SoCal Jet Boats
Tech Talk => Engine Mechanical / Electrical => Topic started by: 502 SPECIAL on April 20, 2011, 05:35:18 PM
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WELL I BOUGHT A HIGH RISE INTAKE FOR MY 502 BBC.IT HAS A 3500-7500 RPM RANGE BUT I THINK I JUMP THE GUN....I WAS LOOKING FOR A LITTLE MORE TOP END AND "LOOKS"OF COARSE.I WAS TOLD I WAS GOING BACKWARDS AND I SHOULD HAVE STARTED WITH A BIGGER CAM.I WAS ALSO TOLD MY CAM WAS BIG ENOUGH BUT "WHO KNOWS"????ANY INFO ON THE SUBJECT WOULD BE MOST APPRECIATED..... :banghead:
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We really need alot more info! What brand intake? How big is the cam? What cylinder heads? What are you using for a carburator? You question is very very vague! Im sure you can get some answers, but we need to know more about your motor!!!!
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I HAVE A EAGLE 502 STROKER KIT.OVAL PORT HEADS THAT HAVE BEEN PORTED,THE PERFORMER RPM THAT IS ON IT HAS BEEN PORT FITTED.THE CAM IS A ISKY RACING CAM.LOBE CENTER 112 DEG. 275 HYD IN. AND 284 HYD EX."I DONT KNOW WHAT ELSE WITH THE CAM INFO YOU MIGHT NEED BUT LET ME KNOW"THE CARB IS A PROFORM 850 THE "RACING"SERIES.THE INTAKE I BOUGHT IS A PRO COMP "CHEAP I KNOW"3036 MODEL.WHICH IS ABOUT THE SAME AS A HURRICAN.I WAS PLANNING ON PUTTING IT ON THE MILL TO OPEN IT UP AND MATCH PORT IT.ANY INFO IS GOOD
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(https://www.socaljetboats.com/proxy.php?request=http%3A%2F%2Fwww.meh.ro%2Foriginal%2F2010_03%2Fmeh.ro1318.jpg&hash=8b151b7612d67459bc6466e19a349b945bca3625)
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WHY AM I SCREAMING?better??
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i got schooled on this when i first got on hear too. caps means your yelling FOOOOO, SO UNLESS YOU HAVE TO YELL AT SOME1, keep the caps off. ;D
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my bad cuz...i should have learned that one on facebook..lol..haha
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WHY AM I SCREAMING?better??
just messin with ya. =)
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Might not be a bad intake specially if its a single plane...just remember that cheap chineese nockoff stuff doesnt exactly fit well...i would also gasket match that intake...seems like a pretty stout mill...just to stick cheap chireese aluminum on top of it...
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yeah i understand that for sure.i was under the impression that i would have to mill"or hog out" any intake out, to match fit,so i figured :screwy:that i would just put a little more work on this one if need be...but is it going to make that much of a difference on the 502??
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Pro Comp bought the rights to use the Professional Products molds for their intake manifolds. Interestingly enough, those manifolds have been proven to make more horsepower than other USA name brand intakes in at least some instances. I have put them on several dirt track racing engines that I have built. I have also put them on a number of boat engines, and never really experienced a problem with fit, sealing or leaking.
One important question that has been left out is what type and size boat is this in, and what rpm range are you running?
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Pro Comp bought the rights to use the Professional Products molds for their intake manifolds. Interestingly enough, those manifolds have been proven to make more horsepower than other USA name brand intakes in at least some instances. I have put them on several dirt track racing engines that I have built. I have also put them on a number of boat engines, and never really experienced a problem with fit, sealing or leaking.
One important question that has been left out is what type and size boat is this in, and what rpm range are you running?
The thing is to me, is the cam doesn't seem close to large enough to FULLY support and take advantage of it, and you did NOT mention compression ratio, but the tunnel will probably perform just fine set up properly with what you have. Not a BBC fan, Barry is more schooled in them than I..............
You hit a fantastic note on the "port matching" part........Tunnel rams depend (and work on) velocity, volume and immediate delivery. Port matching is critical. Gasket matching is one thing, port matching quite another.
You fail to mention your compression ratio, which is a VERY big part on how and why tunnel rams work. I'm going to guess it's on the very modest side, in which case, with that cam, an 8.5:1 compression ratio, a couple 660 CFM's or bigger on it, doubt seriously you'll see much, if any, of a MPH increase. You WILL see a fuel consumption increase, harder to start, and the plugs should read all over the place.
Just my .02, but yeah, it WILL look cool! :thumbup:
Ray
PS, I'd personally stick with what ya got, and build the engine for your Tunnel later when it's tired, you can afford to, or want to do it right, whichever comes first. I first built Moo with a highly modified RPM intake, 950 CFM carb and mostly blower spec cam (comp cams OLD Xtreme marine 305) and it ran like a smart child from Neverland......Tunnel upgrade with 750's actually slowed it down, lots of problems, water in the oil...........anyway, turns out, had the manifold milled to fit the engine, PORT matched it, LOT of machine and file work, right 750 marine carbs, added 800 RPM on the boat. And quick? WOW!
Ray
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im just getting in to boats but have had many drag cars... i do know that u cant just throw big parts at ur motot and expect it to run harder...i think that the cam u have will peter out about 5000 rpm and a singel plane intake of any good size will want to start working about 3500 rpm and will work to 8500.. so think about your combination and where ur motor is going to work if ur cam quits making power at 5000 rpm it will not do you any good to put a intake on that starts to work at 3500.. with a big singel plane intake you will loose alot of torque and torque is a key factor... small oval port heads that r stock ( not ported and no bowl work ) dnt normaly work well at higher rpm.. they make alot of torque in the bottom end of the rpm range...... i may be completly wrong about what works well in a boat motor...but i know what will make a car run a 5.40 at 129 in the 1/8 mile