87 vs. 93

[tweety2300]

Doing a test on mpg difference between 87 octane and 93. First trip was on 87 runing 75-80 mph on interstate got 29 mpg. On the way back I did 80-90 runing with another car on 93 ecu was reset when I got gas and so far even though I was going faster mpg will either be the same or a tiny bit better. Which do to the speed difference will make it better. Both trips ran ac due to 100+ temps

I'm only doing this to solve the argument between what the mp3 runs better mpg with will update when I find out what my mpg was with 93

 

[destineal]

What?

 

[tweety2300]

Some people say that with the mp3 ecu they get better gas mileage with premium than with regular gas. So I figured I would do an actual test and post the results

 

[Preferio]

What?

 

[Krevzi_mp3]

The MP3 ECU advances the timing so running regular gas is not recommended (although you can if you want but it can cause problems down the road) becuase pre-detination is far more likely to occur with advanced timing because of the properties of regular octane gas. Regular gas can also cause carbon buildup on the top of the piston which can worsen this condition as well as it causes higher compression in the cylinder which is already relatively high in an Mp3 engine. High octane gas is far less likely to pre-detonate (hence the higher octane rating) and is recommended for use in the Mp3. So regardless of the mileage gain (which is probably negligible) I wouldn't recommend running low octane fuel for extended periods of time when using an unmodified Mp3 ECU.

 

[tweety2300]

Umm mp3 motor is a regular fsde same as p5 2.0 protege or msp. When you use regular it knocks timing back when it Detects ping.

Either way results are that premium gas does in fact get better mileage.

I know a lot of people have said that premium and regular make absolutely no difference in power or mileage and I proved it wrong 31mpg on premium runing 80-90 mph on interstate and 29 mpg runing 75-80.

 

[Krevzi_mp3]

Yes I know the motor is the same however the MP3 ECU is alot different from the regular ECU in a Protege. Racing Beat tuned the MP3 differently and if you read any information on the Mp3 almost everywhere it suggests the use of Premium Gas because of the advance timing programmed on the mp3 ECU. That's why the Mp3 has a stock 10hp gain (140hp total) compared to the Regular Protege 2L's 130hp. There really is no huge power benefit from Premium gas, it simply allows for less or no knock in engines that are specifically tuned.

 

[tweety2300]

It's not a specific tune previous owner never ran premium I don't believe it had ever had premium fuel before I got it. It's a manufacturer tune if it detects ping it will automatically retard timing. You should do more of your own research the extra 10 hp also comes from the intake mani and exhaust. I can obviously say runing 87 will not hurt anything regardless of what you say or attempt to prove

 

[destineal]

Mp3 has the same compression as a regular protege. 87 octane will only retard timing and reduce mpg. Having said that, your results are not valid because you didn't run the same speeds with the 87 and 93......and you need more runs

 

[Preferio]

Mp3 has the same compression as a regular protege. 87 octane will only retard timing and reduce mpg. Having said that, your results are not valid because you didn't run the same speeds with the 87 and 93......and you need more runs

No, this is scientific proof that can not be disputed because...

First trip was on 87 runing 75-80 mph on interstate got 29 mpg. On the way back I did 80-90 runing with another car on 93 ecu was reset when I got gas and so far even though I was going faster mpg will either be the same or a tiny bit better. Which do to the speed difference will make it better. Both trips ran ac due to 100+ temps

LOL

 

[tweety2300]

It wasn't an all out scientific test, I just did it to find out for myself and figured I'd be generous enough to share. Obviously I should have just kept the info to myself

 

[cphillips23]

So what would happen if you ran 100 octane?

 

[tweety2300]

It won't advance or change the fuel maps but it will burn cooler and more effectively. You won't notice a difference

 

[cphillips23]

Just in your wallet. LOL

 

[tweety2300]

Just in your wallet. LOL

Right? 93 is $3.53 here, I think 100 at the track is like $6ish

 

[talltim]

I am glad you shared your observations.

 

[destineal]

It wasn't an all out scientific test, I just did it to find out for myself and figured I'd be generous enough to share. Obviously I should have just kept the info to myself

Well I wouldn't say that, but I would be careful of claiming mpg with only 1 run. What if on the way you drove up hill and on the way back you drove down hill? Now I know that's rather simplistic, but just giving an example(I do happen to believe the mp3 ecu would result in better mpg, provided you didn't drive it like you stole it).

 

[tweety2300]

I travled on i64 to and from the beach when I got there I filled it up to check mileage and filled it up again before I left and again when I got back. To make sure city driving wasn't added into the mix

 

[Jasonjames]

The higher the octane figure, the slower the burn. Lower octane fuels burn faster reaching peak cylinder pressure sooner. As you say, less advance for lower octane. In some early stationary engines and 4 stroke mowers, the manufacturer advised against using premium/super fuel, because the short stroke [DUE SMALL CAPACITY] meant the fuel was still burning as it left thru the exhaust valve, often damaging the valve over time.

OTOH, in car engines, higher octane does provide a smoother and longer burn. Because it takes longer to burn, ignition needs to be commenced earlier [iow more advance]. While there may not be much difference in octane between some pump gas, I'd prefer a system where you could dial-in the octane of the petrol so the ECU can set-up an ideal timing curve.

JJ

 

[njaremka]

some of you guys need to do more reasearches.

octane is an additive to gasoline that increases the gasoline's resistance to compression ignition. it makes sure the fuel mixture only ignites when the spark plug fires. it doesn't make it burn slower or faster, cooler or hotter.