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Gasoline questions

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Hiho, usually I uy Rapicon 16% Nitro at the local hobbystore. 16% is fine for Tamiya, as they tell us.

Now it happened to get a Savage in my hands and the 4.6 motor needs 20% - 25% nitromix.

Well, I read that you should not change the gasoline once you got hooked on one brand but I think thats not correct.

Now I am thinking to buy 20% nitro also for use with my Tamiya.15 and LRP.18 motor. I dont want to have several different gasolines stored, one for all, all for one!

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I have heard of that too.  

I think it's similar to breaking-in.  I don't know how breaking-in works in molecular level.  But I follow the breaking-in process.  I suppose it is similar to fine sanding.  You make parts grind each other through lubrication, so they'd be fit together.  

I think "using the same fuel" works similarly.  The engine is used to certain amount of lubricant.  Changing fuel might require new breaking-in.  (Personally, I think it has more to do with lubricant content than nitro content.)  Nitro content changes the ignition point, I think. (or is it just cooling?)  Not exactly sure, but higher content ignites sooner?  At any rate, actual burning is done by the alcohol.  

20% nitro would help with ignitions, 70% alcohol would explode, pushing the piston down, 10% oil would lubricate the piston.  Of course, the recipe is all different depending on the product.  (There are gasoline engines too, but I am guessing 4.6 isn't one of them. 30cc for 1/5 buggies would use gasoline.)  

So yes, I think you can change the fuel.  20% is fine all around, I think (just check the temperature of the engine).  Every time I change fuel, I try to run half tank at idle, burn the rest at slow speed.  (But in reality, I'm not very patient. I run it empty for a few minutes and start playing with it at slow speed)  Savage is a beast.  Have fun!  

 

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I have never had any issues changing fuel as long as the engine has been broken in correctly initially. As mentioned I think it is more to do with lubrication than nitro content. I have actually mixed odd bits of fuel together with no issues either. Generally I use 16% for most of the Tamiya nitro and 20% for the more demanding engines like the TNX 5.2r, Nitrage etc.

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First things first.

There is absolutely no problem switching fuel. All you need to be aware of, is the fact that you need to retune your engine when switching.

Secondly. What you want is a good 25% nitro fuel(not gasoline) with 10-12% oil. No more, no less. It's a myth that a lot of oil will make the engine live longer and run cooler. Fact is that too much oil will make it run hot and there's a much smaller tolerance for lean conditions.

Too much oil will also hydrolock your engine more, thus wear out bearings and snap conrods and wrist pins much easier.

Byron 25/11 gen2 mix works great, so does Sidewider 25/12 and Big Bang 25/10.

You can run a 20/16 fuel with castor for initial idle breakin, but not for much else.

What 25% fuel is available where you are? 

All your engines will work well with the suggested fuels. The .28 in your Savage and the LRP will also run very well on 30% nitro.

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Unfortunitly its really hard to find nitro fuel right now. Its not allowed for shipping. Only 4L 16% is what I can get easylie. Brand name is Rapicon, a very good nitomix.

The only 20% and 30% I can get is named helicopter-mix with 22% oil. <_<

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These guys ship

http://www.osengines.gr/index.php?main_page=product_info&products_id=2461&zenid=ih0t4dm61r3fgtqab2khkac1o1

These guys might help too.

https://www.cmldistribution.co.uk/product/B3130191/byron-race-2500-gen2-25-fuel-1-2-gallon-11-

Or these guys

http://www.rcparts.eu/racing-experience-hot-fire-euro-25-nitro-off-road-fuel-5l.html

Here maybe?

https://www.modellsport.gr/index.php?main_page=product_info&cPath=8&products_id=3973

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aaah, no. I woulnd buy it from Greece or UK. Shipping would be more expensive then nitro :D

 

But I have to find a solution, thanks anyway for the linked products.

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2 hours ago, Collin said:

aaah, no. I woulnd buy it from Greece or UK. Shipping would be more expensive then nitro :D

 

But I have to find a solution, thanks anyway for the linked products.

Why can't your local dealer get Rapicon 25% fuel? Not a big fan of Rapicon. Makes too much soot and runs too hot for my liking.

The price of 35 Euro for a gallon of Sidewinder 30% is actually pretty good. Just buy 4-5 jugs to offset the shipping cost. You'll go through it in no time anyway.

Sidewinder is definitely one of the best fuels on the market and well worth the money.

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mhm,... didnt had any other than Rapicon. This one is avalable at a local store. http://www.kyoshoeurope.com/racing-fuel-hotfire-euro25-5-litres.html

 

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36 minutes ago, Collin said:

mhm,... didnt had any other than Rapicon. This one is avalable at a local store.

 

Definitely go with Hotfire if you can get that. It will work well in all your engines. It runs similar to Byron.

I still prefer Sidewinder, but the Hotfire is a good fuel overall.

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I will go for it! Great to know that Rapicon isn´t that good. People sayed its top notch. :blink:

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3 hours ago, Collin said:

I will go for it! Great to know that Rapicon isn´t that good. People sayed its top notch. :blink:

I had two jugs last summer. Every couple of tanks I could spend a ton of time digging out carbon dust. There were litterally a pile of it on top of my piston after I had run the car for an entire day, about 9-10 tanks.

Never again will I run that. When I run either Sidewinder or Modeltechnics Big Bang, my engines are nice and lubed inside, and everything is nice , clean and golden.

Only other fuel I used that also had issues with carbon deposits were Nitrolux.

Hotfire and Byron can leave a tiny bit, but nothing that will hurt anything, and can't be cleaned out when taking the engine apart for general maintenance or prior to long time storage.

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When choosing the right fuel, there is another point to consider: There is extra fuel for aircraft models and car models - just as there are aircraft and car engines. The application as well as the fuel is specially tailored to the different operating conditions.
While an aircraft engine (especially helicopter engine) usually runs at full speed with few load changes, a car engine is exposed to constant load changes (and speeds). The thermal and mechanical stresses are therefore completely different. In the same way the fuel is different: Rapicon is specially designed for flight/heli and therefore has a relatively high nitro and oil content. I wouldn't use this fuel in a car engine. Neither in the opposite case.

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5 hours ago, scoobybooster said:

When choosing the right fuel, there is another point to consider: There is extra fuel for aircraft models and car models - just as there are aircraft and car engines. The application as well as the fuel is specially tailored to the different operating conditions.
While an aircraft engine (especially helicopter engine) usually runs at full speed with few load changes, a car engine is exposed to constant load changes (and speeds). The thermal and mechanical stresses are therefore completely different. In the same way the fuel is different: Rapicon is specially designed for flight/heli and therefore has a relatively high nitro and oil content. I wouldn't use this fuel in a car engine. Neither in the opposite case.

Rapicon also makes both car and boat specific fuels. The fuel I tried and which I found to be chit, was their 25/11 car mix.

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On 8/11/2019 at 12:44 PM, DK308 said:

Definitely go with Hotfire if you can get that. It will work well in all your engines. It runs similar to Byron.

I still prefer Sidewinder, but the Hotfire is a good fuel overall.

Found a local dealer selling 25% Hit Fire in 5l units. hurray!

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