Race Gas!

[fas400ex]

I WAS JUST WANTING TO GET SOME OPPINIONS ON RACE GAS! RIGHT NOW I AM RUNNING 110 OCTANE 50/50 MIX WITH 93 PUMP GAS, IS THERE A ADVANTAGE TO RUNNING STRAIGHT RACE GAS? IS IT BAD ON MOTOR? IS IT A WASTE? WHAT IS A GOOD WAY TO TELL YOU ARE NOT RUNNING TO LOW OCTANE OR TO HIGH? I HAVE A 425 HIGH COMPRESSION JE PISTON AND A STAGE 1 HOTCAM!

[RAPTORAZ]

How high is you're compression? My 10.8:1 Stage 2 416 runs fine on 91 octane unleaded. Unless you're around 12:1 compression, you're probably just wasting money. Also, if you're feeding the motor more octane than it needs, you're actually hurting power.

[cals400ex]

yes, the compression ratio will make a difference.

[kargaaro]

I only run straight 110 octane. In racing it will keep the temp down. For play it would be ok to run a 50/50 mix but I play just as hard so I run 110 all the time. Call Sparks Racing. They told me I should be running at least 100 at all times.

[Glamis400ex]

I was told by the guy that bored and ported my 400ex, that I should now be running in the neighborhood of 100 octane, which I am.

Glamis

[Bad Habit]

Originally posted by kargaaro
I only run straight 110 octane. In racing it will keep the temp down. For play it would be ok to run a 50/50 mix but I play just as hard so I run 110 all the time.

Ya, what he said.

The higher octane fuels burn a little bit cooler which helps keep the temp on the top of the piston and valves down just a little bit. I know everyone says it's $4 or $5 per gallon so it's a waste, but the way I figure it, I'm not running through 100 gallons a weekend so a little extra money for a little extra cooling is worth it. JMO

[BIGRED400]

I have a JE 416 11:1 coated with this http://www.swaintech.com/4whl.html , HotCams Stage 2, White-Bro's E-series w/18 Disc,170 main,I am running 100 Octane and am having a hard time getting a plug reading , I guess because she runs so clean,,Have any of you guys checked your plug color???

[Glamis400ex]

I have the same mods as you with porting and a DMC pipe. I run 50/50 of 91 and VP C-12.

My jetting is 168 main, 42 pilot

I have a nice pic of my plug if you wanna see it.

Glamis

[skemp]

Trying to get a reliable reading on a thumper has gone out the window with me. I can still usually get good plug color on two strokes.

[TheX1992]

I know everyone says it's $4 or $5 per gallon so it's a waste, but the way I figure it, I'm not running through 100 gallons a weekend so a little extra money for a little extra cooling is worth it


4-5 bucks? i pay 3.65/gallon for 118 octane. b-32. works wonders :). turbo blue is the same price, but its only 110 octane (and here its watered down):confused:

[LathersR]

Higher octane, the cleaner your motor runs.. and lil more power.. It' always nice to run higher octane.. if you dont have really any motor work it may not be best to do that.. their have been cases that it runs so hot and burns so quick that the motor will blow.. I run 112 octane it costs me 6.00 a gallon:(

[fas400ex]

MY JE PISTON IS 11:1 COMPRESSION AND I HAVE A PRO CIRCUIT TI4 FULL EXHAUST AND STAGE 1 HOTCAM. SO 50/50 SHOULD BE ADEQUATE?

[2004TRX450R]

The easiest way to tell if you need a higher octane fuel is if it pings. If it starts pinging then you need higher octane. If not you don't. The race fuels are more pure fuel than pump gas so you will usually gain a little bit by running race fuel but if you run to high of an octane the engine will have a hard time burning it right and you will actually loose power. Basicly the octaine rating is telling you the resistance to combustion. The higher the rateing the harder it is to burn. This is why you have to run higher octaine in a high comp. engine. If you have to low octane fuel in it the fuel will actually burn from the compression before the spark plug fires. When it does this you will hear a pinging and it burns WAY hotter and that is why you will burn holes in pistons and such running to low of an octaine fuel. The higher octaine fuel will resist combustion better so at the same compression it won't fire until the spark plug fires.