i got my 05 WDP about 2 months ago....ever since then ive been filling her up with 94 octane rating from sunoco...sunoco has 4 grades......but now with rising gas prices, i wonder if it is worth putting 94 from sunoco....all the other major gas companies only have octane grading upto 93....any comments on this??

 

I can't imagine you'll notice a difference between 93 and 94 octane. I use 93 octane exclusively.

 

The answer is NO.

Octane over 91 provides no performance benefit in a mechanically sound engine. Using 87-89 will have only a marginal effect. This is inarguable fact - I have eng'g studies done by Honda on the NSX that lay it out quite clearly.

There have been all sorts of posts on this with all sorts of interesting, even fascinating, anecdotal comments - it makes for fun reading.

What do I use? I use 93 octane because that is what "premium" fuel is rated for where I live; but if 91 were easily available, that is what I would use. One can mix 50/50 87 and 93 and get pretty close, but this becomes a hassle and leads to inaccurate results.

One strong argument that has varying degrees of real-world validity is that mfrs often put more detergent in their premium fuels. Some will be typing that "the Law requires all fuel to have detergents". True, but as they say, Ther Law is "an ass" sometimes. In this case, not only are the amounts of detergent inadequate, but almost never tested and enforced. So one cannot be sure what level of what quality of detergent additives is in one's fuel. Get the picture?

The above are the drivers that motivate me to recommend the use of quality fuel additives, either regularly (a bottle once/month or just before an oil change) or constantly (by titrating an additive that provides info to make titration sensical). There is an "RR Journal" on fuel additives, but here are ones whose chemistry has been analysed and found good or better than good:

• Techron
• Regane
• Red Line SI-1 or SI-2
• Fuel Power 60 (FP60) available from Lube Control in Texas

 

94? you are wasting your money. go with 91 if available.

 

We've only got 91 in Los Angeles...

 

 

As for octane rating...

The gas station I pump 93 at went up from 257.9 to 277.9 in just 5 days. When I looked at the 91 octane grade it was just 2 cents less. I pumped about 12 gallons so I guess if I really needed the 24 cents. I would have went with the 91. The 89 was 10 cents less and the 87 was 20 cents less.

The same thing applies, if I really had to have that 1.20 then I guess I would have went with it. I know sometime it is just a matter of principle...but... I do not want to mess around with the car. I would stick with at least 91. Noticing a difference between 93 and 94. no way... I doubt if you would bewteen 91 and 93

 

I fill up with 94 regularly reason is the TL drives better with 94 as opposed to 91 ... most of you say it doesn't make a difference ... i dont care!

firstly the difference of filling up a tank of 94 vs 91 is about 2 bucks so why stress over it too much ... go buy a hybrid

 

I used to use Ultra94, but now try to use Shell V-Power 93. It's a little cheaper, and the car seems to like it more.

 

I can get higher fuel mileage with Sunoco 94 than any 93 from Sunoco, Shell or Mobil. The problem is that Sunoco isn't as common as Shell or Mobil around here. But I try to wait.

Sunoco 94 sells for the same price as Mobil and Shell 93, usually. So why not? Especially when it gives me better fuel mileage?

 

For all you titration experts and penny pinchers out there, a half tank of 89 and and half tank of 93 gives you a perfect tank of 91 octane!

 

We have for the most part in W Central FL the choice of 3 octane levels - 87, 89, and 93. I use 93 because it's the only one available above the recommended 91 but I have used 91 when I could find it with no discernable difference.

 

You do not have to mix 50/50. See what Road Rage has to say about this at https://acurazine.com/forums/showthr...=fuel+engineer

 

hey thanx for the replies guys....while im getting many good responses, let me ask you this....do you think there's a difference between gas in major companies like sunoco, exxon, mobil, shell and etc......????!!!! probably not, right?

 

check out the fuel truck next time you seeit filling the tanks it may not say sunoco on it. They all buy gas from local refinereries and add there own secret additives and sell it as Exxon or Sunoco. Go with any major gas company and do your own additives as RR suggested

 

Allow me to educate some of you.

First of all, the higher the RON (octane), the LESS volatile the fuel. The lower the RON, the MORE volatile the fuel. In simple terms, lower octane fuels are easier to ignite than higher octane fuels. If you think different, you are wrong.

I've heard people say their car made more power with higher octane fuel. That is not exactly true. The higher octane fuel didn't increase the power output. Most likely more spark timing is what increased the power output. Higher octane fuel allowed the engine to be less knock constrained. All supercharged and turbocharged engines are knock constrained, so they require higher octane fuels. Also high cylinder pressures can keep an engine knock constrined, this can also be caused by high compression ratios.

Moving on, the chemically correct formula for heptane (which is gasoline) is 14.64:1. Some people say, 14.7:1, I'll except that, but it's really 14.64:1. The ideal Air Fuel Ratio (AFR) is then 14.64:1 or 14.64 parts of air to 1 part fuel. Theoretically, this is the air fuel ratio that the computer would try to maintain under cruise conditions. During wide open throttle (WOT), the AFR is richened from STOICH. All engines run rich at WOT (lean would be any AFR numerically higher than 14.64:1).

What determines power output of any gasoline engine is how efficiently it burns fuel. Air is a limiting factor in power production. However if we can get more air packed into the cylinder then it must be met with the proper amount of fuel.

Spark timing is critical to achieving maximum power output. 1 degree of spark advance can be worth as much as 4-5 HP and 8-10 lb.-ft. of torque on a supercharged engine.

By using a higher octane fuel, the engine is less likely to ping or knock. Engineers can dial in more spark and gain more power. It also ensures the engine won't ping when loaded with a locked-up torque converter (5AT only), the air conditioning on and climbing a grade.

So should you use 94 octane in your 2004-2005 Acura TL? No, you can use it, but you are wasting your money. Using more octane won't hurt anything (unless it's leaded fuel with 100+ octane), but using less octane can be bad. Especially if your engine has hypereutectic pistons.

A-Train

 

15 replies and the answer for the questioner is still the same - No.

The usual anecdotes and SOTP comments are not supported by the science.

There are so many variables affecting fuel economy claims that implying that this or that 93 octane delivers more than another is just specious.

I did some actual dynamic measurments of spark mapping with my test equipment using the 93 octane available to me (Shell, BP, it did not matter one bit), as well as a 91 octane mix i created on my own using the techniques others have posted for me (I forgot about that thread - it just hsows hw these Q's have been "asked and answered" innumerable times).

I downloaded the data and anlysed it. I did not see where Honda dialed in more spark when I used 93 octane than when I used 91. I also did not see changes in the fuel trim. So no more spark, no more fuel = no more power, and no magic improvement in fuel economy (and without factoring in the cost of fuel vs the miles delivered, what point is being made anyway?). Unless one believes in voodoo science and thinks there are magical "x-factors" out there (read and understand what Atrain has shared - there are no x-factors - this science is pretty much a lumped sum, constrained model), it will then be obvious that what was stated initially holds:

In a mechanically sound TL, there is no benefit to using 94 Octane Sunoco.