50/50 c12 and pump gas

[Brehmmotorsport]

Quick question for anyone running this. Does anyone or will i benefit from running half pump and gas and half c12 or is it better to run just pump. My motor is stock except advanced timing. I was running u4 but when it went to u4.1 I don't seem to be getting the same good results. Let me know what you guys think.

[TYayo420]

nah for your setup you dont need any race gas, its a waste of money less u get a big bore kit high comp piston and so forth, and big bore, 440 or bigger 426 and smaller go pump gas.

[Dill]

Originally posted by TYayo420
nah for your setup you dont need any race gas, its a waste of money less u get a big bore kit high comp piston and so forth, and big bore, 440 or bigger 426 and smaller go pump gas.

+1, run pump fuel.

[JOEX]

Originally posted by TYayo420
nah for your setup you dont need any race gas, its a waste of money less u get a big bore kit high comp piston and so forth, and big bore, 440 or bigger 426 and smaller go pump gas.
Bore size alone has nothing to with what octane is required. Compression ratio along with cooling method and timing will have an effect though.

I'm sure GPracer will be able to clear this up better:)

[Brehmmotorsport]

thanks alot guys if there is a good gas to run let me know for the stock compression.

[Dill]

premium unleaded pump fuel will be fine. Generally the stock compression on the 400ex is low enough you could probably run 87 octane as well without any problem.

[TYayo420]

id recommend 93 octane, its what everyone i know runs int here bikes.

[1965 honda]

400ex stock comp is 9 something and 87 octane will do just fine. but a mix of torco 110 and 92 works really well.

[400exrider707]

Anyone paying any amount of money to run race fuel in their stock 400ex motor is a fool. Plus it will make it harder to start, cause the EX motor needs that doesn't it?

I ran 87 a few times on my 400ex with an 11:1 piston and a thin cometic head gasket. I was running a cam which would aid with the cooling too, but still. The 400ex compression ratios advertised on aftermarket pistons are actually much lower than what they claim.

You are wasting your money running anything other than pump, provided your timing isn't extremely advanced. I'm guessing the sparks timing key? The key will add heat. Anything that advances the timing or raises compression generally will add more heat, heat is what causes detonation. Basically what everyone is saying is run pump. GPracer2500 had a very good article a while back about detonation and pre-ignition. Try searchign for it, it was a great read.

[1965 honda]

i do a lot of riding in sand and i do a lot of sand hill climbs. and i tell you from personal experience, with lower octane you bog down much more and lose speed. with my 101 mix i beat 250rs and every other 400 out there. im at bull gap michigan by the way. where there is a 100 ft stretch of deep sand whoops before you even start to go up the hill. thats where the 101 comes in. no bog just fast. mine starts very easy by the way, higher octane cooler running temp

[400exrider707]

Originally posted by 1965 honda
i do a lot of riding in sand and i do a lot of sand hill climbs. and i tell you from personal experience, with lower octane you bog down much more and lose speed. with my 101 mix i beat 250rs and every other 400 out there. im at bull gap michigan by the way. where there is a 100 ft stretch of deep sand whoops before you even start to go up the hill. thats where the 101 comes in. no bog just fast. mine starts very easy by the way, higher octane cooler running temp


So you beat 400's with just race gas? Thats amazing considering most race fuel doesn't do a thing for power.

If it does cure a bog problem, then you are just masking a jetting problem you are not adding power.

[1965 honda]

come on dude did you not see my mods at the bottom of the post. i also said there is a lot of deep whoops before the hill that will make or break you, and yeah with 87 your in second gear while im in third rippin up the hill. i do this every weekend.

[400exrider707]

Originally posted by 1965 honda
come on dude did you not see my mods at the bottom of the post. i also said there is a lot of deep whoops before the hill that will make or break you, and yeah with 87 your in second gear while im in third rippin up the hill. i do this every weekend.

I read your sig, and you have absolutely no reason to be running race fuel. What the heck is a rev chip? Some new invention? Like I said in my last post, your race fuel is not adding power, you obviously do not have it jetted correctly for pump fuel, and the race fuel could be masking your jetting problem. If you want to spend the extra money on it that is fine with me, yes it will run cooler, but you dont need that extra cooling, your motor is stock according to your sig. You are in fact wasting money on race fuel.

[TYayo420]

yeah dude read the net RACE OR HIGH OCTANE FUEL DOES NOTHINGF FOR POWER!!!! and your machine dont need race fuel either. wastin your money big time, but i guess you can feel like your gettin somethin outta that 8 bucks a gallon lmfao

[1965 honda]

like i said personal experience. on pump gas i will beat a stock 400. my jetting i good but better gas will make it run better . personal experience.

[400exrider707]

Originally posted by TYayo420
yeah dude read the net RACE OR HIGH OCTANE FUEL DOES NOTHINGF FOR POWER!!!! and your machine dont need race fuel either. wastin your money big time, but i guess you can feel like your gettin somethin outta that 8 bucks a gallon lmfao

Not all race fuel. If you buy oxygenated fuel it can add power, but it needs to be jetted accordingly, you cant just dump it in and expect power. Simply adding octane does nothing as far as power goes, but certain blends of fuel can add power, oxy gas is where its at, if you like spending $75 on a 5 gallon pail.

[1965 honda]

Originally posted by TYayo420
yeah dude read the net RACE OR HIGH OCTANE FUEL DOES NOTHINGF FOR POWER!!!! and your machine dont need race fuel either. wastin your money big time, but i guess you can feel like your gettin somethin outta that 8 bucks a gallon lmfao
4.99$ a gallon for 110 torco where i live.

[TYayo420]

your going to beat a stock ex dont matter if he ran pump gas!!! you got a pipe chip of some sort, filter, u vs stock u will win dont matter what gas!

[400exrider707]

Originally posted by 1965 honda
4.99$ a gallon for 110 torco where i live.

Thats not oxy fuel, and you can get race fuel cheaper than $4.99 a gallon. I dont believe torco is even leaded so its definitely a waste of money. Oxy fuel will add power when jetter accordingly.

[TYayo420]

these are your mods from your sig that will enable you to beat a stock ex, even if the stocker has race gas andjetted for it, gas doesnt make speed man its your mods!

2001400ex\yellow\
holeshot xc tires on quad rok rims\
^^better traction
aluminum air box no lid\
^^more air is makin more power its not the gas
k&n air filter\
^^again more air flow weith this filter
1rev chip\
^^whatever this does its better then a stock one
jet kit\
^^better then stock right?
knew chain w\ sprockets I went 1 tooth down on the front\
^^makes for quicker take off

so what im gettin at with these mods, no crap your beating stock ex's on pump gas, yourr going to beat a stock ex on rocket fuel race gas nitro alcohol it doesnt matter what gas they run you have mods to beat a astocker!!!
over sized aluminum oil rezzy \

[1965 honda]

Originally posted by TYayo420
your going to beat a stock ex dont matter if he ran pump gas!!! you got a pipe chip of some sort, filter, u vs stock u will win dont matter what gas!
im not arguing that and im not a fuel expert ethier but from personal experince MY 400 runs faster and better and has more power with half 110 and half 92.

[TYayo420]

its a scientific proven fact it doesnt do crap for speed, the type of gas your running, its all hype in your head.

Like if someone is drunk, you givew them a fake drug, they take it, and think there ****ed up from it, but not, this is the samething you spend more $$$ on gas for no reason u dont need it, (prolly just braggin to friends i gotta run race gas guys hahaha) and think your feeling something that is not there, do a internet search, your claiming something proven many many times.

[1965 honda]

i do a lot of riding in sand and i do a lot of sand hill climbs. and i tell you from personal experience, with lower octane you bog down much more and lose speed. with my 101 mix i beat 250rs and every other 400 out there. im at bull gap michigan by the way. where there is a 100 ft stretch of deep sand whoops before you even start to go up the hill. thats where the 101 comes in. no bog just fast. mine starts very easy by the way, higher octane cooler running temp

read this post again its not in my head when i have it in 3rd vs 2nd. maybe some people are just to cheap to by it

[TYayo420]

http://www.truckblog.com/story-447-fuel_economy_myths_high_octane_boosts_fuel_economy

here holmes, says its a myth doesnt make more power, basically all it does is keep it cooler thats about it, your wasting money you do not need race gas at all get 93, **** if you like wastin cash, get 93 octane pump gas, and add octane booster make ya htink your running freakin nitrous.

[TYayo420]

dude, i race TT, i still dont need it, my **** dont bog out, mayeb your carb is bunk? your jetting must be out of whack, youd o nto need it your thinking something dumb get re jetted and you will be like there right your wastin your money your wasting race gas too.

[1965 honda]

i tried a couple of octane boosters and it didnt feel the same.

[TYayo420]

http://www.factorypro.com/tech_tuning_procedures/tuning_fuel_octane_vs_power.html

bust out the glasses, the more you argue its giving you more powert the more articles i got for you

[TYayo420]

Originally posted by 1965 honda
i tried a couple of octane boosters and it didnt feel the same.


yes!!! it's all in your head man, seriously, your thinking i paid 5 a gallon for this crap, so this is doin something its not you have no need for it it will not do a damn thing for your quad, this is a scientific proven fact! wehy dont you be a scientist if your so sure your right?s seriously this has been beat to deatjh on thumpertalk.com too race gas will not add power does not will not and never will, you dont have the right engine work to even need to think abt race gas, most racers i race with run pump too you dont need it unless you have high compression or a big bore, not a 426 or smaller, them are small bores, 440 n up you need race gas with a high comp piston, you have neither.

[1965 honda]

Originally posted by TYayo420
dude, i race TT, i still dont need it, my **** dont bog out, mayeb your carb is bunk? your jetting must be out of whack, youd o nto need it your thinking something dumb get re jetted and you will be like there right your wastin your money your wasting race gas too.

i just bought a 450 carb but i havnt installed it yet. i pretty sure mines good though. when i first bought my 400 in 2001 ihad it piped and jetted by a very credible performce shop. but that was 2001 maybe somethins are out wack alittle. but it still runs good on pump but it'll run better on 101.

[TYayo420]

who the hell runs 87 int here quad anyways? no one i know for as little it takes to fill ur qwaud and good as they are on gas, spend the 20 cents more get 93, if you ran 93 you wouldnt notice theres no race gas in there. id like to take ur quad, put pump 93 in it, then race gas, not tell you when what is in it, do it 10 times with ea gas in it 5 times, see how many times you feel your big investment helps, bet ya will just guess n not be right when ya guess, cuz wont do crap

[Dill]

let him waste his money guys, all you can do is provide the facts and let them make up their own mind.

[TYayo420]

hmm well i never heard of 101, aorund here it s 87 89 91 93, then race gasses of 110 n up, if i could get higher octane pump gas id try it, but i dont believe this but each to there own.

[1965 honda]

what i do is mix 110 with 92

[1965 honda]

Originally posted by TYayo420
http://www.factorypro.com/tech_tuning_procedures/tuning_fuel_octane_vs_power.html

bust out the glasses, the more you argue its giving you more powert the more articles i got for you

i read the artical from that link, they talk about higher octane giving you more power. but its not always appropriate. i under stand that. hey maybe i have a carb problem because there is no mistaking the power gain i feel.

[TYayo420]

Originally posted by 1965 honda
i read the artical from that link, they talk about higher octane giving you more power. but its not always appropriate. i under stand that. hey maybe i have a carb problem because there is no mistaking the power gain i feel.

if what? your engine is knocking.

[1965 honda]

that seemed to be there answer for using it.

look im not trying to argue ok. if im not runnig my 101 mix, im running shell v power gas 92 or93 octane. it dose run good dont get me wrong here, but 101 runs better. i may have carb problem im not sure. my 400 is in the shop getting a new piston , stage 2 cam, and rejet. when its done ill keep an open mind on runnin the 101 vs 93

[TYayo420]

tell ya what, ill get some red gas 110, miux 2 gallons of that n 93 see what happens, if im wrong id be surprised, i dont think ill see a diff. maybe more backfiring or somethin haha well i gotta re jet but ill try this

[underpowered]

plain and simple race fuel will NOT give you more power.

your quad bogs when you run pump because of jettin, not fuel. race fuel will require different jetting than pump. if you jetted your bike for pump gas, it would run just as good as it does on your mix.

re jet your bike, and it will run just fine on pump fuel. differnt fuels require different jetting. the klotz i run will cause a rich condition, but the stuff i get at the drag strip leans out my jetting. i am guessing yorus is causing a lean condition, which is why it runs better and "bogs" on pump.

personal experience or not, the power gains are all in your head. race fuel is worthless unless you truely need to run it due to higher comp. ratio's

[1965 honda]

Originally posted by TYayo420
tell ya what, ill get some red gas 110, miux 2 gallons of that n 93 see what happens, if im wrong id be surprised, i dont think ill see a diff. maybe more backfiring or somethin haha well i gotta re jet but ill try this
try it befor your re jet if you could, and please just let me know

[TYayo420]

alright i will, but i think my theaory is right, but i have som race fuel in the garage i can use up to try this, but i read alot on racew fuels and they say they dont add more power, its just theory but scientifically proven it dont do anything for stock motors.

[1965 honda]

when i do run pump gas the v power shell is the best for me. what would make shell better?

[TYayo420]

idk...i go to a mobile or a sunoco station when i get my pump 93 octane

[400exrider707]

Octane booster is more of a waste of money than race fuel. It barely increases your octane rating one point, and it has a bunch of garbage additives.;)

[1965 honda]

Originally posted by 400exrider707
Octane booster is more of a waste of money than race fuel. It barely increases your octane rating one point, and it has a bunch of garbage additives.;)

ive heard that before, klotz makes 2 diffrent kinds could anyone tell me the diffrences?

[TYayo420]

Originally posted by 400exrider707
Octane booster is more of a waste of money than race fuel. It barely increases your octane rating one point, and it has a bunch of garbage additives.;)

i was being sarcastic.

pretty much sayin there as much a waste of money as race gas, in MOST instances.

[1965 honda]

what im saying is i know booster is junk ive read that on a lot diffrent fourms. but whats the diffrence between the 2? just 4 shxts and giggles id like to know

[GPracer2500]

[Yikes!--I hope this isn't soo long that it's not really useful]

I was planning on staying out of this thread (really, I swear!). There's a thing or two I wanted to mention--but I didn't want a lack of comment about other points to be taken as an endorsement of those ideas. So anyway, I'll try and touch on a few things. But before I do, here's my bottom line regading the OP's original question:

For a stock piston'd 400EX, in my opinion premium pump fuel is the most appropriate choice for most people. Making sure the jetting is as correct as it can be is likely to yield a greater benefit then switching fuels. And if you DID want to explore what benefits there might be from running a different fuel, the best way to do it is to get on a dyno (with an air/fuel meter). Making runs for speed-over-time can reveal differences in "eagerness to rev" created by different fuels that won't show on a power graph. One builder that hangs around these parts is fond of the phrase: If two engines make the same power, the one that does it first will win the race.

If you're particularly good at jetting and particularly good at using techniques that will discern small changes in performance, then you might have success in testing without a dyno. But if you fall into that catagory then you probably wouldn't be asking the question.

There CAN be benefits to running racing gasolines that have nothing to do with octane rating or HP levels. But unless you're racing, my experience has been it's too hard to realize those benefits--especially when you consider the additional cost and inconvenience.

Your advanced timing will increase your engine's required octane rating, so be sure to use the highest octane pump fuel available in your area. If you experience any engine knock or pinging (the audible signals that detonation is occuring) then the discussion changes because you'll be beyond what pump gas will accomidate. Deto is most likely to happen under very high engine loads (like climbing a long, steep hill), wide open throttle, lower to middle RPM, when the engine is very hot, and when the air is very hot. Look for deto under those conditions.





OK, so now that's out of the way....

Fuel choice can be made fairly simple as long as you, well--ummm, keep it simple. ;) In other words, pick a fuel that satisfies the minimum octane requirement for your engine and call it a day. But don't forget that requirement can vary depending on riding conditions. For example: high engine loads, low elevations, low humidity, and high temperature will increase the octane requirement of an engine. Many sand dune riding areas are a "perfect storm" so to speak for conditions that favor detonation (deto being the thing--the ONLY thing--octane rating is concerned with). Just because your engine does fine on the pump fuel available in your area and in your riding conditions doesn't mean that will hold true for someone else with the exact same engine. I could get my old 10.5:1 406cc to audibly knock (signaling deto is taking place) on pump gas even though everybody and their brother swears 11:1 and lower is fine on pump gas. So just keep in mind that what has proven to work for you may not work the same for someone else.


Originally posted by JOEX
Bore size alone has nothing to with what octane is required....
Within the context of a specific engine (the 400EX in this case) this is "true" at a practical level. But bore size does in fact have an influence on an engine's minimum required octane. The larger the bore size the greater the octane requirement. This has to do with the amount of time it takes the expanding flame front of normal combustion to reach the outer edges of the combustion chamber. The larger the bore the longer this takes. The more time the a/f mixture around the edges of the combustion chamber has to sit there and wait before being consumed the more time pre-flame reactions have to go to work on the molecules and break them down into the highly unstable chemicals that will auto-ignite (i.e. deto).

This matters if you're comparing--say--a CR250 with a CR500. But on a 400EX the difference of a few mm in bore size is mostly lost among other, more significant factors. I can envision how an 85mm bore (stock) that just barely gets by deto-free with fuel X might start to have issues with an 89mm bore (all else being equal). But it would just be one fairly small factor among many, more significant factors.


Originally posted by 400exrider707
Anyone paying any amount of money to run race fuel in their stock 400ex motor is a fool....
That's a bold statement. How many different racing fuels have you tested? And who are you to say how much I should value the various benefits that may be afforded by running a racing fuel? Jetting consistency alone could be reason enough for some.


Originally posted by 400exrider707
....Plus it will make it harder to start....
Well, that depends on the front-end volitility specifications and vapor-liquid ratio of the two fuels being compared. Those characteristics can vary significanty from one gasoline to the next.

400exrider707, I'm picking on you a bit to make a point. Racing fuels CAN NOT and SHOULD NOT all be lumped together. There is a staggering selection of racing fuels available. I think VP alone produces over 60 different fuels. They're all different (and I'm pretty sure you already know that). You can subdivide racing fuels into oxy fuel, leaded fuel, and unleaded fuel--but there is still a huge variety available within each of those divisions. Different make-ups = different performance.

And don't forget folks, octane rating is only one of MANY specifications that distiguishes one fuel from another. Octane rating is the one we tend to focus on (and it's very important) but you can have two fuels with identical octane ratings that are otherwise very, very different.



Originally posted by TYayo420
yeah dude read the net RACE OR HIGH OCTANE FUEL DOES NOTHINGF FOR POWER!!!! and your machine dont need race fuel either. wastin your money big time, but i guess you can feel like your gettin somethin outta that 8 bucks a gallon lmfao....

its a scientific proven fact it doesnt do crap for speed, the type of gas your running, its all hype in your head....

http://www.truckblog.com/story-447-fuel_economy_myths_high_octane_boosts_fuel_economy
here holmes, says its a myth doesnt make more power, basically all it does is keep it cooler thats about it, your wasting money you do not need race gas at all get 93, **** if you like wastin cash, get 93 octane pump gas, and add octane booster make ya htink your running freakin nitrous....

http://www.factorypro.com/tech_tuning_procedures/tuning_fuel_octane_vs_power.html

bust out the glasses, the more you argue its giving you more powert the more articles i got for you
I learned a long time ago how deeply misunderstood gasoline and combustion phenomenon really are. I could find countless examples across the Internet of well intentioned folks who get it all wrong. Anymore, when I'm reaserching these topics if the info I'm reading isn't cited, I move on (with rare exceptions--there are a few specific authors I trust). Just recently, on another board, someone posted a link to an article that was an magazine interview with the president of a small race gas company. Should be credible, right? Wrong. The suposed "expert" on gasoline made several statements which were flat out wrong! He may have been the president of a petrochemical company and he may have had all the right vocabulary to put on a good show--but he was obviously not the same person who is actually designing gasoline. Actually, I don't think anyone at that company designs gasoline--I'm pretty sure they just sell re-badged fuel designed and manufactured by someone else. The fella wasn't completely full of it, but if I can spot things incorrect about what he's saying what else is incorrect that I don't already know about. If anyone is interested in reading that artical and my comments, I can give you a link. It's a great example of a source that just oozes credibility yet still manages to spread misinformation.

It's far worse to think you've got answers when you really don't then it is to know you didn't really have them in the first place.


The article from Truckblog.com? I got two sentences into the second paragraph and read the term "pre-detonation" and the alarm bells started ringing. "Pre-detonation" is a nonsense word that is a confused combination of the terms "detonation" and "pre-ignition". Those are two seperate and distinct phenomenon. The author really meant to just say "detonation" but obviously doesn't really know much about it.

It's just another example of someone trying to regurgitate information and screwing up the details in the process. He starts out by saying, "...Can adding higher fuel grades to your vehicle improve overall fuel economy? Lets find out!". And ends by basically saying, follow your manufactures' recommendation and stay away from discount fuels. BRILLIANT! For a second I thought maybe I was going to get an actual test of different grades of fuel run through a truck while carefully measuring MPG....but who needs that when the author wows us with techno-speak like "pre-detonation". :ermm: [note: I mostly agree with the final conclusion, but it sure isn't because of the well executed argument that led to it.]

And the FactoryPro article? Some things are right. Some things aren't. I was encouraged when the first thing I read is, "There IS a difference in fuels, aside from Octane Rating." Then I clicked on Octane Rating for the explination of this measurment and to my dismay found half-truths! "...The RON is determined by chemists, and the MON is (or at least was) determined by running the fuel in a standardized engine with an adjustable compression ratio...". They got the MON part right. But RON is measured on the exact same test equipment--just using different testing stadards. The notion that RON is a calculation determined by chemists on a piece of paper is hogwash. MON uses the ASTM D2700 test method, RON uses the ASTM D2699 test method.

Again, if they got that bit of info wrong, what other "facts" have they got wrong. Seriously, I can't put much stock into that information--as much as I may want to--because I can't trust the source. Some of it IS right (and I know this because of corroborating evidence from eleswhere) but what about the rest?


My point in attacking those links is: BE VERY CAREFULL about what information you take as "fact" about gasoline and combustion. There is more bad info out there than good. Please trust me--I've poured through more of it than I'd care to admit. And I've learned the hard way not to assume that what I'm reading is correct just because someone took the time to write it down.


Originally posted by TYayo420
...it will not do a damn thing for your quad, this is a scientific proven fact! wehy dont you be a scientist if your so sure your right?s seriously this has been beat to deatjh on thumpertalk.com too race gas will not add power does not will not and never will, you dont have the right engine work to even need to think abt race gas, most racers i race with run pump too you dont need it unless you have high compression or a big bore, not a 426 or smaller, them are small bores, 440 n up you need race gas with a high comp piston, you have neither.

So where is all this scientific fact? Show me. Give me the links to the PDF docs of the university level research, OR ANYTHING that is CITED and/or peer reviewed which shows....wait--what is it you're saying exactly? I'm not even sure.

Are you saying octane rating beyond what the engine requires is wasted? That IS true. But what about all the other characteristics that make one fuel different from another? Where's all your "facts" about those things and how the impact performance? Remember, race gas isn't just about octane rating.

Thumpertalk? I've got over 1000 posts over there and am quite familiar with the fuel discussions that go on. Anymore, I'll I try and do is point people in the right direction about where they can learn for themselves about gasoline and combustion phenomenon. They same old ideas are so frequently reinforced I can't begin to make a dent (ok, maybe a really small dent). If you're counting on Thumpertalk to set you straight, think again.


Originally posted by 1965 honda
what im saying is i know booster is junk ive read that on a lot diffrent fourms. but whats the diffrence between the 2? just 4 shxts and giggles id like to know

One contains lead and one dosen't. Most octane boosters are junk. There are exceptions though. Anything that actually contains a significant amount of TEL is likely to raise octane by a meaningful amount.

[400exrider707]

Originally posted by GPracer2500



That's a bold statement. How many different racing fuels have you tested? And who are you to say how much I should value the various benefits that may be afforded by running a racing fuel? Jetting consistency alone could be reason enough for some.



400exrider707, I'm picking on you a bit to make a point. Racing fuels CAN NOT and SHOULD NOT all be lumped together.


I agree it was a bold statement and I stand by it, though you are correct I really cant say what it is worth to someone else, but for the mass population and the kids on here who dont know what a jet looks like, they are the ones the statement was aimed at, my bad, I should have been more specific.

Pick on me all you want, it's ok, I'd rather learn something anyday than not be picked on. Yes race fuels should not be lumped together but far to often they are.

I would like the link with the comments and the article please!


All I can picture right now is waynes world when wayne and garth meet alice cooper and bow down... "We're not worthy"

Thanks for the "brief" discussion, great info as usual.

[JOEX]

Thanks GPracer:) :cool:

[1965 honda]

thank you GPracer2500 you helped me out here 400exrider707 and TYayo420 have been beaten my a-- all day.

[TYayo420]

haha sorry for that, im not book smaret like gpracer in the quad field but i know certain things, but cant explain in details liek him.

[JOEX]

Originally posted by 1965 honda
thank you GPracer2500 you helped me out here 400exrider707 and TYayo420 have been beaten my a-- all day.
I'm glad you were able to keep a level head through out this:) Too many people get overly defensive in discussions like this;)

[exrider49]

race gas just burns cleaner with a higher octane, u wont feel more power w/o more motor mods but atleast u moto will be burnin cleaner

[Valhalla]

Originally posted by exrider49
race gas just burns cleaner with a higher octane, u wont feel more power w/o more motor mods but atleast u moto will be burnin cleaner

race gas actually doesnt burn clean at all. me being a sportbike junkie and having ALOT of time on and around racetracks, knows a little about race gas. race gas, when used often without tearing down your motor for inspections and cleaning will harm your internal seals and actually cause your valves to freeze in place. it creates a residue when it burns that doesnt completely leave when the burnt fuel mixture is expelled. to occasionally run race gas is fine because of the regular pump gas thats used between cycles thats helping clean it out.

one thing ALOT of you are missing in this thread. just because its "race gas" doesnt mean its high octane. race specific gasoline is not only oxygenated, but also has many other additives in it to help your engine make power. it comes on all octane levels and is most commonly used in the 93-100 octane range on race motors. but is also made in the 85-90 octane range for stock compression motors who want a small edge on the competition.

as for "high octane", if your engine doesnt have the compression needed for it. you will actually lose power. you should always run the minimum of what the motor was designed to run on for the most power from your motor. all octane is, is the gasolines resistance to pre-ignition. you dont want it going bang before your spark plug fires. if youre buying 100+ octane gas in either race or pump form and youre not running a high compression purpose built motor, you are wasting your money and making yourself look like a total idiot to those who know what they are talking about.

[GPracer2500]

I've got a few sperate issues with that ^ but the only thing I feel like saying about it at the moment is VP Racing Fuels claims: 10 years ago 75% of their customers were buying C12. Today, with VP's current selection of many dozens of fuels, that's down to 50%. But that's still by far their most popular fuel. And C12 is NOT oxygenated. And it's octane rating is 108 MON.

Obviously, I'm not saying that everyone in every powesport arena is using VP products (or C12). But to say all "race fuels" are oxygneated is way off-base.

OK, one more thing: octane rating is a measure of resistance to detonation, not pre-ignition. They are two separate thngs (and neither is involoved in the normal burn of a/f mixture). You're right that you don't want any combustion before the spark plug fires (pre-ignition) but deto actually happens after the spark plug fires.

[Valhalla]

and im willing to be that 60% at least of their customers are pro race teams.

[Valhalla]

http://science.howstuffworks.com/gasoline3.htm


heres something you may want to read about octane and pre-ignition/knock. detination and pre-ignition are the same thing. it happens when the gas ignites under compression and not from the spark at the top of the compression stroke.

[GPracer2500]

Originally posted by Valhalla
http://science.howstuffworks.com/gasoline3.htm


heres something you may want to read about octane and pre-ignition/knock. detination and pre-ignition are the same thing. it happens when the gas ignites under compression and not from the spark at the top of the compression stroke.

Please believe me--I've done my homework on this stuff. Deto and pre-ignition are not the same thing. RUN away from any source that tells you they are. If you choose not to believe me, do some reasearch that's more indepth than that ^ and you'll discover it for yourself. I encourage you to do some more indepth research either way.

That "How Stuff Works" article doesn't even mention pre-ignition. And the explination of detonation is so simplistic as to be misleading. I can see how after reading that one could think: ok, I see--if there's too much compression from a high compression ratio then the fuel will ignite before the plug has a chance to do it and therefore deto = pre-ignition.

But if that's what you walk away with, you've been mislead. I can forgive "How Stuff Works"--I guess--because the average person pumping gas in their car doesn't want or need to know the details. But if you're going to give out advice about gasoline to powersport enthusiasts then I'd think you should know the details.

Pre-ignition is when a hot spot (glowing carbon or metal) ignites the a/f mix before the spark plug's normal firing does. It is extremely destructive and can destroy an engine in less than a second (literally). Thankfull it's not very common, far far less common then detonation.

Detonation is harder to explain in one short paragraph. Undersand that detonation is a type of combustion. Deflagration = burn and this is the normal type of combustion our engines use. Detonation = explode and it does not occur at all in a gasoline engine that is operating normally. We want our a/f mixtures to deflagrate not detonate.

Here's how detonation happens: The plug fires and the mixture starts burning near the plug, spreading outward toward the cylinder walls. This doesn't happen instantly--it takes time for the flame front to spread out. The mixture out around the edges of the combustion chamber has to sit there and wait for the flame front to get there before it can be consumed. While it's waiting it is being subjected to ever increasing heat and pressure.

What happens is that when gasoline is subjected to extremes of heat and pressure it can begin to chemically break down into NEW chemicals. These processes are called pre-flame reactions. They're called that because they happen prior to any flame being directly involoved in the reactions. Heat and pressure is what is directly involved--heat and pressure being created by burning fuel found elsewhere in the combustion chamber. Many of the chemicals created through pre-flame reactions are so unstable they will ignite all by themselves. That is detonation--when gasoline is broken down into chemicals that will ignite all by themselves.

Only after the plug fires is there enough heat and pressure anywhere in the combustion chamber for those pre-flame reactions to take over. For the a/f mixture that resides around the edges of the combustion chamber it's basically a race for which will happen first: the advancing flame front started by the plug gets there to deflagrate the mixture OR pre-flame reactions take over and detonate the mixture first.