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Full Force 12-10-2014 11:08 AM


Originally Posted by plumbers crack (Post 4232773)
I would dyno after all it's like $500.00 a motor. You could do all your jetting and tuning prior to dropping in. Probably worth it.

Yes I would like to and it's gonna come down to time most likely... If it's may when I am done they go in boat and I run it....use my own dyno, 73mph =600 hp
76-78 mph = 650+ and if it goes over 78 I will chit myself and then pull the RH drive since I will probably have smoked a gearset lol

ICDEDPPL 12-10-2014 11:48 AM


Originally Posted by frickstyle (Post 4232757)
twin Holley HP850s, the new design / compisite bodies they came out with. They are a little on the small side for my application, but have proven themselves on the dyno as "adequate". I would think carbs and heads are limiting factor on my setup, more so the carbs I would think.... Can always change out if needed.

https://www.holley.com/products/fuel...rts/0-80804HBX

Comparable flow numbers to 950s is what I understand. I couldn't tell you what the limit is, but we have reached our goal.

I've decided on the 1050cfm Quick Fuels, boost referenced blower carb, ready to go. Got any pics of the black carbs on the motors? I was considering going with those... With black manifolds might look kinda cool.
I would think you'd need a minimum of 950cfm. My current ones are 850cfm and it works fine... so it'll be interesting to find out what changes they make.. Hard to overcarb a blower motor.
I was considering dominators .

Full Force 12-10-2014 12:48 PM

I will need carbs at the end it looks like also... YAY ..... haha

frickstyle 12-10-2014 12:54 PM


Originally Posted by ICDEDPPL (Post 4232797)
I've decided on the 1050cfm Quick Fuels, boost referenced blower carb, ready to go. Got any pics of the black carbs on the motors? I was considering going with those... With black manifolds might look kinda cool.
I would think you'd need a minimum of 950cfm. My current ones are 850cfm and it works fine... so it'll be interesting to find out what changes they make.. Hard to overcarb a blower motor.
I was considering dominators .

Yes, you are on the right track. If I did it over again, they would be dominators, 1000cfm+. But, I bought the carbs before going to bigger blowers, etc. WE figured they would be fine, then I bought bigger drives, etc, more power, etc. So....... I decided to try the carbs as-is and they wrok just fine. If I would want to make alot fo power, new carbs.

Sorry ICED, my computer with pics went down so I do not have pics of carbs. Will try to locate.

Here:
post #2766 & #2793
http://www.offshoreonly.com/forums/c...ee-em-277.html

1989mach1 12-10-2014 05:02 PM

Hey tim and frickstyle lets try more building and less chating. You two are going to be running out of time:poopoo:

MILD THUNDER 12-10-2014 05:13 PM

I've posted this before, but, just for conversation sake.

On my little blown 468's with 420 blowers, I have twin 850 Holleys. This past summer, I had changed the jets in the driveway on the trailer. Took boat up to traverse city for a fun run that next weekend. I noticed while on the fun run, one engine was down about a full pound of boost. Both would be exactly at 6psi on the gauge at wot normally, but port engine this time was at 5psi. . I thought I had a belt slipping, or maybe the blower was hurt, or something going on. Got back to the marina later that day and checked things out. No belt dust, nothing visual i can see. Then I pulled the flame arrestors off, and put the throttles to WOT. Went back and looked at the butterflies. DAM! 1 carb the secondaries were just barely cracking open. I had pinched the accelerator pump arm when installing the bowl, and it was keeping the secondary on that ONE carb from opening.

Point of the story. While the so called "calculator" says my little engine only requires about 1150CFM, I had 1275CFM of carb flow, but it was still costing me 1lb of boost, and about 200RPM on that engine. Probably 30-40HP. Now, I could run a pair of 650's on that blower, and "Make it work", by pulleying the blower faster to make the boost. But, just because it "works" doesnt make it better. Most guys will say "750's" are plenty for that build, etc, but the only real way to tell, is swap carbs back to back, prefereably on a dyno. Just because you make XXX HP with a certain carb, doesnt necessarily mean its the best carb for the application. Roots blowers push air pretty good, they are not good at drawing air in.

I would like to think Mercury back in the day, when doing some R&D, found their to be some sort of advantage to running a pair of 1050 dominators on a 900sc engine. It wasnt cost, fuel economy, or driveability thats for sure, so something had to make them choose dominators on that engine, while the 800SC (700HP at the prop) engine, utilized twin 850CFM carbs.

Full Force 12-10-2014 05:25 PM


Originally Posted by 1989mach1 (Post 4232961)
Hey tim and frickstyle lets try more building and less chating. You two are going to be running out of time:poopoo:

Shut it and bring us beer....lol

1989mach1 12-10-2014 05:49 PM

I will drink one for ya.....:ernaehrung004:

bigboat28 12-10-2014 08:11 PM


Originally Posted by 1989mach1 (Post 4232961)
Hey tim and frickstyle lets try more building and less chating. You two are going to be running out of time:poopoo:

Tell me about it. Tim way to much talk and not much action, you planning on talking those motors together. LOL

May, what are you talking about, if it is May when they are done, cum on man, summer is half over by then.

Full Force 12-10-2014 08:26 PM


Originally Posted by bigboat28 (Post 4233081)
Tell me about it. Tim way to much talk and not much action, you planning on talking those motors together. LOL

May, what are you talking about, if it is May when they are done, cum on man, summer is half over by then.

Haha you know my rules lol


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