aaron653

iTrader: (1)

I use 91 but for the first few weeks that I owned the car I used 87. I got a consistant 3mpg more from 87 (20mpg). Ever since I've been using 91 it has been 17.XX mpg. can anyone explain this?

VIP1

Is your state's fuel the new blend (90% gasoline, 10% ethanol)? That will explain the drop in mileage. Ethanol has a higher octane rating than gasoline, but it only contains 70% the power of gasoline.

KW4life06

iTrader: (12)

is ethanol better or worse for performance

VIP1

Depends on tuning and fuel grade.

Example:
* E10 (90% Gasoline + 10% Ethanol) at the same octane rating (for instance 91 octane) is worse, because Ethanol has less power potential than gasoline and fuel consuption will go up slightly.

* An engine running E85 (15% Gasoline + 85% Ethanol) at 100 octane can potentially produce more power if properly tuned, but that is due to the octane rating and not the ethanol. The downside is that fuel consumption will increase by almost 30% since ethanol contains only 70% the power of gasoline. Check out the E85 mpg rating of flex fuel vehicles.

* Also, since ethanol is a solvent, its can eat rubber and other soft materials. Therefore the engine has to be built to handle it. This is more of an issue with E85 than E10.

* All that being said, using ethanol as an octane booster is still better for the environment than MTBE. That is why we have E10. Ethanol replaced MTBE.

mycamaroSS

iTrader: (4)

dude dont even think about using anything lower than 93...it will make your engine perform bad and 93 helps a lot with cleaning your engine and gives you more performance in terms in response etc.

Lucas'02SS

iTrader: (4)

I know it has been said several times already, but don't use 89!!! You will notice a significant power difference and most likely gas mileage drop. I had a friend that insisted on running 89 to save money, and he wouldn't listen to another friend or myself when we told him it was going to hurt his performance. He still doesn't understand why his car runs so weak...

ls1chris

always go with the higher octane trust me it makes a difference.you will get bett mpg and it will run better onece you get all the old cheap gas out of the system. on my car it seems to not want to idel smoothly with cheap gas and also wants to seem to smoke a lil more with cheap gas but thats prolly mainly du to me needin a compter tune

SILVER2000WS6T/A

iTrader: (1)

Is Sunoco 94 still around? It was here in New Jersey. Now all I can find is Sunoco 93. Did they stop making it?

Lucas'02SS

iTrader: (4)

I just wish I could find 93! We used to have it here at several stations, but when gas got so expensive last year everyone went to 91.

NDFORSPD

Using Shell 91 Oct(93 isnt avail in Canada, or that Ive seen anyways only 87-89-91) we also have Sunoco 94(highest oct avail - its 87-89-91-94oct as apposed to 93), but I still only use Shell in the Car

mcamarols1

iTrader: (9)

i hate all u guys that have 93-94octane in ur town, LOL, i ve been stationed in el paso and all they got is 91, came to ca and all they got is 91, i never felt what 93-94-100+ octane feels like

woild u guys use 100+ octane for the track? does it make a diffrence?

gonefishn1212

stop mashing the pedal at stop signs and lights, and gunning it on the high way, do the speed limit and dont do hard accelerations and you should see you tank of fuel last longer

brad8266

iTrader: (23)

93 all the time. Youre only gonna save like 3$ by being cheap and trying to use 87.

EchoMirage

iTrader: (3)

you won't feel the slightest bit of differance between 91 or 93/94. 100+, maybe, and that's a BIG maybe. Cars today aren't anything like old school carbed V8s from the 60s and 70s. Those cars need and would feel a differance between a large octane change. Since all LS1s have knock sensors, unless you have very high compression, you wouldn't feel any differance between 91 or 94. Even putting 89 in, you MIGHT sense a slight drop in power at WOT due to the retarded timing. Never run 89 of course, but believe me, there is no differance between 91 and 94, other then your wallet feeling lighter. Think about it, it's a 2 or 3 octane differance between 91 and 93/94. That's kinda like putting the tornado in your intake and expecting to lose a second on the 1/4.

oehm

I too generally see a slight improvement in mileage running 91 octane fuel or better.

kevins2000LS1

iTrader: (11)

i add 5 gallons of CAM2 (110) to my 93octane, every fill up to make it about 99 octane

aaron653

iTrader: (1)

yes i know that...I grew out of that stage a long time ago

KW4life06

iTrader: (12)

smashing it at stop signs and lights? so goin to 5500 on each shift is a bad idea? haha jk... maybe 8)

Runn

Why not go with E85?

VIP1

A few reasons...
* The LS1 was not designed or tuned for it.
* Read my post above, #24 (its only a brief overview)