where did mr2 go?

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#1
i was on the vp website and cannot find the mr2. From what I remember wasn't it called mr-pro-2. Also is it possible to get 2 horse from mixing U2 and mr-pro-2 at 50/50, or is that just the U4 mixed with mr-pro-2. :think:
 
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#2
if this fuel is no longer available is there one that will produce the same power increase as the mr-pro-2. currently i am using U2, jetting is great, as of right now but will it change with the extra o2 that will be added from blending the two fuels.
 
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#3
hey rich

Alright I think I made a mistake and posted basically the same question in the wrong part of the forum. So my question is could you blend equal parts of U4 and MR2 and get 2 horse out of it. I am confused because I dont see the MR2 on vps website is it no longer being produced. Also if that is not around could I use U2 and MR8 and get the same result or is that a big no no. It will be going in my 125 btw. :bang:
 
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#4
wow I feel a little stupid I posted this question in the wrong part of the forum and it was worded goofy too. So if you read this ignore it because I re-posted in the advanced tech part of the forum which is better suited for this type of question Man I have a bad habbit of hounding the hell out of you guys. Thank You again and please dont kick me out of drn I will walk into on coming traffic if that happened J/K
 

Rich Rohrich

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#5
hot125mod said:
. So my question is could you blend equal parts of U4 and MR2 and get 2 horse out of it.
I have no idea what the performance difference would be mixing these VP fuels, verses running MR2 straight. VP has always seemed reluctant to give real technical details about their fuels, so the only way you'll know is to test it and record your results.


What I DO know, is the claims made by marketing people at VP are incredibly optimistic, and idiots at magazines seem pre-disposed to repeat whatever claims VP makes.
 

Rich Rohrich

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#7
hot125mod said:
thanks rich I just thought it may totally botch the two fuels by mixing them.
It won't hurt them, but exactly what you'll end up with isn't really clear and how you would tune for it would take some trial and error testing.
 
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#8
but mixing any pump gas with any race gas is a big no no. like 93 pump and 116,I have friends that seem to think they know all there is to know about race fuel. what kind of moron would mix 116 and 93 thinking they will get 114. Rich you would go ufc on these guys if you heard some of the stuff they say. What is the type of test that is done to find a fuels octane. btw I really like learnig about the science of fuel because it is some what cheap horsepower. :)
 

MikeS

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#9
Well since I am a self proclaimed VP guru of sorts..

Why would you want to mix those fuels ? What path of logic are you basing getting more power?

I am not being smart arsed.

MR2 was always a very good fuel for a 2 stroke. It was a tad over kill on octane for some and was trick to jet, it was also AMA legal in the extra 02 it carried. The Pro series fuels are UnLeaded and are supposed to carry the O2 for performance. The Pro series fuels are pricey since VP has to source out some components to get the fuel to perform properly. For years it has been easy to blend up race fuel with low cost components and add TEL and then MTBE. . The U2 or U4 are just the next generation of the MR2 series... the MR9 and MR are really the ticket for 250 4 strokes but you pay for the specialized components that are used to gain performance.

Back to your quest, Theoretically U2 should provide the best power for your money as it carries up to 6% oxygen into the mix. U4 has a better distillation curve for a hi revving 2 stroke IMO and still carries good oxygen. I have found it stable as long as you keep it cool and out of the sun. Mixing MR2 and U2 or U4 will only increase the octane some and lower the overall amount of Oxygen. I have added MR8 to U4 only to bring up the octane when running on that ragged edge with our old 125..

I have tested U4, U2, MR2, MR8, C12, And a few other brands at both the track and on a dyno in these bikes KTM300, KTM250SX, TM125/125, CRF250/262. All I can say is that the race fuel makes more power and torque verses pump fuel once you get and adjust timing/curves. NONE of these fuels by themselves broke that magic 2 hp number consistently but they did add 1 hp + some foot pounds or so down early in the rpm range that the rider can feel.
 
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#10
ok so i am kind of stuck i am using u2 right now and it is awsome. Since i have a 175lbs of cylinder pressure and that fuel is rated up to 220 or so can i get away with a little ignition advance. It is jetted really well maybe going to drop a main jet size from a 165 to a 162. what is your thought on this?
 
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#11
i am just sick of people that are minnesota racers saying that they know all there is to know about fuel and have no facts to back up their theories. some of that is wack. :bang:
 

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#12
In my findings a custom Vortex ignition is sweet on a 124 or 144. Using a good fuel like MR2 was or now U2 I actually retarded the timing some and got better top end power. Running a tight squish or small chamber would help throttle response and give a better burn without the need for aggressive advance that the factory uses to light off pump fuel.

I played roulette since I would drop the main until it popped on a straight then when up a size.

As far as trying to enhance the U2 fuel by blending, I have added a tail to it to get better piston cooling, the old U4 actually worked well for us, just rain my last batch of U4 today. Anyway if you can scrub some timing and a tad of octane requirement I would look at adding some VP MS105L as it will raise the tail, not kill your octane and almost hold your throttle response... MR9 will work too but watch your detonation. I found I never needed much over 100 MON in our motors (actually 92-96MON has been enough).