how fast

roofer · 21-11-2004, 08:39 PM

how fast will my phantom 18 go with a 2.5efi 280 offshore motor swingin a 25 pitch chopper prop,the boat is being stripped out to race but is heavily built not a lightweight race hull.

BREN · 21-11-2004, 08:42 PM

FAST

roofer · 21-11-2004, 08:44 PM

i know that but how FAST!

K9 racing · 21-11-2004, 08:57 PM

probable beetween 85 and 95mph!!!

Jon Fuller · 21-11-2004, 09:01 PM

I would also guess somewhere around 90

roofer · 21-11-2004, 09:03 PM

i thought about 85,95 would be very very nice

but id have to be anerexic to get that speed

Jon Fuller · 21-11-2004, 09:05 PM

There was a P21 / 2.5 280 that ran 82 at windermere a few years back, and the 18 is a fair bit quicker for the same power, if conditions allow

roofer · 21-11-2004, 09:08 PM

the engine i bought has been tuned and balenced,but i dont know whats been done.

RHINO · 21-11-2004, 10:02 PM

i have the performance record at windermere with my phantom 19 with a 280 efi. it ran 92 mph. the prop you propose will be crap. the prop you need is a raker,and i still have my one if you would like to try it.

Taz · 21-11-2004, 10:02 PM

Sod that it will be well unstable at that speed!

Rather you then me

Jon Fuller · 21-11-2004, 10:03 PM

Quote:

Originally posted by RHINO
i have the performance record at windermere with my phantom 19 with a 280 efi. it ran 92 mph.

That's Mooooovin!

(did you get Mantoss to drive it for you?)

RHINO · 21-11-2004, 10:25 PM

i know it will be hard to believe but it was quite stable and we think it would have faster if we had the next size prop. ask jackie hunt, of 4litre rib fame, as she was my co pilot

Cookee · 22-11-2004, 09:13 AM

Roofer - I reckon it'll be bouncing off the rev limiter if it has one with that prop - it'll swing at least a 26. Mind you do you know what it's been tuned to rev to?

Jon Fuller · 22-11-2004, 10:25 AM

They'll pull 8500 anyways!

Burty · 22-11-2004, 10:27 AM

Roofer, where did the engine come from?
i'm asking because i'm not aware of any software available over here (uk) to increase the rev limit hence not alot more power can be gained from a 280
Johnny knows alot more about it than me so its over to him.

Burty · 22-11-2004, 10:28 AM

Think the rev limit is 8250

roofer · 22-11-2004, 10:36 AM

i was told the engine belonged to charles burnett the american offshore racer,it was left over here when he packed up racing.the engine was tuned by smilin jack florida.

roofer · 22-11-2004, 10:39 AM

cookee,ive just had the prop repitched and resized down from a 26 to a 25 on advice from a man who knows all about the kind of racing i'll be doing.

JamesM · 22-11-2004, 12:14 PM

There are 2 versions of the 280. A consumer one and a race one the consumer one is limited to 7500 and the race one is 8200. I think you only get the race one over here though. If its on a 15" or an offshore mid it will be the race offshore version 8200rpm, assmuing the power heads never been swapped. If you want mega power and revs its best to swap to 260 or Drag electronics and change to a 56PSI (black) fuel reg and ECU. Its not just the limiter on the 280, the igniton cant hadle more than about 8500rpm. Dont know anything about circuit racing but is top speed everything ir do you need acceleration out of the corners too? There was a ski boat in weston (Palpataions, P21 lightweight) that ran 87mph gps with a tuned 280 towing a skier.

Jon Fuller · 22-11-2004, 01:12 PM

I think the circuit motors will pull over 9K