What's going on guys? Just bought my first TL ('05 w/ 70k) about 4 months ago after owning multiple Accords. What a difference! However, the real reason I am posting here today has to do with fuel octane. Since the day I purchsed the car 4 months ago, I have never been able to break the 29mpg (always run 93) mark on long road trips for some reason (yes, I even try doing 70 mph). I just drove to Dallas from Houston last Wed. and again got 29mpg and arrived with a little over 1/4 tank left over. Ran it to empty through the weekend, then filled up with 87 before heading back to Houston. Halfway through the trip and when I arrived home, I was getting 32 mpg and had exactly half a tank left over when I pulled into the garage. To me, that just seems EXTREMELY odd and was hoping someone on here might be able to shed a little light on the subject.

 

needs more testing!
post up your average MPH and average MPG found in the MID.

P.s. Im in houston.

 

Appreciate the quick reply! On the Dallas trip, my average MPH was 78 and MPG were 29 on the trip up running 93. On the way back, MPH was still 78 and MPG were 32.

 

very weird. not sure what to say about this.

 

Welcome aboard!

Moving to the TL section so you can connect with other owners who may have some additional insight...

 

hmm,...interesting. I consistently get 32-33mph whether im driving East ( downhill ) or West ( up hill )

Do you know if previous owner kept up with maintenance? Spark Plugs, air filter, etc...?

 

Whatever the difference, it was probably in spite of the lower octane rating, not because of it.

 

Observe the Speed Limit
(New Information)


While each vehicle reaches its optimal fuel economy at a different speed (or range of speeds), gas mileage usually decreases rapidly at speeds above 50 mph.
You can assume that each 5 mph you drive over 50 mph is like paying an additional $0.27 per gallon for gas.
Observing the speed limit is also safer.

Fuel Economy Benefit:7–14%Equivalent Gasoline Savings:$0.27–$0.54/gallon

http://www.fueleconomy.gov/feg/drivehabits.shtml




However I agree with nspec and justin need some more test

 

Thanks! I facepalmed this morning when I realized I could have posted it in there.

 

I am assuming the previous owner kept up with maintenance. They were the original owner and actually bought it brand new at the dealer that I purchased it from. There were multiple pages missing from the maintenance log, had an interstate battery installed and had the factory antifreeze in it. It's beyond me at this point. Either way, I'll be running 93 after this tank anyways. Probably revert to 87 89 on long road trips.

 

Thanks for the info Evil. However, I'm in Texas, so our highway speed limit is 75. I usually keep it between 75-80 and always use my cruise control. Hell, I even use cruise control on some city streets.

 

I'd guess the difference would have to be attributed mostly to wind. (Yes, Houston is about 300 ft lower in elevation than Dallas, making the net altitude difference 600ft, but I seriously doubt it makes a measurable difference. Maybe not, dunno).

Just curious, was the 87 gas an ethanol blend?

For me, I'd be happy to get 29 MPG at 78 MPH. I usually avg 68MPH and get 30-32 MPG. Personally, I'd be hard pressed to expect 30 MPG at 78 MPH.

 

Do yourself a favor, stay away from 87 or 89 octane, those days are long gone, read the gas cap if it says 93 which im sure it does use 93 period, your only hurting yourself using anything else, use top teir gas also shell, bp, chevron.. you should do a seafoam treatment also see how your mpg look after that has been done just my 2 cents..

 

I figure every 5 mph I have to drive under 80mph is like getting kicked in the junk once. $0.27 or a kick to the junk...

 

I'd uch rather pay $.27 than get kicked in the junk... Or even keep it under 80 on the open highway at that.

 

Yes, it is an ethanol blend. I wasn't aware you could get a non-ethanol blend anymore... And I have always ran 93, just switched to the 87 for the ride home to see what happened. I'll continue to run 93 from here on out. It's just hard to justify not using 87 on my next 300+ mile trip.

 

Sorry NFN, that last part was meant for Kidhova...

 

91 is the min. I don't know why anyone would put anything less than what is instructed by Acura.

My sister did this to her Acura and her engine began misbehaving. It's printed on the gas cap for a reason.

 

Have you calculated the MPG by yourself before? I do mine using the Acar app in Android and consistently see the MID is 1-1.5 mpg higher than my actual.

I just write everything down on the receipt and plug it in when I get home. My Dad started me on this with my first car with a notepad and I took it high-tech with the app, but I have just stuck with it ever since. It's kinda OCD, but interesting to see the patterns that develop.

 

I'm driving from San Antonio to Houston this weekend and I'm going to dare try 87 cause I'm insanely bored.

 

wouldnt 87 make our car run weird?....or even mess it up?

on my 2nd gen TL i once PUMP* regular at a random gas station...i press supreme but i found out the next day..when my car check engine light and all kinds of crazy light was on also the lost of power in my car wouldnt rev up to vtec...i went to diagnose the problem..and they said it was the gas in my car...cause i had pump regular in my TL... yea they put regular gas in the supreme slot...

anyways same thing happen to my ML 430...when i first had it i pump regular...i didnt know that car took supreme only..it did the same thing to me like my 2nd gen...

now i have a 3rd gen TL...i have yet to pump 87 in it...i dont wanna have that scary feeling when im driving when my car just doesnt feel like its supposed to be...

 

I just drove from Wichita to San Antonio and averaged 29 MPGs, on 91 octane gas.

In San Antonio I filled up with 93 octane, and filled up once more in Dallas. Averaged 33 MPGs all they back to Kansas.

I don't want to say a difference of 2 octane would have that much effect, but its just what I noticed.

Speed was between 70 and 75 mph. 80mph on the dallas tollway.

 

Good idea Silver, I might give that a try.

 

I'm not completely sure that your issue wasn't directly a result of bad gas. Or perhaps the older engines were a little different. 87 will not "hurt" your engine short term, although there will be some slight performance deficiencies. Long term effects however, are a different story.

 

Please let us know what your findings are.

 

Welcome 40acres (assume that's a UT campus reference? if so, Hook'Em!).

This is strange because the lower octane would retard your timing to prevent knock so I'd expect gas mileage to get worse. Now if you never gunned it or redlined it, then the computer may not have sensed any ignition knock to respond to.

But I do know that there's often a hell of a tail wind going north from the gulf. This is why most flights at DFW land and take off to the south. Maybe that helped?

 

Hook 'Em indeed my man. I was pretty excited about the 32 mpg heading home from Dallas. Seemed to be the only thing to be excited about that weekend aside from the fried bacon and turkey legs. However, you did make a good point. I never did get on it. I noticed a slight hesitation (I'm sure because of the 87) so I decided to lay off of her.