87 octane vs. 93 octane

[rebeltaz83]

the only motor i ran 93 octane in was on my honda trx 450r....... it was recomended for 91, but 91 is not easy to find around here..... i rode that thing hard...... the header pipe was glowing red coming out of the jug for about 8 inches...... asked the dealer about it, they said it was normal for riding that hard...... was basically wot all the time, i only left off to shift.

 

[wildweasel_pt]

I guess I'll jump into this mess too. The lowest octane you can run makes the highest power. The reason is that Octane, a single component in a blend, burns slowly. The higher the percentage of octane, or the higher the octane rating, the more slowly the blend will burn. Burning slowly means that under some circumstances the fuel will still be burning as it exits the cylinder. After it's out of the cylinder and in the exhaust, it has almost zero impact on generating power.

So, you want the fuel to burn fast enough that it finishes burning in the cylinder, but not fast enough to detonate or ping severely. Anything more than that is wasted in the exhaust.

I don't agree. Im no rocket scientist but i don't see diesel burning faster than gasoline. If you say that lower octane fuels detonate with higher energy i do agree but they do not burn faster. Higher octane fuels are more refined and at the same conditions of pressure and temperature do burn quicker, try to light a match on methanol or white spirit and diesel and see for yourself. One thing is also true, higher octane fuels can withstand higher compression when we are talking about controlled ignition sources (plugs) but for diesel engines that rely on controlled detonations we are talking of compression rates of about 1:18, roughly double of a normal gasoline engine. This is laymans reasoning.

 

[HyperPete]

http://www.fisita.com/education/congress/sc06papers/f2006sc40.pdf

 

[Itgoes]

http://www.fisita.com/education/congress/sc06papers/f2006sc40.pdf

OK........... got it now! :wacko: :ummm: LOL!

 

[HyperPete]

OK, so I oversimplified when I said higher octane burns slower. It does, but there are other factors as well. I concede.

 

[Rusty McNeil]

I just did a lot of reading on a bunch of engine building and fuel sites and found that burn rate/speed and octane are not really tied together that closely.

Octane is resistance to DET, but does not necessarily slow burn speed.

These statements were for the myriad race fuels available.

Not sure how it applies to street gas.

 

[Biker Dash]

http://www.fisita.com/education/congress/sc06papers/f2006sc40.pdf

Someone wanna break this down from a Doctorate level to maybe an Associate's Degree level, please.

 

[Rusty McNeil]

Someone wanna break this down from a Doctorate level to maybe an Associate's Degree level, please.

Haha,

I actually did read the while thing!

I felt like a chicken watching a card trick!

 

[ImCannibal]

Someone wanna break this down from a Doctorate level to maybe an Associate's Degree level, please.

From what I gathered, higher octane requires higher compression for the same amount of fuel to detonate and burn in it's entirety. Which means if someone wanted to built an engine to run 13:1 or higher compression, then 93 would be better suited to run because 87 would be more likely to pre-detonate. Which is why turbo engines need to run higher octane fuel because pre-detonation while in full boost is a very real and dangerous possibility. 87 octane requires less compression to detonate in a leaner (stock) configuration for the VMAX, whereas 93 needs a richer condition to produce the same amount of detonation from equivalent compression.
Adding ethanol essentially raises the octane rating of a fuel, creating a "lean" condition on a sub optimal compression rating for the fuel. So especially with fuel containing ethanol, 87 is the more optimal choice for a VMAX engine with stock compression and jets.
But, I could be wrong, I'm a rocket scientist not an engineer or chemist.

 

[rebeltaz83]

http://www.fisita.com/education/congress/sc06papers/f2006sc40.pdf

so that explains it!!!
i'll just keep using 93 seems how i notice a difference in power, throttle response, and a little better mpg...... maybe the stage one jet kit has something to do with it...... unless the PO forgot to tell me about some major engine work he did :rofl_200:

 

[ImCannibal]

so that explains it!!!
i'll just keep using 93 seems how i notice a difference in power, throttle response, and a little better mpg...... maybe the stage one jet kit has something to do with it...... unless the PO forgot to tell me about some major engine work he did :rofl_200:

Judging by the documentation in that PDF, if your jets are big enough, you would need to run a higher octane, otherwise you would be running rich with 87. With 93 and your stage 1 kit that might be the perfect fuel for your compression and jetting together.

 

[jedi-]

http://www.fisita.com/education/congress/sc06papers/f2006sc40.pdf

Looks a tad complicated to me, I'll just keep running on Kerosene with the removed carb chains and filling up every 500k with unbelievable power.

 

[wildweasel_pt]

Looks a tad complicated to me, I'll just keep running on Kerosene with the removed carb chains and filling up every 500k with unbelievable power.

Hey Steve did you install one of these?

 

[Matt427sohc]

http://www.nhra.net/streetlegal/funfacts.html

http://www.ehow.com/list_7612108_tips-easy-horsepower.html

http://www.strokerengine.com/RodStroke.html

http://www.ajdesigner.com/phphorsepower/horsepower_equation_power_to_weight_ratio.php

http://www.mustangandfords.com/how-to/engine/28898-400-hp-302-small-block/


Please feel free to review the above websites since this forum likes to use the internet instead of building their own stuff and have some else teach them. Go back to my original posts and what is said is verified in the above sites. Note I ALREADY KNOW THIS STUFF and a lot. I came here to find pure vmax owner all I have found is smack smack smack smack. I have two questions to ask becsuse frankly if this is what vmax forum has to offer is constant insults with videos and general smack then I will go else where to find pure vmax owners. I know there is probably alot of really really good individuals out there so my post did not ever mention any name other than biker something attempting to do some horse power to weight ratio thing (made me laugh to be honest). I am glad to have done the oil weep post beacuse I originally join to get my question answer. Only one response which I was grateful for at least someone read my post. Another individual post that the fix I did could help him. I am sure it will. As for the rest DISSAPPOINTED. Anyway this is the last post on this subject stock vmax 87 fine. No need to run 92 but just fine if you want too. 110 will make your bike run better but extra heat will come if rode for extented period of time. I suggest blending. Vmax has very lazy time so until you adjust your time you won't see the results (tuning). I can't believe I have to explain every little thing with a video or quoting some internet website but if that is what it takes here then waste of my time I just go to the internet as I just have to find information. I wanted to talk to other vmax owners but if this is what it takes is to be insulting name calling and mocking videos then this site is useless to me and I will tell everyone it is so. Finally I am sorry I did not get to know the wonderful people here who I never got a chance to meet because of the bad taste left in my mouth from all the blah blah blah.

 

[HyperPete]

Wtf???

 

[rebeltaz83]

Judging by the documentation in that PDF, if your jets are big enough, you would need to run a higher octane, otherwise you would be running rich with 87. With 93 and your stage 1 kit that might be the perfect fuel for your compression and jetting together.

i skimmed threw it....... most of looked like chinese, and i wasn't in the mood to read what i did find. but i will bet your right, i was told the stage one was garbage because it makes the bike run richer. it's night and day between 87 and 93..... vboost is almost enough to give you whiplash. i'm gonna stick with 93, may cost more but it's only 4 gallons, it's not like i'm filling the 35 gallon tank on my truck with it.

 

[HyperPete]

I have the stage 1 kit in my 1999. I see absolutely positively ZERO difference between 87 and 93, other than a lighter wallet.

 

[rebeltaz83]

I have the stage 1 kit in my 1999. I see absolutely positively ZERO difference between 87 and 93, other than a lighter wallet.

if i knew of a dyno close to me i'd go get it dynoed with 87 and 93 and post it up, but the closest i know of is about 3 hours away.

 

[alorio1]

I found the information Matt posted very interesting and I know for a fact that higher octane makes more HP if your engine is jetted and tuned for it.....

 

[sdt354]

Hey Matt, how do you keep am idiot in suspense?