What brand and percentage of nitro do you guys prefer? I've heard that breaking the motor in with 20% is the best but then after broken in what do you think?

Depends on what you do. I run 20% cos i dont race. Most racers use 30% for maximum performance but using such a high content of nitro will decrease your engines life.

What kinda life difference compared to power do you get?

Well personally i wouldnt sacifice performance for life. If you tune your engine right at 20 percent then you should be more than happy with performance and it will save your engine keeping it running consistently for years to come.

I run 30% Trinity monster horsepower - Power blend with 12% Synthetic and racing castor oil. I have over 2 gallons through my SH .28 and have no longevity issues.

My SH dosn't run any hotter on 30% then it did on 20% (About 250 in good tune). If there isn't more heat and the oil content is there, longevity will be nearly the same...Kind of like putting 93 octane in your real car. More performance and the same life expectancy.

Just watch the oil content - some fuels are as low as 8% - that is too low - except for racing. 14+% is too high and will cause one-way bearing slipping and tuning issues. 12% seems to be the right mix.

Many people also swear by O'Donnels, but there isn't any around here.

I'm currently using 16% Sidewinder in my .21 (MGT engine). I would have liked to go to 20%-25%, but this was all that was availible at the time. I'm suprised how well the engine runs using this fuel, the engine was easily run-in, keeps cool, and will idle forever. I might step up to 20%, when i've used this up, but i don't see the point in reducing engine life by using 30% for only a small increase (relatively speaking) in power.

Why do you think it shortens engine life? Mechanically, what is different?

I figured it shortened engine life just like it would in a real car engine because of raising the compression (shortens engine life but produces power). I try to always relate the r/c engine to real engines because I know a lot about real engines. Starting to get back into r/c and just now starting the nitro scene.

30% does produce more power, but does not alter compression...only slightly affects timing. The SH .28 actually recommends it after break-in. In nearly any case, an engine will only need a shim or 2 added to bring timing back into the proper range. Larger engines (Big blocks .21+) are typically able to handle 30% without modification. The oil content is the same as 20% and the engine temps are nearly identical.

The only additional wear might be to the brass ring on the bottom and top of the connecting rod. This would be so minimal that over the average life span of 10-15 gallons, the difference would be negligible and would most like be completely un-noticed.

Are there any brands that you guys prefer over others?

Again, Trinity and O'donnels are good and come highly recommended. Stay away from Blue thunder.

Alright. The guy at my LHS said that he really likes traxxas 20%, what do you think about traxxas fuel?

Ran a quart of that in the Revo, it was ok but Odonnell racing fuel is much better...[8D]

I have tried both 30% sidewinder, and 30% trinity monster horsepower and have found sidewinder seems to make more power. I dunno.

Since my EK4 is has a ringed heli .70 engine I run Coolpower 30%