CrankyCat

is there such a thing as "Too much airflow"?


Hi, recently I experimented with some air filter media. I had to make some because my local RC shop discontinued their Nitro products (Just Electric). anyways I tried some different material and techniques to improvise an air cleaner for HPI, trophy trugy 4.6. nevertheless, I improved my creations until today!!! I made my best air cleaner so far in term of air flow still realised it is very hard to tune the engine for this new filter! it seems impossible to heat the sweet spot now!
I'm not sure if it is because of too much air flow or something else as I did some major maintenance and service regarding the carburettor and engine.
my question is, can to much air flow(compare fo fuel flow) make tuning impossible or impractical?
by the way, I'm sure I could by a new air cleaner online with the fraction of what I spent so far but I feel the hacking and modding is as fun as driving the car if not more! (any thoughts on that?)

1QwkSport2.5r

What other maintenance did you do the carburetor? You shouldn't need to do really anything to it unless the engine isn't running properly. As for the air filter - high air flow should not make it harder to tune. At all. It could be that the old air filter was very dirty limiting airflow requiring a leaner needle setting due to higher fuel draw. A clean air filter will require a richer needle setting - although these are extreme scenarios. Generally you should not need to adjust the needle valves much - maybe 1/4 turn (and that is a LOT) when cleaning the air filter.

Besides reinventing the wheel, you need to make absolute sure that your air filter is trapping dirt and debris and preventing it getting into the engine. I would not favor any filter media that is incapable of being oiled. That sticky air filter oil will capture more debris than any paper filter can (without causing a flow restriction).

Could you post pictures of your homebrew air filter?

phmaximus

ive seen some crazy air filter modifications over the years, my advice is to keep it stock. there is alot of OEM and aftermarket filters to suit ur engine and they are really cheap. most if these modifications generally hurt performance and create other problems of there own.

with the replacement cost of a nitro engine I would always make sure the air filter is perfect, whats the point of saving $2-3 on air filer material where it could potentially destroy a $100 plus engine...

but to answer ur question, no there is no such thing as to much flow. my guess is its just needs re-tuning

1QwkSport2.5r

Airplane engines are run without any air filters whatsoever, just to add to the busted myth.

CrankyCat

Hi mate! thanks for the reply and your help. this filter might sound disappointing or very crude, but I never saw dust or sand penetrate more than the half of the filter length. I made them from aerosol caps. I drilled a hole at the top to connect to L shape plastic hose then I lay down layers of oiled fishtank filter media sandwich between flyscreen mesh (cut in the same diameter of the cap) that way the mesh protect the carb from any possible fibres from filter media. also, that way I could check the top layers for any dirt and sand and replace the top layers if necessary... then I hot glued the top with 2 layers of mesh with 45 degrees rotation to make the holes smaller to capture large particles mostly grass leaves ...