99 Formula 31PC with Merc 415 HP- 502 MPI's, Corsa Q&Q Thru Hulls and Lab Props


B

BeechBoy

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This was a upgrade conversion that was done by Shipyard Marine near Green Bay on the boat in 2001. I have ran it since with great relability.

This upgrade is astounding. It totally changes the personality of the boat. Does it cruise great? You Bet. Is it reliable? Yes. How does it handle the power? Not a problem! Look below and you would swear it is factory.

Shipyard pulled the original 7.4 MPI with 310 HP (620 HP total) and I sold them on Ebay. I bought a pair of 502 MPI's that were pulled from a new go fast boat that put in larger higher HP motors.
This bumped the horsepower on the 31PC from 620 to 830 HP. 1/3 More power or 210 more HP.

Shipyard also installed Corsa Quick and Quiet Plus Thru Hulls which allows you to cruise sounding like a go-fast boat, or as quiet as a normal PC.

I had the Bravo III props tweaked and lab finished by Pro-Peller near Elkhorn WI. Bravo III props leave much to be desired and this guy work some real magic on them. We did my Brother's dual props off his 33' Sea Ray Sundancer and he picked up about 6-8 MPH.

Ok, yada, yada. What about performance?
1/2 throttle cruise at 3,800-3,900 RPM yields 43-44 MPH GPS.
Full Throttle with 4 on board, nearly full fuel and water show 58-60 MPH.
Empty the front water tank and it has hit 62 MPH on the GPS.
Bad habits at that speed? None.

How is this setup on Fuel? No worse or better than the stock setup. Like any boat, just depends how you run it. The props made the boat more efficient, the motors make more torque. You are running lower RPM to get the same speed as the old 7.4 MPI. I have a twin engine FloScan hooked to my GPS.
With Full fuel and water, 3 on board, 43-44 MPH 1.1-1.2 MPG. Slow to 38 MPH and it is 1.3 MPG, slow to 34 and if you trim it right it will get to about 1.4 MPG.

What is the worse thing about this boat? As much as I hate to say it I am thinking about selling it. Why? Because all my **@! friends are getting new Formulas and the peer pressure is killing me.

My challenge is, How do I top a 830 HP, 60 MPH, 31 PC that runs great and still looks like new? I would buy a 370 SS or 400 SS but for our Cruising use that cabin V-berth setup is not what we are looking for.

Anyway. Hopefully I can find the right,,, Formula.....
 
Re: 99 Formula 31PC with Merc 415 HP- 502 MPI's, Corsa Q&Q Thru Hulls and Lab Props

Well if you need to get rid of that "peer pressure" just give that old 99 31pc to me. No more pressure from that old boat. Then you can go out and buy you a new one ;D ;D ;D



Really, Formula is an almost timeless boat like no other. With the performance you have and it best accomodates your uses then just keep it and get you a "peer pressure" boat without cramping your style.


Fastech 382 or 419 are pretty cool.
 
Re: 99 Formula 31PC with Merc 415 HP- 502 MPI's, Corsa Q&Q Thru Hulls and Lab Props

aquaforce said:
Well if you need to get rid of that "peer pressure" just give that old 99 31pc to me. No more pressure from that old boat. Then you can go out and buy you a new one ;D ;D ;D



Really, Formula is an almost timeless boat like no other. With the performance you have and it best accomodates your uses then just keep it and get you a "peer pressure" boat without cramping your style.


Fastech 382 or 419 are pretty cool.
Click to expand...

Although the 382 is a big go-fast, that 31 PC has a great cabin. If you overnight alot I'd stay with what you have.
BTW: I'm leaving in the morning for a 5 day trip with the wife and 3 boys!!!! (2002 382 w A/C, gas grill and a microwave)
 
Re: 99 Formula 31PC with Merc 415 HP- 502 MPI's, Corsa Q&Q Thru Hulls and Lab Pr

what propset did you use? did you use the stock and have the work done to them or change them out for a different set? what pitch?
 
Re: 99 Formula 31PC with Merc 415 HP- 502 MPI's, Corsa Q&Q Thru Hulls and Lab Pr

Couple days ago I questioned the prop set pitch and mods done. I am curious because I have a 93 that still has the bravo 2's in place. Similar to yours, the engines have been replaced. In my case, with 502 magnums that have had a roller cam upgrade, but still dyno between 470 and 494hp. I'm looking for "the next step" and a bravo 3 conversion is a definite possibility and your input would be helpful.

thanks
 
Re: 99 Formula 31PC with Merc 415 HP- 502 MPI's, Corsa Q&Q Thru Hulls and Lab Props

Sorry. I have not looked at the blog forum lately.

The boat is equipped with Bravo III and has provided decent service with them. I would look at least a the Bravo III X drive though.

As for propset, the 31 PC came orginally with the 28 pitch prop set. It used to run about 4500-4600 with the stock 7.4MPI. When I installed the 502's the extra HP brought the RPM close to the desired.

I then took them to DG ProPeller in near Elkhorn WI and he lab them and it now runs up to where it should be. This prop work was outstanding.

My brother has a 340 SeaRay Sundancer. He did his props and he picked up nearly 7 MPH when done.
 
Re: 99 Formula 31PC with Merc 415 HP- 502 MPI's, Corsa Q&Q Thru Hulls and Lab Props

you are right on about john janeke at pro peller in burlington wisconsin. he's more of a outboard guy but he can fix any prop. we are in a boat group that uses him alot. call custom boat service,mark willis, for his phone. mark's no is 262 389 0535 in brookfield wis,central time. good luck triple j
 
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