Racing fuel in a moped, BS I think

A guy I work with who seems to be knowledgable on engines told me I should try running Shell's racing fuel in my Kinetic which would give it more power going up hills. I tend to think this is BS. Higher octane fuel just burns slower which reduces engine knock.

I *think* the octane rating of Shell's racing fuel is 104. Which may vary region to region. Just like 91 is the highest you can get in some metro areas, where around here 93 is high octane. Maybe 100 octane in metro areas if even available.

I do know if an car has an engine management system and the engine knocks, the computer will retard the timing. So yeah I could see how running 93 octane versus 87 octane in a BMW would give you more power.

But running 104 octane in a moped with an 8:1 C/R with fixed timing? I don't see how it could make any more power.

I may have to mix up a gallon just for shits and giggles to see if there is anything to it.

Re: Racing fuel in a moped, BS I think

It will give less power actually due to the slower burn rate.

Re: Racing fuel in a moped, BS I think

Matt Mahloch -- MBM Customs /

There's more to it then that.

Re: Racing fuel in a moped, BS I think

I did word that incorrectly. Octane is resistance to ignition but does not dictate the energy release, that's heptane. But if the fuel is harder to ignite, or takes longer to get to burn then you lose available tome for the fuel to burn during the stroke without advanced timing.

Re: Racing fuel in a moped, BS I think

What amount adding some nitro methane?

Re: Racing fuel in a moped, BS I think

There are a bunch of gas stations here that sell 110 leaded!

Re: Racing fuel in a moped, BS I think

unless you mess with the compression ratio and timing, you'll only be spending a bunch of money on gas.

Re: Racing fuel in a moped, BS I think

Is that sold in cans or out of the pump?

Re: Racing fuel in a moped, BS I think

NEMA Victor (3 Knees Down) /

Sunoco Supreme is out of the pump here. Has it's own station.

VP Racing is out of a can.

Re: Racing fuel in a moped, BS I think

Dirty30 Dillon /

The Mobil in my town carries Cam2...

Still would never buy it.

Re: Racing fuel in a moped, BS I think

Brent Bublitz /

No.. it will not make a difference and may just cause trouble.

Re: Racing fuel in a moped, BS I think

It won't do you any good unless your have a pretty high compression ratio and run at fairly high temperatures. Or if you have forced induction of some kind, I suppose.

That said, it probably doesn't hurt anything either. Go unleaded though: leaded fuel will gunk up your plugs and exhaust packing.

Re: Racing fuel in a moped, BS I think

Matt Mahloch -- MBM Customs /

I run sunoco supreme 112 leaded. It's really great stuff for the high rpms. Fast flame propagation. Temps stay more stable. Smells great =) I can't do the same with 92. Get on sunocos web site some time and read, it's quite interesting. My weed waker likes it too! I'm too lazy to mix more than one can.... crazy 4 cycle weed eaters that use premix.

Re: Racing fuel in a moped, BS I think

Matt Mahloch -- MBM Customs Wrote:

-------------------------------------------------------

> I run sunoco supreme 112 leaded. It's really great

> stuff for the high rpms. Fast flame propagation.

> Temps stay more stable. Smells great =) I can't do

> the same with 92. Get on sunocos web site some

> time and read, it's quite interesting. My weed

> waker likes it too! I'm too lazy to mix more than

> one can.... crazy 4 cycle weed eaters that use

> premix.

This. Hot, higher comp, harder-hitting, higher-revving 2 strokes love leaded gas. It is possible to tune around this, but it's not terribly expensive if it's a hobby vs. a commuter and if one wants to extract everything that their little moped has. My old setup responded extremely well with 50/50 unleaded 0% ethanol 93 and leaded VP C12. It really does smell good!

Basic rule of thumb for me is a minimum of pump 93 for kitted bikes. It's relatively the same price as 87 (what's 25 cents a gallon more for a couple gallons...really) and offers much more knock protection. Not worth the few pennies saved if the engine is more prone to 'nade itself.

Re: Racing fuel in a moped, BS I think

I definitely run a minimum of 91/93 (whatever the station has). After being able to hit the kill switch and have the bike RUN for a second or two at high rpm I know it is at the very least necessary. Granted, a better designed head would likely help stave that off, but still.

Re: Racing fuel in a moped, BS I think

Randy Johnson II /

I just run 87 octane and synthetic 2 stroke oil.

Re: Racing fuel in a moped, BS I think

A little off topic but...

Those crazy 4 stroke weed wackers have poor lubrication for the valve train and end up in the dump a lot quicker than the 2 strokes. As a matter of fact my 2 stroke came from the dump 5 years ago and just needed new fuel line.

My friend has a 4 mix 2 years old and the rocker components wore so much that the push rod fell out of place.

Re: Racing fuel in a moped, BS I think

campeona del mundo /

85 for life.

Re: Racing fuel in a moped, BS I think

♣Slew Foot♣ /

nitromethanol requires 4x's the flow rate of a standard gas running carb

so if you take a standard minamal carb size say 12,8. thats at least a 48,32. i posses a sachs bing 54,36,1625 w/ nitrous in ports to floatbowl.

it was half a rotax airplane carb, relates to a 250cc two stroke.

so if you want to run nitromethanol, a cast iron cyl. is desirable because the compression needed and the heat. a sachs jug could handle the compression ratio. it would just spin the clutch out tho and warp the cylinder. a batavus has a cast iron cylinder but no where to mount the monster without a major plumbing job.

it can be done but it would last like 2 races if you were lucky, nitromethanol might just eat away any plastics and i imagine it would increase the wear on the seals.

the best way to increase power is tuning to the point of "i know it is lean but not lean enough to seize" open air flow and downjet doing chops the whole time to ensure the heat range is on the lower side. get a good pipe/ decarbonize your old one. get new rings.

Re: Racing fuel in a moped, BS I think

i think you're thinking wrong. nitrometh might require a 4x richer air/fuel ratio, but not 4x more air. You don't need a giant carb, just big jets.

Re: Racing fuel in a moped, BS I think

I was just wondering if mixing nitromethane with gasoline might have some benefit. Like a 10/90 ratio or something.

It was my understanding that the same amount of nitromethane compared to gasoline provides more power when it explodes but doesn't require any more air.

But don't know much about it. I know it's used in those tiny RC cars and airplanes.

Unlike methanol or propane. In that case you would need to run oversized jets (15% I think is the rule of thumb) to get the same amount of power as gasoline.

I'm not sure what the benefit of running methanol is. I think it burns cooler and I know it has about 114 octane. So I guess if you are running a radically high C/R it would be of some benefit.

Re: Racing fuel in a moped, BS I think

What about pure gas? There is a website that lists all the places that offer ethanol free gas. I was thinking of picking some up. So is it better to just top off with shell premium or use ethanol free gas stored in a can?

Re: Racing fuel in a moped, BS I think

simon thokaar /

Dylan C. Wrote:

-------------------------------------------------------

> What about pure gas? There is a website that

> lists all the places that offer ethanol free gas.

> I was thinking of picking some up. So is it better

> to just top off with shell premium or use ethanol

> free gas stored in a can?

phillips 66 is the best pump gas, at least thats what my mechanic buddy says... its gums up engines the least out of em all..

Re: Racing fuel in a moped, BS I think

Is gas with out ethanol better than premium?

Re: Racing fuel in a moped, BS I think

simon thokaar /

Dylan C. Wrote:

-------------------------------------------------------

> Is gas with out ethanol better than premium?

for a stock bike yes, on a kitted high compression bike you want the higher octanes to prevent detonation and run cooler overall.

Re: Racing fuel in a moped, BS I think

So a stock bike runs better on pure gasoline? And if that is true how long should someone keep gas in a plastic gas can?

Re: Racing fuel in a moped, BS I think

simon thokaar /

pure gas would stay good for several months. If ethanol gas has been sitting for a month i wouldnt use it in anything but a lawnmower i dont give a shit about.

Re: Racing fuel in a moped, BS I think

Race fuel should have more energy than pump gas, but you wouldn’t want to pay for it unless you’re cornered; & by cornered, I mean your engine is at the point where it destroys itself without you either mixing in exotic alcohols or going entirely over to aviation fuel AND you have a race coming up AND you’ll lose the girl if you don’t win the race. Fussing with burn rates changes the conversation, I’m only talking about the energy stored in the fuel molecules.

Race fuel will out perform your home brewed octane booster & your av gas.

Burn rates: we’re barely keeping track of burn rates now, so don’t worry about them unless you change your engine (re-time with a kit, a change in fuel/oil mix ect.). a CDI with a store bought curve (that has no visibility of throttle position, pipe, clutch ect.) is an approximation at best. Tune not to blow up.

Nitromethane is outstanding liquid God because you’re dumping fuel that’s already bound to oxygen into your engine (in liquid form). Air super sucks. It’s 70% inert filler-trash & it isn’t very dense. If our lungs ran on liquid oxygen, we’d rip on other mammals. It’d be ugly…(edited)

Re: Racing fuel in a moped, BS I think

Here are a couple great articles to read - they might make some reconsider what he/she thinks about race fuel:

http://www.racegas.com/article/10

http://www.racegas.com/article/38

Re: Racing fuel in a moped, BS I think

#CrazyWayne™ rocks. #CrazyWayne /

Flumes from beer cans soking in nitric acid ftw.

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