Offshoreonly.com - 382 Fastech Imco SCX 2x900hp prop ideas

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Quote:

Originally Posted by Bompa (Post 4607602)

Hi

would like some ideas for my 2001 382 Fastech with 900hp motors, Imco scx drives, no boxes. I run Maximus 32 out of box and spinning props out. Are now in the 90mph range and 60mph at cruise 3500rpm. But would like top end speed.
Any ideas or experience?

Thanks

What rpm are you hitting at 90? Is it on the limiter?

Quote:

Originally Posted by Sydwayz (Post 4607810)

Russ/Thp500s should chime in on his experience on his 382 with HP500s and ProChargers. He eventually rebuilt as NA, but ran it for one season with the blowers.

I'm not sure how much help I can offer. I bought my 382 with 8 PSI Prochargers and standard length XR's w/o boxes. Magicfloat, who sold it to me, reported a top speed of 98 @ 830hp. However I also bought the boat after the engines had been overheated and "hurt". (I was told they run now but could let go in 5 min). I only ran them hard once at the end of the season knowing they were coming out. I saw 95 mph on a short straight running 34P Bravos.

New motors that winter were 9.8 to 1 540's, ported Iron eagles, ported plenum, cams, etc. Mark boos dyno'd fully dressed at 630hp/700tq. With full diameter 28P maximus she ran 58-60 @ 3,500 and 83 @ 5,200. 30P Bravos netted 87 @ 5,650 rpms.

Seems to me to cross the 100mph mark in those heavy pigs you'll need surface drives. The ASD kit is probably your best chance.

Nope not hitting the revlimit, are at 5400-5500 rpm at wot, revlimiter set at 6000rpm. Maybe should be at 5800-5900rpm at wot.

Limiter may be at 6000, but where is the power peak on your motors ? If they stop pulling past 5500, that is all you get. Try going up in pitch until it won't go to 5500 anymore, then you've hit the wall.

Peak power would be at 5800-5900 so i would need some more rpm.
The question is, should i do some job to the stock Maximus or should i try a different prop? What will work best on this hull?

are the Max 32's 5 blade ?

Yes they are 5 blades and the hook up real good, no cavitation at all when getting on plane.

Still winter here in Finland so cant do some testing at the moment, but will cut the diffuser ring on the Maximus and do some grinding to the 1300 lowers and see if it would give me some speed.

Feels like the boat would like some more bowlift, it likes trim at speed and runs flat.

Quote:

Originally Posted by Bompa (Post 4608092)

Some report the SCX hurts speed. It probably needs to be pretty high X.

Might want to try some labbed 30 or 32 four blade with some cup to carry the nose a bit, Id hit up a couple of the prop shop's and see if they have a known recipe for your hull

Arnesons it is, does anyone have some prop ideas for Arnesons setup? 1:36 ratio!
What do others run on their Formulas? Rake, diameter, pitch, spinning in or out?