I have a hyper 21 8 port (run in heat cycle) in a hyper 8.5 pro, running it at the park today it seems to be struggling to peak out ,temps at 230 f (which is good and low ends fine), when i give it full throttle it hesitates to get there, like as if its running out of petrol, any ideas guys????

the only thing i can do is point you in this direction http://www.rcuniverse.com/forum/m_55...tm.htm#5517128

maybe your low speed needle is to lean or too rich.

read the nitro guide at the top of the forum, thats what i wrote it for, its hard for us to tell you exactly what to do so you will just have to try things until you get it there, if you richen it up and it gets worse then obviously its too rich

i had this prob. after break in (running very rich) tried tunning and it would almost bog out at mid range, found out it was just the glow plug that needed to be replaced. try putting in a new glow plug to see if that helps. oh and read the nitro guide hpi apollo wrote, helped me out.