What Race Fuel should I use?
05-28-2003, 01:20 AM
#1
What Race Fuel should I use? Since I am planning on running Open Road Race events my motor will be seeing 5K+ in the RPM range for an extended period of time so I was thinking of using some race fuel in the car but had NO IDEA what type to use with the LS1 Oxygen sensor driven motors. I have always used VP-C12 on all my carbed cars and that stuff was great. But with the LS1 I am concerned about eating the O2 sensors and how much octane is to much. I Finally found a place real close to the house that carry's VP Race fuels so I stopped by and picked up a brochure the other day. And after reading it I have narrowed it down to 2 fuels that might do the job.
PERFORMANCE UNLEADED
(as per VP Brochure)
Performance unleaded is well suited for high performance, street legal cars. It meets ASTM D-439 standards and does not contain any metal compounds. Performance unleaded will not harm catalytic converters or Oxygen sensors. Performance unleaded will typically allow turbo engines to raise boost levels from the stock 8-10 lbs. to 20-25 lbs. Works well on the latest generation of electronically controlled turbo engines.
Color:Light Yellow
Unleaded
Motor Octane: R+M/2: 100
Specific Gravity:.79 at 60 degress F
And the other
(As per VP Brochure)
MOTORSPORTS
Motorsports 103 is VP's name for its street legal gasoline, designed for maximum power and throttle response. Motorsports 103 in an unleaded fuel of high octane that provides power and protection equal to some leaded race fuels. Meets California RFG Requirements. Recommended for: High performance street car, boats, snow mobiles, personal water craft and high performance import cars. Spec fuel for Professonal Sports Car in 1999.
Color:Clear
Unleaded
R+M/2:103
Motor Octane:99
Specific Gravity:.743 at 60 degrees F
All of the technical stuff under the description is pretty much chineese to me other than the octane part. I was thinking of going with the first one since the motor octane is higher than the second. Not only that but the Performance unleaded is designed for CARS not snow mobiles, personal water craft etc. They have other unleaded fuels like A5, M8, C10, CSP, but those sounded like fuels for pretty hardcore race cars. But what made me think is that all of the hard core fuels have a LOWER octane rating than the 2 I listed. And its starts getting confusing when they mention "Motor octane" and "Research Octane". What the heck does that mean?
As far as I always knew, the higher the octane the better (to a point). Any input or advice on what fuel to use for a little safer operation at high RPM's would be great. And would these fuels be safe for constant use on a motor?
PERFORMANCE UNLEADED
(as per VP Brochure)
Performance unleaded is well suited for high performance, street legal cars. It meets ASTM D-439 standards and does not contain any metal compounds. Performance unleaded will not harm catalytic converters or Oxygen sensors. Performance unleaded will typically allow turbo engines to raise boost levels from the stock 8-10 lbs. to 20-25 lbs. Works well on the latest generation of electronically controlled turbo engines.
Color:Light Yellow
Unleaded
Motor Octane: R+M/2: 100
Specific Gravity:.79 at 60 degress F
And the other
(As per VP Brochure)
MOTORSPORTS
Motorsports 103 is VP's name for its street legal gasoline, designed for maximum power and throttle response. Motorsports 103 in an unleaded fuel of high octane that provides power and protection equal to some leaded race fuels. Meets California RFG Requirements. Recommended for: High performance street car, boats, snow mobiles, personal water craft and high performance import cars. Spec fuel for Professonal Sports Car in 1999.
Color:Clear
Unleaded
R+M/2:103
Motor Octane:99
Specific Gravity:.743 at 60 degrees F
All of the technical stuff under the description is pretty much chineese to me other than the octane part. I was thinking of going with the first one since the motor octane is higher than the second. Not only that but the Performance unleaded is designed for CARS not snow mobiles, personal water craft etc. They have other unleaded fuels like A5, M8, C10, CSP, but those sounded like fuels for pretty hardcore race cars. But what made me think is that all of the hard core fuels have a LOWER octane rating than the 2 I listed. And its starts getting confusing when they mention "Motor octane" and "Research Octane". What the heck does that mean?
As far as I always knew, the higher the octane the better (to a point). Any input or advice on what fuel to use for a little safer operation at high RPM's would be great. And would these fuels be safe for constant use on a motor?
05-28-2003, 12:16 PM
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Re: What Race Fuel should I use? i know sunoco makes GT 100 and GT 104 unleaded gas for street cars, but only the 100 is "street legal"... expensive tho, and only a few stations carry it... try here with ur zip code to see if its near u: http://www.racegas.com/gt100locals/default.asp
05-28-2003, 06:13 PM
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Re: What Race Fuel should I use? Well lets go over this one at a time?
All of the technical stuff under the description is pretty much chineese to me other than the octane part. I was thinking of going with the first one since the motor octane is higher than the second. Not only that but the Performance unleaded is designed for CARS not snow mobiles, personal water craft etc. They have other unleaded fuels like A5, M8, C10, CSP, but those sounded like fuels for pretty hardcore race cars. But what made me think is that all of the hard core fuels have a LOWER octane rating than the 2 I listed. And its starts getting confusing when they mention "Motor octane" and "Research Octane". What the heck does that mean?
First off it seems you have some typos in what you typed down. So let me put down what matters. Also, VP doesn't list the research octane of Performance Unleaded so I had to figure that out.
PERFORMANCE UNLEADED
R+M/2 = 100
Research Octane: 106.5
Motor Octane: 93.5
Specific Gravity: .795 at 60° F
MOTORSPORT 103
R+M/2: 103
Research Octane: 107
Motor Octane: 99
Specific Gravity: .743 at 60° F
The Research Octane is established in a single cylinder motor with a 3.5" bore and a 4.5" stroke, with overhead valving and variable compression. The engine is run at 600 rpm, the timing is fixed at 13 degrees BTDC, and the intake air temp is 100 degrees F.
The Motor Octane is computed in a similar fashion except the engine has variable timing (between 14 and 26 degrees BTDC), it is now turning 900 rpms, and the intake air temp is 300 degrees F.
In racing or severe applications, the MON is most important because this is most applicable to high rpm high inlet temp situations. The RON is seen as more of a number for heavy trucking or extended low rpm use.
Now when you go to the pumps, you see the M+R/2, which is known as the antiknock index, and is the number commonly referred to when ppl say "octane". Since you are averaging the 2, there are unlimited combinations, which is why your car can run much better on one brand of 93 (or 100) octane than another. So to us racers, a high MON is more important than a high overall antiknock index. You could have 2 fuels infront of you, one could be 100 MON and 100 RON, and the other could be 92 MON and 108 RON, but both would appear as 100 octane on the sticker, while they would run much differently in the car.
This brings me to another point, fuel stability. A fuel that has the MON and RON that are the same, such as VP's C18, is seen as a very stable fuel. A fuel like Turbo Blue 115 has an octane differntial of 10.5 (between its MON and RON). This means its a less stable fuel, as well as it might not work as well in an race engine because its MON is 104.5, while VP's C14 has the same 115 R+M/2, but its MON is 114. To my knowledge, stability only really matters if you're going to be storing it for a long time though.
The specific gravity of the fuel is very important, as it determine's which fuel has the most energy potential. Water is given a weight of 1, and then the specific gravity of these fuels you are looking at is .795 and .743 Most leaded fuels have a SG of less than .740, while most unleaded ones have an SG above .750. This matters because if the specific gravity is higher, it has a higher mass. A lower specific gravity fuel has less potential energy than a one of higher density (keeping all other things equal). The fuel with the higher specific gravity will produce more power because it it bringing with it more hydrocarbons to burn.
So I'd find out what MON you want to run at, and pick the fuel with the highest specific gravity and that MON.
You can search to see where your closest Sunoco dealer is at http://racegas.com/distributormap/default.asp as they offer 2 unleaded racing fuels that may interest you.
J.
All of the technical stuff under the description is pretty much chineese to me other than the octane part. I was thinking of going with the first one since the motor octane is higher than the second. Not only that but the Performance unleaded is designed for CARS not snow mobiles, personal water craft etc. They have other unleaded fuels like A5, M8, C10, CSP, but those sounded like fuels for pretty hardcore race cars. But what made me think is that all of the hard core fuels have a LOWER octane rating than the 2 I listed. And its starts getting confusing when they mention "Motor octane" and "Research Octane". What the heck does that mean?
PERFORMANCE UNLEADED
R+M/2 = 100
Research Octane: 106.5
Motor Octane: 93.5
Specific Gravity: .795 at 60° F
MOTORSPORT 103
R+M/2: 103
Research Octane: 107
Motor Octane: 99
Specific Gravity: .743 at 60° F
The Research Octane is established in a single cylinder motor with a 3.5" bore and a 4.5" stroke, with overhead valving and variable compression. The engine is run at 600 rpm, the timing is fixed at 13 degrees BTDC, and the intake air temp is 100 degrees F.
The Motor Octane is computed in a similar fashion except the engine has variable timing (between 14 and 26 degrees BTDC), it is now turning 900 rpms, and the intake air temp is 300 degrees F.
In racing or severe applications, the MON is most important because this is most applicable to high rpm high inlet temp situations. The RON is seen as more of a number for heavy trucking or extended low rpm use.
Now when you go to the pumps, you see the M+R/2, which is known as the antiknock index, and is the number commonly referred to when ppl say "octane". Since you are averaging the 2, there are unlimited combinations, which is why your car can run much better on one brand of 93 (or 100) octane than another. So to us racers, a high MON is more important than a high overall antiknock index. You could have 2 fuels infront of you, one could be 100 MON and 100 RON, and the other could be 92 MON and 108 RON, but both would appear as 100 octane on the sticker, while they would run much differently in the car.
This brings me to another point, fuel stability. A fuel that has the MON and RON that are the same, such as VP's C18, is seen as a very stable fuel. A fuel like Turbo Blue 115 has an octane differntial of 10.5 (between its MON and RON). This means its a less stable fuel, as well as it might not work as well in an race engine because its MON is 104.5, while VP's C14 has the same 115 R+M/2, but its MON is 114. To my knowledge, stability only really matters if you're going to be storing it for a long time though.
The specific gravity of the fuel is very important, as it determine's which fuel has the most energy potential. Water is given a weight of 1, and then the specific gravity of these fuels you are looking at is .795 and .743 Most leaded fuels have a SG of less than .740, while most unleaded ones have an SG above .750. This matters because if the specific gravity is higher, it has a higher mass. A lower specific gravity fuel has less potential energy than a one of higher density (keeping all other things equal). The fuel with the higher specific gravity will produce more power because it it bringing with it more hydrocarbons to burn.
So I'd find out what MON you want to run at, and pick the fuel with the highest specific gravity and that MON.
You can search to see where your closest Sunoco dealer is at http://racegas.com/distributormap/default.asp as they offer 2 unleaded racing fuels that may interest you.
J.
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05-29-2003, 12:44 AM
#8
Re: What Race Fuel should I use? well, I am out of luck on the SUNOCO. Closest distributor to the seattle area is in Oaksdale CA.
My car is an MTI Stage 2 LS6 and X1 set up. 10.8:1 compression and I cant remember off the top of my head what kind of timing I am running.
CrazyQuik: My head hurts after reading your post
. Care to put that in plain engrish! 
. Also I checked the brochure for VP and it says "motor octane" for the performance unleaded is 100
My car is an MTI Stage 2 LS6 and X1 set up. 10.8:1 compression and I cant remember off the top of my head what kind of timing I am running.
CrazyQuik: My head hurts after reading your post
. Care to put that in plain engrish! . Also I checked the brochure for VP and it says "motor octane" for the performance unleaded is 100 
05-29-2003, 09:08 AM
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Re: What Race Fuel should I use? VP's website says the R+M/2 is 100, but the motor octane is 93.5 (so they fucked up somewhere)
http://vpracingfuels.com/vp_10_techd...D802E46AFA9F0A
High Specific Gravity = good
High Motor Octane = really good
J.
http://vpracingfuels.com/vp_10_techd...D802E46AFA9F0A
High Specific Gravity = good
High Motor Octane = really good
J.
05-29-2003, 11:11 AM
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Re: What Race Fuel should I use? Okay here it is in simple Engligh. Mix a few gallons of either unleaded 100 or 103 with a half tank or so of 93 and you will be fine. Unless your compression is over 11:1 you really shouldn't need any race gas but a little mixed in is a good insurance idea. If your compression is higher then mix in a little more. Simple as that.
07-10-2021, 03:45 PM
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07-11-2021, 09:33 AM
#14
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SHHHH.... he's on a roll..... lol
