XRAY - Model racing cars

david, I got the motor tuned oh so perfect tonight, then we got a thunder storm-flooded the track and went out for pizza. so won't know till next week how I did. But it really felt good.

Good deal. Here is how I tune at a new track.

1. Fatten HSN 1/4 turn.
2. Tune HSN on track so it pulls 3/4 the way down the straight.
3. Set LSN so I have the punch I want.
4. Set idle so motor doesn't high idle or low idle and die.

Always start from fat to lean, #2 is the hardest to get, the rest is easy. If you motor is too lean then it may top out 1/2 down the straight but there will be a high pitched sound and little smoke. If it is too fat it can top out 1/2 down but it won't high pitched and won't be going very fast (lot of smoke). I want the car to pull almost to the end. If you set your motor to pull for the complete length of the straight then you will usually find yourself wanting to feel it top out every time and you will over shoot the sweeper or turn.

because of the bad weather approaching I was more or less alone and stood on the straight and just kept going back and forth till I was happy with the top end.( also found a few bumps I never knew about) then I got the bottom to idle for 5 seconds and punch it to immeadiate full bore ballon the tires from a stop. then I richend up the low end a touch and set the idle. it felt really good. I was actually overshooting the little doubles cause I was used to how it was tuned last week. big difference.last thing I did was check the temp and it was 240F.

240f on a stock head is typically the sweet spot (best performance all around on a correctly tuned P5, top and bottom). Sounds like you got it nailed. Remember that day time and night time tunes will vary a few hours usually on top.

David; I've been thinking about this and have a few points/questions to make.

tuning the HSN to only make power 3/4 down the straight - what if such a short straight that the engine ends up so rich it won't warm up to operating temp?( bad for piston/sleeve and not helping the glow plug do it's job)

if the HSN ends up excessively rich will the LSN end up lean to the point of no smoke to compensate?
then will there be a transition problem between low and high needing a mid range adjustment?
turns out my local track is just perfect for this tuning method but I can see if I tuned it on the indoor 1/10 scale track we have it would be so rich with a 40 foot straight I don't think this would work?

I wish someone would start using a gas analyzer to tune for Co and be more accurate.... (hint fuel injection in the future....

Can anyone tell me what is good temperature with Axe Rossi 160R21 LSK.?

In Celsius ratings please.

Auto2 - doing it like that won't work for a small track. That is an extreme condition running a 8th scale car on a small straights. Typically for a small track you run the motor very lean because you can get away with it because you are hardly in the upper RPM range (that creates the most heat).

Once you run the motor long enough you will get used to the sound the engine makes at good operating settings. I tune more to sound and feel now but you need to know what to expect from your motor/pipe/fuel before you do that.