Is their a big difference in performance between Dana marines exhaust manifolds and cmi,s full tubular headers?
How many run the Dana setup? I really like the look of them and the price seems very cheap compared to cmi,s. can only assume Dana,s make less hp but do they not leak?

Raylar and Bob at Full Throttle tested both systems fairly well and there are threads here on OSO giving that information in great detail. JMO, but I feel in fiarly mild 400HP to 700HP normally aspirated marine engines the differences in power are very negligable and the real determiners will be overall cost and reliability. dont forget to consider the Keith Eickert 755's cast header as a candidate!

Best Regards,
Ray @ Raylar

Ray i have some KE's and some other cast manifolds and noticed the inside passages tend to be a bit on the rough side. Would there be any advantage in having them extrude honed to smooth them out? Does anyone even still do that?

I don't think the gains would be even measurable and the cost of extrude hone is pretty pricey for that part I would suspect.
Again, I guess it's a "IF It Ain't Broke, Don't Fix It" kinda answer.

Best Regards,
Ray @ Raylar

Board Member ( Check300 ) has 3 years on his now.

572" tall Deck twin turbo 1,500 HP

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Post 33


Jon

I have owned both. The Dana's work just fine. I doubt you will see a noticeable difference.

I have had great luck with the Dana's

Have always been very impressed with Dana marine's stuff.
With all the problems people are having with cmi headers leaking and if it's true the differences in performance are minimal up to 700hp why don't more people swap to them? Especially considering they are a fraction of the price.
Has anyone chucked a set on a 525 merc as a replacement that can vouch for power gain/loss?
Just seems as though every new power build has cmi's or similar these days so I guess my general assumption was they must be that much better that they are worth the leaking risk?

thats what i am thinking,,,,,,,,anybody??

I think people just like the bling
and are willing to take the Ding X2

Initially to build the headers

Second ding to the wallet is when they leak and hurt parts.



I think Dana builds the nicest cast manifold from and engineering and cosmetic stand point.
They designed the header look into there product and it's much easier on the eyes.


Jon