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Having my bike tuned this Sat.
Hey guys. Sat I'm going to Lake Charles, La to Third Coast Speed to have my bike tuned. They're a very reputable shop and I know several people who have had their bikes tuned by them. But here's the thing... I talked to him about tuning it on race gas. (I'm stock motor, no spray) He said that I didn't need race gas and that I would actually make more power on pump 87. Does this make sense to anybody? If so, please explain that to me. If not, should I just tell him to tune it both ways and see what makes more power?
 

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yes your bike will make more power with 87 pump bc its burns faster. ive seen 2-3 hp on the dyno same bike with 87 vs 93. now if you got deep pockets you will make more power with oxygenated race gas but will need to retune and drain gas after or it will eat your pump up.
 

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I don't get it!


Is it only my bike that has a sticker that tells me to use 90 octane or higher gas only?


Ooops! Perhaps you are talking something other than the Gen4, ignore me, I'll get my coat!

Rob
 

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Discussion Starter #4
That's pretty wild! So I guess I would just run 87 all the time after I get it tuned, huh?
 

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While they are right, they are still leaving a fairly important part out. 87 will make more power because it burns faster/easier/at a slightly lower temperature, however, that's only of you don experience detonation. The high compression ratios of these bikes create high internal cylinder temperatures. Compressing air and fuel causes them to heat up just by the nature of the beast. And with high CR's and low octane fuel, it sometimes gets too hot, and the fuel burns before TDC, before the spark plug fires. Pretty bad for just about all your motor's internals. So if you can run it with no pinging, you will make more power. Sometimes you can even run it seemingly with no problems, but then when you start to really hammer on it a lot, that's when it start to detonate.


Sent from my Motorcycle iPhone app
 

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If I recall correctly you're running a stock motor and looking for low 9s/high 8s, in which case 87 is going to yield the most power when compared to premium pump and in most cases 100+ octane NON-oxygenated race fuel. I've ran 87 in my gen3 w a thin HG and decked head w no detonation issues.

However, if you want to get the most power out of it, get yourself some MR12 oxygenated/leaded race fuel. Will put down a lot more power than any pump fuel.

That being said, it is kind of a pain. You'll want a map switch for a second map if you street ride so you can switch back to a pump gas map. And as previously stated, mr12 needs to be drained after racing or it'll eat apart your fuel system. Also very pricey at around $125 per 5 gal can on average.
 

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However, if you want to get the most power out of it, get yourself some MR12 oxygenated/leaded race fuel. Will put down a lot more power than any pump fuel.

That being said, it is kind of a pain. You'll want a map switch for a second map if you street ride so you can switch back to a pump gas map. And as previously stated, mr12 needs to be drained after racing or it'll eat apart your fuel system. Also very pricey at around $125 per 5 gal can on average.
What method do you use to drain the fuel out of the tank at the end of a race day if you are using a fuel like this?
 

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You can pour VP's U4.4 race fuel into a stock motor, without dyno'ing specifically for it...and get some HP gains. You will gain more if you tune for it, but you don't HAVE to. I race with people all the time who pour U4.4 into their stock bikes.

MR12 will get you more HP, but it is currently around $135 for 5gal (U4.4 is around $75-ish for 5gal).

As far as draining it, it is pretty easy. You don't have to do it IMMEDIATELY. If i am doing back to back weekends, i won't worry about it. But if the bike is going to sit for longer, then i get it out.

I use a siphon (one with a small, 1/4" ID hose with a weight of some sort on it so it can reach the bottom) and get out all i can. Then i pour some pump gas in there and let it run till i can't smell race fuel coming out of the exhaust. Then i will let it run for a few more minutes and it is good.
 

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I have heard 87 will make more power and some guys have had good luck with it. However not all knock is audible so just because it sounds like it's running fine doesn't mean it is. I'd rather play it on the safe side and run premium.
 

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I have heard 87 will make more power and some guys have had good luck with it. However not all knock is audible so just because it sounds like it's running fine doesn't mean it is. I'd rather play it on the safe side and run premium.

You can play it safe if you want but famous racers like Rickey Gadson and some fast riders on this site use 87 all the time...and I do sometimes too :lol:

bottom line do a search it depends on conditions like air temp and mods but works good for many :heyyou::cool::wink:

bloo
 

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You can play it safe if you want but famous racers like Rickey Gadson and some fast riders on this site use 87 all the time...and I do sometimes too :lol:

bottom line do a search it depends on conditions like air temp and mods but works good for many :heyyou::cool::wink:

bloo
Yeah, that's why I said some people have had good luck running it. However I know what low octane and hot air can do in a high compression engine therefore I'd rather be safe than sorry.
 
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