Went to check my compression after a fresh topend rebuild and the first time i checked it it was at 120, after break in proccess it shot up to 145psiI:I, but dont know if i should run high octane gas?
What premix-ratio should i use for 145psi?
- Thread starter blasterbogger
- Start date
wait premix or octane???? premix 32:1 for almost all situations. and for your psi 87 or 89 would be fine
i have 180 psi and i run 32:1 premium only
id say your safe to run regular @ 32:1
congragulations on the great break-in
id say your safe to run regular @ 32:1
congragulations on the great break-in
Specialized7 what octane do you run because my comp is 180 and I don't know if I should run race gas
damn thats high compression if i were you id run race gas\
probly 110 octane, or if you cant find a place to sell 110, you could always buy premium gas(93 octane) and use some of that octane booster you can buy, but the down side about that is you never no the true octane your running
probly 110 octane, or if you cant find a place to sell 110, you could always buy premium gas(93 octane) and use some of that octane booster you can buy, but the down side about that is you never no the true octane your running
is the jet ski air cooled? if so there's a huge difference.....
and i've never had good experience with octane booster. just buy the right fuel
lucas octane booster is the only one thats been proven to work...
but 93 with a good oil is fine, if your runing aforged piston and good gas its fine..
my buddy ran 98? octane in him trx250r that was 210 psi
but 93 with a good oil is fine, if your runing aforged piston and good gas its fine..
my buddy ran 98? octane in him trx250r that was 210 psi
I'm sure some of you already know this but there are a couple different chemicals you can use to boost your octane that you might already have, Acetone and Toluene which are both used as paint thinners but when mixed with gas in the correct amounts, will raise the octane level a couple points. I have read where companies state that there octane booster's raise the fuels octane +3/+6 when in actuality it is .3 or .6 so its not even a hole octane.
I also always run 32:1
I also always run 32:1
Acetone and toluene are not suitable octane boosters in great quantity. As gridlock stated "in the correct amounts" (which is low) they can raise the octane rating but they both have downsides...
Acetone does not delay the onset of precombustion as it's autoignition temperature is ~ 850 degrees F. What it does do is draw off more latent heat as it evaporates cooling the overall mixture down significantly to the point it inhibits precombustion slightly. But, it also produces acetone peroxide in small quantities as it oxidizes. Acetone peroxide is extremely shock sensitive and will initiate precombustion. Also, the fuel only has three carbon atoms per molecule so it's relatively light on energy.
Toluene is a good octane booster BUT the chemical does not have the lubricity that gasoline does. It causes an extraordinary amount of top end wear and because of it's reactive nature you have to use special rubber in the fuel system. It will eat the float needle tip and the crank seal lips causing problems later on. Also, you have to heat the fuel significantly before it will ignite. Because the fuel is used on the blaster engine as a significant source of cooling, I doubt the toluene component of the fuel mixture will reach the required 160 degrees F before the moment of spark timing meaning that it actually changes WHEN your engine is timed. The resulting late explosion would rush down the tuned pipe. That may help scavenging and it may not but I can tell you it will change the tune of your engine. The good news is, toluene has seven carbon atoms in it's molecule which means it's relatively energy dense.
If you don't mind searching for the proper float needle tip, you could find a service station that sells E85. It's 85% ethanol and 15% gasoline. It's octane rating is ~109. It, like the others in this post, eats organic rubber (but not as much as toluene) so the float tip has to be special but it can be bought by the gallon much cheaper than paint thinner. Unfortunately, it's relatively energy poor. Ethanol only has two carbon atoms so mixing too much of it with gasoline raises the octane rating but hurts energy density (which is why E85 powered vehicles get about 80% of the fuel economy that gasoline powered vehicles get).
Now, if you don't mind setting up a mixing station you can blend your own custom fuel out of a combination of the chemicals to take advantage of each's characteristics while keeping under the limit for damage from any one chemical. Start with 93 octane pump gas. Mix in 20% ethanol by volume, 8% acetone, and 15% toluene. You'll end up with almost twice as much fuel as you started with and several octane points higher.
Remember, if you do try an exotic blend of fuels, you'll have to rejet. Most of them are carbon poor and hydrogen rich. They evaporate cooler but burn hotter than gasoline, you must run more fuel than straight gasoline.
Now, after the chemisty lesson, back to the post. You generally do not change the pre-mix ratio for engine modifcations. The pre-mix ratio is set because it is independent of the amount of fuel needed for proper combustion. As soon as the fuel passes into the crankcase, the fuel atomizes but the oil doesn't. The oil spurts into the crankcase as whole droplets while the fuel is sucked up into the transfers with the air. Once you determine how much oil your engine needs to stay in one piece you don't vary the ratio to get more or less oil. You change jetting to affect how much fuel is allowed to mix with the incoming air to change the burn characteristics, the oil is just along for the ride.
Acetone does not delay the onset of precombustion as it's autoignition temperature is ~ 850 degrees F. What it does do is draw off more latent heat as it evaporates cooling the overall mixture down significantly to the point it inhibits precombustion slightly. But, it also produces acetone peroxide in small quantities as it oxidizes. Acetone peroxide is extremely shock sensitive and will initiate precombustion. Also, the fuel only has three carbon atoms per molecule so it's relatively light on energy.
Toluene is a good octane booster BUT the chemical does not have the lubricity that gasoline does. It causes an extraordinary amount of top end wear and because of it's reactive nature you have to use special rubber in the fuel system. It will eat the float needle tip and the crank seal lips causing problems later on. Also, you have to heat the fuel significantly before it will ignite. Because the fuel is used on the blaster engine as a significant source of cooling, I doubt the toluene component of the fuel mixture will reach the required 160 degrees F before the moment of spark timing meaning that it actually changes WHEN your engine is timed. The resulting late explosion would rush down the tuned pipe. That may help scavenging and it may not but I can tell you it will change the tune of your engine. The good news is, toluene has seven carbon atoms in it's molecule which means it's relatively energy dense.
If you don't mind searching for the proper float needle tip, you could find a service station that sells E85. It's 85% ethanol and 15% gasoline. It's octane rating is ~109. It, like the others in this post, eats organic rubber (but not as much as toluene) so the float tip has to be special but it can be bought by the gallon much cheaper than paint thinner. Unfortunately, it's relatively energy poor. Ethanol only has two carbon atoms so mixing too much of it with gasoline raises the octane rating but hurts energy density (which is why E85 powered vehicles get about 80% of the fuel economy that gasoline powered vehicles get).
Now, if you don't mind setting up a mixing station you can blend your own custom fuel out of a combination of the chemicals to take advantage of each's characteristics while keeping under the limit for damage from any one chemical. Start with 93 octane pump gas. Mix in 20% ethanol by volume, 8% acetone, and 15% toluene. You'll end up with almost twice as much fuel as you started with and several octane points higher.
Remember, if you do try an exotic blend of fuels, you'll have to rejet. Most of them are carbon poor and hydrogen rich. They evaporate cooler but burn hotter than gasoline, you must run more fuel than straight gasoline.
Now, after the chemisty lesson, back to the post. You generally do not change the pre-mix ratio for engine modifcations. The pre-mix ratio is set because it is independent of the amount of fuel needed for proper combustion. As soon as the fuel passes into the crankcase, the fuel atomizes but the oil doesn't. The oil spurts into the crankcase as whole droplets while the fuel is sucked up into the transfers with the air. Once you determine how much oil your engine needs to stay in one piece you don't vary the ratio to get more or less oil. You change jetting to affect how much fuel is allowed to mix with the incoming air to change the burn characteristics, the oil is just along for the ride.
woahh 180 psi's thats high compression! well thanks for all the info u guys are helpfull, i guess im going to run 40:1 with 93 pump gas if its to lean ill go with 32:1
I would run 32:1 oil ratio anyway, there is little advantage to running less oil other than you use less oil but you also run the risk of getting it a little hotter than normal one time and losing your oil film and pushing your quad home to do a top end rebuild. All it takes is about 1 second with no oil on the piston skirt for it to seize tight as a drum.
Putting more oil in your fuel isn't the way to lean it out. Changing your jetting is how you tune.
Putting more oil in your fuel isn't the way to lean it out. Changing your jetting is how you tune.
I have read quite a bit on mixtue ratios and what i learned was that leaning out the mixture also robs you of power. the lower oil content decreases your compression bc of the lack of lubrication. the studdies i read were getting more power running a more oil rich mixture like 32:1
I've read that oil mixtures down to 12:1 (with the proper jetting of course) put out the same amount of power as a dangerously low ratio of oil. There really is no advantage to running less oil other than the fact you will use 2oz less oil per 2 gallons of gas but could be putting a new engine together if something happens...
I have 210psi on my kdx and run 32:1 and 87 with no issues when the local statiions out of 89.I prefer 93 but don't have issues when I run it so I don't really see spending all the extra money on the expensive gas.look around there's guys running higher than my 210 on pump gas don't see why the blaster is so different.
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