HEADS UP!!!

Site upgrade in progress... Core site functions are working, but some non-critical features/functions will be temporarily unavailable while we work to restore them over the next couple of weeks.

Please post any bugs you encounter, but before you do, check to see if it's already listed.

Thanks for your patience while we work to improve the community.

Sign in to follow this  
Followers 0
78sharpshooter

? Best fuel for the 426

21 posts in this topic

I know there are differences in fuel quality amongst the various companies but was wondering what your preferences are? 76, Mobil, Exon, Chevron etc

Share this post


Link to post
Share on other sites

Go find some race gas. about 100 octane with 4% oxygen. That will wake up the bike to the tune of around 4hp.

Share this post


Link to post
Share on other sites

I just use Shell. Whatever the highest octane is.

The only thing that I have ever heard about gas is not to use BP. Everyone says that BP gas has the most contaminants.

I've thought about using Race gas a couple of times, but every time that I get that itch, I just read the posts on TT and the itch goes away. Seems to be more of a hassle than it is worth unless you are a top guy in your class. (Which I definitely am not)

Share this post


Link to post
Share on other sites
Gas is gas. Use whatever is the cheapest and most convenient.
There is something to that, alright.

If you want the "best gas", then you're going to want something like VP U4, but there's a price to pay for that, and some associated hassle.

As far as pump gas goes, here's a dirty little secret, at least in SoCal; it's all the same stuff. All the gas from whichever refiner is run into town through the same pipeline, and stored in the same tanks at a fuel depot. The empty tanker trucks get an additive package dumped in at their respective yards as they leave, and all line up at the same tanks to fill up and head for the retail stations. So, in that sense, gas really is just gas.

Additive packages do differ in quality and expense, however, so I recommend shopping for a price on a major brand, and see if it works OK for you. You can compare it to other brands, but I doubt there will be much difference you can see as long as you buy a major, and buy from a higher volume station so the gas is normally fresher. I use ARCO, because it's the lowest price major in my area, generally speaking. Chevron also works very well for about a dime/gal more.

Share this post


Link to post
Share on other sites

For racing, I will try to find some VP, and then just mix it 50/50 with a good super. Saves on cost a bit, and you get a bit more performance factor. There is a kart track close to home, and they carry a couple of different fuels.

But never would I buy anything other than a good 92+ octane ie Shell, Chevron etc.

I do like the smell of race gas in the morning.

Tom

Share this post


Link to post
Share on other sites
For racing, I will try to find some VP, and then just mix it 50/50 with a good super. Saves on cost a bit, and you get a bit more performance factor.
The trouble with this is that it's sort of like mixing dog crap with ice cream. Even at 50/50, the resulting mixture is going to look, smell, and taste much more like dog crap than it does ice cream.

You take $2.50/gal premium and $10 U4 mixed 50/50 and you have...something...that cost you $6.75/gal and runs like maybe $4.00 if you're lucky. You will raise the octane about one point, but that won't help, because pump premium has a high enough octane number already.

If you want a cheap performance boost, get a gallon of toluene from Ace Hardware and mix it about 15% with pump gas. (toluene is a component of many high quality fuels and race gas blends) Cheaper and very effective. You can go 25% if you kick the jetting up a bit.

Share this post


Link to post
Share on other sites

From the O-chem courses I took I remember toluene being pretty volatile. How clean does it burn and are there any drawbacks to throwing it into the 426?

Share this post


Link to post
Share on other sites

As a forrmer chemist that used to blend gas mixtures for all major gas companies I can say toluene is not harmful on your motor in reasonable levels. It is already a component of your gas mixture. I used to use it as a octane boost in an 11.5:1 motor I had in a mustang when I couldn't get high enough octane locally or didn't want to spend the money on race gas for cruising. It does burn reasonably clean and a little hotter then normal gas.

The percentages of gas components change during the winter and summer months to either raise or lower the vapor pressure as needed. With that said Toluene is on the lighter end of of gas components (meaning it will vaporize fast and reduce in overall concentration compared to the heavier components of gas). So don't mix much more than you are going to use and then cap the rest. It is also a known carcinogen. Don't bathe in it or use it as a parts washer, even though it works really good in that regard.

Now the disclaimer, I do not recommend or suggest you use this but if you do "your on your own"!!!!!!!

Like someone else already said. Higher octane does not make your bike run better unless you are already having a problem with detonation. This can be caused by excessive heat and or to high of compression.

Share this post


Link to post
Share on other sites
Do NOT use gas provided by Ricky Carmichael or his mechanic.

I'm dead serious.

:thumbsup:

LOL :thumbsup:...That sucks for Ricky but rules are rules....

Share this post


Link to post
Share on other sites

The VP C12 is a good mixer for 2 strokes anyway.. When my ultralight detonates and diesels on some stale old fuel left in the tank, I add some VP C 12 and it stops detonating and dieseling. The lead in the C-12 has a nice chemical reaction with the old fuel raising its octane real good. The lead is not so good for the modern 4 strokes though.

Share this post


Link to post
Share on other sites

If you want a cheap performance boost, get a gallon of toluene from Ace Hardware and mix it about 15% with pump gas. (toluene is a component of many high quality fuels and race gas blends) Cheaper and very effective. You can go 25% if you kick the jetting up a bit.

Absolutely and completely true, My neighbor is a chemist at Chevron and told me the exact same thing.

Share this post


Link to post
Share on other sites

I ran a 20% mixture of tolulene in turboed car, holy mother of god....

My ECU didn't yank timing anywhere and it felt like the hand of god was pushing the car, awful mileage but worth every cent. The ECU has three boost maps(91, 93 and 100), 100 is asking for jailtime.

That being said, you'd need to lean the bike out some or piddle with CR to get real gains from a higher octane rating, you know, put that higher threshold of detonation to work somehow.

Share this post


Link to post
Share on other sites

I heard some people at the local track talking about using aviation fuel. What would be the advantage of this? And anyone know the price per gallon? Can you go the airport and just buy it like normal gas?

Share this post


Link to post
Share on other sites
I heard some people at the local track talking about using aviation fuel. What would be the advantage of this?
None whatsoever in most cases. The vaporization rates are calculated for big cylinders connected to long intake tracts, turning low, constant RPMs at ambient temps of 30 degrees or less. Not at all optimum for a modern MX 4-stroke.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now
Sign in to follow this  
Followers 0