Regular or Premium?

Aaaargh !!! What a lot of answers by people who don't know what they are talking about.

The purpose of octane is to allow increased compression ratios at high RPM and full throttle. ALL OF THIS together at the same time - which is why racing engines require high octane.

At low RPM, part throttle conditions a much lower octane suffices. Even a high compression engine driven at low throttle settings will run just fine on lower octane fuels. My 10.5 compression big-block runs on 85 octane at altitude with NO problems !!!

Lower octane fuels actually have MORE energy density, and will provide better mileage. An extreme example of this is diesel fuel which has about 15% more energy per gallon than does gasoline (it just won't burn steadily in a standard gasoline engine so don't try to fuel up with it).

High octane fuels have less energy - wait till you see your 50% or more fuel mileage drop using E85 (ethanol) which has a very high octane rating.

As to deposits, all fuels of one company carry the same detergents and thus help reduce normal aging deposits.

Your ECU will retard the timing as required - it's actually not the ECU itself, but having a knock sensor - which your car does have.

so many thumbs down on such good advice.

And what a full up themselves person above.Say what you like but i have had Japanese cars for years.

And that might be some facts but me bouncing around a car park with the low octane fuel told me to but high ron in.

Stick to the fuel it needs.As said what a small bit extra per fill up out weighs repairs.

You will get the people whom will say no its fine or low gas.

But there the sametype of people whom.said the Titanic couldnt sink .

If the maker says you need it then you need it.

Some Japanese cars i have had wouldnt even run without stalling on a low ron fuel.

The ecu (sensor)will reset itself but that doesnt mean its good fuel and not causing any problems.

You won't directly damage your engine running lower grade fuel but you will experience a relatively fast buildup of deposits. That will, in the long run, negate the few dollars you're saving per tankful.

If it is possible to retard the timing on the vehicle that will help but power will suffer and fuel mileage will be so-so, both also negating the savings from using lower-grade fuel.

Bottom line: you're better off using the mid-grade fuel of 91 octane.

your computer will try to stop pinging through readings of the O2 sensor, Acura has a higher piston compression than most and should be run with medium octane ( 89) as a minimum

If you want to save on fuel, don't buy a high compression engine in a sports car. Follow the recommendations of the manufacturer. It will damage things if you don't.

Just put in the regular and add a fuel addative like booster or something - I dont think the 91 Acura will last forever anyways so why mot send it home early...

Buy Premium you with save cash in the long run

don't retard your timming your just asking for trouble the premium may cost a little more but you will actually get better fuel milage with it

you save a few pennies onthe fill up but the damage to the engine will be very costly to repair. reconsider you position.

yes the timming will retard....it will cause lower MPG and lower power...engine was built to run on premium...use it...