Dmstckiller

here in iowa we are blessed with octanes at the pump from 87 all the way to 93.5. At a local airfield i can buy 100 and 114 octanes respectively. the prices vary from day to day but the 100 octance is around $4.15 and the 114 is around 12 something. Is this too high for my seven?

RestoTII

you might want to do some reading into what the octance means and which you should run. I've got an 87TII with a few mods and I run erither 93 or 94 (whichever is at the pump). I pay around $1.50-1.65 a gallon. I've never considered octance boosters or anything like that, since the 93-94 should be plenty high. It's just the resistance to knocking, and does not create more power if you use a higher octane. Someone else may spend a little more time to give you a nice description, but I'll assume you just wanted an answer and you can research on your own if you want to find out why I said it won't help over 93.

ColumbusTurboTwo

iTrader: (7)

i run 94 because i run premix, the only problem i can see with high octane is that many of the higher octane ratings (100+) are leaded.

Dmstckiller

is the octane rating a percentage of knock resistance?

deadRX7Conv

Your profile lists a GTU. If it is still an NA, you don't need octane. Save your money for mods. Try various gas stations and octanes and use the one that feels/sounds the best. This is mostly psychological. Pick a gas station that does lots of business. This way the fuel is always fresh.
Unless your engine has knocking/detonation/preignition, then higher octane isn't gonna make a difference. If your engine has those issues, its probably toast already.

My NA runs great on 89 during the summer and 87 during the winter. I also have my timing advanced. Engine carbon buildup on high mileage vehicles might increase your CR a little also. My cooling system works perfectly.

iam1ru12

Hello Everyone,
Check out the FTC's Site on Octane .

To sum it up, octance ratings measure a gasoline's ability to resist engine knock/rattle/pinging/etc. Engine knock is caused by the fuel/air igniting prematurally (detonation). If you have a high compression engine you should use a high octane gas but check your owner's manual or consult your tunner.

As far as higher octane gas being cleaner, this a huge farse/marketing campaign by the oil companies (Shell, Exxon, etc) to get you to buy more expensive gas.

-Mike

Icemark

Its been proven on dynos time and again that Stock NA engines actually make more power on 87 or 89 octane than they do on 91 or higher.

T2s however are a whole 'nother bird all together when it comes to octane.

BlackFC

Depends on the car. An NA RX7 probably won't benefit at all from higher octane. But going from 93 to 114 in my Talon was an easy extra 75whp+. This was not from the higher octane of the gas, but in the increased timing and boost (19psi and 19 - 20deg adv on pump and 29psi and 26+deg advance on the leaded stuff). And leaded gas smells better.

Daniel

Tec

All my friends and i run 100 octain avation fuel in our turbo cars! It's not leaded! and you should only pay $1.65 to $1.80 a gallon! Rob @ pineapple runs it in some of the cars he builds! Just stay away from leaded fuel if you still have cats on your car!

Kai

Well, from what I heard the octane rating of gasoline fuel is the ratio of octane (a near detonation-proof eight carbon hydrocarbon chain) versus heptane (a highly explosive, detonation-prone seven carbon chain). By that logic, the higher percentage of octane vs. heptane allows the air/fuel mixture to be compressed more. That compression is only important in high-compression NA race engines and turbo engine. As said before, the majority of us NA guys have no reason to dump the extra $green$ in our tanks.

BTW, leaded gas kills O2 sensors.

Icemark

Your lucky to find $1.80 for gallon of 91 octane in my area

Tec

Send me some $$ and i'll send you a 55 gal drum

zelgadiss-san

hrm... my unmodded N/A likes 93 better than 87 or 89. the price isn't that bad, $1.55/gal, but I don't have to worry about that since my parents pay for my gas because I mainly use the car to get myself and my sister to and from school.

Evil Aviator

Yes, most aviation fuel IS leaded. Note that the common "blue stuff" is 100LL (100 Low Lead). Low-lead is a relative term which does not mean "no lead", and it actually has about the same concentration of lead (4ml/gallon) as leaded automotive fuels.
http://www.eaa.org/education/fuel/autogas_vs_avgas.pdf
http://www.dragracingpinoy.com/tech_avgas.html

If your NA likes 93 better, then it has tuning and/or hot spot problems. The higher octane fuel will act as a band-aid for now, but I have never known engine problems to get better with time. Sorry.

jacobcartmill

iTrader: (6)

damn, 93 octane gas is like 1.33 a gallon here.

RETed

You might also want to keep in mind running "AV gas" is ILLEGAL in an automobile on federal roads.&nbsp These fuels are not taxed for automobile use and therefore illegal to be used in cars.&nbsp Yes, the chances are slim you'd get caught, but don't cry if you get slapped with a HUGE federal fine and jail time...


-Ted

Tec

Thats funny! The police station is right next door, like a hundred yards away.