
Fuel additives
- Mattjin
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Re: Fuel additives
It wont mix too well with petrol anyway unless you use it straight away. Methanol on the other hand...... 

- MAXUMIS
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Re: Fuel additives
If you ratio it with normal fuel (5% to 10%) EDIT AS A STARTING POINT, you could get a happy meadiam but the bike will need to be on a dyno to get it tuned write.The main thing is to not run out of injectors hence needing bigger ones.i would not leave it in a tank for any time thow if you can get a decent ratio as it will f*ck everthing in its path!!oldman wrote:I talked to a few people about adding nitro methane to my fuel and it sounds like a bad idea. According to the "experts" my power commander would not be able to supply enough fuel to keep it from running way lean and even if it did run a proper mixture the combustion chamber pressures without head, piston and lower end work would probably smoke my motor.
I have a gallon of very expensive fuel now and the storage life on nitro methane is very short. Time for a Jim to think this over. Perhaps a bomb??
Last edited by MAXUMIS on Thu Jul 12, 2012 9:13 pm, edited 2 times in total.
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- Gosling1
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Re: Fuel additives
you wouldn't bother using a 95/5 mix of normal fuel and nitromethane - top-fuel dragsters run it straight. The extra 5% would result in very little real difference and would probaby result in less power not more.
Nitromethane only has about twice the amount of power as normal fuel for a given amount of air. It also has about 1/4 the energy density of normal fuel.
Oldman ? make a bomb. Way more fun
This has reminded me of a story from riding dirtbikes a few years ago down in Bendethra. One of the guys on the ride went to shitloads of trouble to mix his fuel - 50/50 unleaded & Avgas. Yes you heard that right - 50% leaded, 50% unleaded. He was convinced that his XR600 had some serious engine work and *absolutely* had to have a high-octane fuel in order to work properly......
he also did his best to convince all of us that the bike would not run at all on normal fuel, but also couldn't run on straight Avgas as this would "..blow the top end to pieces.."
After the first day where he fucked around mixing fuels and falling off.....we got on the piss that night and after listening to him bullshit on for a while - I pointed out that for all his work - all he was doing was diluting good Avgas with shitty unleaded fuel !!
he thought that he was improving the octane rating of the unleaded by adding Avgas......
of course, when he ran out of his special mix halfway through the next day, he had to fill his tank with normal unleaded fuel......and crazy but true - his bike ran just fine for the rest of the day.......

Nitromethane only has about twice the amount of power as normal fuel for a given amount of air. It also has about 1/4 the energy density of normal fuel.
Oldman ? make a bomb. Way more fun

This has reminded me of a story from riding dirtbikes a few years ago down in Bendethra. One of the guys on the ride went to shitloads of trouble to mix his fuel - 50/50 unleaded & Avgas. Yes you heard that right - 50% leaded, 50% unleaded. He was convinced that his XR600 had some serious engine work and *absolutely* had to have a high-octane fuel in order to work properly......

After the first day where he fucked around mixing fuels and falling off.....we got on the piss that night and after listening to him bullshit on for a while - I pointed out that for all his work - all he was doing was diluting good Avgas with shitty unleaded fuel !!


of course, when he ran out of his special mix halfway through the next day, he had to fill his tank with normal unleaded fuel......and crazy but true - his bike ran just fine for the rest of the day.......

".....shut the gate on this one Maxie......it's the ducks guts !!............."
- Wattie
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Re: Fuel additives
I had a mate with a shit hot cr250...
his words anyway.
He used to mix the fuel and oil at 32.5:1.
He assured me this was the perfect mix. I laughed and spent the days watching him have to rev the crap out of it everytime we stopped coz it was fowling up.
Oh and it had gold valves, so it handled like no other apparently

He used to mix the fuel and oil at 32.5:1.
He assured me this was the perfect mix. I laughed and spent the days watching him have to rev the crap out of it everytime we stopped coz it was fowling up.

Oh and it had gold valves, so it handled like no other apparently

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- Gosling1
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Re: Fuel additives
its amazing how some people can convince themselves that something like 32.5:1 *MUST* be used everytime.....
If he was using fully-synth 2T oil, it should have been up around 45:1 or even a bit higher..........32:1 is pretty rich for synth 2T.
For mineral oil or castor oil - 32:1 is a good ratio. You wouldn't want to go much leaner than that, but I have run some of my old-dunger 2T motors down as rich as 25:1 with SuperTT.......plenty of smoke but you *know* the bastard is never going to seize !

If he was using fully-synth 2T oil, it should have been up around 45:1 or even a bit higher..........32:1 is pretty rich for synth 2T.
For mineral oil or castor oil - 32:1 is a good ratio. You wouldn't want to go much leaner than that, but I have run some of my old-dunger 2T motors down as rich as 25:1 with SuperTT.......plenty of smoke but you *know* the bastard is never going to seize !

".....shut the gate on this one Maxie......it's the ducks guts !!............."
- MAXUMIS
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Re: Fuel additives
Was the mix with methonal??Wattie wrote:I had a mate with a shit hot cr250...his words anyway.
He used to mix the fuel and oil at 32.5:1.
He assured me this was the perfect mix. I laughed and spent the days watching him have to rev the crap out of it everytime we stopped coz it was fowling up.![]()
Oh and it had gold valves, so it handled like no other apparently
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- pittster
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Re: Fuel additives
From my old 2 stroke boat motor building days 25:1 for run in 50:1 for most motors, the new variable ratio oil pumps run 200:1 at idle and 80:1 at full throttle. A boat motor is not quite as stressed out as a 250 bike 2 stroke but they do sit on 6,000rpm for hours non stop. Again I have been out of that game for years so the ratio's have probably all changed
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- Wattie
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Re: Fuel additives
I had a 4hp mercury on an inflatable boat. It had a 100:1 sticker on it from factory.pittster wrote:From my old 2 stroke boat motor building days 25:1 for run in 50:1 for most motors, the new variable ratio oil pumps run 200:1 at idle and 80:1 at full throttle. A boat motor is not quite as stressed out as a 250 bike 2 stroke but they do sit on 6,000rpm for hours non stop. Again I have been out of that game for years so the ratio's have probably all changed
We ran it in on 50:1. Then went to 100:1
Not much oil in there!
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- pittster
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Re: Fuel additives
If in doubt thin it outWattie wrote:I had a 4hp mercury on an inflatable boat. It had a 100:1 sticker on it from factory.pittster wrote:From my old 2 stroke boat motor building days 25:1 for run in 50:1 for most motors, the new variable ratio oil pumps run 200:1 at idle and 80:1 at full throttle. A boat motor is not quite as stressed out as a 250 bike 2 stroke but they do sit on 6,000rpm for hours non stop. Again I have been out of that game for years so the ratio's have probably all changed
We ran it in on 50:1. Then went to 100:1
Not much oil in there!

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- Gosling1
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Re: Fuel additives
If he was mixing with methanol, 32.5:1 would be way rich. Even on pump fuel - synthetic 2T pre-mix is normally way leaner than that...MAXUMIS wrote:Was the mix with methonal??Wattie wrote:I had a mate with a shit hot cr250...his words anyway.
He used to mix the fuel and oil at 32.5:1.
He assured me this was the perfect mix. I laughed and spent the days watching him have to rev the crap out of it everytime we stopped coz it was fowling up.![]()
Oh and it had gold valves, so it handled like no other apparently
older 2T boat motors about 50:1 was on the money, but remember that outboard oil is an entirely different animal to m/cycle engine oil. The changes in mixture ratio are less about engine longevity and far more about emissions and *nothing* else these days for outboards.Wattie wrote:I had a 4hp mercury on an inflatable boat. It had a 100:1 sticker on it from factory.pittster wrote:From my old 2 stroke boat motor building days 25:1 for run in 50:1 for most motors, the new variable ratio oil pumps run 200:1 at idle and 80:1 at full throttle. A boat motor is not quite as stressed out as a 250 bike 2 stroke but they do sit on 6,000rpm for hours non stop. Again I have been out of that game for years so the ratio's have probably all changed
We ran it in on 50:1. Then went to 100:1
Not much oil in there!
Modern-day 2T outboard motors are the pinnacle of 2T motor development. Direct fuel injection with almost zero emissions, incredible power outputs from not much capacity......this is where you find the best 2T motors in the world.
How good would a 400hp V8 2T motor be in decent frame ???



".....shut the gate on this one Maxie......it's the ducks guts !!............."
- pittster
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Re: Fuel additives
Yeah worked on a few mercury 300hp V6 2 strokes with direct injection putting out about 380 hp at the prop awesome design and this was in 2002
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- MAXUMIS
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Re: Fuel additives
We used to run around 50 to one with normal fuel but always went richer with methonal as you have to throw so much more fuel into it to get the power+if you run 50 to one with methonal it will seize very quickly as compared to running richer.PS funny that this has turned to two strocks 

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- Gosling1
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Re: Fuel additives
what sort of engines were you running a 50:1 mix of nitro in ?
2T rule
2T rule

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- seiko1
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Re: Fuel additives
Throw the shit on your President.....while he's hugging the dumb fucken thing we're stuck witholdman wrote:I talked to a few people about adding nitro methane to my fuel and it sounds like a bad idea. According to the "experts" my power commander would not be able to supply enough fuel to keep it from running way lean and even if it did run a proper mixture the combustion chamber pressures without head, piston and lower end work would probably smoke my motor.
I have a gallon of very expensive fuel now and the storage life on nitro methane is very short. Time for a Jim to think this over. Perhaps a bomb??

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- MAXUMIS
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Re: Fuel additives
I have never run nitro at all (other than remote control cars),i did run methonal in my kx 125 many moons ago not at 50:1, 30:1 was all i ended up going after it seized the big end ,I must admit i never cleaned out the motor with normal fuel (witch could of caused the problem) as the highly air rated fuels can cause a lot of corrosion. PS the cast oil is not cheep either .I am no pro at all but used to have fun trying things + love the smell.Gosling1 wrote:what sort of engines were you running a 50:1 mix of nitro in ?
2T rule
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