Just purchased an '04 TL 6 Speed. I have been using 89 octane with no engine pinging. Is there any possible damage from not using 91 octane or greater?

 

try searching all in all, yes there is possible damage to be done! you'll end spending more to fix it in the longer run...unfortunately

 

i would stick with 91, ive tried running a lower octane in mine and my gas mileage was horrible. if you think about it, its only going to be an extra 5 or so bucks to fill up your car

 

The engine has a knock sensor, so running lower octaine gas should not cause damage, but its a waste, as the knock sensor retards the timing, and you get worse MPG and lower power output, and I think in most cases, it costs MORE to run cheap gas, the lower mpg more than makes up for the lower fuel cost.

Now in winter, when the engine has less tendancy to ping because of the cold intake air, you might be able to run mid grade, but not in high heat or high load situations.

The difference in price is minor really, if you want to run regular, you need to get a honda.

Brett

 

In Tampa, price difference is pretty consistently $.20 per gallon. At the $4.00 per gallon level, that amounts to 5% more.

Assume you got 17 mpg using regular. If you only achieved 17.85 mpg using premium, you'd be breaking even. I think realistically you'd pick up more than 1 mpg using premium over regular.

Steve

 

for me it cost more to use the mid grade over the premium...i get about 30-50 more miles from a tank of premium vrs mid....use the premium....

 

great post

 

Steve, I am achieving 25MPG mixed driving but mostly non highway. I got 28 on the only real highway trip I've done.
(heck, I get almost 16 MPG mixed in my Yukon Denali)

All of you have convinced me to go with the 91 octane but I am relieved to know that I can use 89 without causing damage.

Thanks all

 

No one running 87 or 89 has done oil test or boroscope inspection or scanner while driving--- to know if there is any engine damage happening in the long run.
A few tanks in emergency in flat country is no problem-

Just because YOU cant hear the pinging---- doesnt mean its not happening!!!!
If its loud enough to hear from inside the car, you have a serious problem

If you insist on running lower octane than specified- especially the higher compression Type S motors, at least run a GOOD fuel cleaner thru it every 5000 miles, and run brand name gas.
The TL is supposed to get Tier 1 gas brands with their secret sauce- thats most major names in the 91 octane rating (techroline not in 87 chevron- only the 91, shell vpower is only in their 91...
- Shell chevron 76 all are on the list for Tier 1- google for more

 

Thanks 01.

I'll run a bottle of Techron through the old girl and start feeding her the good stuff.

 

Holy cow, you are THE MAN if you get 25mpg out of your TL in 'mixed' driving and 16mpg out of a Denali. Unless your definition of mixed is different than mine.

I get 17-18 out of my '06 TL in pretty much city driving (limited highway) and the best I've gotten highway was 29mpg.

My '00 Explorer (4.0 SOHC) got 16 and 22 respectively - but then it's aerodynamically impaired.

Thanks for the info!
Steve

 

rizz, do this, go 70 MPH on a highway and reset the trip computer, tell us what it tells as the MPG, do not touch the brakes or gas, let the cruise handle it on a flat level road.

 

CS,

I'll can try that but what are we looking to do? Check calibration? I forgot to mention that my calculations were done manually. I didn't check the computer.

 

Basically what this will do is tell us how much MPG the car is getting with the retarded timing due to the 89 octane. since the timing is retarded, the motor has to work harder to keep the same speed in hypothesis, thus resulting in more fuel consumption. I just want to see if I can prove it right with your car, and that way we can determine if 89 is really worth it.

 

my 05'tl consistently gets 24-26 mpg mixed driving and 32-34 mpg on long highway drives...

 

I tried some experiments with chevron premium and regular.
My work commute is 19 miles of 45 mph surface streets with a light about every mile. I get 26 on this commute with premium, 27 with regular, confirmed with 2 tanks of each.
On 2 seperate trips from Tucson to Phoenix a week apart, I ran regular on one and preimum on the other. I got 28 with the regular and 30 with the preimum.

 

that hard start and shaking you get every morning is due to low octane.92 or high only .

 

I find this interesting. I had a '03 V6 VW Passat and it stated "use premium only". When I bought it new, I was told specifically by the dealer Not to use Premium. After I had about 8000 miles on it, it wouldn't start one morning. Got it towed to the dealer. First thing they asked was what kind of gas am I using. I told them I was using regular. They said good, because the VW's have problems when using Premium.

Grant it, that car was only a 180 hp V6 not the 270 hp V6 that I have in the Acura. But I also read on general car forums that using premium was a waste of money unless you are experiencing problems. When I got my 05 TL, it had about 47,000 miles on it. The trip computer showed the previous owner never reset it and had averaged 21 mpg and 24 mph. I reset it and used regular gas for the next 10,000 miles and averaged the exact same results. Very hard to believe that both the mileage and average mph were the same. I reset it again and have averaged about 19 mpg and 22 mph

 

i also use regular in my 05 with no problems. 27 mpg local and 30-33 hwy.