Still up in the air about heads
09-02-2004, 02:38 PM
#21
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Re: Still up in the air about heads
Robyw1,
I am well familiar with 383 combo with 200 cc heads for boat engines. It works quite well. . .well enough that the outdrive if an alpha will take a beating. One thing I haven't brought up is the RAM effect. Small cams with larger heads create this more so then other combo's unless dealing with some very high induction velocities. But that column of air will still pack the cylinder after the piston has started up. This is how you get VE measurement of over 100% on the dyno. I'm no saying the 180s wouldn't work, but with the better chamber design on the 200's and a larger valve throat area, I feel the 200's would be a better choice in this case.
Chris
I am well familiar with 383 combo with 200 cc heads for boat engines. It works quite well. . .well enough that the outdrive if an alpha will take a beating. One thing I haven't brought up is the RAM effect. Small cams with larger heads create this more so then other combo's unless dealing with some very high induction velocities. But that column of air will still pack the cylinder after the piston has started up. This is how you get VE measurement of over 100% on the dyno. I'm no saying the 180s wouldn't work, but with the better chamber design on the 200's and a larger valve throat area, I feel the 200's would be a better choice in this case.
Chris
09-02-2004, 02:52 PM
#23
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Re: Still up in the air about heads
You seem to forget that the fuel needs the velocity normally associated with a small port to stay properly atomized and suspended. Plus we need more than just peak horsepower here. His engine has to be able to carry his boat to that peak horsepower. If it can't then his engine will have a loud bark but no teeth. Also I want to see this engine you got 100% VE. The baddest of the bad normally aspirated engines are getting about 88 to 90% volumetric efficiency. The N/A formula 1 engines are getting mid-90s. Are you sure about your numbers?
No offense here, Just want to know.
Roby
No offense here, Just want to know.
Roby
09-02-2004, 02:56 PM
#24
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Re: Still up in the air about heads
Just for your info, the drive is an OMC King Cobra, and it can take the beating. Plus I know how to drive it without breaking it (I hope!)
09-02-2004, 03:04 PM
#26
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Re: Still up in the air about heads
Hi all, you guys have to check out this site awesome TV show you can watch the show online i copied this below from there home page.
NJR
On this weeks show we start out by taking you to the “Outerlimits” of shore performance boats facility that is. And what makes these “Outerlimits” boats attain such record breaking speeds? Well besides great designing and construction you would have to say, those Monstrous engines.
It takes special people in special shops to build these 1,200 plus horsepower engines and this week we take to visit two of the countries finest, Sterling Performance, just outside Detroit, Michigan and Gellner Engineering in Parma, Ohio. We’ll take you behind the doors of these two shops and see just how they are able to get all those ponies out of their engines.
CHECK OUT THIS WEBSITE http://www.boatingtodaytv.com/
NJR
On this weeks show we start out by taking you to the “Outerlimits” of shore performance boats facility that is. And what makes these “Outerlimits” boats attain such record breaking speeds? Well besides great designing and construction you would have to say, those Monstrous engines.
It takes special people in special shops to build these 1,200 plus horsepower engines and this week we take to visit two of the countries finest, Sterling Performance, just outside Detroit, Michigan and Gellner Engineering in Parma, Ohio. We’ll take you behind the doors of these two shops and see just how they are able to get all those ponies out of their engines.
CHECK OUT THIS WEBSITE http://www.boatingtodaytv.com/
09-02-2004, 03:15 PM
#27
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Re: Still up in the air about heads
Where did that come from???
I thought we were talking about heads, and sending my out drive to the bottom of the lake.
Do they make a brass lined aluminum manifold for the small block?
I thought we were talking about heads, and sending my out drive to the bottom of the lake.
Do they make a brass lined aluminum manifold for the small block?
09-02-2004, 03:16 PM
#28
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Re: Still up in the air about heads
Originally Posted by Liberator21
Where did that come from???
I thought we were talking about heads, and sending my out drive to the bottom of the lake.
Do they make a brass lined aluminum manifold for the small block?
I thought we were talking about heads, and sending my out drive to the bottom of the lake.
Do they make a brass lined aluminum manifold for the small block?
you can't have too much powerRoby
09-02-2004, 04:12 PM
#30
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Re: Still up in the air about heads
Roby,
I'll be more then happy to fax you dyno sheets with VE%'s. I don't know where your numbers are but PS and Cup engines due to RAM effect run in the 1Teen's in VE%I agree, power is over the curve not peak. Peak numbers sell engines (HP), torque bands win races and moves boats. Lib will not loose any bottom end with a well matched combination. Stick big heads and a big stick, hell ya your right it will never see 5000 rpm because you would have to put an 11 pitch prop on it.
I learned a long time ago its good to get the 1st sale, it the best to get the 100th sale to a customer. I live with engine builder customers everyday, if I give bad advice, I loose a customer. I did one of these for a guy with a 21ft Rinker. Sportman II's, cam was 214/224, .470/490 on a 112, hyd flat, air gap 6.00rods. Gained 13 or 14 mph and was a bear out of the hole. Think he turned it 5200 till the alpha gave up the gear.
Look at the fords, the 165cc AFR is designed for the 302 CID. Intake ratio of CC to CID is .54 They run very well with these heads to 6000 rpm. 200 cc to 383 CID is .52. Yes lower rpm put percentage is close.
Chris
I'll be more then happy to fax you dyno sheets with VE%'s. I don't know where your numbers are but PS and Cup engines due to RAM effect run in the 1Teen's in VE%I agree, power is over the curve not peak. Peak numbers sell engines (HP), torque bands win races and moves boats. Lib will not loose any bottom end with a well matched combination. Stick big heads and a big stick, hell ya your right it will never see 5000 rpm because you would have to put an 11 pitch prop on it.
I learned a long time ago its good to get the 1st sale, it the best to get the 100th sale to a customer. I live with engine builder customers everyday, if I give bad advice, I loose a customer. I did one of these for a guy with a 21ft Rinker. Sportman II's, cam was 214/224, .470/490 on a 112, hyd flat, air gap 6.00rods. Gained 13 or 14 mph and was a bear out of the hole. Think he turned it 5200 till the alpha gave up the gear.
Look at the fords, the 165cc AFR is designed for the 302 CID. Intake ratio of CC to CID is .54 They run very well with these heads to 6000 rpm. 200 cc to 383 CID is .52. Yes lower rpm put percentage is close.
Chris
