Hey Guys,

Do you think there is a big difference in power with 91 Octance v.s 94 Octane?
I have absolutley nothing done to my car. Just a KNN Drop in filter. What do you guys think a difference in 4-7hp? or more? less?

To add to that I was coming of a turn with a 2010 GTI beside me and noticed that he gunned it. ( He prob had about a 1.3 Second advantage on hitting the gas) so I gunned it as well and found that I did not really catch him too fast as he was ahead. I mean ..... I was gaining ground on him but slowly. We ran out of straight road, before we had to get of the gas.

I know the mid range grunt is kind of sloppy on this car so I guess that accounts for it. ( as well as my 91 Octane)

 

higher octane level in gasoline does not make more horse power.........

.........nor is it "better gas".

a higher octane level will allow the use of a more advanced spark timing.

the advanced tining is what COULD make more horse power.

if a car has not been "tuned"...running gasoline with more octane is a waste.

 

+1 Another benifit to higher octaine is it doesnt knock :]

haha and it can be smoother when u accelerate

 

what's knocking?

 

"spark knock" is caused by unstable or multiple combustions in the combustion chamber of the engine.

higher octane levels in gas help minimize knock by slowing down the burn of the fuel.

the ecu in our car will not allow knock to occur. if one count of knock is "sensed"...

....the ecu changes the ignition parameters to stop the knock.

 

Does that mean that the car will ultimatley sacrifice performance when it changes the iginitipon parameters? I'm assuming to counter the knocking.

 

I heard that argument but........
The RA manual asks for 93 Octane. If "necesary" you can use 91 octane but expect a power drop. Going below 91 Octane is NOT RECOMMENDED unless its an emergency.

Just wanted to see what everyones take on that was as not all can get 93-94 Octance in the states they live in.

 

if the ecu detects a count of knock it will change something.........

.......that would most likely be retarding the spark timing.

if you are using a fuel that is "low octane" the ecu would not

just automatically retard the timing. it would run the normal parameters until a knock was sensed.

if driven very conservativley you could probably run 87 oct. and not knock.

 

It's half marketing, half bs.


These cars are also based out of Japan where they use a different way of calculating Octane. Like mentioned before running anything more than 91 without a tune for the higher octane is a waste.

 

Hahahaha these cars are made by a japenses company to US standards, Mitsubishi MMNA sound familiar?

So its just our emissions and to get the most hp for marketing this car

 

So you're saying that there wouldn't be much difference on using 91 and 93 octanes??

 

For a stock car.. No there will be no difference.. Only real reason to use higher oct is if you are tuned for it... just don't go below 91 unless you have no other option.

 

About 10 to 15 hp.

Log your car on California 91 octane (not sure about other states) and you will see knock, and ignition being pulled to compensate for the knock. This results in lower mid range torque, and lower high end HP. Run the same EVO or Ralliart on 93 octane and you see zero knock and full engine timing.

Keith

 

It can knock, but higher resistance to it.

To clarify, cause it seems like there is some circling in this thread, it isn't marketing. The car ships with a tune expecting 93. You can run 91 but it will likely sense knock and retard the timing which will result in lost performance. Make sense?

So the other poster was right - get it tuned for what octane you typically run and you will see the most of your performance. Run higher octane if you want, but don't expect anything except maybe a tiny bit of increased mileage (arguable).

To the OP - best not to post stories of public racing; the mods don't take too kindly to that.

 

So If I run 91 OCT with GST boostpill and 91 oct basetune, would it knock? or would the tune compensate for the lower oct??