Sternal2000
New Member
Just wondering what everyone using for octane. I just noticed my said premium fuel only the other day but I've always used the 87 octane in it with no detenaion
Octane
- Thread starter Sternal2000
- Start date
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olympic
SHO Member
I believe it's "premium fuel recommended", not "required". If your car runs fine on 87 then keep on using it. You won't gain anything from 91 or 93 octane except a lighter wallet. I use 87 for daily driving and 93 for race days.
monsterside
New Member
If you dont gain anything from higher octane fuel then why do you use it on race day? 
Sternal2000
New Member
Yea I don't plan to run a higher octane. I just wanted to see what other people used in their cars. I also wouldn't see the benefit also of running 93 on race day if you normally run 87. It doesn't add any power or anything. I think I remember reading that it will actually decrease your hp since it burns slower, buts its a negligible amount
Whiner
Cptn. Realistic
When I had my SHO it ran 10x better when i ran premium. Premium will keep everything cleaner too.
HopefulSHO
SHO Member
From what I understand, during WOT, the computer dosen't look at the knock sensor..it uses pre-defined tables for spark; so octane ratings probably won't affect WOT power. However crusing is a different story. I get better milage with premium; and since it's 'reccomended', I run it.
I've seen a couple gas stations claim they put more detergent in their premium gas; don't know how many really do that though.
I've seen a couple gas stations claim they put more detergent in their premium gas; don't know how many really do that though.
AutoSHO
No SHO = Mo $$$
The computer does look at the Knock Sensor under all conditions. I have seen this firsthand looking at datalogs from several people's SHOs - you can see the computer kicking the timing back, even at high RPMs. My car run best on premium due to the advanced timing I am running. On a stock SHO, 87 octane should be adequate.
FOSHO94
Chillin
I recently bought a new SHO and the owner ran 87 in it for 83k miles, and then i bought it, and since then i've been runing 93, but i noticed a rasp in the exhaust when i started running 93, any relation? or am i hearing things?
Rockledge
Pluggin' away
Your not getting detonation because your computer is programmed to listen to the knock sensor and is retarding timing every time it senses a ping or two. You could run 85 octane and the computer and KS would still probably be able to adjust.Sternal2000 said:
Axianator
I am a banana!
Actually, there is a limit to how much timing the EEC can and will pull.Rockledge said:
Use 85 octane and you may wish you hadn't.
Rob94
New Member
Chris Cicotte said:
Premium will NOT keep anything cleaner. The only difference between regular, midgrade, and premium is the octance reading. The fuel's resistance to burning. The detergent levels are the exact same. Federal law dictates so.
Rockledge
Pluggin' away
Yes, a limit that 85 octane just might push, I see your point.Axianator said:Actually, there is a limit to how much timing the EEC can and will pull.
Use 85 octane and you may wish you hadn't.
My point is actually along the same lines, in that, just because someone isn't experiencing pinging doesn't mean they are running the best choice of octane gasoline through their SHO's system. It may only mean that their ignition timing is being ******** so that the engine runs below the pinging threshhold, as programmed into the computer.
FWIW, I believe that anything under 89 octane and your robbing your SHO of possible power, at least under some conditions, keeping in mind the median ages and average condition(s) of the Yamaha engine(s) and the likleyhood that they might experience detonation. Myself, I feel that "Premium Recommended" is written on the instrument panel for a reason. My positon being more fully explained in this thread:
http://www.shoforum.com/showthread.php?p=253020#post253020
olympic
SHO Member
monsterside said:If you dont gain anything from higher octane fuel then why do you use it on race day?
Because I have nitrous. But even on a road course where the N20 isn't used premium fuel is a good safety precaution. On the street the engine will never see this kind of punishment so regular fuel is fine as long as it doesn't ping.
Some facts about premium fuel:
-it burns slower and contains less energy per gallon than regular. High performance cars make more power on premium because they have the compression ratio and spark advance to take advantage of the higher octane. But if your car can achieve full spark advance on regular without detonation then there will be no gains.
-it will leave more deposits on your valves and pistons. I believe this is why cars that always run premium get "hooked" on it and can't run regular.
-the octane rating of fuel drops as it sits in storage. Far fewer people buy premium than regular so it sits in the stations tanks longer. So you never really know what you are getting.
WOT probably doesn't matter as above, but for cruising I get much better mileage with 92 than with other. Higher octane means more advance and power, but also less fuel burned. You can buy more fuel for the same distance, or less fuel with a lesser alternative. The variables probably end up meeting in the same place - mileage vs. cost vs. distance. The same argument can be made about E-85 vs. "normal" gasoline. Then it falls to what will benefit the engine long term. I'll pony up the extra ching for a small chunk of insurance.
Ferendon
New Member
Both of my SHOs, and my friends 90 run like **** on anything but 93. He ran 87 for a while, and we thought the car just needed a tune up. It was free, and had a few problems. When he switched up, it ran fine, and still runs great. My first SHO did the same thing, and when I bought my second SHO it had regular grade in it, and ran even worse then it does now. (Head replacement soon), but when I added some premium it got better, and after the next fill-up it actually ran ok...
Ferendon said:
From what I've been told, many times, by the fuel truck drivers, the fuel being pumped into the 93 octane tanks are actually 91. They pump only 87 and 91, for 89, the station has a blender that blends the two fuels together to get your 89.
sdpatt
Sr. SHO Engr.
I use the number posted on the gas pump.
Tommy's SHO
SHO Member #535
I have always used 93 octane in the States and 91 in Canada because I get more miles/gallon with the premium fuel.
My work truck is a 2004 Chevy Express 3500 gas engine (6.0L 300hp ). We fueled it up with regular and it ran a distance of 372 miles/tankfull. With premium fuel it runs 435 miles/tankfull......and yes we hauled the same weight.
My work truck is a 2004 Chevy Express 3500 gas engine (6.0L 300hp
). We fueled it up with regular and it ran a distance of 372 miles/tankfull. With premium fuel it runs 435 miles/tankfull......and yes we hauled the same weight.93EmeraldMTX
New Member
Rob94 said:
federal law dictates the minimum requirement of detergents. gasses like shell's new v power have 5 times the detergent requirement while still having the same 93 octane rating.
morpho18
Member
Good thing livin in iowa is....god I just sounded like Yoda, but anyways, I use 90 octane. In Iowa it is blended with ethanol produced from Iowa soybeans, so the price for the gas is cheaper. just yesterday I filled up, here were the prices:
87: $1.83/gal
90: $1.72/gal
91: $1.94/gal
When I know that prices are going to go up soon, and 90 is going to cost what 91 previously cost, I fill up on 91 and save a few pennies that way.
87: $1.83/gal
90: $1.72/gal
91: $1.94/gal
When I know that prices are going to go up soon, and 90 is going to cost what 91 previously cost, I fill up on 91 and save a few pennies that way.
