hello sea ray owners i bought a 1999 sea ray sundancer 260 da last oct with a rod nock rebuilt engine over the winter and would like to know what others are getting for top speed.i never drove boat before rebuild. it had a 5.7 chevy 250hp engine with brovo 11 it now makes 430hp on dyno. it does 42mph at 4200. i have alittle to much prop but i am thinking of leaving it.
You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an alternative browser.
You should upgrade or use an alternative browser.
top speed in sundancer 260 da
- Thread starter 44fowk44
- Start date
- Joined
- Mar 8, 2004
- RO Number
- 12942
- Messages
- 320
I can't imagine how a 5.7L engine can turn out 475 hp. The only way that could be possible would be with a charger.
jtsmlarson
Member
- Joined
- Jul 7, 2002
- RO Number
- 9256
- Messages
- 411
I'm guessing that should be 330 hp? That would be reasonable with a 5.7 I think. Based on the numbers and rpms, it's probably a lot closer too. If it had 430, I'd think over 50 would be a possibility! Is that 42 based on GPS?
i made the 5.7 a 383 400 crank 6 inch rods better heads same block. it made 430hp at 5200 rpm on dyno. i have a brovo 11 with a 25 pitch stainless prop.the last run of 2008 it went 44mph at 4400. 44 mph was on gps.the prop is holding engine rps back.i guest wrong on pitch. i would have to spend 520.00 on another prop and get another ignition system without a rev limmit of 4850. the boat has a lot of power. it planes right now loaded and full of fuel. it will stay on plane at 19mph.hp was taken at flywheel before i reistalled it.all of you sea ray owners should have your exhaust flappers checked.this boat only had 250hrs when i bought it and it was allready on 2nd engine. it had a ripped flapper.i put 100hrs on boat this season.the cam in this engine is a comp marine grind not all that big for a roller cam. idles fine at 600 rpm.i would have made more hp with a bigger cam but i wanted relibability.
Correct me if I am wrong, but I do believe the horsepower ratings are taken at the prop shaft and not the flywheel.
Also, on small blocks, big horsepower numbers come in in the top end, but torque falls off significantly after 4000 rpms. This is rule of thumb and might not apply to a built race or stroker motor. But if the camshaft is that radical, water ingestion is going to be a concern.
With that said, I would change the prop down one size so that 4800 could be obtained.
Ken
Also, on small blocks, big horsepower numbers come in in the top end, but torque falls off significantly after 4000 rpms. This is rule of thumb and might not apply to a built race or stroker motor. But if the camshaft is that radical, water ingestion is going to be a concern.
With that said, I would change the prop down one size so that 4800 could be obtained.
Ken
At one time Chrysler/Force outboards were using engine HP instead of prop shaft HP.
Those were dog engines.
But if you have over 430 HP at the engine, you should still have a lot of horses at
the shaft.
Longer shafts take away some of the torque and HP, so the longer it is, the less you would
have at the prop end.
Those were dog engines.
But if you have over 430 HP at the engine, you should still have a lot of horses at
the shaft.
Longer shafts take away some of the torque and HP, so the longer it is, the less you would
have at the prop end.