VP U4.2 fuel??

Gray what do you think about this Startron stuff? They sell it at my local shop is it worth it?

I've been using Star tron for a few years now. I work in the marine industry and we see a ton of issues with ethanol and what is called phase separation. The star tron works pretty well at keeping the fuel and ethanol from separating out. I've used all of the additives out there and it works the best.

As far as using VP, I use it for the consitency plus my shop is a VP dealer. I see to many problems with ethanol fuels and wouldn't want to put any of the ethanol in my bike.

I will throw this in for the people who like to read, it is a pretty good write up on the ethanol situation (At least with boats) http://northamerica.mercurymarine.com/serviceandwarranty/mercruiserfaqs/ethanol.php

Edited by Shogren65
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I've been using Star tron for a few years now. I work in the marine industry and we see a ton of issues with ethanol and what is called phase separation. The star tron works pretty well at keeping the fuel and ethanol from separating out. I've used all of the additives out there and it works the best.

As far as using VP, I use it for the consitency plus my shop is a VP dealer. I see to many problems with ethanol fuels and wouldn't want to put any of the ethanol in my bike.

I will throw this in for the people who like to read, it is a pretty good write up on the ethanol situation (At least with boats) http://northamerica.mercurymarine.com/serviceandwarranty/mercruiserfaqs/ethanol.php

I have a Super Air Nautique and I run ethanol free fuel from the crazy Native American fuel station about 4 miles from my house. Not sure how they get away with it but my boat sure runs better on it!:thumbsup:

Ya there is some stations that can get good old gasoline. None around me other than on the water stations and they are too far to make it worth it.

The point I want to make about E10 based fuel is shelf life. Peticulary the "short" shelf life.. (as little as 30 days) before the "phase separation" can begin. Ethanol is also a mositure attractant. Which is not good either. Those of you that run your bikes frequently on a weekly basis really have little to worry about. It's those of us washed up old warriors who's bikes may sit unused for a few months are the ones who need to use a fuel stabilizer.

BTW, as I understand, race fuel doesn't make "more" hp, race fuel eliminates the potential for hp robbing detonation. So those of you with bumped compression and aggresive ignition curves will need race fuel. I really think you're wasting your hard earned money running race fuel in a stock engine if you are looking for more power... (just my opinion)

If I have my facts wrong Gray will be verbally b!tch slapping me shortly. :thumbsup:

Oxygenated race fuels (like VP U4.x and MR9) make more HP than pump fuel...jetting/mapping may need to be changed to accomplish the increase in HP.

BTW, as I understand, race fuel doesn't make "more" hp, race fuel eliminates the potential for hp robbing detonation. So those of you with bumped compression and aggresive ignition curves will need race fuel. I really think you're wasting your hard earned money running race fuel in a stock engine if you are looking for more power... (just my opinion)

Nope that's wrong, at least some of it is.

Race fuels make more power because the chemical components release more thermal energy when they are burned, simple as that. Oxygenation does mean that there are components in the blend that release free oxygen into the combustion process, but that only increases the power output compared to the same fuel blend without the oxygenating agent. In other words, if you oxygenate a junk fuel, it will make more power than it did, but not as much as a high energy, nomn-oxygenated fuel. Most pump gas these days is oxygenated to reduce emissions, but most are not high energy fuels.

Octane is unrelated to any of that. Octane has the same relationship to power output and combustion temperature that shape of an object has to its weight and color; none. Octane is a unit of measure used to quantify a fuels resistance to detonation. Fuel is supposed to burn in a wave, not detonate. Detonation is when fuel explodes spontaneously because it got hot, and octane indicates how well the fuel resists that. If the octane of a fuel is high enough to avoid pinging (the early stages of detonation), it's as high as it needs to be, and increasing octane number beyond that point has no effect on anything.

It IS true, though, that raising compression or using more ignition advance increases the chances of detonation, and may require a higher octane fuel, even though it might not need to be higher than pump premium anyway.

As far as a waste of money, I look at it like this. You really can just go down to the VP store and buy 2 hp and pour it right into your tank (you have to rejet to get the most from most race fuels). In that sense, it's the easiest 2 hp you can get. You could probably get an almost identical result from a good port job and a high compression piston on pump gas. Let's say the port work cost $800 altogether. For the price of a can of gas, you get the same thing. But that same $800 will only but 30-40 gallons of race gas, so your horsepower bargain ends after the 6th or 8th can.

Gray... what fuel would you recommend running for desert racing in my YZ450 with hi-comp piston. And are there race fuels that don't require (as much) jetting changes? It would be nice to practice/play ride on pump gas or a blend and only race with the good stuff on the weekend to save some money for that port job :thumbsup:

Thanks!

And are there race fuels that don't require (as much) jetting changes?
I don't know that any exist, although they may. I don't have any particular recommendations along those lines, either.

I have not done this but this is a question I have never heard answered before so I figured maybe someone here has read something on the subject before.

What is the effect of running a bit (95, 90, 85, 80 or 75:1 of Gas:Diesel) diesel fuel with Gasoline as far as Detonation goes. I dont know if diesel has a higher R/M rating or not but I do know that it has a higher BTU rating then regular gasoline.

I am a major motor head and have read tens of thousands of articles but have never even heard this mentioned before. I am just curious!

Joe

Diesel fuel has an octane number of around 40-50. Furthermore, it is more viscous than gasoline, so it will not flow through the jets as readily under the same pressures, which would tend to lean the A/F ratio somewhat.

Otherwise, it's a fabulous idea.

VP said you can run the motosport 103 without ever draining or gumming up

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