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Originally Posted by endeavour32
(Post 3507120)
What is the RPM range of the cam? Dry headers are pretty much a no go for most of us, dry to the tip is loud. Full dry is asking for serious trouble, so with that said your cam is going to have to work with a wet exhaust. Your engine is putting out 1.19 hp per cubic inch with really poor heads. I'm running IMO the best 454 head which is the AFR 265 Ovals, 9.9:1 compression and a custom cam, I'm also making 1.19 hp per c.i.. I have better heads, higher compression and a cam from one of the best cam guys in the marine world. I just don't see how you can make the same power per cubic inch. Dynos can vary a lot, unless both engines are dynoed on the same unit we're comparing apples to oranges in my opinion.
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Originally Posted by Itsallgood995
(Post 3507395)
I’m not seeing a reason why that cam wouldn’t work w/ 112LC. If you read the 496 Dyno /myth busting article http://www.fullthrottlemarine.com/ HP loss would be minimum w/ a good wet exhaust system. The article says there is no HP improvement (“Next we removed the boat exhaust and routed it straight. No change”) over the Dana Marines. The article goes on to say the test engine lost 3hp to the Dana’s with Lightning headers.
As a super quick fyi: exhaust tuning (runner size, length and collector size and length) can help draw more intake charge. How's this ? During valve overlap. Most stock camshafts, including the 496, don't offer enough overlap for exhaust tuning to make big differences. |
You'd have to understand exhaust tuning...not just 'restriction.'
SB Hmm, maybe you do know a thing or two about engine design... |
I told you SAE.
Congratulations they are some good numbers and good luck on the Peanut port engine project. Try this test 5800 for 20 minutes,now your in the boating world. I will stick with Dart,AFR and Jesel. Thanks Dave |
Guess I understand enough to get myself in trouble.:lolhit:
SB, If I understand you correctly your saying the overlap on the 496 cam in the article isn’t big enough to take advantage of a tuned exhaust? @ what overlap do you think a cam would benefit from a tuned exhaust… What is an example of a tuned exhaust? Vortec Pro says it would be significant on his 530hp motor? Neither the Dana Marines or the Lightning Headers are a cheap upgrade, how much HP loss are we talking about? The article says the Danas gain 23hp or 15.2hp w/ the turbulators removed over the stock exhaust system. Are we talking about another 15-20hp gain with a tuned header over a good wet exhaust? |
Originally Posted by Vortecpro
(Post 3505168)
Why would anyone turning a 454 5000 RPM want a bigger runner than what a 236/peanut would provide. Air speed is the key here. Bob care to comment on my post?
“. Air speed is the key here.” Ok, good point. I don’t see any quantitative or qualitative data to support any comparative analysis here. No MCSA, localized velocity profiles, runner length, pitot data, etc. Absent data (of any kind) it would appear to be a rhetorical question. Bob |
Originally Posted by DWES
(Post 3508440)
I told you SAE.
Congratulations they are some good numbers and good luck on the Peanut port engine project. Try this test 5800 for 20 minutes,now your in the boating world. I will stick with Dart,AFR and Jesel. Thanks Dave |
Originally Posted by rmbuilder
(Post 3508800)
Thank you for that invitation, however, it does not appear there is anything of any substance to comment on here.
“. Air speed is the key here.” Ok, good point. I don’t see any quantitative or qualitative data to support any comparative analysis here. No MCSA, localized velocity profiles, runner length, pitot data, etc. Absent data (of any kind) it would appear to be a rhetorical question. Bob |
Um, I don't remember Bob saying anything about a "mine is bigger than yours". Plus what would be the point of using the same compression and cam profiles? That would take all the knowledge and skill out of it. I would think a better comment would have been "it has to run on 87 octane and live at WTO for 20 minutes on the dyno and idle with full wet exhaust @ 600 rpms for 20 minutes!" To me that would make more sense!
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Originally Posted by endeavour32
(Post 3509299)
Um, I don't remember Bob saying anything about a "mine is bigger than yours". Plus what would be the point of using the same compression and cam profiles? That would take all the knowledge and skill out of it. I would think a better comment would have been "it has to run on 87 octane and live at WTO for 20 minutes on the dyno and idle with full wet exhaust @ 600 rpms for 20 minutes!" To me that would make more sense!
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