Turning 4600 RPM - next step?
 

Hey guys,

My twin 6.2L Dominator is turning about 4600 RPM when maxed out. It currently has Mirage Plus 23p props. What do I need to do to get it in to the 4800-5200 range Mercruiser states? Are there some downsides to messing with the props it came with?

If you are happy with the over all performance of the boat...don't change anything. The 4600 RPM is not a bad number. How is the cruise and does it come up on a plane easily? If not drop to a 21"....you will burn more fuel but over all may have more throttle response.

It performs great! So no complaints there, was just wondering if I was leaving something on the table by not turning faster. Thanks for the info.

Only way to know is to drop a size in props or get a set of labbed 23's Some times you lose rpms but pick up mph, or you can pick up mph and lose rpms. With the engines not spinning hard, your adding some life to them :drink:

John jr

Get them labbed.

By not turning in the recommended WOT range I would think your engines are not getting a chance to make their peak hp and perform up to their actual ability.

That motor does make best power up closer to 5,000 rpm. By lugging it at 4,600 you ARE giving up a little bit of potential speed.

Like has been said, though, if you are pleased with the performance, then don't sweat it.
21 pitch Mirage will get you into the rpm range you want to be in, and you may see a couple of mph as well.

Lab thinning your 23 will also get you a few more revs, but not usually 400 revs.

Make sure your throttles are opening ALL the way open.
Make sure you are trimming the boat properly for max speed/rpm.
If you have to run a LOT of positive trim for best speed, relocate as much weight rearward as possible.
Make sure your bottom is clean, and your props are not tweaked/dinged.

If you are still at 4600, then find a prop shop that will let you try props (with a deposit of course) and go try a 21 Mirage, as well as something in a thin-blade performance 22 and whatever else the propr guy recommends for your boat. Then go play. Keep your GPS with you and use it for recording speeds - do not trust the boat speedo when you are splitting hairs.

MC