Engine setup for racing

[robriguez]

Since entering the world of Nitro (2-months) all I've been doing is running around parking lots. I've been running lean to maximize top speed and kick ass but I've decided to enter my first race. It will be in about 2-3 weeks so I'm trying to get the car all set up. I've been told that I should richen things up a bit so that I can get a better jump off the line. Lower end power is more important to get a good exit speed from the corner than is top end speed in the back straight away.

Well, when I richen the HSN I cannot start the car no matter what I try. I used a buddy's starter box last night and no matter what i did, whether I primed the engine or not, it would not start unless I leaned the HSN to 2 7/12 turns out.

So I left it there and started playing with the LSN. I have always kept it at 3 turns out. If I try to lean it, the car will not stay still unless I hold the brake. If I richen it any more than 3 or 4/12ths it will bog down and die almost immediatly when I try to accellerate from a dead stop.

If I keep the needles at HSN=2 1/2...LSN=3 3/12 it runs ok but lacks the performance I had before. Both high end and low end seem to suffer. What gives??

 

[Somers Racing]

What you need to do is put the needle back where it was and try to play with the low. I suggest you give the car 2 degrees camber on all fours, angle you shocks as much as you can so the are closest to being horizontal. That will allow you to run the car hard through the turns. Have the chassis ride height 3 to 5mm high.
If you can get your hsn set so you have max top end without being to lean your good, get your lsn so you have really sharp excelleration.
Hope this helps
Peter

 

[Nitroaddict]

rob - that last post was a good start - also keep in mind, that u will never reach top speed on a race track, unless it is just HUGE! to set your acceration stronger, u would want to lean the LSN, not richen it. also, u dont have a starter box? if not, get one! nothing worse than stalling on the track, and not being able to restart. the number one rule for racing still holds true : to finish first, you first must finish. dont worry about dialing in your car the first race u goto. set it up to be reliable and forgiving, and jsut do your best to not crash. if u can finsih in a novice race, u will most likely get in the top 3. good luck!!!!

BTW - didnt i tell u about that rossi being tempermental? lol.

 

[mjime714]

what kind of track are you running? if it a short twisty track, you want a lot of acceleration. if it is a big track with long straights, you want to go with more top speed. also, if you want to gain acceleration you should play with the gearing. I like the idea of richening the engine a little, but not for more low end punch, but to run cooler.

As for tuning the motor, I would start from the stock breaking settings. The reason the motor dies when rich is because the extra fuel is dousing the glow plug. I would start with a new glow plug. The lean setting is making the engine rev high which will engage the clutch. Not good. From the stock breakin settings, I start to tune the LSN first. Do the pinch test and then fine tune by how well it jumps off the line and performance. Adjust by 1 hour incraments.

Once you got it to a point where you like it, start to lean out the HSN by 1/8th of a turn at a time. Tune to temp as a starting point, then tune to sound, smoke, performance. Once you get to a point where you like it, richen it by 1/8th just to be on the safe side.

When leaning out the HSN, you may see a loss in the performance off the line. This happens because of a lack of fuel in the low end. By leaning out the HSN, you are also effecting the low end. Compensate for this by richening the LSN by 1 hour incraments. That should clear that up if you have any low end problems.

Good Luck.