Offshoreonly.com - CMI headers

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The 509's in my Sunsation had Lightnings. While the appearance is personnel opinion, they were for all intents and purposes awesome 13+ years and still going.

The early CMI sweepers on the 525's had issues but I think the later design with the cool collar is much improved and not as susceptible to leaks, ethanol and salt will eat stainless over time.

I forget who did the test back in the day. Hot boat maybe?
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I believe Raylar did some header comparisons on the dyno also, only on a 496.

Re Eickert(lightning) headers, I cant say for sure about power gain or loss, my motors were dynoed with dyno headers. But I do know that the builder liked the runner length both for power and reversion. IMO...Bang for the buck you cant touch them with anything else.

Can O2 bungs effectively be added to the Thunder and lightenings?

Quote:

Originally Posted by endeavour32 (Post 4667654)

Sport tubes are supposed to produce about 15 hp more then e-tops, and in the old HP 500 test I believe the Eickerts made 18 more hp the e tops, so I would say that the Sport Tubes and Eickerts are very close. I'm not at all going to disagree with the bling factor with the CMIs. I love looking at the CMIs on my 525s, but when the time comes, they will be replaced with Thunder and Lightnings. CMIs are 2x the price and no benefit other than bling. Give the thunder anhttps://cimg7.ibsrv.net/gimg/www.off...99933e29dc.jpg
d lightings a nice two stage power coat, and you can get a bit of the bling back, lol.

Here is CMI's tests on the Merc Racing 520. Stock the engine comes with the same manifold/riser setups the 8.1 496s had. Etops and GenX Sporttubes tested.

Thanks for everyone’s help
sabre nice boat and thanks for the info
f2 thanks for the tips
going to get a couple of sets from offshore specialties
i forgot about those guys as I bought a set from them a couple of years ago

Quote:

Originally Posted by endeavour32 (Post 4667654)

Sport tubes are supposed to produce about 15 hp more then e-tops, and in the old HP 500 test I believe the Eickerts made 18 more hp the e tops, so I would say that the Sport Tubes and Eickerts are very close. I'm not at all going to disagree with the bling factor with the CMIs. I love looking at the CMIs on my 525s, but when the time comes, they will be replaced with Thunder and Lightnings. CMIs are 2x the price and no benefit other than bling. Give the thunder and lightings a nice two stage power coat, and you can get a bit of the bling back, lol.

That is the old test I had and if I remember the one thing the lightings had was a bit of a midrange hole. But with a bigger motor and more agrressive cam who knows.

The builder i know just did some 540’s that full trim was in the 640-645hp range with full CMI long tube headers. I wish he could have put a set of the lightings on that would have been interesting.

Too bad we dont have more real side by side data. I wonder if Eddie Y has ever done any tests. For cost you can not beat the price of the lightings.

I have heard that with big cube engines or blower set up's the T L exhaust doesn't have big enough tubes to flow properly.