At very high racing levels, one less fuel stop can give you a ten second advantage or more: 4minute motors might be a disadvantage in the long run....

Its only a disavantage if you're the only one running a 4 minute motor. If you're driver D and drivers A, B and C are running 4 minute motors then to beat them you need to do the same. For the majority of us a 4 minute motor wont make a big difference, but if you're in the top 10 then you need to have the same performance from your equipment in order to beat the other 9

Does a 4minute motor wear the tires quicker ???
Hopefully more test runs will reveal the truth....

Simple equation, it takes FUEL to make HORSEPOWER

So no matter how the design changes, this type of engine already max out its fuel efficiency?

Even if yhou push theese engies to the absolute max, therer are only x-amount of fuel the are able to burn becasue of the max 3,5ccm volume. To solve the problem, just go to a tank capacity that larger than the amount of fuel an engine can burn . (as long as there ara a limit of nitro %).

Omg sorry guys I cant even believe al this talk about not pushing motors and saving the motor! and bla bla bla this is racing lean that motor out and fry the dam thing!!! and go fast!!! I really cant stand when people bring money issues into nitro racing, even if I had 5 bucks left in my pocket ill fry that motor to win!!! go fly airplanes!!! this is racing!! and it should be 7 min quals!!!!

I think RC guys in America complain about way too much crap. Just race and have fun. YOLO

Could not agree more big pooh!!

pooh answer me this when your at a race are you worried or even thinking about saving your motor for the next race!!!?????

I don't go out to blow them. If they are near blowing you're not getting the best performance out of them. A the same time you have to trust yourself and tune it to perform at its best! I'm like you Ralph, I don't worry about blowing engines. I worry about tuning correctly to get the best performance out of them.

Don't get me wrong i don't want to blow them either and of course i tune for best proformance not on the edge. just think over the years they (ROAR) have been killing the class.... It's an open class and it's slowly becoming not open !!

It's still open. I think they should let the engines continue to get better.

still waiting for them to get rid of ins box dam it!! 9 out of 10 places dont have a noise ordinance concern its all bull!!! open them up and let them breath !!

I remember the days before the INS box. You'd hear cars a full 6 hrs after racing was over. I'm glad we have to have them!

I just hope there is no push for the new "silent" rear exhaust, which is a shame as well.