hi,
seems like nobody uses 16%nitro for their .21 engines? any reasons?

Less power. The only time I see people in the USA running that low of a nitro content is to improve runtime.

16% is great if you need more runtime. You may not see the average dude using it since it's easier to make runtime when you're 1-2 laps off the pace but many pros use it on runtime sensitive tracks.

if engine is shimmed for 25%, to use 16% i just need to remove 0.1mm shim right?

wouldn't that compensate for the power loss and thus actually be similar to 25% power?

But it would run hotter with %16...

It will run hotter. Also if shimmed correctly it will still be fast, just a little less torque. I recommend using a hotter than normal plug if you do this.

DJ Apolaro

We used 16% with the JP Black Mod Eagle 9S at 301 Raceway and it worked great. Vincent Jackson TQ'd using that combo. We left the head clearance the same/normal so that we could run a little leaner without detonation. Performance was great and fuel consumption increased +1 lap from 20% and +2 laps from 25%. IMO it's the best way to improve runtime with the super hot mod motors.

running 16% on .12 engines also likewise hotter?
generally hotter by how much?

I think it depends but it can be around 20celcius...

20 celcious if you go from 25% to 16%?
naaaa i don't think so!

20degC hotter if from 25% to 16% is alot!

I currently run a cold plug with 25%. I'm switching to 16%. Should I move to medium plug? This will be for Novarossi .12 3sct
And I should expect my engine to run a little warmer when running 16% vice 25%?

ok ok I admit that I exaggerated

for my case, when i use 16% on my engine that is tuned for 25% and shim for 25%, the temp goes lower and i need to lean the high end to get the power. the temp diff range is like 10-15 degree c! this is for my .21 off road engine!

well if you shim the engine on 16% then yes it should run hotter than with the 25%...