its so technical i dont want to write a page on it but its been explained tons of times. The most power is made by using the Lowest possible octane without detonation. raptors only have 9.1 compression and are made to run on low octane fuel (87). using 93 is just throwing your money away and losing a few ponies at the same time.

 

i guess that helps. i always thought higher octane made more power. we cant be right all the time. i guess ill have to read up on this subject. thanks for the info by the way!

 

higher octane does make more power if you have the compression that needs it. throw a 11:1 piston in your raptor and run premium and you will feel a difference.cars are different, generally if you run higher octane in your car the computer will pick it up and automaticly advance the timing to take advantage of it, and vuola, more power. quads (for now...) dont do this.

 

if you want more power from fuel go with U4 or MR9

 

Yes, too high octane rating will make less power than the optimum octane rating.

Also, VP U4 (used to be called Ultimate 4) will give you the most power on a stock compression raptor, even one up to around 12.5:1. It is around 99 octane, can't remember, but is is very highly oxygenated. There is extra oxygen added to the fuel in the form of MTBE, so you need to increase your jetting to make up for the extra oxygen. You need to run 2-3 jet sizes richer.

This fuel will make about 6% more power than standard (non-oxygentated) fuel. That means, if you have a 50 HP raptor, just by changing fuel and rejetting you can increase it to around 53 HP.

One thing to mention, this fuel smells VERY strong. People will be able to smell it from a mile away. You can even smell it seeping out of a sealed metal drum.

RaptorRacer1

 

I never really knew the answer to this question either. I once ran Supreme pump gas rated at 93 oct and it made my 660r run hot and crappy. I actually had to drain the remaining fuel out and replace it with 87 oct because it was runninr so hot the headers were glowing red and my legs were becoming extremely crispy.

 

Yea....I was'nt told that I'd need to run race fuel after putting in a new piston (now 13.1 comp). I'm wondering if it was worth now since I have to pay $9 per gallon for the stuff.

 

what gas are you running now on the 13:1?? and is this for the Raptor or your YFZ? because timing also plays a role in what fuel to use. and yes, oxogenated fuel does add hp because more oxygen= more power so you get more oxygen in each stroke.

 

Its for the YFZ and its Ultimate 4 fuel. Long story short........after getting the piston installed .....2 riding hours later I broke a valve. Yamaha built me a new engine for free but then told me I HAVE TO use a race fuel or they would not warrant any more parts on the engine. And yes....the race fuel does add more power to the bike...I can tell the difference b/t reg. gas and this stuff. Not a lot...but noticable.

Cuddos to Yamaha...they did'nt have to give me a new engine...very nice people to work with.

 

yea thats because of the new 13:1 piston you used. you need to use race fuel with that or else you will get detonation as you saw and blow up your engine