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Quote:

Originally Posted by MILD THUNDER (Post 4412523)

I think you have that backwards scott. A roots moves air and does not compress it within the case, where as a whipple does compress it .

You are Correct.

Quote:

Originally Posted by horsepower1 (Post 4412522)

A roots style blower is an air compressor...a whipple is an air mover and does not compress the air like a roots. That's why they run so much cooler and take less power.

Totally wrong
Best go read whipples website

Quote:

Originally Posted by tommymonza (Post 4412486)

So to really confuse the matter. Why the resistance to turbo charging .

Back n the day Brownie talks of all the old turbo charged Daytona motors and what a hot package they were.

Than Mercruiser came out with the 454 daul turbo motor that made 475 horse with its tiny non water jacketed housings.

I ran little 300 horse turbo Yanmar diesels that had no lag what so ever . So what is the hold up with turbos?

What I see is the complexity of them. new exhaust manifolds, Correct oil drainage, new exhaust pipes, heat shields over the turbos. Plus turbos dont have that muscular sound at idle. My boat is really quiet at idle. Even at speed it is quieter that other boats, and when you get into boost all you pretty much hear is the whistle. There is no universal bolt on turbo system available. Hardin Marine was developing a twin turbo kit stage 1 kit for the 525 EFi
that would boost the power to 775 HP. It had a starting price of $12K, but it seems like the project stalled. http://speedonthewater.com/in-the-ne...-in-miami.html

I'm guessing for $12K you can buy a blower for much cheaper and be able to bolt it on in a weekend with minimal amount of fabrication and achieve similar power levels

Quote:

Originally Posted by MILD THUNDER (Post 4412523)

I think you have that backwards scott. A roots moves air and does not compress it within the case, where as a whipple does compress it .

I belive a screw has less drag due to the much finer tolerances and no contact of rotor stripping , etc .

this is correct but both roots and screw blowers do the same thing,pack air into the cylinders.the screw blower just does it more efficiently.on another note,nitrous oxide does the the same thing in a different way,it puts oxygen in the cylinder.

Quote:

Originally Posted by MILD THUNDER (Post 4412431)

A 557ci, with an 871, should make 750HP, running on 7 cylinders, unless it was a total chitbomb of a build.

I agree Joe, my friend's engines were built by a guy named Norm---his business is called "Ultratech" in Indiana close to the Michigan border near South Bend, Michawaka or something like that. Whether it was 750hp or only 700hp I honestly don't know, but I still think those supercharged engines of his should have beat me easily.

Anyway, my 565cid NA's made something like 660-670 lbs of torque....and I still believe my friend's boat should have kicked my arss from the torque alone with those Superchargers---especially from 3500rpm up. I surely thought he would have pulled away from me as we both climbed to 5600rpm, but he couldn't do it---we tried several times on different days.

Quote:

Originally Posted by tommymonza (Post 4412428)

Huge advantage there. True horsepower from Big Dave and 2, not dragging half of your propulsion, huge drag no matter how much power you have

True HP from Dave's dyno---yes,... and that was with all the belts and pullies, and there has to be something said about how the drives were set up on my boat too.

Quote:

Originally Posted by sutphen 30 (Post 4412346)

thats a good story,,I guess we can stand to reason, his engines didn't make anywhere near 750hp. its even funnier about the drive thing.

Bill, you could be right about the power of his engines not truly making 750hp, again, maybe only 700hp, I really don't know, but I still think he should have whipped me from the midrange 3500rpm on up with those superchargers.

Mild, that chart has quite an intake temp... 241*? Wow, is that with a barbecue grill cooking some hot dogs on a 100* day above the intake?
:lolhit:

Quote:

Originally Posted by mike tkach (Post 4412445)

the xtra power is because1 the whipple is so much more efficient and2 because it takes less power to turn it,less parasitic loss.the down side is the price,they are not cheep.a lot of boaters have them,the ones that don,t have one want one!

That 16/71 was not a high helix was it?

Quote:

Originally Posted by MILD THUNDER (Post 4412523)

I was thinking it but you said it! LOL