87 octane or 93?

Hey ive been told to use 87 octane in my 04 VFR and i have also been told to use 93 octane...what do all of you guys/gals run in your VFRs? Thanks

 

I've run both and see absolutely no difference. The owners manual says 87 so why pay more for 93.

 

i agree...why pay more...ive been running 93 i didnt know that it would run on 87...i guess ima give it a try thanks

 

When it comes to octane, consider a few things first. Load, Altitude, temperature, Compression, and wheather your bike is knocking.

Higher octane fuels are mainly designed for anti-knock that is often associated with higher active compression engines. If you are running 2 up, riding under heavy acceleration, in hot weather or at altitudes above 5k, you may experince pinging or knocking from your valves expericing detonation instead of a burning fuel inside the cylinder. Running 91 or 93 Octane can help elminate that knocking. Other than that, 87 Octane should work well. When I tour, I vary each fill up depending on the next leg of my tour.

Just watch out for cheap fuel that may clog your throttle-body or carbs.

Hope this helps.

 

I put 93 in my first tank on the way home from the dealer because I assumed it was required (and force of habit from my last bike). Then, I went home and read the owners manual and it's been 87 every since - no problems & less $$$...

 

There are some neat articles on octane rating and the potential energy in gasoline. Since the V-4 in the VFR is not tuned with a high compression ratio or aggressive timing the higher octane fuels are not needed, esp on the 6th gen with EFI.

I've never had a knock in the first 11K miles using 87 octane. Note that I've never had her over 4K feet above sea level either.

here's one of the articles I've found interesting and informative
http://www.answers.com/topic/octane-rating-1

this quote from the article explains why some folks put higher octane fuel in their VFR thinking it will help with performance... it doesn't unless you increase the V-4's compression....
It might seem odd that fuels with higher octane ratings explode less easily, yet are popularly thought of as more powerful. The misunderstanding is caused by confusing the ability of the fuel to resist compression detonation as opposed to the ability of the fuel to burn (combustion).

 

Okay, that settles the octane issue, but is there any other additives in premium fuel that will make the engine work better? I don't have the article handy, but I did read a report that said that premium fuels contain additives that may actually plug up valves.

 

Hey Nozzle
This is an interesting topic. There are so many opinions. All seeminigly quite valid. I often use the higher octane. You mention that "Since the V-4 in the VFR is not tuned with a high compression ratio"...... I'm wondering what is "high compression"? I believe the 6th gen is in the order of 11.6:1. Back "in the day" anything over 10:1 was considered a high compression engine and called for "premium" gas. I have a Honda S2000. Compression ratio 11:1. Also an Acura RDX. Compression ratio 8.8:1. Both require high octane fuel. But those are cars. 11.6:1 seems high to me. I think that the "chip" tuning and the research that has gone into these engines allows for the use of lower octanes. Which I find remarkable. I have to agree that if the manufacturer makes a recommendation why not go with it. 87 is good donkey! But that might lead us all to believe that we should go with the manufacturers recomendtions for Oil, Antifreeze, yes even tire pressures. Yikes!!!! Gee do you think they might be on to something.

 

6th gen 11.6:1 with 87 octane ( 98?hp @ ?rpm from 781cc)
BMW K1200S 13:1 with 93 octane ( 167hp @ 10250rpm from 1200cc)
S2K with 11.1:1 with 93 octane (237hp @ 7800rpm from 2,200cc)

don't know the answer, but I'm guessing... combustion chamber shape, valve/cam lobes, and ignition timing. Someone smarter than me can say why.

 

I have about 2500 miles on my ’07 bike now and, as force of habit when I first got the bike, put 91 octane into the tank. After reading a manual, I switched to 87. I noticed a big difference. Under 91 octane (premium in CA), the bike had throttle control problems (hesitation while giving it gas, then a lunging forward). I consistently had the problem at the lower RPMs. I felt overall, the bike had more power but not consistently—either no power or too much, never just right. With 87 octane gas, the hesitation and lurching problems are gone.

I recently put high octane in the tank (again force of habit) and experienced the same problem. So, for me and my riding style I’m using 87 octane fuel.

 

BMW K1200S is a tranverse mounted, inline 4. Yep, 167 ponies at 10250. Compression ration 13:1.

 

yep, my bad. i forgot they put a I4 in that model. right you are pvancle!
the problem you've experienced with your bike, the hesitation, lunging, etc; i've experience the same things. i guess i need to switch to 87 and see what happens. it's always felt like driveline lash, but we'll see how it acts w/ 87 octane. thanks for the info.
cheers,
Jeff

 

I noticed the off- and on-throttle hesitation early on. On my previous ride, ’98 Valkyrie, drive-line lash, hesitation, whatever, is unheard of. On the Valkyrie, there is a lot of engine braking, so it’s important to use the throttle to even out the bike. The throttle respond is silky smooth and linear. I can downshift and late brake into a corner with a modicum of throttle and bike will balance front to rear and fall into the lean. The VFR’s initial hesitation really sapped my confidence. I started re-thinking everything I was doing and was picking up bad habits, such as looking to the turning point of a corner instead of through the corner. I’ve always been faster on the VFR through the corners—but that may have been more a factor of the weight, length, and steering of the Valkyrie.

Switching back and forth between both bikes, I realized it was the throttle response. The lower octane helps, although the VFR cannot match the Valkyrie’s silkness—I’m now more accustom to the VFR’s response. As for the bad habits, I’m starting to shed them again as well as pick up confidence in the twisties.

 

Most modern combustion chambers use what is called a"pent roof" design, and also a lot of what is called "squish area". The squish area is the part of the combustion chamber that is "squished", as in it squishes the air/fuel mixture out into the "working" combustion chamber, for lack of a better way to put it. What this comes down to is that combustion in the modern gasoline engine is very fast and efficient. Add to that microprocessor controlled ignition timing and fuel injection, and there are not nearly as many compromises in place as there used to be.

I always use the highest octane fuel in my bikes because I never know when the mood will strike me to, well, take advantage of the power-to-weight ratio for as long as I can get away with it. High loads for sustained periods make detonation more possible. 87 would probably be fine, but 91 makes me feel better somehow. I'm sure that I would be cited and/or arrested before there was an engine problem, but I guess we're all creatures of habit to some extent. Must be all those air cooled bikes in my past or something..

 

What's the book say, 87. Someone a lot smarter than me figured that out. But consider this. When you go to a service station to buy fuel, which fuel has the most turn-over, 87. So which is normally the freshest, 87. And with the advent of $4.00 a gallon gas I'll be d..... if I'm going to pay another 30 cents a gallon to some oil exec for a few points boost of octane that aint going to make a gnats ass difference. M/O.

 

Like most people i figured motorcycle = 93 octane. After reading this thread i realized my 04 VFR also has that low end throttle hesitation. Where coming out of a really slow turn and starting to accelerate the bike hesitates then lurches forward. (and yes i considered I might be the problem but no matter how smooth I roll on the power it happens). I just thought it was a viffer characteristic. I've run nothing but 93 octane since i bought the bike. So i'm going to try 87 and see if there is a change.

 

Just curious if anyone knows if the FI VFR's have a knock sensor?

One thing I was thinking about is, if the fuel pump has just one hose for all the octane levels, I am getting probably 1/4 gallon or so of whatever grade the previous customer purchased. Not a huge deal when buying 10 or more gallons for a car, but sometimes if just 'topping off' with a gallon or so for the viffer it stinks.

 

I used to run 93 but I read the manual and switched to 87 I have had no problems with it
Porcupine Gas Pumps have an automatic drain back which empties the hose after you shut the pump off. try this before you turn on the pump lift the nozzle and squeeze the trigger and see if any gas comes out.