|
|
23-08-2005, 01:29 PM
|
#21
|
hello
Join Date: Mar 2004
Posts: 2,739
|
If you do take the airbox off then either get some stacks or cut the airbox up to make an S2000 style intake plate. Cut the front and sides off just leaving the part that surounds the carb entries. You need this part as it rounds the edges of the carb mouths thus stoping the air from becoming turbulent. Without it it wont be much better than with the airbox on. You may need to jet up one size, two to be on the safe side.
__________________
|
|
|
23-08-2005, 01:58 PM
|
#22
|
Registered User
Location: hayling island
Boat name: snow monkey
Boat make: extreme 24
Engines: mercruiser 6.2
Join Date: May 2004
Location: hayling island
Posts: 2,082
|
7200
__________________
|
|
|
23-08-2005, 02:05 PM
|
#23
|
Registered User
Country: Scotland
Location: Kirkcudbright
Interests: Boats n Lambrettas
Boat make: Boatless
Join Date: Mar 2004
Location: Kirkcudbright
Posts: 978
|
I like the sound of these velocity stacks. Where can you get them and how do they fit ??
|
|
|
23-08-2005, 02:59 PM
|
#24
|
Registered User
Country: England
Location: Crayford, Kent.
Occupation: Electrical gezza!
Interests: Petrolhead
Boat name: Wayne Kerr
Boat make: Phantom xl
Engines: Mercury 2.5, 200(ish)
Cruising area: Essex, Hampshire, Mediterranean
Join Date: Sep 2004
Location: Crayford, Kent.
Posts: 1,199
|
Quote:
Originally posted by mike k
I like the sound of these velocity stacks. Where can you get them and how do they fit ??
|
Mike, Bob's Machine Shop has them, 65 of yer US squids!
|
|
|
23-08-2005, 03:36 PM
|
#25
|
Registered User
Country: Scotland
Location: Kirkcudbright
Interests: Boats n Lambrettas
Boat make: Boatless
Join Date: Mar 2004
Location: Kirkcudbright
Posts: 978
|
Thanks Trev I'll check out their web site and talk to Clive about jets.
|
|
|
23-08-2005, 07:11 PM
|
#26
|
hello
Join Date: Mar 2004
Posts: 2,739
|
Quote:
Originally posted by carly baby
7200
|
Bit more detail would be nice, prop size, gear ratio, speed etc.
|
|
|
23-08-2005, 07:22 PM
|
#27
|
Registered User
Location: hayling island
Boat name: snow monkey
Boat make: extreme 24
Engines: mercruiser 6.2
Join Date: May 2004
Location: hayling island
Posts: 2,082
|
man of little words me,but, its a 24" prop 1.87 gears and 72mph,with no lifter or set back
|
|
|
23-08-2005, 08:01 PM
|
#28
|
hello
Join Date: Mar 2004
Posts: 2,739
|
Thats quick dude is your boat quite light then?
|
|
|
23-08-2005, 08:24 PM
|
#29
|
hello
Join Date: Mar 2004
Posts: 2,739
|
Velocity stacks
|
|
|
23-08-2005, 08:25 PM
|
#30
|
hello
Join Date: Mar 2004
Posts: 2,739
|
S2000 intake plate. You can make something very similar to this by cutting up your old airbox!!!
|
|
|
23-08-2005, 09:20 PM
|
#31
|
Registered User
Country: England
Location: Crayford, Kent.
Occupation: Electrical gezza!
Interests: Petrolhead
Boat name: Wayne Kerr
Boat make: Phantom xl
Engines: Mercury 2.5, 200(ish)
Cruising area: Essex, Hampshire, Mediterranean
Join Date: Sep 2004
Location: Crayford, Kent.
Posts: 1,199
|
Quote:
Originally posted by Johnny Boat Dude
S2000 intake plate. You can make something very similar to this by cutting up your old airbox!!!
|
OK, got-ya, looks good (exept the sun down syndome on the wall).
Well done, we'll look into this ,,,,,,,,, Top Stuff !!!!!!!
|
|
|
23-08-2005, 10:43 PM
|
#32
|
hello
Join Date: Mar 2004
Posts: 2,739
|
The first picture is off scream and fly. The second one I took myself with my rubbish £15 digi camera. Its one of those 0.3 mega pixel no proper lens and no LCD screen jobbies. It takes shockingly bad photos
|
|
|
23-08-2005, 11:17 PM
|
#33
|
hello
Join Date: Mar 2004
Posts: 2,739
|
Here's another picture of a carb plate
|
|
|
23-08-2005, 11:19 PM
|
#34
|
hello
Join Date: Mar 2004
Posts: 2,739
|
And here's a cut down airbox I found on S and F!!! In the foreground you can see some v. stacks (red)
|
|
|
24-08-2005, 03:20 AM
|
#35
|
Registered User
Country: England
Location: Great Horwood
Join Date: Mar 2005
Location: Great Horwood
Posts: 2,372
|
I have never understood the fascination with revs! If you rev 5300 and do 56 mph, is it less exciting to rev at 6000 (with a different prop) and run 55 mph?
Surely an engine has a power band, the plan should be to run at the top of that band.
Certain factors have to be taken into consideration off course, calm sea bigger prop lower revs, rough sea smaller prop higher revs to get you out of the hole.
Going back many years ago with our 21’ cat XR2 we revved 5600 (2.1 ratio) with a worked QSS 26’ which produced 74 mph (Windermere certified)
Going back a couple of years ago with our 17’ cat Yam 90 we revved 5600 (took a long time to get there) (2.1 ratio) with a Cleaver 26’ which produced 81 mph (Windermere certified)
|
|
|
24-08-2005, 01:07 PM
|
#36
|
hello
Join Date: Mar 2004
Posts: 2,739
|
My motors peak output is at 6K but produces good power all the way into the high 6's. So why prop it to only rev to the power peak. That would mean taller prop that would give less acceleration.
Plus if you gained some revs then you must have gained some power and speed.
|
|
|
24-08-2005, 01:13 PM
|
#37
|
numbskull
Country: United Kingdom
Location: South
Occupation: none
Interests: none
Boat name: Leviathan
Boat make: Phantom 28
Cruising area: South Coast
Join Date: Mar 2004
Location: South
Posts: 15,959
|
Quote:
Originally posted by Johnny Boat Dude
Plus if you gained some revs then you must have gained some power and speed.
|
It aint quite as straight forward as that, is it.
If you gained the revs by a prop change, or by raising the motor, or changing the gear ratio, then no.
__________________
.
"I Agree with everything you say really!" - John Cooke to Jon Fuller - 26-01-2013
|
|
|
24-08-2005, 01:16 PM
|
#38
|
hello
Join Date: Mar 2004
Posts: 2,739
|
Yeah but I was refuring to changes made to the power head only. Like removing the airbox fitting stacks and jetting up may gain you some RPM.
|
|
|
25-08-2005, 04:07 PM
|
#39
|
Registered User
Country: UK
Location: Thorpe Bay
Occupation: IT Director, www.lighthouseit.co.uk
Interests: Boats, Surfing & Snowboarding
Boat name: Isabella / Cool Runnings II / Bella / Sea Pup / Sea Dog / Speedy II / Bernico F3
Boat make: Colvic 35 Suncruiser / Bernico F3 / Phantom 16 / Zodiac 420 YL / RIB / Apollo 9
Engines: 2 x Perkins Sabre 225ti / Mercury Pro XS /Mercury Pro XS 115/ Tohatsu 2.5 / Mercury 25 / Mercury 50
Cruising area: Thames Estuary / River Crouch / Salcombe
Join Date: Jun 2004
Location: Thorpe Bay
Posts: 932
|
P20, XR2, 23P Laser II, will rev just over 7K if trimmed right up, Max speed seems to be approx 6.6k - 6.8K Fully fuelled (50 Gallons) top speed with 1 person in the boat was 64 mph. If you remove the front tank it will do closer to 68mph in the flat.
Hope that helps.
After blowing my last engine up I try to keep the revs below 7K now!
__________________
Loving the Spitfire with a 25HP Mercury
|
|
|
25-08-2005, 06:47 PM
|
#40
|
hello
Join Date: Mar 2004
Posts: 2,739
|
Is that 1.87:1 or 2:1?
__________________
|
|
|
|
|
Posting Rules
|
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts
HTML code is Off
|
|
|
|
» Recent Threads |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|