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Fuel Percentages

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GruberRacing97

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I have always ran BT 20%.I went to the hobby shop today and got a quart of fuel,but when i got home I noticed it was 30% instead of the 20.and I live about 40 min, from the hobby shop.

My question is: Can i run this quart of 30%? Will i have to richen it up a notch or two.Or should i get another quart of 20%?



Thanks
Stan
 
Usually it is a good idea to pick a fuel and stick with it until you either get a new car or a new mill. I suppose there would be no problem running a new fuel, just make sure to do a complete retune and break-in. I think it would be easier to just drive the forty minutes lol.
 
If your driving 40 minutes, I'd be buying the gallon... What engine? If it's a 21 size (big block), you should really add a head shim before running anything over 25%. If it's a small block, you should be ok as long as you re-tune.
 
without knowing what engine you have, ....i belive some engines you have to add a head shim to run 30% but I'm not sure ...it would be easier to drive back & get the 20%

*****

damn i type slow...thats the second time olds has posted while i was writing ( & watching football) :)
 
The motor is a AE .15 My wife grabbed it for me.I was busy getting my son his first real rc,and some parts for mine.I didn't notice till i got home nor did i check before we left the store.

Thanks
Stan
 
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You can add a shim as others have said, however, I have read that once you go to 30% you should not go back to 20%. I can't recall the article and I'm not sure how just a quart would effect that theory. It's a pain, but you might want to drive back. BTW, welcome.
 
they say that higher fuel content stretches the sleeve out, and you can't go down. This is what i have heard.
 
the sleeve doesn't get stretched, the conrod does....you're forcing it down w/ a LOT more power than before...on the bottom of the stroke it beats the lil brass bushing to hell.......I switched to 25% and find it has all the punch of the 30% and less wear on your engine.......where an RG maybe lasted 5-6 gallons (max) before and it would just grenade the whole thing, I'm getting over 10 and they are still tight....conrod hasn't stretched and the brass bushing is still intact....
 
Can I get another quart of 20% and mix the 30% together and get 25%? I have a closer HS to me that has the 20,The reason we went to the other HS because they had the truck my son wanted?

Thanks
Stan
 
not trying to derail this thread, but i didnt want to start a new one for this one question. I used wildcats 20% nitro content, and 18% oil blend fuel, and now I'm using the same stuff but with 4% less oil content in it. Will it make it run cooler? i have heard this from a few people.
 
OFNA buggy basher said:
What is the advantage of running a higher than 20% nitro fuel? Just curious.
Click to expand...
More power off the line. If I'm not mistaken, the nitro is more for the low end grunt. I'm sure it helps some in the top end, but I believe most of the extra power is in the low end of the RPM range.
aj200415 said:
not trying to derail this thread, but i didn't want to start a new one for this one question. I used wildcats 20% nitro content, and 18% oil blend fuel, and now I'm using the same stuff but with 4% less oil content in it. Will it make it run cooler? i have heard this from a few people.
Click to expand...
It will let you run it richer which may in turn make the engine run cooler. You will be less prone to leaning it for power, but it's less safe if you don't know how to tune well. Although, 14% oil is still pretty conservative. I've run 12% for the 4 or 5 years (can't remember) I've been in the hobby.
 
Yes you can mix em...try and get the same brand to mix....I wouldn't mix brands at all if I can help it.......if I can't get 25% I buy 2 gallons and mix em......I've been adding a little more oil to the mix as well lately......my buddy got some and we dump 1/4 cup into 2 gallons of fuel....I forget the brand but you can buy it at any plane shop......it's a castor oil I think.....I don't know I tried it and it works well, so I'll keep doing it.......
Olds is right the higher contect is more for low end but on my P5 I notice mine revs way higher than a friends who runs 20%.......
 
olds97_lss said:
It will let you run it richer which may in turn make the engine run cooler. You will be less prone to leaning it for power, but it's less safe if you don't know how to tune well. Although, 14% oil is still pretty conservative. I've run 12% for the 4 or 5 years (can't remember) I've been in the hobby.
Click to expand...

first off i wanted to say thanks for going into depth on everything in this thread. you guys gave me a few pointers. now correct me if I'm wrong but richer mixture will produce more heat. as leaner mixtures wont produce as much heat due to more oxygen. i've been told to alway tune to stoichiometric which is 14.7:1 and at these levels combustion is optimum. at the same time it's for a real car and it's more of an economical issue. as for performance i've been taught to always tune on a 13.9 to a 12.9 fuel ratio (meaning id be on the richer side). either way if any of us are running richer we're always gonna see more heat. so my main question is is how should i tune my car? i know i should be on the rich side but how high on the rich side? I'm still a bit confused on oil content. and what that has to do with heat rather than lubrication my mill.
 
BlandAnalogy said:
first off i wanted to say thanks for going into depth on everything in this thread. you guys gave me a few pointers. now correct me if I'm wrong but richer mixture will produce more heat. as leaner mixtures wont produce as much heat due to more oxygen. i've been told to alway tune to stoichiometric which is 14.7:1 and at these levels combustion is optimum. at the same time it's for a real car and it's more of an economical issue. as for performance i've been taught to always tune on a 13.9 to a 12.9 fuel ratio (meaning id be on the richer side). either way if any of us are running richer we're always gonna see more heat. so my main question is is how should i tune my car? i know i should be on the rich side but how high on the rich side? I'm still a bit confused on oil content. and what that has to do with heat rather than lubrication my mill.
Click to expand...

woah nellie.....you went way out into orbit w/ that stuff....first off richer = cooler...leaner = hotter.....the oil content is listed on your fuel bottle...it helps keep temps down because it gives better lubrication = reduced friction = reduced heat....the oil thaat is in your fuel is the only lubrication your engine gets....everyone has prefferences on which fuel is best so I'll leave that to your discretion....personally I don't even look at oil content......I try what the fastest guys at my track try and go w/ the one I can tune best w/.....as far as "how" to tune your car......tune it to the performace you expect.....BUT, as you go leaner and leaner for performance you sacrifice engine life as well...it's a trade off....do you want to go fast???? speed costs money, how fast can you afford to go????.....tuning is something you MUST learn to do if you want to play w/ the cool RC toy you got....I suggest to every beginner to read the Ultimate nitro tuning guide...it explains alot of stuff in a easy to read.....
 
What is a great 30% with high oil content? Wanting to try 30% in a .12 cv-r with a o.s # 5 glow plug.(instead of the factory # 8).
 

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