Two Stroke Motocross
Two Stroke Motocross Forum => General Two Stroke Talk => Topic started by: 6IX on September 02, 2010, 12:54:55 PM
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It's been awhile, but I need to track down some VP to mix in with my weekly pump gas diet... I ran C12 a few years back but I notice VP mas quite a few available.
I guess I could just read up on it all here, but some personal opinions / experiences never hurt. I'm wondering the price per gallon difference as well.
http://www.vpracingfuels.com/page469683.html (http://www.vpracingfuels.com/page469683.html)
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Damn! that is a lot of choices you got there
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C12 is still about the best all around for your 2 stroke. If you just want to
bump the octane for detonation protection, 110 will work fine and cost less.
If you want more horsepower and have stock compression, try MRX01. It's
oxygenated and will add 2-3 hp.
Unfortunately, the best "witches brew" VP made was MR2. It cost a fortune,
burned your eyes when you opened the container and provided a noticeable
gain over all the other fuels. MR2 disapeared when the AMA/FIM mandated
unleaded fuel for MX and SX.
dogger
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I run a mix of c12 and pump gas 93octane (no alcohol) at a 50/50 mix.Yamaha lube R2. I got this mix from MAX POWER after they did my big bore.
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From what I was told (not sure if I remembered the right fuel) one of the VP fuels MR Pro 4.1 cost $50. per GALLON!! :o :o
It's the fuel the factory guys use!!
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Ok someone who knows needs to set me straight cause I keep getting different info from users than from mechanics. My shop mechanic said race fuel by no means increases power at all. He just said it makes everything run cooler and smoother so whats the truth cause everyone keeps claiming hp gains?????
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On a stock motor you wont get any horsepower gains with race fuel.
The benefit with race fuels is if you have higher compression you wont get detination.
The higher octane rating allows you to have higher compression which gives you more horspower.To a point.
The modern Japanese 2 strokes are designed to run on pump gas.
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The modern Japanese 2 strokes are designed to run on pump gas.
Yes but they toe the line... The owners manual on a YZ calls for "a research octane number of 95 or higher".
I always ran octane booster to band aid it, but I finally had to run straight pump gas last weekend, and I can 100% say the bike sounded a bit ratty and just didnt seem quite the same.
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My shop mechanic said race fuel by no means increases power at all.
Yes and no. Straight high octane race gas will not add horsepower to a low compression
engine designed to run on pump gas. However, oxygenated fuel like MRX01 and U4.4 will
definately add hp, even to a stock bike. Go to VP's website and check out the various
oxygenated fuels. Those hp claims are real and verifiable. I use to run VP Ultimate 4.1
in my CRFs. It was good for 3 hp over pump gas on the dyno.
The only advantage to running race gas in a stock bike is repeatability, i.e. each gallon is
the same - a claim you can't make with pump gas. Now you have to ask yourself, "Do I
have money to burn for that?"
The owners manual on a YZ calls for "a research octane number of 95 or higher".
Not a problem. The octane number you see at your local gas station is an average of the
Research octane number (RON) and the motor octane number (MON). For example:
RON=98 + MON=88 = 186/2 = 93 Since RON runs about 8-10 points above MON, you will
be well within the Yamaha limits using premium (93 octane) pump gas.
Again, once you up the compression ratio, straight race or a pump/race mix is advisable.
dogger
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John the MR Pro 4.1 is $36.50 a gallon at dealer cost. I ran it this year because I almost got it for running illegal gas last year.
As far as HP goes. I am not sure on the 2-stroke but I know back in the day when I ran Nutec in my mod 250F at Lorettas it dyno'd at 5.3 hp gain from just the fuel.
On the topic of the modern 2-strokes being designed to run on pump gas, that is false. If you run straight pump gas in a new YZ250 I guarantee it grenades! I did it to one of mine three times with in 6 hours of run time..... We got the bike replaced under the lemon law, ran pump gas in the new one and it blew with 1.2 hours on it. Rebuilt it and started running straight race gas and havent had a problem 1.
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I went through a rash of seizures and broken pistons on 91 octane pump gas (all you can get in so cal).
I switched to 50/50 C12 and 91 unleaded, I haven't hurt an engine in two years. I don't race MX, But I run them really hard in the desert.
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I've heard from a reliable source that the fuel the AMA requires the pro's to run hurts the power output of the 2 stroke's, but not the 4T's. Thus, another disadvantage to the 2 storke pro-rider. There are fines for not using the proper fuel, like what happened to RC a few years back.
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Great read...(I own a highly modified 2000 YZ 250)...
If your bike is jetted corectly (2stroke) it will run great on VP C12....It is one of the best overall fuels for all riding/racing.The engine will be crisp and clean!...There are other great fuels but are cost limiting to me!
The advantage with quality race fuel is that it is a consistent burn.Since my compression has been changed my YZ will not run on pump fuel anyway,but I would not run straight pump fuel in any stock 2 stroke racing bike...I would at least mix it 50/50 with a quality race fuel like VP C12.
Yamahas YZ's come jetted very close to perfect and reg fuel will sometimes be very bad to use under high load circumstances... and cause detonation probs..
Pump gas these days is pretty junky stuff and not what I would use (without mixing) in any 2 stroke racer (if riding agressively especially).. AND.. Keep the fuel out of the SUN!!
Now 4-strokes are a whole different story!....Yikes!
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So whats the easiest way to get a perfect, say 4:1 ratio if I'm not mixing 5 gallons of gas at a time? It's be easy to put 1 gallon of race gas in a can, then put in 4 gallons of pump gas, add premix for 5 gallons and go ride... But what if I want the same ratio for only 2 gallons..??..
I'm not very good at math, but I'm thinking I'll need to put in 1.8 gallons at the pump (204.8oz) and then add 51.2oz of race gas for 256oz (2 gallons) total and then premix for 2 gallons to get it spot on..??.. Am I way off here. ???
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Watch "Lethal weapon 4".
They explain it nicely ;D
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Roo16 is the best VP fuel. Actualy race fuel can allow you to jet close to the point of detonation thus an increase in power.
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Itā??s official! Even stock 2-strokes love a little bit of race gas. My bike ran so clean this weekend, and I only mixed it with a 3:1 ratio of pump:race gas. A noticeable difference. I donā??t know if Iā??ll be able to go back to using just Octane Booster. :P
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Itā??s official! Even stock 2-strokes love a little bit of race gas. My bike ran so clean this weekend, and I only mixed it with a 3:1 ratio of pump:race gas. A noticeable difference. I donā??t know if Iā??ll be able to go back to using just Octane Booster. :P
Same here 2 weeks ago, had some left over 50/50 c-12/91 chevron that i run in the yz250. Tried it in the cr500, holly crap what a difference, ran really clean, more power everywhere. Good Chit!
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Anyone know what the Legal VP fuel is for Lorreta Lynns ? The goverment just passed a law that gas stations can sell gas with 15% enthanal, the USA today paper said most stations won,t switch over because of the cost to do so. They also said pre 07 engines would be harmed from the 15% enthanal fuel, I guess there trying to get us all to buy new vehicles.