Parasitic Loss and the Imco SCX
 

I see where quite a few guys took a fair speed loss with this drive but haven't seen it stated what the parasitic losses , crankshaft to prop shaft , actually are . Anyone know ? I believe the Bravo 1 is -25 HP . Trying to get a handle on which drive will best suit my needs . 25' Warlock SXT Cat with a blown 509ci 855hp@6000rpm 792ft lbs@4900rpm . Currently have a good Bravo 1 HP and would rather sell it than grenade it . Goal is to take it into trips and not break it . :flag:

Sam, with your horsepower I don't think parasitic loss is going to be an issue. You're just gonna have to get something that will stay together. Offshoredrillin is running a combination he seems to be happy with. Maybe he'll chime in........

SCX w the duel downshaft. Its a shortie type.

I have 509 blown 725 HP- 700+ Ft lbs or so in front of my full SCXs- T/S Gun. Very happy. I did lose 5-8 mph maybe? HP parasitic loss? Have not really thought about that. just thought it was the big azz drive.
4 yrs w NO issues before i sent back to IMCO just for peace of mind. Eating XRs like Cake before.
I wish I would have known about the duel's, I might have had Fred slap some on.

I’d say 40-50hp, but very worth the reliability.

Im not sold on the dual downshaft lower. It’s the same diameter as a bravo/sc bullet, so maybe 1” total diameter, .5” each side? Not small like a #5 or #6. If there was a big speed increase to justify the price they’d be posting those numbers up all over.

I have an scx upper and a -2 sc lower, it planes easily and i went from 87 to 92 with them... however right after that was when my paint issues started so I still have some tweaking, any losses I may see from the scx are diminished by the reliabilty. the new twin shaft may be an option but figure out your needs vs your wants. the sc lower still runs xr gears and i havent had enough run time on mine to see anything. I still have some prop testing and setup to do on mine.

One thing in my favor is a relatively light low drag hull as far as the xr geared lower . What was the paint problem , guess I missed that . I'm curious what power you're running because you seem to be a minority that had a speed gain although I understand it was probably due to the -2 shorties . Scrubbed hp but also lessened drag substantially . I'm already surfacing the blade tips @ WFO with a standard length drive at 1.5 positive trim on the gauge which is the sweet spot . I see also that the SCX sets the prop shaft back 3/4" so that no doubt means I'll have to go a little shorter on the lower . Thanks for the reply .