HPI T-15 Engine stalling

[MustangMan]

I've recently gotten back into RC and this is my first ever nitro car (HPI RS4 Evo). I've got about 12 tanks of gas through her (finished the quart of Trinity 20% that came in the break in kit) and I've got an intermittent stalling problem.

Here in Central Florida it's hot as balls as the humidity is like 1000%. :flaming: Once running I lean out the HSN to get a nice trail of smoke at WOT and my head temps are usually around 220-230.

Problem is, I'll be bashing a bit up and down the block and she'll die like she's too lean. I put her back on my work stand, let her cool for about five minutes, and she's hard to start. I usually have to give the radio some throttle to get it up and running.

I've got the idle speed screw set for the proper opening like the manual says, filter is clean, no fuel leaks, running an OS8 glow plug. :shrug:

Can I get some suggestions? She runs like a raped ape and I've clocked it at 40 mph already (my LHS says it will get a bit faster) but it sucks when I do some hard braking, whip the car around to bring it back and she dies (it's a long friggin walk!).

Thanks for any ideas. Love this nitro stuff!

 

[jon2]

really sounds like you are starving it of either fuel or air. Do you have a temp gun to check the temps right after it dies? Sounds like you run it well but your gap opening in the carb maybe small and when you brake you kill it. I wouldn't play with the opening.

First How is your top speed at start up? Do you notice that it is strong and punchy at the start but once it warms up you lose power at top? Do you lose power at the start of acceleration? If you are losing power at the top you are too lean on the HSN. If you are losing power at the low end you are too rich on the LSN. I don't have experience with that engine but generally I have tuned to those rules. Good luck

Jon

 

[MustangMan]

When you say at start up, are referring to cold start, or after it stalls? From a cold start it is fat down low. I give it some part throttle laps for about two-three minutes until it warms up and then I make a couple of full throttle runs, checking head temps and lean it out as needed. I haven't touched the LSN from the factory setting. I've been reading up on the "pinch test" and wonder if my LSN is running lean.

Like I said in my first post, I checked and set the carb opening to 1mm like HPI states in their manual. I think the idle may even be a tad high (clutch not engaging or anything, just seems a bit high, but then again I'm a nitro noob...)

 

[jon2]

You should set your carb opening then try to lean the HSN first then the LSN and then retune your idle. The pinch test I could never get the same results all the time so I use a the temp gun and the exhaust coming out of the pipe.

As far as your clutch not engaging could be a few reasons. your springs are weak or your shoes need to be scuffed up as they may have a little glaze to them. I am assuming you have the stock shoes so they are the teflon ones, I think.

 

[Rolex]

If you are sliding it, then hitting throttle again, and THEN it's dying, it's your LSN. Try richening it 1/16th turn at a time. The HSN if for WOT running, and that end sounds good.

 

[MustangMan]

What I meant was the idle wasn't so high that the clutch engaged and spun the drivetrain at idle. The clutch engages fine when I get on the gas...

I guess I'll have to play with the LSN a bit.

Thanks...