Opinions on Headers
 

Looking to upgrade Headers from Cast IMCO Powerflow. Running Blown 540 at 900 HP. Any opinions on CMI versus Lightening versus anything else? Also if any suggestions what model?

I ran 1040 HP thorugh CMI Elbow Tops for a year, no issues. Gary Taylor puts them on his engines up to 1200 HP.

I think that they are a grea header and if you have a standard deck block and standard brove transom exhaust you can even go with the Unitops which are an etop with a welded tail and are even less money.

CMI are the best, the others are good too, but they are not CMIs.

Yeah what he said ,tried the Imcos on some 540s and then changed to CMI elbow tops and never looked back.good luck BIG Daddy

I would think that if you got enough bump stick to push 900hp the Lightnings will revert water.

I have CMI's on my 850 and like them.

hey stormbauer how much for the imco's? [email protected]

Mercury Racing has replaced quite a few motors due to cracked CMI headers. Just check warranty claims. They are certainly not as pretty, but the cast aluminum headers by Eickert support big numbers and will not crack!

Those were mostly sweepers. The E-tops have a much better record.

I'm just wondering what the percentage of failures really are? Does anyone REALLY know? How would it be determined?

Salt or fresh water? DId the owner flush their engines after running?

How would YOU go about this? I'm not trying to be an azz here, but it just seems to me everyone wants to blame someone for something. I've had my 2 sets of E-tops for 4 seasons with NO failures or leaks. They still look like they just came out of the box. Show me the numbers and percentages and I'll eat the crow!

Dave

Mercury headers are thinner and of a different alloy than the CMI headers. You guys really need to keep your facts straight.

I dont know of anyone that has had a failure of CMI headers, not the Mercury product!!!

If you pick up a set of 500 EFi headers vs an Elbow Top, you'd see what the difference is.

They are the best flowing exhaust on the market - period!!

Thats why Mercury buys them, except they make them out of a less quality alloy than the SS CMI does. And they are thinner!!

Bingo,

Give Elite here a shout, he has some nice prices on E-tops. They are worth it. I did a bunch of homework on this.

Running CMI e-tops on 540s. Looks as though I made a good choice.

CMI Big Tube E-tops should be the best for a 900HP 540 blower motor. Strong, reasonably priced and real pretty in polished! Just my two cents.

Regards,
Ray @ Raylar

From what I have seen, in salt applications with 900+ hp big tube set ups, you get to 225+ hours with either Stellings or CMI you can get ready to start chasing cracks at the collector and flanges. Once they start developing, they just keep on coming. I haven't heard of any official studies done nor do I expect a mfg to divulge their warranty or product health numbers.

From what I have seen CMI makes two types of Headers , The ones that Leak and the ones that are going to leak . Just my $0.02.

Youre logic is a little circular, dont you think?

Besides the $$$ what are the major performance differences with the Big E-tops versus the Big Tubes? Also at what HP is it necessary to go with the stepped E-tops?

Have had imco powerflows,Eickert manifolds, cmi e tops, cmi big tubes, other than the prices, have'nt noticed any difference in performance, with them, I've had from 725hp to 1150hp, save your money.

I have not heard of a lot of CMI E-tops cracking and leaking, I cannot say that about regular or big tube CMI sweepers. Most blower motors will make better power with the big tube E-tops than with any sort of long tube header. I understand that the Stainless Marine High Torque III header/manifolds also work very well on blower motors.
Just my two cents.

Best Regards,
Ray @ Raylar

Here is some CMI comparisons done at Keith Eicherts. All done on a NA 500 CI
Big E-tops - 765 HP
Sport Tubes (1 7/8" ID) - 785 HP
Big Tubes (2 1/4" ID) 800 HP

Blower motors generally need different headers
 

I believe this post was started with the motor being a 540" blown motor. Header results for blower motors will be totaly different than those for a N/A motor. Just thought I would clarify so those not in the know would not get further confused.

Regards,
Ray @ Raylar

Well my first question I guess is? Is it a freshwater application or a Saltwater application? I don't think anyone makes a bad header today. Lightning builds the best if not only freshwater header on the market today with a warranty that exceeds CMI. Elite is correct that the after market CMI is a different version than the OEM unit. And ask anyone with a 525 Merc If they have gotten three years out of their headers before they fell apart? But I will say anyone in the engine business of making horsepower knows that the standard elbow top chokes any motor over 600HP. Did you notice Mercury didn't use them on anything over 500HP? Notice the 525 and all engines on up all have long tube headers?. I know this always starts some war because somewhere someone used them on some engine bigger than that with success. If success means that the engine made some power or maximum power well thats the determination of what success is. But that doesn't mean it was the best choice just because it bolted on the engine. If your going to build a 900HP plus engine it deserves to use a true long tube header. Take a look at these headers form both Lightning (freshwater) and Hardin Marine (salt water). Now before everyone starts screaming remember this is a 900HP plus application!!!!!!!!

My 945 hp blown 540 reverted water BAD with the lightning headers at idle,I switched to stainless marine 3's with 5" tails. They are big & ugly but work very well,Smitty

Just a reminder for anyone running a procharger,the keith Eickerts do not clear the blower at all,Smitty

It is nearly impossible remember I said "nearly" to run any wet style tail pipe exhaust system at 900plus horsepower. Lightning makes a system with a water jacketed "Dry" tail pipe that will accommodate this application with no problems.

Lightning pipe looks like it actually has runners that are close to being equal length. I may be wrong, but as the pipes become more "equal in length" or closer to being a tuned runner length, don't they exagerate the reversion deal as they in effect, suck and blow harder? Cylinder "scavenging" is improved with a "tuned header" as well? In other words, a trade off for better performance upstairs?

And the Dana's are a VERY tight fit if you go with big heads.

My motor made 945 hp and does not have problems with CMI's.

Heck, I think that Kennyo's motor was reverting pretty bad at 800hp or so with standard Lightnings.

Stellings......
over 300 hrs in fresh and salt water....
Pfaff 1000's

I think all of the BIG tube ( CMI ,Stellings, IMCO, Stainless Marine ) or what ever work great and dont have issius if installed and COOLED ( again COOLED ) right.

The biggest problem they all have to fail is enuff cooling.
They will all suck water back if the valves are overlaping to make power. But they only damage if not installed right.

My engine always has a little salt in #7 and #8 cylinder.
But never did anything to the engine because its min.
As soon as you run high RPM it will not even get there its from iddle at the dock .

You get the best power out of stellings or Stainless high tourqe III, thats a fact.
But with the Stellings ,alot of cooling is ness. and the aluminum Stainless safe weight and have no cooling issius at all. make the same amount of power.

Just what i learnd for alot of $$$$$$$$ on my $hit.:cool:

Never seen a Stainless High Tourge III ,that is not DRY ?!:eek:

I bought my lightning headers from you guys,they worked great for 5 years on my blown 502 then blown 540,I just "outgrew" them when I went from 750 hp to 945,I'm not *****ing,I was able to sell them used for a decent price. The stainless marine hi tq 3's have been great also,they just look less sexy with more function,Smitty

Right know, and i dont mean to pi$$ anybody off.

I think the SM HT III is the best on the market, lightweight big runners ,dont break. I have seen them on 1400 HP blowermotors working great.
I have seen them in blown up engines hot ass hell and still run with no leaks, act. mine :eek:.

The looks of them ,,,,,,,,,,,,,i think they look great, they also make the same header for a 34 centerline , so you can fit them in there.

$$$$ wise they are very in expensive too, so what is there to think about ?
+ Brownie at SM and everybody else there are bretty cool and help where they can.

Just my 2 C, but i have seen alot of the others break.
Most of them due to not enuff cooling SS needs cooling aluminum needs it also but not that much since its getting ridd of heat alot faster.
Damn i'm smart. LOL:drink:

Probably the bottom line in this decision is what are you trying to accomplish and at what cost. If you are looking at maximizing hp then in a naturally aspirated application you should be looking towards a "tuned" exhaust with at least equal runner length? To say all are created equall is BS. There have only been a couple actual comparisons done and that was back in the 97-98 time frame. I believe Fountain hired Innovation to look at some different offerings as did Volvo. That was when Volvo had the 600 hp packages back in 97 or 98? There was maybe 40 hp difference between good and bad and that was only looking at hp 500's up to 5200 rpm or so. There would have been a bigger difference yet if they would have looked at applications in a higher rpm range. Eickert's website had some of the data and Hot Boats did a couple comparisons. What I found interesting was when you looked at some of the IR 4 into 1 configs due to the large difference in their runner length, they really didn't do all that well.

i WISH i HAD 800 hp!!! I still have a new set of Lightnings with 02 bungs $1700!! What a deal!

Thats the point,,,,,,,the Stainless work on both and gain performance,,,,on N/A and Blowermotors.

The runners are ( i think 22" long ) and have all the same volume.

I know of a lot of big power boats running wet exhaust. I even run downturns on my 1400's CMI headers are the way to go. Manifolds are for cars.

How the heck did we get talking about manifolds here anyways? Wasn't the question about headers? The fact is Yes S/M Gen 3 manifolds are excellent quality and perform super and Brownie is quite possibly the nicest guy in the world. But we were talking about headers. A little clarification here "Dry" means no water enters the exhaust stream. The pipes are still water jacketed thus cooled. No water in the exhaust stream means no-reversion. Most engines once again "MOST" engines with a camshaft exceeding .240 of duration @.050 will require a dry exhaust system. Thus anything making more than about 650 horsepower with a header will likely require a dry tailpipe.

http://i37.tinypic.com/10nt2k9.jpg

can you put muflers on these?

Of course you can, we even sell em http://www.cpperformance.com/SearchR...CategoryID=182:drink:

Can anyone tell what is a CMI Elbow Split Top?