100 octane pump gas vs mixed 91 and 110 race gas???


10 replies to this topic
  • anestech

Posted March 05, 2006 - 12:05 PM

#1

Hi all,

I just picked up a modded RM-Z250 with a higher compression piston, stainless valves, valve springs, and a cam. The guy I bought it from said to run 100 octane (per the engine builder). They ran half and half race gas (either U4 or EV, not sure which). There is a Union 76 station near my work that sells 100 octane unleaded Sunoco GT 100 out of the pump. Obviously it would be much cheaper (and convenient) for me to run the 100 octane pump gas since it is only aroud $5/gallon. I'm trying to get in touch with the engine builder to get his opinion, but in the mean time, I WANT TO RIDE!

What do you guys think: good, bad, no difference, engine's gonna blow instantly, what?

  • Honda80

Posted March 05, 2006 - 12:08 PM

#2

I dont think it will blow the engine....but you will have to rejet

  • anestech

Posted March 05, 2006 - 12:09 PM

#3

I dont think it will blow the engine....but you will have to rejet


Why would I have to rejet? The engine is currently jetted and built to run on 100ish octane?

  • Honda80

Posted March 05, 2006 - 12:11 PM

#4

yes but the gas is different octane....you might have to rich it a little

  • anestech

Posted March 05, 2006 - 12:19 PM

#5

yes but the gas is different octane....you might have to rich it a little


half 110, and half 91 = 100.5 octane vs 100 octane. Is that really going to make a difference??? Doubt it.

  • Honda80

Posted March 05, 2006 - 12:21 PM

#6

oh sorry only read last part of post...it should be fine

  • GENE426

Posted March 05, 2006 - 12:39 PM

#7

your good to go
wish they had pump 100 octane close to me

  • urlosin

Posted March 05, 2006 - 01:25 PM

#8

half 110, and half 91 = 100.5 octane vs 100 octane. Is that really going to make a difference??? Doubt it.


This is correct. Not all 100 octane fuels are equal, but unless you are getting into some of the exotic class specific fuels you will be just fine with either one. The only thing I will add is that if you are mixing gases do it in a can and then dump into the tank. That way you assure it is always a true 50/50 blend.

  • anestech

Posted March 05, 2006 - 01:27 PM

#9

This is correct. Not all 100 octane fuels are equal, but unless you are getting into some of the exotic class specific fuels you will be just fine with either one. The only thing I will add is that if you are mixing gases do it in a can and then dump into the tank. That way you assure it is always a true 50/50 blend.


Oh yeah, I would definetly mix it in the can first. I like to run with a full tank, and I top off every time we come back to camp.

  • motopainter

Posted March 05, 2006 - 03:11 PM

#10

How old is this fuel? Check with the station as to how long its been since delivery.Old gas is bad gas.I buy mine five gallons at a time in a dated sealed container cant go wrong.

  • anestech

Posted March 05, 2006 - 03:21 PM

#11

How old is this fuel? Check with the station as to how long its been since delivery.Old gas is bad gas.I buy mine five gallons at a time in a dated sealed container cant go wrong.


Good question, but I already thought of that. They say that it moves pretty fast (and I have heard that from people in the area as well).





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