frickstyle

Mild - Ha, I needed that. Thanks.

I just figured we put them on because:

1. It was more to polish instead actually boating, yay!

2. It made everything taller, therefore, the original sleek hatch GlassDave did such a nice job on now has pro stock scoops glued on top with holes cut in the pretty hatch. (Dave, I know they are not glued, right?) And also rendering the sunpad useless.

3. It's a project, so, why not?

4. Who doesn't like more plumbing / rigging / water running through their boat?

5. I get to buy more rebuild stuff!

6. Turn up the boost, duh. "My mustang makes 14 PSI, your boat only makes how much? Gay."
(kidding)

MILD THUNDER

iTrader: (3)

lol, I totally hear ya. They look bad azz! Dont get me wrong, I am not saying they do not work, because they do! You just need to look at the big picture when setting them up. With their 14-71's, their intercoolers, you simply should have a great package from an induction standpoint.

We know scientifically, that when you compress air, you heat air. There is no changing physics. But in the roots blower deal, the heat problem, is more so from overdriving the blower, rather than the psi number in the intake. What I am saying is, if you had a 6-71 at 25% over making 7psi in the manifold, it will be a much hotter charge, than a 14-71 at 10% under, making 7psi in the manifold. And still probably hotter, than the 14-71 making 10psi at 1:1. Many guys simply follow the rule of "7lbs max", without looking at the entire setup. Does that mean that if you see cool temps, that you can crank the boost way up? IMO, no. You still have to consider the boost level, vs the static compression, and realize you want to run pump fuel. You can only get so much cylinder pressure before you exceed the fuels resistance to ignite itself prematurely. This is why without a blower, N/A, you still have to abide by the compression/vs octane requirements. A N/A 12.5:1 engine, can make lots of peak cyl pressure. the blower version, can withstand the same peak cyl pressure, however, it will have more cylinder pressure thruout the combustion process, which is why you get more power. Cam specs, static compression, boost pressure, intake air temps, ignition timing, chamber design, all play a part. This is why some builders can make a marine engine live at 10lbs of boost all day, and some cant make one live with 5lbs of boost.

Really looking forward to your results on your build. Should be great.

donzi matt

iTrader: (1)

You forgot #7, more water dumps out of the transom look extra bada$$.

buck35

I wish I knew as much about engines as you you fellas had forgotten, and I work on equipment on a daily basis.

SB

iTrader: (1)

Most have learned from breakin a ton of schit .

Are you up for it ?

This used to be a signature of mine:
"Breaking parts can be fun. It just depends on what kind of mood your in."

Likefastboats

iTrader: (1)

Through the years of my own drag racing, then 9 years of a 4 car Jr Drag racing team, multiple sand cars and now go fast boats I have broken way more than my share of expensive parts. I've never found it to be much fun no matter what mood I'm in. LOL Altough if your breaking parts I guess that means your having fun. If that makes sence?

buck35

I'd love to build my next engine .... but if you don't have a trusted machinist to work with you are just playing Russian roulette, I learned that on my last build, bout 30 years ago, ran great but the rings never seated properly or valve guides, but a big puff of smoke every time you started up. Embarrassing!

mmb

I have coolers and leave the sea strainer valves closed; so 99% of the time they are never in use on my boat... I run 420 Mega Blowers with 30% Overdrive and never have a problem.

If you look through my engine build thread I pressure tested them, you can see what I used and how I did it.

MILD THUNDER

iTrader: (3)

A little data from a recent build I was involved with from the dyno session.

Engine was a 522ci, 10-71 blower. Blower shop intercooler.

At idle on the dyno, IAT's were in the 120's with no water flowing thru the intercooler, at idle. I turned the water on, waited a few, and the temp dropped about 3 or 4 degrees. At 6lbs of boost, 8lbs of boost, and 10lbs of boost, at max throttle, the IATs were 110-115 degrees. This was a teflon stripped littlefield blower, just the outside of the rotors stripped.

My buddy's 540ci build, also with a 10-71 but no intercooler, made around 140-150* temps at idle, and at wide open dropped to around 130-135ish. However, this was a stage 3 blower, stripped on both the inside and outside of the rotors.

According to some things I've read about regarding roots blowers, is that a tighter blower, will make more boost, however, it will also make more heat. A looser blower, makes less boost, but also less heat. I almost wonder if the 540ci build, with the stage 3 style blower, simply made more heat, because of the tighter tolerances. 20-25 degree hotter at idle.

I would have thought that with cold tap water going thru the core at idle, that by turning the water on/off, we would have saw a more substantial drop in IAT's than just a few degrees. It would have been cool to simply remove the intercooler completely and do a pull, record IAT temps and HP.

MILD THUNDER

iTrader: (3)

Have you tried running without them mounted on the engines? I'd imagine you'd be able to slow the blower down a bit without having to blow thru the core?