HUNdave

hi all!
i have a problem with my nitro rc car's engine. so the thing is that whenever my rc car reaches the full speed, it stays there for a second and then bogs down.
why is that?

thanks!
-Dave

llkoolskillet

Its probably too lean. Whats the temp? I would richen the HSN about a full turn and see how she acts

Shenanigans

My Feedback: (12)

Agree with above, but not with richening a full turn.  try 1/8th or 1/4 turn richer and do a high speed pass.  If it bogs completely down, or stalls at top speed...she is a bit lean.  If it struggles to get to high speed and is sluggish she is probably too rich.  Adjust accordingly after high speed passes.

1QwkSport2.5r

My approach to tuning an engine is simple. Tune the high speed needle FIRST, idle mixture needle SECOND. Use your ears! With the engine fully warmed up, run a WOT pass. Listen to it. If the rpms go up as the car speeds up and then kind-of fall off or sag, its too lean. If it winds up slow and really smokey, its too rich. I set my high speed mixture by ear, and check it with a handheld GPS. When its peaked out, the rpm will not sag at full throttle and will give you the fastest speed. Once the high speed is peaked, set the idle mixture for fast throttle response from idle to WOT. (Quick WOT jabs from idle work well or use the fuel line pinch test)

purenitro33

Try this tuning guide, it does sound like a lean HSN but this may help get it running right.

http://extremercmods.com/content/tuning-popup.html

HUNdave

ok ill try to richen the hsn a bit.

HUNdave

thanks for the guide! thats the best one ive seen.

HUNdave

thank you very much for your help guys! the car seems to be fine now.