Reply With QuoteHere's some of the latest:
http://www2.***boat.com/forums/showthread.php?t=101960
496 HO and headers?
I just picked up a new Conquest Top cat II with a 496 HO. I was looking at headers for a bit more scoot. The same boat goes about 10 mph faster with the 525HP. The 525HP is 100 hp more than the 425hp the 496HO has. S.W.A.G. ing that I should get 5 mph out of the CMI headers for the 496 HO "55HP on dyno." (S.W.A.G. scientific wild ass guess)
There are many others out there: Bassett, Lighting, Hardin both cyclone and typhoon, Imco, Eddie.
I was looking for info on what works, pricing and any first hand experience I can get.
Thanks
Rod
Rod2614@aol.com
Here's some of the latest:
http://www2.***boat.com/forums/showthread.php?t=101960
[QUOTE=Rod2614]496 HO and headers?
I just picked up a new Conquest Top cat II with a 496 HO. I was looking at headers for a bit more scoot. The same boat goes about 10 mph faster with the 525HP. The 525HP is 100 hp more than the 425hp the 496HO has. S.W.A.G. ing that I should get 5 mph out of the CMI headers for the 496 HO "55HP on dyno." (S.W.A.G. scientific wild ass guess)
There are many others out there: Bassett, Lighting, Hardin both cyclone and typhoon, Imco, Eddie.
I was looking for info on what works, pricing and any first hand experience I can get.
Thanks
Rod
Rod,
I recently installed CMI's on the 496 HO that powers my Ultra 26 Shadow Deck. A very noticeable increase in performance accross the board. I have had the boat above 80 on the GPS. Prior to the CMI's the best GPS speed I saw was 75.8. I am now running a Merc labbed 28, which I can spin at 5000 RPM's. While I have no way to measure it, the fuel economy seems to have improved. also. If you have any questions, I will be happy answer if I can.
John M
The CMIs will be pricier, but from what I understand it is a whole kit and not just the headers. It relocates the oil filter, PS res, and other related components.
From what I have seen here, the other mfgs don't necessarily have all the required stuff and you are kinda on your own for relocating and such. Thousands of dollars less, though.
I have always been a fan of full tube headers so the CMIs or Lightnings would be my pick. I like the Lightnings a little better than the CMIs in the looks department.
Here is a beautiful set of Lightnings on a Raylar equipped 496:
http://media.putfile.com/Bents-Nordic-Engine
CMI's are my choice, and believe me I know, I tried taking out the tubulators and that did about nothing, then Bought Eddie Marines that were a complete JOKE from beginning to end. So I took them Back and got CMI's no proplem at all. Jumped up to a Mercury Lab 26. Picked up about 5 on top but the mid range was way better. With 8 audults on board I had no ploblem getting on plane. Before the pipes it took a while. By the way I have a 28ft deck boat :crossx:
Dont take the cheep way out trust me it will bite you in the ass later
True numbers on a dyno show that the Lightnings gain more across the board than the CMI's do, How much? About 9 HP more, and the torque curve was extended by about 600 rpm and added 72 ft lbs of torque. The CMI's are nice, but the dyno tells me to go with Lightnings.
Either way, You will find increases all the way across.
True numbers on a dyno show that the Lightnings gain more across the board than the CMI's do, How much? About 9 HP more, and the torque curve was extended by about 600 rpm and added 72 ft lbs of torque. The CMI's are nice, but the dyno tells me to go with Lightnings.
Either way, You will find increases all the way across.
Is the dyno test you are referring to on a 496?
Thanks
From what Ive heard here is that you are seeing about 5mph from just the addition of the CMI's on a 496HO? That kind of improvement over what is supposedly a fairly decent factory setup is almost unbelieveable, that is a LOT of improvement, not saying you are lying but hard to believe for me. Also I've heard that the kit is not all it's cracked up to be and requires improvisation (sp) on the installers part?? They look nice but as for me I would have to ride in and see that kind of improvement before I would spend that kind of $$$$$. NSF
From what Ive heard here is that you are seeing about 5mph from just the addition of the CMI's on a 496HO? That kind of improvement over what is supposedly a fairly decent factory setup is almost unbelieveable, that is a LOT of improvement, not saying you are lying but hard to believe for me. Also I've heard that the kit is not all it's cracked up to be and requires improvisation (sp) on the installers part?? They look nice but as for me I would have to ride in and see that kind of improvement before I would spend that kind of $$$$$. NSF
There is no doubt that the kit is not all it's cracked up to be. There wasn't one part of the relocation kit that bolted right on. If you ever get the chance, look closely at the stock 496 manifolds with the riser removed. The exhaust ports are tiny, 2 inches or smaller. After hearing about how great the stock 496 exhaust is, I was amazed at how restrictive the stock system really is. I have to believe that any increase in top speed, resulting from CMI's, will vary by hull design and specific motor.
John M
In the pics I've seen- the lightnings appear bigger/ wider- how are they going to fit with twins and close hatches- in my case the twins are kinda slammed outboard with lots of room between them
guess I'll have to search their site
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