100 octane fuel
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From: UNITED STATES OF AMERICA/ LIGHTNING FAST
100 octane fuel
High octane gas 100 octane is avaible here in my area how much should i use in my 2003 lightning with 6# pulley with chip installed in my lightning. should i mix it half & half with 93 octane or should i run straight all the time????? or just stay with 93 can any one who has a svt lightning with this setup or anyone in this field advise me thanks for any input you may have i put 5 gal in today and my truck really preformed better. about 80% degrees here today took her out on interstate and step down on it for about half mile i can tell the difference in power thanks for you help/ tommy
Last edited by tlfwatch; Jul 23, 2003 at 05:07 PM.
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From: Virginia
Hi Tommy,
Forget using straight 100 octane unless you have had that engine specifically tuned for it. You'll lose power and fuel mileage as well otherwise.
The reason for this is the higher the octane level, the longer it takes to initiate the combustion event, thus the motor lays down if you go much over about 95-96 octane fuel in the tank (and octane mixing is linear, I.E., 5 gals. of 100 octane and 5 gals, of 90 octane = 10 gals of 95 octane) unless it is tuned for specifically.
Use this as a guide:
x gals. of 100 octane = x number of octane points (I.E., 5 gals times 100 octane = 500 octane points, 20 gals. of 93 octane = 1860 octane "points"): add total number of octane "points," divide that by the number of total gallons, and you have the actual resulting octane from this mixing.
Soooo.........
If we have 20 gals. of 93 octane (20x93=1860 octane "points"), and we add to that 5 gals. of 100 octane (5x100=500 octane "points"), then we get a true octane level of about 94 1/2 octane (1860+500/25=94.4 octane).
If you add 7 gallons of 100 octane unleaded gasoline to 18 gallons of 93 octane (you have a 25 gallon tank), you end up with about 95 octane, which is *plenty*. Any more and the vehicle needs to be tuned for it so it won't "lay down" on you at higher rpms because the weak factory COP ignition system can't get the mixture fired & burnt on time.
We recommend always filling the tank full, don't try small mixes. Fill up when the low fuel light comes on (at that point you have 3.5 gallons left in the system), putting the 7 gallons of 100 octane in first. Then fill the tank the rest of the way with the 93 octane, and you've got your mix. This method will result in the fuel being well mixed pretty much immediately.
Don't just drop 5 gallons of 100 octane in when you see the gas gauge indicate 1/2 full, for example. Do this mixing when *filling* the tank, so you *know* just what your actual octane really is.
Ultra-high octane can backfire on you, for example, I had a situation in which I went to VMS (our 1/4 mile sanctioned drag strip), and I added 10 gallons of 100 octane to fill the tank, the rest was 93 octane. So I had about 96 octane in the tank. Well, the humidity just happened to be 98% that day, and guess what? I *slowed down* almost a full second from my normal ET's, and could barely break into the 12's. Why? The ignition system just couldn't fire thru the humidity well enough to get 96 octane burning properly and quickly enough.
So don't go crazy with octane, use no more than 7 gallons of 100 octane mixed with 18 gallons of 93, for an end result of about 95 octane, that's *plenty* for any level of boost that the Eaton M112 blower can deliver.
Have fun!
Forget using straight 100 octane unless you have had that engine specifically tuned for it. You'll lose power and fuel mileage as well otherwise.
The reason for this is the higher the octane level, the longer it takes to initiate the combustion event, thus the motor lays down if you go much over about 95-96 octane fuel in the tank (and octane mixing is linear, I.E., 5 gals. of 100 octane and 5 gals, of 90 octane = 10 gals of 95 octane) unless it is tuned for specifically.
Use this as a guide:
x gals. of 100 octane = x number of octane points (I.E., 5 gals times 100 octane = 500 octane points, 20 gals. of 93 octane = 1860 octane "points"): add total number of octane "points," divide that by the number of total gallons, and you have the actual resulting octane from this mixing.
Soooo.........
If we have 20 gals. of 93 octane (20x93=1860 octane "points"), and we add to that 5 gals. of 100 octane (5x100=500 octane "points"), then we get a true octane level of about 94 1/2 octane (1860+500/25=94.4 octane).
If you add 7 gallons of 100 octane unleaded gasoline to 18 gallons of 93 octane (you have a 25 gallon tank), you end up with about 95 octane, which is *plenty*. Any more and the vehicle needs to be tuned for it so it won't "lay down" on you at higher rpms because the weak factory COP ignition system can't get the mixture fired & burnt on time.
We recommend always filling the tank full, don't try small mixes. Fill up when the low fuel light comes on (at that point you have 3.5 gallons left in the system), putting the 7 gallons of 100 octane in first. Then fill the tank the rest of the way with the 93 octane, and you've got your mix. This method will result in the fuel being well mixed pretty much immediately.
Don't just drop 5 gallons of 100 octane in when you see the gas gauge indicate 1/2 full, for example. Do this mixing when *filling* the tank, so you *know* just what your actual octane really is.
Ultra-high octane can backfire on you, for example, I had a situation in which I went to VMS (our 1/4 mile sanctioned drag strip), and I added 10 gallons of 100 octane to fill the tank, the rest was 93 octane. So I had about 96 octane in the tank. Well, the humidity just happened to be 98% that day, and guess what? I *slowed down* almost a full second from my normal ET's, and could barely break into the 12's. Why? The ignition system just couldn't fire thru the humidity well enough to get 96 octane burning properly and quickly enough.
So don't go crazy with octane, use no more than 7 gallons of 100 octane mixed with 18 gallons of 93, for an end result of about 95 octane, that's *plenty* for any level of boost that the Eaton M112 blower can deliver.
Have fun!
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From: UNITED STATES OF AMERICA/ LIGHTNING FAST
Thanks mike
Thanks mike very informative. and information i was looking for i understand a lot more now about how the octane rating works i should be safe running 94 octane thanks again mike.
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From: NJ
I use Sunoco 94 every once and awhile; my truck seems to run stronger and smoother in the upper range when I do. Should a truck in mine's state of tune benefit from this, or does it mean I'm running the wrong program in the chip? The chip is set for a stock truck; have my mods been enough to need reprograming?
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From: UNITED STATES OF AMERICA/ LIGHTNING FAST
If you have added mods
If your truck is running good on the 94 octane and you have added mods you should send your chip back to your tuner and explain your mods. i posted this about octane subject today on what state weight and measures of arkansas found not to long ago at several stations they were selling 92 octane gas at pumps after being tested for true octane rating it tested 90 or below so i am very careful were i get my gas if you have added mods i would have my chipreburned for them your tuner most of the time just charges for shipping and handling.
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From: Virginia
Hi F Dragon,
No, you do *not* need to have your chip reprogrammed just because you are using 94 octane premium gas instead of 91, 92 or 93 octane premium gas. Nor do you have any mods on that vehicle that require any custom engine tuning, or I should say, I see nothing in your signature that requires custom tuning. One potential exception is if it's a '99 or newer truck, then we *could* recalibrate your speedometer for those larger tires if need be. But otherwise, nothing else I see there requires any program changes.
And yes, it will feel a bit stronger on the 94 octane Sunoco Ultra (that's the best performance fuel available at a standard pump, by the way, so use it whenever you have access to it!) as compared to lower octane fuels, as the knock sensor will activate less (if at all), but 94 octane is all it will respond to. Using 96 or higher won't get you any more *additional* power unless we re-tuned that engine *specifically* for it's use.
Have fun!
No, you do *not* need to have your chip reprogrammed just because you are using 94 octane premium gas instead of 91, 92 or 93 octane premium gas. Nor do you have any mods on that vehicle that require any custom engine tuning, or I should say, I see nothing in your signature that requires custom tuning. One potential exception is if it's a '99 or newer truck, then we *could* recalibrate your speedometer for those larger tires if need be. But otherwise, nothing else I see there requires any program changes.
And yes, it will feel a bit stronger on the 94 octane Sunoco Ultra (that's the best performance fuel available at a standard pump, by the way, so use it whenever you have access to it!) as compared to lower octane fuels, as the knock sensor will activate less (if at all), but 94 octane is all it will respond to. Using 96 or higher won't get you any more *additional* power unless we re-tuned that engine *specifically* for it's use.
Have fun!