Plus (89) Fuel Performance - 2002 I35

[chillin2345]

Saw a post earlier regarding using Premium vs. Regular fuel and had a similar question.

I drive a 2002 I35 and put in Plus (89 octane) on a regular basis. Every 2 or 3 fill-ups, I'll put in premium (91). When gas got really expensive in CA, I would put regular (87) every now and then to save some money.

Is there any official word from Nissan/Infiniti on how much performance suffers from not using premium fuel (as recommended)? I can definitely feel the loss of power as I drop down each octane grade, but would like to know if there are any firm HP and torque ratings I could refer to? Thanks.

[allensteiner]

it's more about the quality of premium vs any lower grade. you can add stuff to gas to give it more octanes than premium but it'll still be crappy fuel. premium fuels are designed for a good burn but also to keep the fuel system clean. shell, chevron and phillips/conoco are some of the best manufacturers.

when running reg or plus gas it's good to use fuel additives like stp or techron.

[untrueparadox]

haha. that original post was mine. i can tell u that when i got to using 91, i get considerably more miles on it when driving local. i fuel up about twice every three weeks and now i can stretch it to about every two weeks. when im going up a highway ramp with decent a/c on, i used to have to floor it but with 91 i can go about 3/4 of the way down. also when accelerating from a stop, i dont have to press so hard on the pedal. i think the fuel efficiency itself is worth the price. considering its only 20c more per gallon. since you have experience in both, you can decide yourself.

and about the additive, i dont see why you would use that. a tank of gas usually runs around 13-14 gallons for me, and the price difference is like $3 between 87 and 91, and a bottle of techron can easily be more than that. might as well just buy chevron with techron.

[MinisterofDOOM]

I have never seen any firm numbers. It'd be hard to come up with any, most likely, as the margin of variance between 89 and 91 is probably small enough to fall within the range of dyno variances (maybe 15hp ish, I'd guess, but that's just a blind guess).

it's more about the quality of premium vs any lower grade. you can add stuff to gas to give it more octanes than premium but it'll still be crappy fuel. premium fuels are designed for a good burn but also to keep the fuel system clean. shell, chevron and phillips/conoco are some of the best manufacturers.

It's worth noting that this depends heavily on the station you're getting your fuel from. Some brands only put detergents (or only put their best detergent) in their premium fuel. Others, like Chevron, put the same detergents in all grades. Shell's new "nitrogen enriched" detergent (which appears very similar to techron from what I've researched) is also now found in all 3 grades. Of course, you can always run a bottle of Techron or Redline S-1 every few fill-ups and get close to the same benefits even with crappy low-octane fuel. But as noted above, you're not likely to save any money and you're certainly not saving any time or effort.

[allensteiner]

It's worth noting that this depends heavily on the station you're getting your fuel from. Some brands only put detergents (or only put their best detergent) in their premium fuel. Others, like Chevron, put the same detergents in all grades. Shell's new "nitrogen enriched" detergent (which appears very similar to techron from what I've researched) is also now found in all 3 grades.

exxon's premium has less detergents than conoco/phillips premium. also depends how old/new the tanks are and how much fuel is in them at the time of fueling - the older the tanks and the less fuel in them - you'll get a bunch of crap in the gas (don't trust the filters).

however, the discussion on gasoline is endless...

[untrueparadox]

ya, but it makes a big difference if u live in places like utah where they sell 85 octane gas lol. if 89 to 91 is 15hp, and then from 85 to 91 is like 45hp. for myself, it was probably like a 10% increase going from 87 to 91, and if u can find 93, thats even more power.

[allensteiner]

boise, id metro area - shell v-power is 94 octane

[MinisterofDOOM]

ya, but it makes a big difference if u live in places like utah where they sell 85 octane gas lol. if 89 to 91 is 15hp, and then from 85 to 91 is like 45hp. for myself, it was probably like a 10% increase going from 87 to 91, and if u can find 93, thats even more power.

Most places here in Utah, 87 is regular. 85 is less common. Usually it's 87, 89, 91. Some places offer 4 grades or skip 87, though.