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Fuel for HPI Firestorm??

Old 10-30-2011, 01:40 PM
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Lewis.
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Default Fuel for HPI Firestorm??

I have a question on this, as most people tend to run 16% yet the manual recommends 25%? Does it run better on 16% or what?

Thanks all
Old 10-30-2011, 02:23 PM
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wrighty8766
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Default RE: Fuel for HPI Firestorm??

probly just get a little more engine life with 16%

and its much easier to tune with lower %
Old 10-30-2011, 04:42 PM
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Default RE: Fuel for HPI Firestorm??

Are we talking oil content or nitro content? If its oil, I break-in on 14-16% oil and drop down to 12% for normal running. If its nitro, I run 20% all the time. The more nitro you have the wider the tuning window (sweet spot) it will have. Less nitro narrows your tuning window so the perfect tune is a little trickier to get depending on the engine. Less nitro is more efficient, since the needle is leaner. More nitro needs a fatter needle to compensate for the extra oxygen in the fuel (nitro = full of oxygen molecules)

Most engines will run just fine on 10% nitro, but most folks want a little more power so stepping up the nitro a tad will give more power. It comes down to how much you're willing to spend. The engine isnt going to care much what you run in it as long as it has some methanol and oil in it. If you're a good tuner, you could run it on 0-5% nitro too with a few easy modifications.

Old 10-31-2011, 01:26 PM
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Default RE: Fuel for HPI Firestorm??


ORIGINAL: 1QwkSport2.5r

Are we talking oil content or nitro content? If its oil, I break-in on 14-16% oil and drop down to 12% for normal running. If its nitro, I run 20% all the time. The more nitro you have the wider the tuning window (sweet spot) it will have. Less nitro narrows your tuning window so the perfect tune is a little trickier to get depending on the engine. Less nitro is more efficient, since the needle is leaner. More nitro needs a fatter needle to compensate for the extra oxygen in the fuel (nitro = full of oxygen molecules)

Most engines will run just fine on 10% nitro, but most folks want a little more power so stepping up the nitro a tad will give more power. It comes down to how much you're willing to spend. The engine isnt going to care much what you run in it as long as it has some methanol and oil in it. If you're a good tuner, you could run it on 0-5% nitro too with a few easy modifications.


i thought it was easier with lower nitro?

i might be thinking RTR and race blended fuel!

Old 10-31-2011, 02:06 PM
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Default RE: Fuel for HPI Firestorm??

When you mentioned 16%, I got confused because "standard" nitro percentages are 10%, 20%, and 30% for example. I haven't seen 16% nitro before, so thats why I questioned it.
Old 10-31-2011, 02:29 PM
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Default RE: Fuel for HPI Firestorm??

iv never used 16% myself, iv seen it once or twice though!

used to use 10% about 10 years ago when i was young, i use 25% tornado now, its really good fuel just a bit expensive. 
Old 10-31-2011, 02:43 PM
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Lewis.
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Default RE: Fuel for HPI Firestorm??

I was talking 16% like this:

www.modelsport.co.uk/modelsport-uk-performance-16-glow-fuel-1-litre/rc-car-products/29346

The manual for my Firestorm recommends 25% but it seemed a nightmare to tune on that. Kept cutting out and wouldn't start for ****. I have read loads so figure I am pretty clued up. Is it easier to tune the car when running a lower percentage of nitro?

thanks again guys
Old 10-31-2011, 03:04 PM
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Default RE: Fuel for HPI Firestorm??


ORIGINAL: Lewis.

I was talking 16% like this:

http://www.modelsport.co.uk/modelspo...products/29346

The manual for my Firestorm recommends 25% but it seemed a nightmare to tune on that. Kept cutting out and wouldn't start for ****. I have read loads so figure I am pretty clued up. Is it easier to tune the car when running a lower percentage of nitro?

thanks again guys
More nitro is easier to tune and adds power. If it revs slow and really smokey, its too rich. If it cuts out its too lean. The idle needle controls fuel mixture from idle to about 3/4 throttle, and the main needle (high speed) controls that last 3/4-WOT bit. Richen your low speed mixture a 1/4 turn or so and run a WOT pass or two to get the main needle set, then set your idle. Never set it the other way around.

Going from 16% nitro to 25% nitro would probably need the needles richened 1/4-1/2 turn to compensate for the extra nitro. More nitro = richer needles.
Old 11-01-2011, 01:17 PM
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Lewis.
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Default RE: Fuel for HPI Firestorm??


ORIGINAL: 1QwkSport2.5r


ORIGINAL: Lewis.

I was talking 16% like this:

http://www.modelsport.co.uk/modelspo...products/29346

The manual for my Firestorm recommends 25% but it seemed a nightmare to tune on that. Kept cutting out and wouldn't start for ****. I have read loads so figure I am pretty clued up. Is it easier to tune the car when running a lower percentage of nitro?

thanks again guys
More nitro is easier to tune and adds power. If it revs slow and really smokey, its too rich. If it cuts out its too lean. The idle needle controls fuel mixture from idle to about 3/4 throttle, and the main needle (high speed) controls that last 3/4-WOT bit. Richen your low speed mixture a 1/4 turn or so and run a WOT pass or two to get the main needle set, then set your idle. Never set it the other way around.

Going from 16% nitro to 25% nitro would probably need the needles richened 1/4-1/2 turn to compensate for the extra nitro. More nitro = richer needles.

Hi mate,

That's excellent thanks. So when you say the idle needle, you mean the idle needle and not the LSN (low speed needle?) Just checking - thanks for your help again!

Old 11-01-2011, 05:40 PM
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1QwkSport2.5r
 
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Default RE: Fuel for HPI Firestorm??


ORIGINAL: Lewis.


ORIGINAL: 1QwkSport2.5r


ORIGINAL: Lewis.

I was talking 16% like this:

http://www.modelsport.co.uk/modelspo...products/29346

The manual for my Firestorm recommends 25% but it seemed a nightmare to tune on that. Kept cutting out and wouldn't start for ****. I have read loads so figure I am pretty clued up. Is it easier to tune the car when running a lower percentage of nitro?

thanks again guys
More nitro is easier to tune and adds power. If it revs slow and really smokey, its too rich. If it cuts out its too lean. The idle needle controls fuel mixture from idle to about 3/4 throttle, and the main needle (high speed) controls that last 3/4-WOT bit. Richen your low speed mixture a 1/4 turn or so and run a WOT pass or two to get the main needle set, then set your idle. Never set it the other way around.

Going from 16% nitro to 25% nitro would probably need the needles richened 1/4-1/2 turn to compensate for the extra nitro. More nitro = richer needles.

Hi mate,

That's excellent thanks. So when you say the idle needle, you mean the idle needle and not the LSN (low speed needle?) Just checking - thanks for your help again!

When I speak of a "needle" I mean mixture needle. Most often, car guys call it the low speed needle though its the idle/midrange mixture adjustment. The main needle, or aka the needle valve is the "high speed mixture needle". The idle speed adjustment (controls idle speed, not mixture) isnt a needle, it just controls how far open the carb's slide or barrel is. The idle speed adjustment will effect idle/midrange fuel mixture. If you drop the idle rpm, you will in effect lean the idle mixture. If the idle rpm is changed, the idle mixture needle will probably need to be adjusted a little to compensate.

The high speed or main mixture needle is in a fixed seat, unlike the idle needle. For this reason the main needle is always set first, and idle second. Some carburetors will not take a proper setting if the idle rpm is too high. Most of the time, low rpm mixture problems come from too high of an idle speed. Shoot for a idle gap of 1.0mm or slightly less.


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