DeepBlue47

Hey there,
I'm new to the forum and I have tried to do some hunting around with search on my own to find some answers, but I looking for peoples thoughts as many of you see very knowledgeable.

I don't have what you would traditionally call a "Go-Fast" boat, but I am hopeful that you guys can still help me out. Its a Riviera M470 with twin 496 Mag HO's. This past winter I went ahead and put Dana Marine's Thru-hull exhaust on her and figured I would see how the season went. I didnt see any real gains (just great noise!) so I am currently re-examining the props (still stock). But ultimately, I dont think props can possibly get me where I want to be (I currently top out 45-47 but want to be 55+).
This leaves me with either going for a Raylar kit that boosts me up to 525 or so, or going with a Whipple supercharger. Going with the whipple means I will have to swap my drives for something else (any suggestions?), but its something I would look into.

Thanks for any help guys!
Oh here is a pic of the boat:



this is apparently the best pic of the headers I have


My biggest concern with the supercharger is there may not be enough airflow in the engine bay and temps will get too high....

Thanks again

CB-BLR

Beautiful Boat !!

At what RPM is your top speed currently?. ie. how fast are the motors spinning?

Having asked that... I will tell you that I am a Whipple fan.

Since having a Whipple motor, I will never go any other route.
Power is fantastic, and Dustin Whipple has got to be the most helpful guy on the planet when it comes to boat motor setup.

1 vote for Whipple

Chris

DeepBlue47

Thanks! Its a great boat, we have a blast with her!

Currently the max rpm seen is 5000 to 5200 or just under. I know thats a bit to high for her and she should be around 49-5000 range which i believe is a sign the props need to go.

The drives I believe are only rated to 450....so 600 is waaay out there for them no? lol

Another concern I have is that I could get new props for this season, but if I am doing Whipple for the new season, wont I just have to do new props again? That kinda wastes the money im throwing at the props for this year...is it worth it?

Carder

Don't get new props until after you do your HP upgrades. Your current props will give good baseline numbers, and help estimate what final size/ gear ratio will be best. Are you currently using the 2.0/1 gears?

Carder

ezstriper

it's going to take some serious H/P to get a big boat like that to that speed, I think you are going to be sorry with reliability with your currant engines....big diesels are the way to go in something like that trying to run that fast...my .02....Rob

DeepBlue47

Haha....thanks.


I thought one of the biggest pro's to the whipple supercharger was that they are hugely reliable, ect? Like OEM ect? I know that going FI isnt going to be easy and that I will have issues, but I wonder unreliable the system will be?

I agree some big power will be needed, so I am looking at alternatives other then replacing the engines. Would you suggest I look at other options then whipple?

DeepBlue47

I have gotten up to 47 with the boat stock (i.e. No thru hull exhaust), so moving up to 55 shouldn't be terrible I would have thought. 50 is the minimum goal for the boat really...but 55+ would be welcome :-)
That said, I wouldn't think it would too hard to hit these goals?

CB-BLR

How much does the boat weigh?

Chris

DeepBlue47

About 22,000lbs (dry)

CB-BLR

You should go play around with this site to figure out how much hp you will need to go 55mph.

http://go-fast.com/boat_speed_predictions.htm

I entered in your boat weight at 23000 lbs and your top speed of 47 mph to come up with a constant.

I then plugged in 55 mph and solved for horsepower, and it spit out 1169 hp or about 585 hp per side in order to get to 55 mph.

I have found this site, and speed predictor to be very accurate.

Given your horsepower requirements to go 55, Whipple is the natural selection. They make a kit for your motor to take it to aproximately 620 hp per side which would take your top speed to aproximately 57 mph... or about 10 mph more than you are going now.

I have found the whipple kits to be very complete, and Dustin is the man when it comes to re-programming the stock PCM.

I would not hesitate in the slightest in recommending his products.

He is at the Florida boat show right now, but can be reached via phone most any weekday from 10am - 4 pm at 559-442-1261.

I am not associated with Whipple in any way... he is just that good of a guy in my opinion. He has helped me on innumerable occasions, while working on my own projects.

Chris