Boatmad.com


Reply
 
Thread Tools Display Modes
 
Old 25-07-2007, 08:39 AM   #41
Registered User
 
The Docta's Avatar
 
Country: UK
Location: Coventry (but from Lee on Solent)
Occupation: Sales Director
Interests: My Boat of course
Boat make: Extreme 21
Engines: Merc V8
Cruising area: Solent

Join Date: Jul 2005
Location: Coventry (but from Lee on Solent)
Posts: 587
Hi Scotty

Did you ever find out why your XR2 was under reving??
__________________

__________________
The Docta
The Docta is offline   Reply With Quote
Old 25-07-2007, 11:12 AM   #42
Registered User
 
cfun's Avatar
 
Country: uk
Location: poole
Occupation: retail
Interests: sport and being lazy
Boat make: ring rib
Engines: merc xr2
Cruising area: bournemouth bay

Join Date: Jan 2006
Location: poole
Posts: 1,681
Back in the mid 80's our 21 Ring with a 2ltr 150 v6 ran a chopper prop 24p on 2:1 ran 5800 at 58mph about 12% slip boat set up for rough water as calm weather always going to be back of the pack, most Phantoms were lighter and motor set higher speed I guess around 60/61mph for them.......old style xr2 2ltr 162hp on 3 pointer set higher but no lifter on 2:1 26p worked chopper 6400rpm 70/71mph around 10% slip (death machine).......Marshan old style xr2 162 hp 2:1 26p worked chopper 6200rpm 65/66 about 12% slip (slip on the 26p may have been slightly higher due to cupping in worked prop this may have given a slightly higher pitch)
If I remember correctly Michael Frode and Neil Holmes used to set there red lines at 7800rpm on xr2 I did ask M Frode if this red line was achievable he just said we come to win (implied yes maybe) therefore those xr2 can no way have been standard
__________________

__________________
i can na give her any more captain
cfun is offline   Reply With Quote
Old 25-07-2007, 12:28 PM   #43
Registered User
 
The Docta's Avatar
 
Country: UK
Location: Coventry (but from Lee on Solent)
Occupation: Sales Director
Interests: My Boat of course
Boat make: Extreme 21
Engines: Merc V8
Cruising area: Solent

Join Date: Jul 2005
Location: Coventry (but from Lee on Solent)
Posts: 587
Thanks for the info

My R21 with Xr2 200 has run 6700-6800 when trimmed out with a worked chopper 21. However most recently runs at more like 6k consistenly but every once in a while seems to find the extra revs? She seems to be running sweet but is just not consistently making the revs that I have had before.

I havn't changed the setup at all - Any ideas?? The motor has velocity stacks and has been jetted accordingly
__________________
The Docta
The Docta is offline   Reply With Quote
Old 25-07-2007, 03:33 PM   #44
Registered User
 
Country: England
Location: South West
Occupation: Development engineer
Interests: Fast boats
Boat name: Xtreme
Boat make: Bernico 21
Engines: Mercury F1, 300 Drag, XR2 "Fingerported"
Cruising area: South West

Join Date: Mar 2004
Location: South West
Posts: 1,043
8k +

Posted by Cfun:
If I remember correctly Michael Frode and Neil Holmes used to set there red lines at 7800rpm on xr2 I did ask M Frode if this red line was achievable he just said we come to win (implied yes maybe) therefore those xr2 can no way have been standard[/QUOTE]

Think about the S2000 class (lightweight cat) which runs a left hand rotating XR2 they rev over 8K, less load for sure but we are talking revs here.
Cyco is offline   Reply With Quote
Old 25-07-2007, 05:05 PM   #45
Registered User
 
cfun's Avatar
 
Country: uk
Location: poole
Occupation: retail
Interests: sport and being lazy
Boat make: ring rib
Engines: merc xr2
Cruising area: bournemouth bay

Join Date: Jan 2006
Location: poole
Posts: 1,681
did not realise the S2000 engine was a stock xr2...do mercury not give the max power for an xr2 at between 67-7000rpm so I would gather at 78-8000rpm it is well past peak power would this not be counter productive unless the engine had been modified ??? had watched the inshore races with a few boats in that class they sure were fast and sounded much higher revving than your offshore version
__________________
i can na give her any more captain
cfun is offline   Reply With Quote
Old 25-07-2007, 07:16 PM   #46
Registered User
 
scottyboy's Avatar
 
Country: United kingdom
Location: West Sussex
Occupation: Grease Monkey
Interests: Makin my boat faster!
Boat name: S.B Racing
Boat make: Ocke mannerfelt canopied B23 / Zapcat
Engines: Merc 200XS Gen 2 / Tohatsu 50
Cruising area: littlehampton/Southampton

Join Date: Jan 2005
Location: West Sussex
Posts: 2,656
It was on my p21 tandem deck.I had it abit better but after a stator change and carb overhaul. It was on my phantom and i just put it down to boat weight and the fact it was set up for rough water with a belly tank going forward quite away in the end!
__________________
Class 3C Mono EPA National speed record holder 95.35 mph Avg!
scottyboy is offline   Reply With Quote
Old 25-07-2007, 07:57 PM   #47
CB1
Registered User
 
CB1's Avatar
 
Location: poole dorset

Join Date: Mar 2004
Location: poole dorset
Posts: 868
"Stock" XR2's reach peak power @ 6800 - 6900 rpm. After that the curve drop away sharply and all your doing is wasteing fuel. Heard all sorts of crap about rpms never seen it myself with a decent prop set up.
__________________

CB1 is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Powered by vBadvanced CMPS v3.2.3

All times are GMT +1. The time now is 01:58 PM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
×