• If you log in, the ads disappear in the forum and gallery. If you need help logging in or getting registered, send request to: webmaster@southernairboat.com

300HP 520's???

Southern Airboat Gallery Archives

Rain is coming
Quick Slick
100_02191
Okeechobee rimcanal boat refloat
Frankies Catch Dog
b4 airboats
blackpowderscout

blackpowderscout

Well-known member
I have an IO520C that is rated by the manufacturer at 285HP at 2700RPM. How does everyone else have 300+HP 520's when most if not all that I've seen are clearly rated from the factory at 285HP?? What am I missing out on?? Is it all extra work by builders or is the manufacturer understating their #'s??

Thanks

Adam
 
BPS, Most 520's are rated at 285hp from the factory but continentals are very receptive to modifications by builders.
 
How many airboaters turn their motors at 2700 RPM??? None that I know anyways!! Yes, your motor is rated for 285 hp at 2700. Typically airboaters can and do run slightly higher RPM's like for running the hill. Say 2800-2900 RPM when it is needed and therfore more RPM more HP. I think a 220 GPU when run in a generator is rated at 190 hp at 2500 rpm or something close to that.
 
MJD291":35ci0mvl said:
How many airboaters turn their motors at 2700 RPM??? None that I know anyways!!
Click to expand...

Mine is set up to turn 2750 max RPM. She does fine on the hill. My old 0470 would spin the paddleprop I had on there up over 3100 according to the tach so I understand all about turning higher RPM's.

I was just curious..that's all.

Adam
 
I have a handheld prop tach ..... a little electronic gadget that measures propeller RPM.
I'll try to remember to bring it with me to the ride Dec. 16th in case any of y'all want to verify your tachometers.

olf
 
I'm thinking like geneva0550 and would like one of those gadgets myself. That would be a good topic in "Airboat Talk" as I'm sure there are a lot of others who might be interested.
 
BPS;all 520s are 285HP.and all are fuel injected they never made a 520 that was carbuerated those that are have been converted everyone thinks the harder you turn it the more power you make.
 
BPS;all 520s are 285HP.and all are fuel injected they never made a 520 that was carbuerated those that are have been converted everyone thinks the harder you turn it the more power you make.
 
I have one we use at work to check rpm on equipment saws grinders I use it a couple weeks at Kissimmiee on a boat with a new prop
 
I belive the harder you turn the more power you make to a certian point. Some cams are made to make power up to 3400 is like super chargers. Its just like a direct drive car motor, and a gear box, the box makes the motor turn higher and create more power. I have seen some injected 520's that will turn a 310 horsepower 540 prop.
 
Here is a link to a spec sheet on an IO520D that shows the takeoff power at 300hp@2850, http://www.tcmlink.com/EngSpecSheetDocs/IO520F.pdf Adam, your 520C does not list that takeoff rating but list the same 285hp continuous output so it should be putting out the same hp at the higher rpm's. The motor is not officially rated for those engine speeds.

Larry
 
Larry, that's a great point and one that I'll admit to being hesitant to bring up ....... when I hear about the RPM's some folks are turning their A/C motors to I have to cringe.

These are torque motors, guys. Turning them faster than they were designed to be run is doing nothing but shortening their life.
If you can't get the job done within a normal operating range, then you either need to put more prop on it or lighten your boat. JMO.

olf
 
Good post larry, I missed that one when I browsed the tcm spec sheets. 2850 is closer to what rpm we run on airboats. I know some who run 2900 to 3000 but I think 2850 is just right for A/C in an airboat. That is the only 520 or 550 that showed takeoff hp. out of all the ones listed.
 
You must log in or register to reply here.
Back
Top