoenix
E320
Where are the racers at?
No ricer answers please. Everone who has ever been envolved in racing should know that 89 or 91 octane compared to 100 unleaded is a big difference. When you have a faster burning fuel it pushes the rotating assembly alot harder and faster which means more horsepower, now a flat hood ornament or "euro" lamps is a waste of money. I don't mind paying to play but I want to minimize damage to my 02 sensor, cat and anything else that might be an issue. Also if anyone is reprograming the fuel and timing values on chips let me know.
Super Member
Joined: Dec 2001
Posts: 581
Likes: 4
From: Dallas
C32 AMG
ricer? 
I'm pretty sure higher octane means the fuel burns SLOWER, e.g. the less tendency to knock.
http://www.howstuffworks.com/gasoline3.htm
As long as your engine is running at the optimum advance (e.g. is not retarded due to the knock sensors) higher octane fuel does no good.
Higher octane will allow you to run higher compression, but most engines (except that experimental SAAB engine ) can't change their compression ratios.
Of course, I could be all wrong. ANyone else?
I'm pretty sure higher octane means the fuel burns SLOWER, e.g. the less tendency to knock.
http://www.howstuffworks.com/gasoline3.htm
As long as your engine is running at the optimum advance (e.g. is not retarded due to the knock sensors) higher octane fuel does no good.
Higher octane will allow you to run higher compression, but most engines (except that experimental SAAB engine ) can't change their compression ratios.
Of course, I could be all wrong. ANyone else?
Last edited by jswedberg; Jan 17, 2003 at 04:50 PM.
Super Member
Joined: Dec 2001
Posts: 581
Likes: 4
From: Dallas
C32 AMG
Well, after researching a little more,
http://www.diabolicalperformance.com/hotrodoctane.html
It lloks like that in some cases higher octane DOES make a difference.
These guys tested up to 114 octane fuel in a 360 Mopar.
114 octane had 2% more horsepower than 91.
But if you read carefully, again they say that the power increase was because the octane boost hindered ABNORMAL combustion.
So maybe you have some abnormal combustion (knock) going on?
http://www.diabolicalperformance.com/hotrodoctane.html
It lloks like that in some cases higher octane DOES make a difference.
These guys tested up to 114 octane fuel in a 360 Mopar.
114 octane had 2% more horsepower than 91.
But if you read carefully, again they say that the power increase was because the octane boost hindered ABNORMAL combustion.
So maybe you have some abnormal combustion (knock) going on?
Thread Starter
Newbie
Joined: Jul 2002
Posts: 21
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From: Phoenix
E320
If I do have any knock I don't hear it. Usually the computer will adjust the timing if the knock sensor goes off. I'm not expecting the race fuel to add 50+ horsepower but 10 would be nice. With 91 octane available as the highest rating at most pumps here I'm going to have a little knock retard (KR) happening. I don't want that I would like to have it dialed in perfect and consistant for the occasional 1/4 mile run.
Thread Starter
Newbie
Joined: Jul 2002
Posts: 21
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From: Phoenix
E320
Ok, I will try some sunoco GT109 should make a big difference a little over $4 a gallon. I only need to use about 5 gallons though. I won't be mixing it with the 91. This is what they recommended at my race gas supplier, designed to be sensor safe 
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Joined: Dec 2001
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From: 20854
new balance
I dont belive you will see much of an improvement at all in your time slips, especially on a 320, the computer will not add timing with respect to fuel octane, it is designed to retard timing. And to add, dont knock someone because of a suggetion and call them a liar, thats not fair.
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Super Member
Joined: Dec 2001
Posts: 581
Likes: 4
From: Dallas
C32 AMG
I just thought it was funny. I'm not sure I've ever been called a ricer before. I'm not sure what it was that caused Chad to label me that way.
But the octane thing IS confusing and lot of people have misconceptions about it.
But the octane thing IS confusing and lot of people have misconceptions about it.
Junior Member
Joined: Oct 2002
Posts: 52
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From: Portland, Oregon
96 C220 with Turbo
I run 101 unleaded race gas when I hit the dragstrip. Primarly, to help avoid any possible detonation when I turn up the boost to 9 on my 10:1 compression engine (although I think I have my A/F ratio pretty dialed now, so I'm at pretty low risk even without it). However, I would say that it does help shave about a tenth off of my times over the 92 that I normally run on the street. At least that's been my experience. But remember that I'm running a custom turbo setup with altered timing, so I don't know if it would do much in a stock non-forced induction engine?
Jason
Jason
Super Member
Joined: Apr 2002
Posts: 592
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From: Sacramento
AMG C43, 1999
You might see a couple of Hp if you run the race Unleaded fuel at 100-103 octane.
And it might help your car run slightly cooler due to the properties of the unleaded race gas, but that is about all.
Jeff
AFM Champion 1998 & 1999
Thunderhill Lap Record Holder (motorcycle)
And it might help your car run slightly cooler due to the properties of the unleaded race gas, but that is about all.
Jeff
AFM Champion 1998 & 1999
Thunderhill Lap Record Holder (motorcycle)
