Low Speed needle extremely touchy!

[pitbull14218]

Is the LSN the trickiest part of tuning? Is it the most sensitive needle?

I have a Savage 25, and basically i thought my motor was shot, i never took the engine completely apart to check the piston and sleeve but due to its poor performance i figured it was shot.....

TODAY!!!! Yay! I got it to run ok some how messing with both needles until it basically ran long enough to drive it around without stalling.

I leaned the HSN out watching the temps. I kept gradually leaning it out and the trucks top end performance kept improving..... until my reciever battery pack died

So basically now that i can go WOT without stalling and other problems like slow accerlation until at high speed, I'm affraid to touch the LSN because everytime i get a tune that the truck runs ok with once i try to get it to perform even better i ruin the tune

So basically since I'm a noob and this is the first truck i ever owned, let alone i bought it used who knows if it was broken-in correctly..... Is the low speed needle the hardest part to tune? my top end is ok, but there is a hick-up in the bottom and mid range that i would like to fix, but I'm affraid of ruining what i finally achieved!!!!!! maybe i can get it to do wheelies? seems once the motor gets a chance to rev out it is pretty strong!!!!

Thanks

 

[olds97_lss]

You tune your HSN to get it relatively good, then you adjust your LSN for power off the line.

Just adjust the LSN using very little adjustments and make sure to run it a few decent runs between adjustments. Trying to adjust too much too fast is how you get your tune all jacked.

Once you get an engine tuned really well, it usually only requires a mild adjustment day to day as the weather changes.

Give these a read:
http://www.rchobbies.org/cars_eng-tuning.htm
http://home.comcast.net/~98gmarquee/pics/misc/ParisRacingEngineTuningTechTips.pdf

Both are really good for new people that don't have tuning down and even for seasoned RC'rs that need a refresher.

 

[pitbull14218]

Thanks!

 

[pitbull14218]

I read in the article that Big Blocks use colder plugs? Maybe that could be a problem i have a hot plug? but that was for the winter, but is still in the engine.

 

[olds97_lss]

BB's generally like a "cooler" plug for proper fuel burn. I run OS #8's (medium-hot) in mine and they do ok. I know when I went from OS A3 (hot) to the OS8, the tune changed and I got more power out of the few engines I was running at the time. The OS8's ran good in my small blocks as well, so that's all I used to have around. However, late last season, I threw a McCoy MC8 (medium-cold) in my XTM24.7 and it made it run a lot better. I keep forgetting to try one in my LRP's to see if it improves.


EDIT:
Looks like OS changed out the A3 for a new number, #6:
http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXCB26&P=ML