huskyrider

iTrader: (1)

I know my boat wasn't designed to be the fastest boat on the water but I'm sure she's able to achieve a bit more speed with the right powertrains.
My 525 SC's are nearing 500 hours and I'm gearing up to either refresh, repower, or rebuild with new cranks/rods to get more displacement.
I'm curious as to what you members have seen or know about some of the higher top speeds that have been achieved with this hull and how much power per side it took to get there.
I currently have stock 525 SC's with the pulley upgrades, sc intercoolers, and extension boxes on my drives. The powertrain survey a few months ago aced the compression and leakdowns. At a minimum I'm going to switch over to a roller cam/lifters from the standard cam/lifters it currently has, a top end freshen up, and have the blowers serviced.
But I'm torn on my decision, I've had quite a few tell me these are tough motors that can deliver some good return based on the stock displacement.
I've decided to sell my and my sons crotch rockets and a couple of ski's that we haven't used this season. Once I do this I'll have the equity necessary to handle the minimum or a great head start on a complete rebuild or repower.
This is a decision I'll have to live with for quite a while after I move forward.
I'm open to all input from the membership.
As always, thanks for y'alls insight, you guys and girls are the best source of quality info I've ever found.

See ya,
Kelly

Smitty

iTrader: (1)

Question is how fast are you going now ??? How fast do you want to go at top speed ???


Generally speaking, it takes 20 horsepower more to increase 1 MPH. So if you add 200 HP total, you will see an additional 10 MPH in top speed. IMO I think your hull will be limited to a top speed around 80 mph based on the Bravo drives and max power out of your motors.

huskyrider

iTrader: (1)

I can hit low 70's with anything up to 1/2 tank of fuel and 4-5 passengers, it's like I'm hitting a wall. I was hoping to get near 80 or better.
I really don't see gaining an additional 100 hp per side with just a cam/lifter change even if it's more aggressive.
Equally, I don't want to fork out the coin to upsize the mill, or repower, and only walk away with 3 or 4 more mph when a new roller cam/lifters, springs, and valve job would cost much less.
Thanks for your input, I look forward to more.

See ya,
Kelly

Quinlan

iTrader: (1)

Those things are a big azz tank.
Enjoy what it is and crank up the AC when everybody else is sweatin.
Any more power and Drives will be first on the list.

JaayTeee

A friend of mine had a 97' w525Sc's that he built up
to somewhere in the 650 hp range, and as I recall
it ran 73ish.....they do seem to hit the wall in the low 70's

huskyrider

iTrader: (1)

That's the same exact speed she ran on the seatrial with my surveyors GPS recording it.
I think I might try playing with props to see if there may be a little to milk out of her.
I'm kind of at the point where I'll probably just go for the roller valvetrain over the flat tappets, respring, see if it needs a valve job or not, and service the blowers.

Your absolutely correct, she's a whole lot of boat to push across the drink. And, it does have all the comforts of a very small apartment.
Well you know how it is, a man just always wants more, LOL !!!

See ya,
Kelly

A.O. Razor

This is just a thought.

How about going with Arneson #7M's and just have the 525sc's rebuild by a good builder like YPM or Potter ect. to 600 hp or so? Fast and bomb proof. Ask Rik @ Arneson what he thinks would be the speed gain from the drives alone. If the claims of 10 mph from the drive alone, also applies to your boat, and then by "just" adding 75 or so hp per side, you are looking at the most reliable and efficient 82-85+ mph ride ever.

huskyrider

iTrader: (1)

I actually talked to his shop a month ago about the bravo replacement surface drives, they were very expensive.
Afterwords I talked to the Bravo shop about Bmax drives, they were much more affordable but the project would be way higher once added to my repower or rebuild to more displacement as compared to just refreshening.
Now I've hit another wall, the money wall, LOL !!!

I'm curious, what's the fastest 38 Special you've heard of?
If it's only mid to high 70's I won't entertain the additional expenses, if it's more like low to mid 80's I'd have to get quotes to approximate the total costs to determine if it's really worth it or not.

Thank you for all your insight.

See ya,
Kelly

JaayTeee

I've never heard of one going over 80

They have a high center of gravity, I know we were
on it's side a couple of times (in my friends boat) when it
fell off the pad ( not a real fun feeling) at 70+

I wouldnt waste the money trying to make it do something
that it isnt going to be able to do very well.

A.O. Razor

What you have to look at is, how much the combined cost is to get to fx. 85 mph.

Yes, the Arnies are more expensive, to begin with. But how much do the Bmax cost, when you add hydraulic steering, props ect.? The Arnies only needs props.

Look at it from this angle.
If run 70 with normal load and you get to 80 mph by the Arnesons, no power added, you will need about 600hp pr. side to run 85, as an everyday number. 600 hp from a set of well build 502/509's should run very reliable, and the drives won't even notice the power. This package that consists of 600 hp motors, #7M's props and rigging, has a price of xx,xxx.xx$ + Gas and maintenence = xx,xxx.xx$.

Now a set of Bmax drives are useually a bit slower than standard XR's. More weight, parasitic loss ect. Let's say when running 70 with XR's and then lose 1-2 mph by running Bmax's, you will need atleast 800 hp a side to run 85. Now it gets funny. Add the price of 800 hp motors to the price of Bmax drives with steering and props, then remember the Bmax runs standard xr gears in the lowers (drive rebuild) + the added build price, maintenence and fuel running 800 hp mill's compared to 600 hp mill's.
This package that consists of 800+ hp motors, Bmax drives, steering, props and rigging comes in at xx,xxx.xx$ + gas and maintenence = xx,xxx.xx$.
It get's real expensive real fast. The Bmax drives are good drives for what they are, but they will still be a weak link on the 38 with big power.

I'm not trying to give you 100% accurate numbers here, I know they aren't, it's just a way of looking at it.

What numbers did Rik give you speed wise?