#1
IP: 173.9.105.253
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Enhanced Manifold Exhaust Flange
I would like to see the exhaust flange offered in the catalog opened up for 1 1/2" NPT which would match the manifold casting. An adapter could then be added for those who wish to continue blocking off a third of the exhaust flow cross sectional area.
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#2
IP: 199.173.224.31
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Could we just drill out the current one?
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#3
IP: 173.9.105.253
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That is exactly what I did but the cost of a 1 1/2" NPT pipe tap is around $50. Maybe a plumber friend would loan you one.
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#4
IP: 199.173.224.31
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Did you cut the gasket bigger?
I think a local machine shop might drill mine for less than the cost of a pipe tap. |
#5
IP: 173.9.105.253
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If memory serves, the gasket matches the manifold size, not the flange. For a machine shop the modification will be a piece of cake.
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#6
IP: 71.118.13.238
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Opinion oh boy
I don't think you would notice any differanc on a direct drive set up and seriously doubt that it would be noticeable on a hi-rpm reduction set up unless you were running a dry stack. That little engine just doesn't pump that much air even at 30HP.
As I have bragged and I'll bet my old tired A-4's performance numbers with 25' 1 1/4 pipe 1 1/2" hose will beat or meet anyones. I'm open for attack. Dave Neptune |
#7
IP: 173.166.26.241
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You're On!
Meet me at Mile "0" on the ICW and I'll blow your doors off, bridge to bridge.
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#8
IP: 216.115.121.253
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Race him for pinks dude, You can take him!
So-Cal rodder meets Yankee tinker—match up of the century. Dave probably has lake pipes running along his boot stripe. Anyone seen my Lucky Strikes?
__________________
Whiskeyjack a '68 Columbia 36 rebuilt A-4 with 2:1 "Since when is napping doing nothing?" |
#9
IP: 24.136.67.99
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Ooh yeh!
That's a challenge I'd love to participate in. Although the reduction unit and put more power to the water via another 8-900 RPM's. We probably weigh about the same so it would be a good comparison side by side on the course. Unfortunately my neck is sore so I won't be able to look back to see the look on your face.
Actually mine would probably expire if I pushe it for long to the wood. How far between the bridges? Oh yeh, Hanley will you be using my prop? Dave Neptune So. Cal. |
#10
IP: 71.252.2.87
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What I wouldn't give for a 2:1 reduction drive without the "V".
__________________
-Shawn "Holiday" - '89 Alura 35 #109 "Twice Around" - '77 C-30, #511 with original A-4 & MMI manifold - SOLD! (no longer a two boat owner!!) |
#11
IP: 72.83.115.37
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Yes, the v-drive is both a curse and a blessing. Those extra rpms really do make a power difference.
I did some speed trials yesterday, and on flat calm water with no wind, wide open throttle stabilized at 3100 rpm and 6.7 kts. And its a heavy boat. 32.3 ft and 12,800 lbs. Hull speed is just a hair over 7 kts, so I'm pretty satisfied with 6.7. And, oh yes. I've got a 1 1/4" exhaust system.
__________________
@(^.^)@ Ed 1977 Pearson P-323 "Dolce Vita" with rebuilt Atomic-4 |
#12
IP: 173.166.26.241
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Yeah, heh heh, secret weapon - The Prop.
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#13
IP: 216.115.121.253
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So tru mon. All de ponies in da worl' don' mean nuttun if you don' hook up.
I hear da Boss singin in my head jus now. ...We shut `em up and then we shut `em down..
__________________
Whiskeyjack a '68 Columbia 36 rebuilt A-4 with 2:1 "Since when is napping doing nothing?" Last edited by lat 64; 05-18-2011 at 12:50 AM. Reason: fixed that |
#14
IP: 193.253.220.149
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Oooooh...the trash talk! I love it! Imagine getting all excited about 10 miles per hour!!
__________________
Kelly 1964 Cheoy Lee Bermuda Ketch, Wind and Atomic powered |
#15
IP: 24.152.131.220
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Kinda like the elderly racing their Rascal scooters. Or a foot race in walkers.
__________________
Neil 1977 Catalina 30 San Pedro, California prior boats 1987 Westsail 32, 1970 Catalina 22 Had my hands in a few others |
#16
IP: 173.166.26.241
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I'll Be Back
All right, Schmartzenheimers, just wait 'till I get back from my geriatricians's clinic, Dave and I will show you a hoarse race.
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#17
IP: 24.136.67.99
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Banter banter
Hanley will the "hoarse" race be from banter back and forth?
Kelly you dare to mention the "holley grail" of Atomic powered yacht racing of 10 MPH, why you could even get a ticket in the marina at such speeds. Wouldn't that be something to show the P/V boyz On a serious note, does anyone know if Tom Stevens has a graph that shows how much power his Indigo prop uses at any specific RPM's. I would be curious and willing to compile some similar performance figures using RPM and manifold preassure as a baseline. I just made a noticeable performance improvement on my old beastie tinkerin' with the carb. It's what I was working on at the end of last season and I finally got to try it on the water not on the dock lines. Dave Neptune |
#18
IP: 161.213.49.1
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Is This Something New?
Quote:
TRUE GRIT |
#19
IP: 199.173.224.31
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#20
IP: 71.118.13.238
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Racing
Hey Grit, you ever done a "predicted log race" in a sailboat? It's fun and coming in ahead of any of the PB's sure gets under their skin.
Dave Neptune |
#21
IP: 206.125.176.3
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Dave, why do you always tease us so!?!?!?!?
__________________
-Shawn "Holiday" - '89 Alura 35 #109 "Twice Around" - '77 C-30, #511 with original A-4 & MMI manifold - SOLD! (no longer a two boat owner!!) |
#22
IP: 71.118.13.238
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Tease
Shawn, perhaps I should start a thread on this sometime. I have been unhappy with the way the carb transfers from the idle circuit to the hi-speed circuit. This is something I have talked to Don about and he expressed the same opinion. I have been playing with fuel jetting and float levels with very little success. I also tried playing with the idle jet itself and am now convinced that the "hi-speed" circuit comes in to soon not the idle circuit hanging on too long. My most recent change was to start adjusting the amount of air in the "fuel-air" stream before it gets to the venturi. It made a big differance on how clean the plugs stay and the engine seems happier (smoother) and I picked up a bit of performance in the 1200 ~ 1600 rpm range and a solid gain at my cruise of 2000 RPM. I haven't done a WOT check yet however I don't expect much if anything at WOT.
My RJ8J plugs now look a creamy grey which is about right. I may be able to add a bit of advance to the timing but haven't attempted that yet. Dave Neptune |
#23
IP: 216.115.121.253
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Quote:
"It's not how fast you are, or how quick, it's how long you can stay in the saddle that counts" Words to live by. R. Walk on.
__________________
Whiskeyjack a '68 Columbia 36 rebuilt A-4 with 2:1 "Since when is napping doing nothing?" Last edited by lat 64; 05-19-2011 at 08:39 PM. |
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