99 42 staggered
 

how fast should a 99 42 staggered 500hp bravo boat run??

I would guess 70ish

friend of mine had one with sealed 500efis, ran 77-78ish

75-76

i figured close to the 80 area. a buddy of mine had 540's built and is going slower than he did with 500hp's we are just trying to figure out where he went wrong..... or why he isnt making the power.

I was talking with the man who owns one of the local custom boat shops, and he pointed out that Mercury Racing HP numbers are very different from engine shop HP numbers, such that a Mercury 600 ran faster than an engine builder's 900.

this 42 will only pull 5000 rpm's with 26 hydro's. the motors are new. the only thing used was the blocks and they stroked them to 540's with dart iron eagles (345cc), merlin intakes, 850 holleys, msd etc. never dynoed but i would think 650 hp. it runs 75-76 mph and that's it. very disappointed with the whole deal. what do you think, be honest, you won't hurt my feelings, it's not my boat. lol it's hard to believe that these motors won't make more hp than 500's

looks like we have another boater that should have left the stock 500's in their boat!!!!!!!!!!!!!:hitfan:

i bet the blocks werent the only "used parts":party-smiley-004:

Those are big heads (runner's). I would think that is where his problem lies. With a smaller runner it probably would make more HP.

sounds like he does not have the right combination of components.the heads have to big of runners for a natural aspirated motor . the problem he's having is no velocity of air in the intake system. the merlin intake manifold doesn't help that either. a brodix high rise manifold works much better. also the combustion chamber cc's have a lot to do with the initial compression ratio. the cam also has to work with all of these componets. i had a similiar problem with some 540's i had and all i did was change the heads. i had older chevy zl 1 alum. heads and i changed them to brodix bb2 x's and the motors never ran the same. i had to add superchargers to them to gain back the velocity that i lost by using those big runners on those heads. hope that helps you.

Assume it has a cam matched with the rest of the components ?

Have you trailered the boat to a scale to see what it actually weighs as opposed to what it is supposed to weigh ?

Who built the motors ? I had Dart 345's on a 540 but with an M4 Procharger creating intake charge.

i have dart 345's on my 548. made night and day power over the gm performance heads i took off. way better mid range and 400 rpm on the top end. put some blowers on it and get that thing moving!!!

kellyO your boy cigrocket made a wise decision by heading south

Who built the motors ? Was it the builders recipe ?

a local establishment

Was it HTG Racing ? I have heard of more bad dealings with them lately. Don't know for sure if any of it's true...but people are starting to call them HTG....HOPE TO GOD....as in "hope to god it doesn't blow up"..."hope to god
I get my parts back"..."hope to god it doesn't take years to finish my motor"..."hope to god he used the parts he said he would".


Don't know if it's his workmanship or ethics...just saying whats being said out on the water by many lately. :confused:

Real Fast Marine
 

I would guess 78-80 mph. If we can help you or anyone on this thread with service or customization please give us a call. Our website is under development right now but Facebook is up...Real Fast Marine....252.561.6070

what kind of power does it take to make the 42 hit 90?

;)real 650

I own a 99 with carbed 500's ran 78.4
Not staggered though

I'm only looking for 1.6mph more...

I had a 99 42 with Innovation 600's, they were NA closed cooled motors and dynoed at 625hp and 630hp. Best the boat saw was 92mph but that was nothing in the boat and light on fuel. Two people and roughly half a tank I could hit 89-90mph.

Good luck.

Jay

Single With Twins

When those were dynoed, What exhaust did they run on the dyno? Was it the exhaust you ran in the boat or a pair of dyno headers?

I ran a 1998 42 500hp non staggered with 27 Hydromotives turning in this weekend and was plesantly surprised how good it ran and how fast it got there.

lose the arch & it may touch 80:lolhit:

Eddie
Did you take both hands off the wheel to take that picture???

No one was on the throttles ! :coolcowboy:

Which correction factor does he use? From what I recall, Merc, Volvo and Ilmor uses the SAE J1349, which I personally think is the correct one to use. If he used the SAE J607 factor as many smaller custom builders do, even though it's more generous, the difference would not be 300 hp. What each engine builder use, is pretty much up to them, but when comparing apples to apples, you need to use the same factor. I have no knowledge about the guy you are referring to and this by no means anything personal, but if hes 900 hp motor does not run faster than a Merc 600, I kind of doubt hes numbers and would find out what correction factor he uses.

Just my 02's

Carry on

time to get the compresion and leak-down gages out and start draging the water.thats how you get to the bottom of your problem.

It got pretty close!

http://youtu.be/tDVaoGTM_wQ

seems to run good, it does get there pretty fast for a 42, that is the same year hull & set up I have... 98 Big Step & side by side, I love mine, even though thats a water fed speedo, it does read within 1 mph on my gps