5.7 litre WOT??

[mirvin]

Anyone know the WOT rpm for a 5.7 350? I'm spinnin' 6,000 rpm at WOT with a 15R17 prop.

[Wetter the Better]

usually most 5.7 or 350 max is 5000,try a 23 pitch prop, that should get you with in range, good luck
later stan

[Snorider]

I would suggest jumping to a 21, not a 23. A 23 is a lot of prop to turn for a 350. Usually, every 2 inches of pitch drops your rpm by about 400. So, an 800 rpm drop would be a 21. (5200rpm) A larger diameter will also reduce the RPMs, so if your boat has a 13.75" on it, and you go to a 14.25, it should put you right around 5000.
There are no definates on which prop will turn 5000 on your boat, no matter what it will be trial and error.
[ August 11, 2003, 06:33 PM: Message edited by: Snorider ]

[77charger]

i have a 350 mag (250 prpshft hp)and turn a 3 blade mirage 21p to 4850 rpm.prop has been tuned thinner blades and cupped

[mirvin]

So what do you guys think? Right now I have a 15' diameter 17" pitch. I'm thinking I'll try the 21" pitch first but should I mess with the diameter too, or just the pitch?

[Wetter the Better]

going to a 21 will only get ya bout 5100 to 5200 still a little on the high side,gettn ready to run a 23 with my 350, i know several folks runn 24's on a 350 w/alpha's
Good luck
Later stan

[mirvin]

Hey Stan, any input on the diameter?, or should I stay with the 15"? I'm turning a Volvo Penta 290 with a pretty stock 5.7.
So right now I think I'm looking at a 15/21 and maybe a 15/23 based on what you're saying. I've actually had a couple shops recommend a 19 but they probably want to sell me a couple props huh?

[mirvin]

Ordered a 15/21 and I'll be picking it up tomorrow. I'll letcha know what happens.

[Wetter the Better]

most companys say for every 2 inches is roughly 400 rpm.I was runn a 14 1/4x19 @5300 now it is 4850 with a 14 3/4. i have not try a 15" wheel yet but soon hope to. in your case i would stay with a 15" wheel and change pitch good luck and keep up informed
later stan :D :D

[mirvin]

Just figured out I gotta short shaft. . . . Gotta order another prop!!

[Wetter the Better]

hey mirv what year you working with?is it the thru prop exhaust style???
later stan

[mirvin]

hey mirv what year you working with?is it the thru prop exhaust style??? Stan,
It's a '88 Volvo Penta 290. It's not really through prop but through the outdrive. There's an exhaust port above the prop.
It looks like I'll be going with a 15/19. They don't make a 15/21 for that drive (at least no one can seem to find one). I could go with a 14/21 though, I just don't know.

[Wetter the Better]

hey mirv
did you check to see if mercury or michigan wheel has one to fit your application ,ive heard they make a interchangable hubs for volvo drives to run mercury style prop
later stan

[mirvin]

Stan,
I've been looking at Mich Wheel. The biggest they make for the 290 standard is a 15/19 or a 14/21.
I didn't know about the Merc adaptor though. Who's that through, Mich or Merc?

[Wetter the Better]

also here is a thought do a 14 3/4 you will not see much of a change and by the way Quicksilver does offer a prop for you 710-qa35006r which is a 14x21 but u still may need a 23

[mirvin]

Well I got pretty good results with a 15R19 prop this weekend. WOT is now sittin at 5400 rpm. Don't know the speed cuz my spedo only goes to 50!! Still had plenty of power to pull up skiers. Maybe next year I'll try a 15R21.

[Havasu Hangin']

mirvin...make that drive a LH rotation and I'll "rent" you my 14 1/2 x 23"....hehehe...
BTW...is that a 17 or 19 spline? More props around than you may think.

[77charger]

Havasu Hangin':
mirvin...make that drive a LH rotation and I'll "rent" you my 14 1/2 x 23"....hehehe...
BTW...is that a 17 or 19 spline? More props around than you may think. do you think you can lend me the motor.I bet my boat would move pretty good. :D

[Havasu Hangin']

77charger:
do you think you can lend me the motor.I bet my boat would move pretty good. :D How about I sell it to you? The only catch is the boat goes with it...

[mirvin]

BTW...is that a 17 or 19 spline? I have no idea? How do you know other than by counting. I just ordered the prop and it fit, they never asked me about it.
What's with the left and right rotation? Is it so if you need two they'll be balanced?
Oh yeah, my little fin thingy above the prop under the cav plate came loose and I haven't been able to get it set right? Any tips. I've tried it in several positions but still get pretty crazy over/under steer past 4000 rpm!!

[Havasu Hangin']

mirvin:
I have no idea? How do you know other than by counting. I just ordered the prop and it fit, they never asked me about it.I think the older 290's are 17 spline, but the newer ones I think went to 19. I have 17 splines on my 280...quite a few props around if you know where to look.
mirvin:
What's with the left and right rotation? Is it so if you need two they'll be balanced?Your drive can run either RH or LH rotation. All you need to do is take off the back cover and switch the cable.
Most 4 cyl Volvos came with RH rotation. The bigger engines (V-8's and diesels) came with LH rotation. The reason is that in LH rotation, it puts the stress on the upper (stronger gears) in forward, but in RH rotation, you are putting more stress on the lower gears in forward.
Most people will switch rotaion because it may balance the boat better (for example- if the driver is on the right side and the boat tends to lean), or they may have more RH props around.
Either way, if you have some HP, I'd look into LH rotation if you have the props and your boat is balanced in either direction. Most of the bigger props I've seen are LH rotation for this reason.
mirvin:
Oh yeah, my little fin thingy above the prop under the cav plate came loose and I haven't been able to get it set right? Any tips. I've tried it in several positions but still get pretty crazy over/under steer past 4000 rpm!! I'd start in the middle, and work in small increments (checking it at all speeds and trim positions). They are a pain to get perfect, and don't like alot of torque. Locktite is always a good idea (on the prop bolt, too).
Also, if you have cable steering, check for slop- too much will cause some wacky steering input.
[ August 29, 2003, 06:55 PM: Message edited by: Havasu Hangin' ]

[mirvin]

Well HH, once again you've overwhelmed my mental capacity and I've begun to drool....
Really though, thanks for the info. I'm running a stock 350 right now so unless I have problems with the lower drive or juice up the motor I should be fine, huh?
Next time I'm out I'll work on the "fin thingy". I'm such a dope that now I've got 2 quarter inch allen wrenches sittin' at the bottom of San Antonio!!! Oh, I also just figured out that I had the thing 180 degrees backwards! That was a wild ride.
I think I owe you a beer or twelve.......let me know how you like it.....(the beer that is)

[BajaMike]

Mirv, I didn't see anyone mention it, but you shouldn't run the 5.7 350 engine at 6000 rpm for long....on the Mercruiser, I believe it red lines at 4400 to 4800 rpm. I'm not sure about the Volvo, but I don't think it's much different.
My Mercruiser 350 Magnum starts the alarm buzzer if I run it over about 5100 rpm.
You could damage your engine (or just wear it out sooner) running at 6000 rpm.
See attached link on the Mercruiser engine.
web page (http://www.mercurymarine.com/5.7l_sd_-_250_hp)
Good luck...Like to hear how the new prop works.
Mike
[ September 03, 2003, 10:37 PM: Message edited by: BajaMike ]

[mirvin]

Hey Baja, thanks for looking out for me. I quickly realized that I shouldn't be opening this thing all the way up. Now I know why the motor is brand spankin new. I just bought the boat this summer. BTW the 19 is getting me close to 60mph @ 5400rpm so I'm gonna try a 21 eventually. Skiing is our primary goal so I gotta have some bottom end........

[fxinc]

I run a 23 SS on my 350 5.7 and it turns 4600 at WOT. Has a great holeshot and top end(55-60 depending on conditions).
[ September 05, 2003, 09:47 AM: Message edited by: fxinc ]

[mirvin]

Hey fxinc, thanks for the info. You think I should go with a 23 huh? What year and model is your 5.7 / outdrive? Is your motor stock? Is 4600 the recommended WOT? It seems low, but maybe cuz I started at 6000.
Thanks

[UltraLucky]

Little more info for you, I have similar sized boat with modified 350 and Alpha drive 1.46:1 ratio. I have tried the following props.
1) Mercury 5 blade P=21 D=13.75 (High Five)
2) Mercury 3 blade P=23 D=14.? (Mirage)
3) Solas 4 blade p=21 D=14
5 blade is best all around but hit 5300 rev limiter. 23 pitch 3 blade would barly pull up a skier and maxed at 4600 rpm (mid range pull was excelent). 4 blade did not pull as hard as 5 blade but dropped rpms by approx. 200 at upper limits @ 4000 rpm boat speed was 50.0 with 4 blade. I am still looking for a 21p 14"dia. to demo. Hope some of this info helps.