Which way is it better to set your engine, rich or lean on top?

Rich on top should really protect your engine of not overheating.
But this is a little slow to get high rpm/speed. But sure to finish the race.

Lean on top might cause overheating when you change the rate of gunning
the gas. Also on longer runs you might keep on pushing the car that will
tend to overheating. However, this setup lean on top is faster for the
engine to reach high rpm/speed. Also I get better lap time in this setting.

What can you say on this? What would you prefer?

I guess that, if you run just a tad leaner on top, you will have the performance. If you have the money for that! (leaner on top you are taking from the engine "longevity")

And see, you should not run lean.
Its just that optimal performance point, where the engine is at maximum. That point is leaner than the setup I would recommend... Just a bit ...

ah... the on going debate between run it rich or lean.

I've read in more places that running it rich CAN be more damaging to the engine than running lean. But then again, you can find the same amount of articles stating the exact opposite.

As long as you have good smoke coming outta the pipe in the powerband... AND you are definitely not overheating, you have it set right where you need to be. The perfect tune!

When running in really hot and really humid weather. Should you ever make changes to glow plugs or shim the head differently?

You shud not run lean on the HSN becuase you will ruin the engine. but it does not mean you need to run rich if you are racing. Look at the plug at all times. There shud be a slight film of fuel around the edge of the coil and the coils are shiny. This shud give you 90-95% power. If the edge is not wet but the coils are shiny then it is 100% and anything leaner will start damaging the engine. I will not use the amount of smoke for indication becuase there are too many brands and the smoke can vary depend which oil they are using, not a good indication at all.

most of our fuels come from 1 of a very few factories here in the USA. There might be 30-40 different brands, but those 30-40 come out of like 1-5 factories here in the USA.

OIL commonly used is Klotz.

You will amaze how many brands use Union Carbide lubricants for their synthetic oils.... Maybe Dennis (Richey) remembers some old posts regarding this.

we've used klotz in our snowmobiles and dirtbikes. I've come to the point where if a nitro fuel doesnt use amsoil or klotz, i dont run with it.

Just felt like giving this a bump

Thanks all good info for tuning.

What setting do you always run? lean side on top and rich side on bottom?
good for a small and tight track
Or rich side on top and lean side on bottom?
say for a open and big track

thanks in advance for your comment on this.

I need to mark this thread......