prop

[Essex29]

What prop should I be running? I upgraded from the 7.4 mpi 310 hp to the 502 mpi 415 hp...Does anyone have this similar set up or have a good recomendation for the right prop ?
With the 7.4 I was running a 4 blade bravo and saw top speed of 61, any idea's on what I will get now?

[j-rod]

I really don't know what prop to recommend, but it you can get a tail like the one in your avatar I wouldn't change a thing......sorry for the lack of help

[Starloans]

Ok Goose. Ya have to give us a little more info than that. What kind of boat do you have? How big? What pitch prop do you have now? And what was your rpm at WOT before? Is that 61 mph you have using GPS, radar or wet thumb in the air?
Give me that info and I will give you my most gross imcompetent, unbiased recommendation. :D
Ballpark guess 105 hp increase 2 pitch possibly 4 pitch increase in prop. Need to know WOT rpm before.
I did at least 4 speed runs with a single new prop this past weekend and now I consider myself an expert!!!! :D :D :D
Dave

[gnarley]

Originally posted by Starloans
I did at least 4 speed runs with a single new prop this past weekend and now I consider myself an expert!!!! :D :D :D
Dave
OK now you know enough to be dangerous

[Starloans]

Originally posted by gnarley
OK now you know enough to be dangerous
Hey, that's what a boating expert is......someone who had either done it one time and/or read it on HB!!!!!!! :D

[XTRM22]

Originally posted by Starloans
Ok Goose. Ya have to give us a little more info than that. What kind of boat do you have? How big? What pitch prop do you have now? And what was your rpm at WOT before? Is that 61 mph you have using GPS, radar or wet thumb in the air?
Give me that info and I will give you my most gross imcompetent, unbiased recommendation. :D
Ballpark guess 105 hp increase 2 pitch possibly 4 pitch increase in prop. Need to know WOT rpm before.
I did at least 4 speed runs with a single new prop this past weekend and now I consider myself an expert!!!! :D :D :D
Dave
Yeah, what he said! I'm almost an expert (cause I tied up next to StarLoans once and I also own a DCB Vee even though mine is smaller) I'm gonna take a EWAG at this question. (EWAG= Educated Wild Ass Guess) If you were runnin 61mph with a 7.4 and a 4 blade prop, I'm guessing 22pitch and about 4800 rpm. You can turn a 502 up to I believe 5100rpms so I'd start with StarLoans guess and go to a 24" 4 blade and WFO throttle will land around 72-75.
Chuck

[Starloans]

Originally posted by XTRM22
Yeah, what he said! I'm almost an expert (cause I tied up next to StarLoans once and I also own a DCB Vee even though mine is smaller) I'm gonna take a EWAG at this question. (EWAG= Educated Wild Ass Guess) If you were runnin 61mph with a 7.4 and a 4 blade prop, I'm guessing 22pitch and about 4800 rpm. You can turn a 502 up to I believe 5100rpms so I'd start with StarLoans guess and go to a 24" 4 blade and WFO throttle will land around 72-75.
Chuck
Yeah, what he said. :D
Goose, are ya there?
Hello? You got me interested.

[XTRM22]

Hey StarLoans, since we're just standin around waitin for the Grey Goose to come back, what prop are you runnin? and what's the fastest you've seen?
Chuck

[Lakeshow]

I am trying to figure out the same thing. Just faxed my dyno sheet to Bronson Hill and am waiting to hear what he has to say.

[Starloans]

Originally posted by XTRM22
Hey StarLoans, since we're just standin around waitin for the Grey Goose to come back, what prop are you runnin? and what's the fastest you've seen?
Chuck
As it turns out I did some laps on San Diego bay this past weekend. Dave let me borrow a 28 labbed 4 blade and I got 80 & change on GPS. See Catalina run thread with pics. Thread (http://www.***boat.com/forums/showthread.php?s=&threadid=37269)

[Lakeshow]

What RPM???
BTW - How is the salt water effecting your trailer? Are you doing anything to protect it?

[HTM4ME]

I am running a 502 in a 24 HTM u use a 24 bravo and run about 67 68 on havasu or i run a 23 powertech and get about 3 more mph at 4900 rpm

[Starloans]

Looked like about 5200 rpm to me when I had a chance to eyeball it.
I pretty much just wash the trailer real good. Stick the hose in the holes on the bottom and rinse good. Seems to be doing fine. No apparent rust so far.
What's your dyno sheet say?

[Lakeshow]

Max HP 697.9 @ 5400 RPM
Max Torque 691.8 @ 4700 RPM
It is looking like it is going to take a tuned 30 for the best performance - we'll see.

[Essex29]

sorry for the wait...
I think I was getting about 4200 rpm's out of the 7.4 (sound right?)
72-75 would be the shit, but I don't think I will pick up that much.
I have no idea where that avatar came from.

[XTRM22]

Originally posted by Starloans
As it turns out I did some laps on San Diego bay this past weekend. Dave let me borrow a 28 labbed 4 blade and I got 80 & change on GPS. See Catalina run thread with pics. Thread (http://www.***boat.com/forums/showthread.php?s=&threadid=37269)
Damn! aren't you runnin a 525? that is flat haulin ass. Between you, Tony, Joey,and FlyNVees, I am the slowest DCB Vee by like 20mph.
Hey Grey Goose for the record (so I can recalculate my EWAG) WHat kinda boat do you have? I was guessing 21-22' Vee from looking at the avatar, but that now sounds baked. :)
Chuck

[Starloans]

Goose, ya still gotta give me more info than that. See previous post. I'm getting impatient now, hurry up already! :D BTW, 4200rpm sounds a little low.
XTRM22, I am running HP525 but keep in mind Joey, FlynV and now Tony all have CRAZY engines. I pretty much have the slowest boat......well except for yours. But we'll have to work on that. :D What exactly is your setup?

[XTRM22]

22' open bow Extreme, built in 97. I think I have about the oldest "one owner" DCB in existence. We used the last non-mag carbed 454 that Dave could locate. The only mods are are Imco powerflows (they didn't add much but look cool), carb spacer,better plug wires and the ignition module from a mag motor to raise the rev limiter and speed up advance slightly. We are turning a labbed 23" 3 blade at about 4700-4900 rpms and 63-65 mph gps, depending on conditions. I think we'll keep it a while, it's almost paid for!:D Plus with 370 hrs on the motor I don't intend on rebuilding or replacing for a year or two.:p
Chuck

[Starloans]

IMO 2 things.
#1 Almost paid for? Perfect!
#2 63-65.. great. What's wrong with that? 7.4L sounds like its running right.
I saw your rig. Thats a nice setup. Nice boat. However, I bet if you went with a 496HO that would be perfect and reliable. You may even be able to find a low hours used one. That should get you close to 80 probably spinning a 26 bravo possibly 28. Unless, of course, you wanna get CRAZY! :D

[Essex29]

I guess you did ask for that...
Lavey Craft Nu Era 24 open bow/cuddy Bravo 1 22pitch
The 61 was Gps verified.

[Starloans]

Originally posted by TheGreyGoose
I guess you did ask for that...
Lavey Craft Nu Era 24 open bow/cuddy Bravo 1 22pitch
The 61 was Gps verified.
HOLD IT!!!!!!
24 Lavey?????
Where are you Faster Daddy???? Faster has a 24 Lavey running a HO, 425hp with, I believe, a 26 4 blade bravo. I think he said he hit 75 on his recently. What's the scoop Faster???? And what do you think Goose will be able to achieve with his new setup???
My guess for yours is 24 spinning 5000 rpm will be 68mph according to the online prop calculator and my experience. Now I think you may be borderline able to run a 26 Bravo in the right weather conditions.
I used to have a DCB 24 Extreme with a 454mag, 385 hp and I could run 68 all day with a 24 Bravo. In the right weather, down stream with a tail wind I saw 72. You should become friends with a local prop dealer or boat dealer who has props in stock that will let you borrow one to test. You may in fact wind up with 2 props, a 24 for summer and a 26 for winter.....that is if you run in the winter. I'll see if I can get Faster over here to give you his opinion. Good luck.

[XTRM22]

Laveyman has a 24 NuEra closed bow, with a 385hp 454 mag, and is runnin pretty much exactly the same numbers as StarLoans 24'DCB did. I'm revising my EWAG to say a labbed 26' bravo turning 4900, at 72-75 mph and I'm willing to put a beer on it.;)
Chuck

[Starloans]

HOLY SHIT CHUCK!!!
We're friggin experts now! Where do we send the bill?????? :D :D :D
Let's get to work on Tony's.
He's thinking a 30 labbed. 697hp @ 5400 rpm. He emailed me the dyno sheet. With a 10% slip the calculator says he should be in the low 90s. If he can spin a 32 he should be in the high 90s.
If I have 525hp @ 5200 rpm spinning a 28 I don't see why Tony couldn't spin a 32. I don't have a lot of experience with the CRAZY engines. I'm a poor boater! :D
High 90s in 28 ft Extreme is friggin CRAZY! :eek:
What do ya think?

[Faster Daddy]

Originally posted by Starloans
HOLD IT!!!!!!
24 Lavey?????
Where are you Faster Daddy???? Faster has a 24 Lavey running a HO, 425hp with, I believe, a 26 4 blade bravo. I think he said he hit 75 on his recently. What's the scoop Faster???? And what do you think Goose will be able to achieve with his new setup???
My guess for yours is 24 spinning 5000 rpm will be 68mph according to the online prop calculator and my experience. Now I think you may be borderline able to run a 26 Bravo in the right weather conditions.
I used to have a DCB 24 Extreme with a 454mag, 385 hp and I could run 68 all day with a 24 Bravo. In the right weather, down stream with a tail wind I saw 72. You should become friends with a local prop dealer or boat dealer who has props in stock that will let you borrow one to test. You may in fact wind up with 2 props, a 24 for summer and a 26 for winter.....that is if you run in the winter. I'll see if I can get Faster over here to give you his opinion. Good luck.
Goose,
I am only "expert" on what I've run. LOL :D So hear is what I know. I have a 24' Lavey cuddy/open running a 496 HO, 425 hp. I have a stock Bravo 1 24" pitch that I easily push to the rev limiter at 5150 rpm. Trimed out that was good for 72 mph on gps in 1 ft chop. On flat glass normally run 69/70 mph.
I am currently running a lab Bravo 1 26" from Bronson Hill which has been worked to a 25" pitch. I also easily run this prop to the limiter for a max 74 mph gps on glassey lake water.
On the 28th I'm picking up both a 26 and 28 Bravo 1 as demos. I would like to be running at 4800-4900 rpm at WOT. I let you know how that goes.
If you want to try either the 24 or the 26 I have I'd be happy to help you out. Your boat will only be happy when its able to run 70
:D

[XTRM22]

Originally posted by Starloans
HOLY SHIT CHUCK!!!
We're friggin experts now! Where do we send the bill?????? :D :D :D
Let's get to work on Tony's.
He's thinking a 30 labbed. 697hp @ 5400 rpm. He emailed me the dyno sheet. With a 10% slip the calculator says he should be in the low 90s. If he can spin a 32 he should be in the high 90s.
If I have 525hp @ 5200 rpm spinning a 28 I don't see why Tony couldn't spin a 32. I don't have a lot of experience with the CRAZY engines. I'm a poor boater! :D
High 90s in 28 ft Extreme is friggin CRAZY! :eek:
What do ya think?
Well like all experts I start getting ambiguous when the stakes get higher. FlyNVees are running 800+ hp and I think just touch the 90 mph mark. In as much as a DCB 28 Extreme is my dream boat I'm guessing that somewhere in the low 80s you start hitting diminishing returns, and it take more Hp to push through it. Then again everybody told me a 28' with a 500 efi would just break 70 on a good day, and there you are runnin 80 with just 25 more hp? I"d lke to see the torque comparison between a 525, and Tony's new Phaff motor. I'm a little outdated on technology, let me go punch some numbers into my abacus and I'll get back to you. As far as the billing, I'd say when the Goose crosses the 70mph mark he owes us each a beer!
:p :D :D
Chuck

[Essex29]

If I can cross that 70 mph mark I'll gladly buy the beer.
Faster, thanks for the first hand expertise...I may take you up on the prop demo, but first let me know how you do with the non-lab 26....I dont think my 415 hpo is enough for a 28, but let me know that too.
thanks for all the awesome responses!

[Starloans]

Originally posted by XTRM22
Well like all experts I start getting ambiguous when the stakes get higher. FlyNVees are running 800+ hp and I think just touch the 90 mph mark. In as much as a DCB 28 Extreme is my dream boat I'm guessing that somewhere in the low 80s you start hitting diminishing returns, and it take more Hp to push through it. Then again everybody told me a 28' with a 500 efi would just break 70 on a good day, and there you are runnin 80 with just 25 more hp? I"d lke to see the torque comparison between a 525, and Tony's new Phaff motor. I'm a little outdated on technology, let me go punch some numbers into my abacus and I'll get back to you. As far as the billing, I'd say when the Goose crosses the 70mph mark he owes us each a beer!
:p :D :D
Chuck
Chuck....although my hp to speed to prop comparisons seems logical I believe you are right. :D There will be a point that it will take more hp to achieve each mph. Tony USED to have the 500 in his but I don't rememeber what his top was. Seems like it was about 72 or so. Maybe he can tell us.
As for the the 500 & 525 I have seen the hp published two different ways by magazines, dealers and internet. Maybe it has something to do with crankshaft vs propshaft.
hp500= 470hp & 500hp
hp525= 500hp & 525hp
I don't know what the torque is on either. In any case here is what the Merc website says. Merc (http://www.mercurymarine.com/8226hp525_efi_-_525_hp)

[Havasu Cig]

I read on OSO that a 525 dynoed at 555 hp. That might explain why they are getting the sppeds they are. They were talking about a Cig, I believe a Top Gun, with 525's running neck and neck with one with 575's. I think Merc underates there motors.
Cig1, that posts on here once in a while just bought a T/G with 525's that is running 93 mph. That is great performance with reliable Merc motors.

[Starloans]

I heard they were a little higher hp also Cig but I haven't seen it in writing. My power pack is great. I love it. I'll just get there a few seconds after everyone else. :D

[Faster Daddy]

Originally posted by TheGreyGoose
If I can cross that 70 mph mark I'll gladly buy the beer.
Faster, thanks for the first hand expertise...I may take you up on the prop demo, but first let me know how you do with the non-lab 26....I dont think my 415 hpo is enough for a 28, but let me know that too.
thanks for all the awesome responses!
Your also welcome to try the lab finished 26 thats worked to a 25, I'm sure we'll get you running 70+ :cool:

[Essex29]

Sounds good man! Thanks a lot.

[Lakeshow]

Here's my .02 on the props, HP and the DCB 28. Chuck is absolutey right - the 28 does hit a wall in the 80's and I think that I will be lucky to see much over 85 with my set up and running a 28.
I ran my lab 26 today with Dave driving and we got 78 (gps) and we ran out of lake (San Vincente). The boat was accelerating at about 5700 RPM and Dave thought we could have hit 82 - I think 80 but he is the expert:D.
Tomorrow I am going to run a lab 28 and see what it does.
A friend of mine has a 30 and I may swing by and pick it up in the morning just for sh@# and grins.
BTW if I haven't mentioned it I am absolutely thrilled with the Pfaff 700. Turnkey 700HP, EFI, NA power = trouble free boating.

[Essex29]

Hey Star...
How about posting some pics of the 28? I like the graphics..

[Starloans]

Hey thanks Goose...I'll dig some good pics up. I took some of Tony's 28 today. We were on San Diego bay "running some test" on his.

[XTRM22]

Originally posted by Lakeshow
. Chuck is absolutey right .
I just had to quote that line, I hear it so rarely and that's the first time I've ever seen it in print!
:D :p :D
I hope you guys get all this figured out so that when I can afford a 28' Extreme I can just set it up like yours!
Chuck

[GRASS PAY$]

Hey Chuck I think Iam the slowest one right now.After the boat show she sould be fix and The boat was running great until you know.Hey I wish I had 10% slip I have 24% slip that sucks.

[XTRM22]

Originally posted by GRASS PAY$
Hey Chuck I think Iam the slowest one right now.After the boat show she sould be fix and The boat was running great until you know.Hey I wish I had 10% slip I have 24% slip that sucks.
Hey Joey, nice to see you still remember how to use the computer:) , I don't know about you being the slowest I think it was a close match between me and your pontoon, of course that was with "The Ompalompa" probably sleeping behind the wheel. man 24% seems like a huge number, but I guess when your making that kinda HP pushin a 28' Vee it can happen. Glad you didn't sink it, I'm lookin forward to crawling through it at the boat show next week.;) :D
Chuck

[Lakeshow]

Just remember to take your shoes off :D.

[LAVEYSABRE575]

lakeshow glad to hear you have your ride all back together.Are you headed out to the springs on the 24th ?...derek

[Lakeshow]

Happy to have it back. Doesn't look good for that weekend. We were going to head out there this weekend but the wife just came down with that flu crud :yuk:.