CMI Headers/496 HO
10-04-2006, 06:01 PM
#12
Re: CMI Headers/496 HO
Originally Posted by turnerrd
Before you do anything pull your "turbulator plates" out (between the manifold, risor). It is good for 10-15 hp. Raylar will verify that for you.
Do a search on this forum for 496 exhaust manifolds and you will find a thread were Ray talks about porting work on the stock manifolds which are actually made by Gill. In a nut shell he says they are not bad for a stock manifold and with some porting work he can really wake them up. I think it also states that he has made up to 550 hp on the stockers with the porting work in conjuction with his kits. If you check out his web page you'll see several of his motors are running the stock manifold only with the paint removed and then polished. They look pretty good. Between the turbulator plates and the porting you could easily see the same 35 hp gain at a fraction of the cost.
Do a search on this forum for 496 exhaust manifolds and you will find a thread were Ray talks about porting work on the stock manifolds which are actually made by Gill. In a nut shell he says they are not bad for a stock manifold and with some porting work he can really wake them up. I think it also states that he has made up to 550 hp on the stockers with the porting work in conjuction with his kits. If you check out his web page you'll see several of his motors are running the stock manifold only with the paint removed and then polished. They look pretty good. Between the turbulator plates and the porting you could easily see the same 35 hp gain at a fraction of the cost.
Anyone can say anything on a forum. Show me some sie by side dyno tests proving your claims.
If you can do that, I'll gladly recommend my customers just modify their stock exhaust.
10-04-2006, 06:41 PM
#13
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Re: CMI Headers/496 HO
Originally Posted by TRICK
I'm a little old fashion. How about some proof that removing the turbulators and porting will produce the same results as a set of CMI headers.
Anyone can say anything on a forum. Show me some sie by side dyno tests proving your claims. If you can do that, I'll gladly recommend my customers just modify their stock exhaust.
Anyone can say anything on a forum. Show me some sie by side dyno tests proving your claims.
If you can do that, I'll gladly recommend my customers just modify their stock exhaust.Although CMIs are a fine piece. They are a little overkill for a stock 496. If your gonna go big then CMI's all the way!!!
If you follow some of Rays threads on the 496 you'll see the biggest restriction to air flow is actually the stock intake manifold not the stock exhaust manifolds.
Raylar has tested their porting work on a flowbench and I'm sure he can back his claims with dyno sheets along with removing the turbulators.
I'm not trying to starv yor sales, but the man asked the question if they were worth the money or not? Just letting him know there are other options out there if money is an issue
10-05-2006, 06:30 AM
#14
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Re: CMI Headers/496 HO
Originally Posted by screamingeagle
I know a guy that installed a Raylar setup on his boat and saw only 5mph gain and has nothing but problems. I definately am not badmouthing Ray by any means, but for the money I don't think you can go wrong on the CMI's. There isn't as much that can be done to the 496 without major costs. If your looking for 525 hp gains you better look at blue motors. There's no comparison to the blue motors versus black...they have better internals and where designed to run. JMO
Last edited by Canada Jeff; 10-05-2006 at 06:33 AM.
10-05-2006, 08:04 AM
#15
Lakeside Restorations.com
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Re: CMI Headers/496 HO
By having the tubulators removed & porting the stock manifolds you can pick up some power because you are fine tuning them. The headers will still be the best option though because they will scavenge & help pull the exhaust out rather than let it just flow out a little better. 
Jamie / Lakeside
fyi: If you remove the turbulators (which are are not so much there to stop reversion as they are to help prevent corrostion)you run the risk of allowing condensation to leak down onto the valves causing corrosion or rust..
Jamie / Lakesidefyi: If you remove the turbulators (which are are not so much there to stop reversion as they are to help prevent corrostion)you run the risk of allowing condensation to leak down onto the valves causing corrosion or rust..
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We Make Fast Toys Faster, Cool Toys Cooler and Old Toys New!.. Performance, Custom & OEM Parts & much MORE![/CENTER]
www.LakesideRestorations.com 570-639-2628
We Make Fast Toys Faster, Cool Toys Cooler and Old Toys New!.. Performance, Custom & OEM Parts & much MORE![/CENTER]
Last edited by LAKESIDE RESTORATIONS; 10-05-2006 at 08:06 AM.
10-05-2006, 08:37 AM
#16
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Re: CMI Headers/496 HO
Originally Posted by screamingeagle
I know a guy that installed a Raylar setup on his boat and saw only 5mph gain and has nothing but problems. I definately am not badmouthing Ray by any means, but for the money I don't think you can go wrong on the CMI's. There isn't as much that can be done to the 496 without major costs. If your looking for 525 hp gains you better look at blue motors. There's no comparison to the blue motors versus black...they have better internals and where designed to run. JMO
10-05-2006, 12:26 PM
#17
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Re: CMI Headers/496 HO
Just to clear the air here a little (PUN)! Removing the turbulators on a stock 496HO yields about 10HP and yes we didi dyno pulls to confirm it. We have never recommended porting the stock Mercruiser manifolds on stock 496's because the benefits would be nominal. Stock 496's don't breathe well enough at WOT to take real advantage of big exhaust only changes. Also the stock valves in the stock 496's are steel and they rust easily when exposed to a lot of moisture, especially in salt water, sans the reason for turbulator plates to cook off this condensation. We do give some clean up porting tricks on the manifolds to our kit purchasers that do help the motor because after the kit install ,it benefits from exhaust side deep breathing and we use stainless nitirided valves that don't rust. We saw about 10-15HP at WOT on these mods. If you really want to see a Raylar HO525 or a HO600 deep breathe then install a good set of headers like the CMI's and yould see overall numbers around 560-570 HP and 625-630 HP on the HO600. Yes we dynoed those to confirm. Our Raylar/LaveyCraft race boat has our HO525 engine with 496/CMI's and I can only say that it outruns the same hull with a HP525 blue motor. It will be running this weekend in the OSS/OPA races at Lake Mead outside Las Vegas. There should be some surprised looks when the weekends over!
Last edited by Raylar; 10-05-2006 at 12:29 PM.
10-06-2006, 04:07 PM
#18
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Re: CMI Headers/496 HO
Originally Posted by Sydwayz
Raylar has about 6 different stages or options for 496s. Perhaps the guy you know only paid for 5mph.
