ibglowin

OK,

Sorry if this has been asked and answered a hundred times before.

Do you absolutely need to run premium unleaded gas?

Will mid grade unleaded work.

Would you damage your engine with regular unleaded.

I'm not talking for going to the track per say but rather a daily commute.

Thanks for any info!

lanbrown

First, never use gas, use gasoline.

Anyway, the engine will retard the timing to keep from damaging itself from knocking and pinging. You will have less power, worse fuel mileage and could shorten the lifespan of the motor. How much shorter, who knows. If you had an engine problem and it was discovered that you ran the mid-grade, they could decide not to warranty it. If you don't want to run premium, don't buy a vehicle that requires it. Using non-premium because you have to is one thing, doing it on a consistent basis is another. I also wouldn't VTEC at all on anything but premium.

rickycrx

You will also get such horrible gas mileage that the price increase to run premium more than makes up for the cost of using it.

lanbrown

Is that from experience?

ibglowin

My question or concerns on this.

I live at 7000 feet above sea level. Our top "premium" unleaded is $0.25 more per gallon and its only 90-91 octane, not 93-95 like what you can find at lower elevations.

Wondering what impact if any this would have.

HI SPEEDR

I'd never use anything less than premium when your engine has over 11:1 compression ratio. That's asking for trouble.

Road Rage

I have several engineering studies from American Honda on the use of different grades in the NSX, so this is a response by proxy.

The difference in HP is not that much - perhaps 5-8. Torque is about 10 lbs less.

You can easily use 87 octane for highway driving, since it uses only a fraction of the power of the car. I disagree that the loss of power will offset the increased cost of fuel.

In the US, different grades of fuel have different amounts of detergents, so if you plan to use regular a lot, I would regualry use a good injector cleaner, like SI-2, Regane, or Techron.

Personally, I would use premium most of the time, and if you hear persistent pinging, check the knock sensor.

Hockey

From experience, I used mid-grade for about a month straight when fuel prices sky-rocketed at the threat of war. I experienced the following:

- loss of power (maybe 5%)
- mileage difference was not significant
- no pinging during WOT (wide open throttle)

According to the owner's manual, it is approved by Honda to use grades other than premium, so the warranty being voided claim is incorrect.

I do not do this on a regular basis, just when the fuel prices approached $2.50/gal

Yikes

slalom44

I agree with Road Rage, and Hockey's observations are similar to mine. I use the cheap stuff when I take long road trips and I spend most of the time at constant speed. I've never had any knocking, and I get around 31 mpg on those trips. I don't VTEC with low octane gas.

An engineer from HRA in Marysville told me that low octane fuel works fine in this car, and doesn't do any harm. He's the same guy that talked me into buying my car in the first place.