Outrunner size in 1/10 summit
 

How big does a outrunner need to be ,to replace the stock titan 775 motor in a summit ?

Size is one issue, kv rating is another- most outrunners are no where near fast enough unless you were building a true crawler. That's why the few guys that experimented with outrunners got rid of the transmission usually, and hooked the front/rear driveshafts straight to the motor. Not always the case though, as the 3rd link below shows...

Some reading material:

http://www.rc-monster.com/forum/showthread.php?t=8536

http://www.rc-monster.com/forum/showthread.php?t=25847

http://www.rc-monster.com/forum/showthread.php?t=9793

http://www.rc-monster.com/forum/showthread.php?t=9906

http://www.rc-monster.com/forum/showthread.php?t=9871

I used one of the big castle creations outrunners, pretty sure it was 700kv or so. It is a big motor. Ran it on 4s with a MM. This truck was setup to crawl, but still had decent speed with the wide ratio trans in 2nd. Tons of torque from the outrunner with the trans, easily break mip axles. And do backflips. I ran some big tires from rc4wd, rock stomper 40 series, maybe? Sold it to a buddy an he still runs it.

An Axi 41 series or larger would be comparable to what I used.

fightercat racing has a few bigger out runners up to 2000kv t-600 size lots of people have been using them in there bl boats with great results, i think there a 40 mm can about 3/4 the length of a castle 2200kv, 3000 watts rated so they say, they r 6mm shaft though. i have a typhoon 1800kv its a 500 series and i have run it in my 1/8 scale buggy on 5s i think it would be better suited with 4s because of its smaller size, motors at fightercat r around $50 great price

check ithttp://fightercatracing.com/index.ph...emart&Itemid=1