is the uniflow tank mod the best to fix half tank lean these days? or a new tank?

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pelicanprentice

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hello, i have a savage x 4.6 and i think i started getting the htl. last week my savage x ran completely fine, it had tons of power and was popping wheelies and the temps stayed at the desired range. however this weekend, it was acting up. i was using the same fuel from the same bottle. i believe i am getting symptoms of htl. it wouldnt hold a tune properly, it would start overheating and i would have to richen it, and then when i richened it, i had to richen it way too much to actually get it to stay around 230f and then it got all groggy. the ambient temp was around 70f and i am running 30% nitro with a traxxas 3232x which is a medium heat plug. i also noticed at some points i could see air bubbles in my fuel line.

i know my o ring for the tank was bad and was kinda chipped and stuff so i picked up a set of o rings at my local hardware store and i got a size thats pretty similar. it seems to seal the tank pretty good. when i close the other end and i blow into the tank, its not perfectly sealed but its seems to be sealing atleast 90%, i can hear a slight air hiss. however ill try a diff size o ring and see if i can get it sealed perfectly fine.

however moving forward i want to do something jsut to get rid of a potential htl once and for all, i did my google research however most of the topics on this are old so i was wondering if anything changed or if theres a better method to fix htl now in 2021.

personally if i can find a new tank that mounts easily on my savage x and doesn't have HTL i would totally prefer that first, secondly i was thinking of doing the uniflow mod until my new tank comes in. so I'm looking for tank recommendations and preferably one with a threaded gas cap, i dont really like the spring cap, i feel like a threaded would always seal best

looking for recommendations!!
 
it definitely sounds like your problems are due to an air leak, any leak of the pressurization of the fuel system will cause it to run off/wrong. at higher throttle (higher pressure from exhaust) the tank will loose more of its pressure because of the leak and will cause the engine to run leaner.
i know one of the fixes for the HTL was to lower the tank a bit, few write ups on HPIsavageforum.com regarding that.
not many Nitro RC tanks use threaded cap style of tank lid, so unsure on that front.
 
I really don't think that is the problem? If the pressure drops in the tank that is the problem and that what causes the lean run at the bottom of the tank. As the engine heats up the compression will drop lowering the pressure in the tank. It all comes back to oil lube. Less oil lube and the engine looses compression. Which lower's tank pressure at bottom tank. When the tank is full and engine is cold is runs fine. When engine runs hot tank pressure drops and that's what causes lean run with low oil lube. I have never had problems threw the entire tanks of any of my trucks with pressure loss. Even after repeat runs. The problem is the temp and compression loss lowering the tank pressure from not enough oil lube. Engine temp should be 200-250 degrees.
 
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I really don't think that is the problem? If the pressure drops in the tank that is the problem and that what causes the lean run at the bottom of the tank. As the engine heats up the compression will drop lowering the pressure in the tank. It all comes back to oil lube. Less oil lube and the engine looses compression. Which lower's tank pressure at bottom tank. When the tank is full and engine is cold is runs fine. When engine runs hot tank pressure drops and that's what causes lean run with low oil lube. I have never had problems threw the entire tanks of any of my trucks with pressure loss. Even after repeat runs. The problem is the temp and compression loss lowering the tank pressure from not enough oil lube. Engine temp should be 200-250 degrees.
Do you have a savage? This problem has plagued the savage forever. And yes I have a savage ss. Also, how will you know what the engine temps are without that "crutch" you spoke of, you know, a temp gun. You do realize that the answer to every nitro related issue is not "run it rich" or " low oil lube".
 
Do you have a savage? This problem has plagued the savage forever. And yes I have a savage ss. Also, how will you know what the engine temps are without that "crutch" you spoke of, you know, a temp gun. You do realize that the answer to every nitro related issue is not "run it rich" or " low oil lube".
thank you lol
 
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