NEWBIE: Looking for some Tuning Tips

[V6king]

Hey guys.. I just got an HPI RTR EVO 3 and I'm new to the RC world... I got my car running somewhat nice and I'm trying to tune it for the best performance.

I did notice that it stalls frequently when I gun it suddenly and just dies. Sometimes instead of just dying out it actually hesitates and then stalls if that helps. The most established temperature was around 215, should it be more? Which carb screw should I adjust and to what direction. Any tips or ideas will be appreciated. ALSO, it spits out ALOT of fuel through the exhaust, however it also seems to be burning it correctly because its smokes under acceleration.

ANy tips will be appreciated. THANKS!

::JP

 

[Got Nitro?]

If you bought this car brand new,in the owners manual there should be engine factory settings,try setting it back to them, you should have 3 needl's, High speed needle,Low speed needle,And your idle needle. The high speed needle is bigger,usually sticking out of the carb and very noticable,lowspeed is located on the side of the carb,near the throat,screw needle should be located near the lowspeed needle. now that you got the general idea of your needle locations

Go to the low speed needle and richen it up about a 1/16-1/8 of a turn,that way your run just a tad bit fatter on low speed's and take off,keep's engine running better to a point,When you adjust the needle,Clockwise tightening is leaning it out.Counter clockwise is richening it up. What engine do you have in it,might help a bit more if we all know exactlly what it is.

 

[V6king]

Thanks NITRO for your quick response, I've been in direct CONCENTRATION with the manual (lol) yea my problem definitely seems to be from the lower needle...
HOW CAN I SET IT BACK TO THE DEFAULT LEVEL?

 

[Monkey Wrench]

JP, first off, if you can share what brand engine and what size it is, that helps us a great deal in assisting you in troubleshooting this issue. Also, let us know if you have run through the entire break-in procedure as well.

With respect to Got Nitro, you want to avoid adjusting the low-speed needle if you can avoid it, as generally that is not the root of the problem. Additionally, never adjust the low-speed until you have the high-speed dialed in. If you have adjusted the LSN, return it to factory setting, then focus on the HSN. The "idle needle" Got Nitro refers to is actually a screw, and will not factor into this right now. It has nothing to do with fuel flow within the carb., so don't worry about it right now.

OK, assuming you've completely broken-in the engine and have returned the LSN & HSN to factory settings, run the car until it comes up to temp. Most nitro engines run in the 230-250 range, so you're goal is to get in that window and maintain it there. Think of the HSN as a clock face with each digit as an adjustment mark. Turning the needle clockwise "leans" and engine out, meaning more air than fuel. "Lean" = fast & hot. Turning the needle counter-clockwise "richens" the engine. "Rich" = slow & cold. The goal is to find a happy medium here. If you run the car and it continues to bog at open throttle, you need to "lean" your HSN a bit. Because of the HSN setting, the engine is getting a bunch of fuel and not enough air at one time, so it bogs and stalls. It's also why your temp. is low. Turn your HSN needle one degree (i.e. "12" to "1") clockwise, run it again. Check it with a temp. gun and keep doing this until you get to a point where you notice no more performance improvements. What's critical is that you ALWAYS SEE A TRAIL OF BLUISH SMOKE OUT OF THE EXHAUST PIPE! If you do not see smoke when it's running, or see smoke coming from the head, you're too HOT!

Rather than overwhelm you, try going this route first. Once you have the HSN dialed in, you can look at your LSN, but generally speaking, you won't have many problems from that aspect.

 

[Got Nitro?]

Yeah listen to monkey wrench,he has a tendicy to be less confusing than I,Thanks monkey for correcting my mistakes,don't do everything backwards when it comes to tuning like i do,it will work,just a pain in the arse to a extent.

 

[V6king]

Monkey that's sounds excellent definitely I will try it once I have a chance..

::JP

 

[Monkey Wrench]

As for factory settings, without knowing the engine you have, it's hard to say. Generally, the LSN is set to flush with the carb. body. HSN generally is 3 turns out from closed. Check your manual, if it's not there, go the HPI web site, it'll be there.

 

[kx250ryder]

I just posted similar tuning advice on another thread. Sorry its a little long winded.

 

[Revo Rancher]

Most likely you have the stock. .15 motor in your HPI. If you do you will only have a HSN and a LSN. Get the two needles back to factory settings and then tune the HSN by leaning it 1/16 of a turn at a time until your car can take throttle at all ranges smoothly. In other words, you can slowly roll on the throttle and it will keep running smoothly up through the entire range, and at half throttle you can nail it and it will not die. Stop at this point and check your engine temps and make sure you are still getting a decent smoke trail. Then you can start high performance tuning with your LSN. If you lose your smoke trail, get high engine temps or the motor cuts out, when you are adjusting either needle, you are too lean.