Professor Frink

does anyone know what the max horsepower and rpm for the 2.5R is?

DaveG55

Traxxas does not publish that info.
as a rule the raw numbers out there for these engines are pretty useless. they are not really even any good for engine comparrison. for them to have any nmeaning they would have had to been tested on the same machine in exactly the same enviromental conditions.
having said that, the common perception is the 2.5r developes 1.33bhp
for rpm, i'd "guess" that it's in the 30k - 35k range but that's strictly a guess.
why do you want to know?

foxracing500r

I read somewhere HP is like.0058 or something, Its so small, knowone cares

trdcorolla

in my touring car magazine it stated that the trx 2.5 had a claimed HP of 1.33 so I'm guessing the 2.5r is more.

Professor Frink

i was wondering cuz i was thinking of getting an os .12 or .18 or the 2.5R and i wasn't sure if there is much of a difference between them

trdcorolla

max rpm is 50k but I believe anything above 35k torque and hp goes down.

DaveG55

Well, of those three I'd get the OS.18. Since you've posted on the Traxxas fourm I guess that you're looking at putting it in a Revo or T-Maxx. If that's the case I'd say go with the OS.18TM. It's usually $2220-$230 but can be bought with the correct header and is a quick, easy swap out and you can even use the ez-start if you wish.
The OS.18CV-RX is only about $100 but needs a new header and a clutch adapter nut and you have to modify (cut) the crankshaft and I don't think the ez-start will work with it. It's also not quite as powerful as the TM.
I don't know anything about the OS.12. I'm sure it's a good motor, it's an OS. But it seems kinda small for either of those trucks.
The Traxxas 2.5r is a good little motor but, IMHO, not quite in the same league as the OS motors.

DaveG55

Just courious where you got that 50k figure?

Professor Frink

thanks Dave
i think i'll go with the os .18cv-rx cuz its cheeper (i'm only 15)
i'm thinking of just using the pull start since itsa smaller engine i figured it would be pretty easy
i've never used a pull start... just the easy start... and the roto on my LST (sure fire .32 in there soon)
i'm hoping that that the pull start wont be too bad
ez and roto are really nice on a stubborn engine


yeah i highly doubt 50K... but i might be wrong

trdcorolla

It was on my revo box, thats what I remembered the most the 50k rpm.

DaveG55

A pull start is ALL about tuning. If you are good at tuning then a ps is nothing to worry about. The engines I have that run ps all take 4-5 pulls on a cold engine (2 to prime and 2-3 to start). A warmed up engine will start on 1 pull. A poorly tuned engine will give you blisters.
One thing to remember about a pull start - never, never pull it all the way out. It won't last long if you do.

foxracing500r

Yeah try to do that with our pressure washers, It bust your hands up bad