turbo5513

Hi,
I am a newbie to R/C nitro and I have just received my RTR truggy 2 days ago. I am running a Hpi Trophy Truggy 4.6 (0.28) (which has the same engine as the savage x 4.6) I have just completed earlier today and did some bashing right after and kept the same rich settings. While I was bashing, I decided to put the body shell on for the first time and I continued to monitor my temps. They were 15-20 degrees higher because of lack of air flow, but I was still confused because my needles where very very rich and my temp with the body shell on was 235 which is meant to be the temp when the car is leaned out and tuned. The manual says that above 250 is the 'danger zone'...Am I meant to drive faster or possiblly tune the car which I will do tomorrow but I'm worried because of those temps. Oh and I am using Jets R/C fuel 20%. If you take your time to read all of this, I would like to say thankyou

hustler777

iTrader: (1)

there is no "magic temp" with these little motors....i've seen them scream all day at temps ranging from 170 all the way to 290+....the "rule of thumb" is to keep temps at around 230...i for one don't temp motors anymore, even for a base line....i tune by smoke and sound.......if your motor is still running rich, lean it out 1 hour at a time to where it's just barely rich until most of the mechanical pinch is gone from the piston/sleeve...then take it the rest of the way to a full tune...

thkelly

iTrader: (6)

+1

I agree exactly with what he said. I don't tune by temps, I tune by sound smoke. Some engines like to run warmer than others on a perfect tune, some cooler. The only time I use temperature readings is when I am preheating the engine prior to running it...and during break in.

turbo5513

Thanks so much guys, today I will tune the car and see how it goes

WildManDriving

iTrader: (30)

Also if you have started to run the tank dry, or close to, this will lean mixtures out an add temp to the motor.

turbo5513

I just finished tuning and I only touched the HSN for now. I turned it 3 hours and it was amazing what a difference it made. The temps surprisingly stayed below 210 degrees. I still have a good amount of smoke coming out of the pipe and it doesn't seem to be bogging or anything like that. I turned it then 1 more hour and the speed was blinding!! Although when I gave it full gas from the start it sort of like bogged like it was going to accelerate then the throttle shut off a bit then accelerated back again. I had good smoke and the temps stayed the same so to be safe I just set it back to 3 hours. Could it be that the LSN needs tuning now?

beidle99

iTrader: (9)

Sounds like you are now to lean on the HSN. Open it back up 1 to 1.5 hours from your 4 hours leaner and run it. You were experiencing what sounds like a lean bog. It could also be that you are not fully broke in yet and there is still mechanical pinch causing the temps to climb. and if you haven't read it yet read the engine tuning bible at the top of the page.

turbo5513

I turned the needle 1 hour anti clockwise (my 3 hour position in the previous post) and the car is still fast but slightly sluggish. When I had turned the needle 4 hours I still had a good amount of smoke and cool temps. All that worried me was that slight hesitation. When I was driving it on full throttle, there was no sign of hesitation besides when I give it full gas on the start. So it the hesitation could be a lean sign? Even though I have smoke and all that?

xrocket21

iTrader: (58)

you want a slight hesitation from the start, that means your low speed needle is correct. If it just rips out of the hole, your lsn is too lean

dooug1960

iTrader: (6)

i have no hesitation on full throttle pull from start. after engine has been run and everything is operating temps do the pinch test to set your lsn. if you arnt familiar with pinch test just do a search for it on you tube or google it

Klimpen717

WHAT ??? You want a slight hesitation?
That is by my standard NOT TRUE. If you can tune an engine perfectly you SHOULD NOT have any hesitation when you squeeze that throttle.
From idle to full throttle as fast as you finger can move and the engine should LAUNCH....

You are best off trying to tune the HSN first and when you have that down and prefect you can go back and tune the LSN if you want.
You hesitation probably come from metal pinch that is still left in the engine.
Don't worry too much about it just yet, if it becomes worse you have to adjust.

sschultz

iTrader: (15)

If you have good smoke at WOT, and temps are where you want them, lean the LSN in 1/2hr turns till hesitation is gone. Temps should be used as a reference,210 is is on the low side, imo. 230-245 is good running temp, imo. You do need some heat in these engines to run efficiently. If you tune your low speed needle according to "the tuning bible" at the top of forum, you'll get the best results... good luck...

hustler777

iTrader: (1)

Glad to hear your having some good results!! Like others have said, now start with the low speed needle (the one on the carb slide)...I would go @ 2 hours richer and see if the big gets worse or better...if worse, lean it out 1 hour at a time, if better, keep richening it till you have good consistent power from idle to wide open throttle

turbo5513

Thanks so much guys, I will now try to tune the LSN tomorrow.

turbo5513

Just had a look at the tuning bible, it is very extensive, I will definitely use this to help me.