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-   -   Eddie Marine Exhaust = 10%+ HP/Tq gains! (https://www.offshoreonly.com/forums/general-boating-discussion/118237-eddie-marine-exhaust-%3D-10%25-hp-tq-gains.html)

Harper220 12-31-2005 05:56 PM

Re: Eddie Marine Exhaust = 10%+ HP/Tq gains!
 
New Powerboat magazine has a big new add on these.

Has anybody dynoed these yet to get actual hp and tq gains vs. stock? They say 10% gains which would be 40+ hp.

This is exactly what the 496/ho needs without getting into expensive stainless tube headers. If the claims are true? :D

Too Old 12-31-2005 08:13 PM

Re: Eddie Marine Exhaust = 10%+ HP/Tq gains!
 
No dyno numbers that I'm aware of.

Psychostroker 12-31-2005 08:26 PM

Re: Eddie Marine Exhaust = 10%+ HP/Tq gains!
 
I heard a rumor that Eddie has not installed or tested his new 496 version yet even though its being advertised....anybody know if thats true?

Raylar 01-01-2006 01:56 PM

Re: Real gains with exhaust changes on 496's
 
I thought I might chime in here to kind of even out the questions of horsepower and torque gains from exhaust upgrades on 496's. First, keep in mind that for any motor to gain horsepower or torque it must basically get more efficient. Obviously any things changed on a motor that increase the volumetric efficiency can increase power. There are basically three types of marine exhaust manifolds,

1. The tradtional old mercruiser log manofolds that came on the 350 thru 502 carburated and MPI motors from 60's thru mid 90's. these manifolds because of their log (all exhaust ports dump close to the head into a long square chamber and then exit a back end up thru a small vertical riser entrance) are very innefficient, heavy (iron) and were poor at letting the motor develop hp and torque.

2. The aftermarket and new Mercury (Gil) short runner, center riser manifolds. These are aluminum units like Eddie,, Revolution Imco, Gil, CMI E-tops and 496 Merc., etc. they all have similar short runners 8" - 10" that merge into center riser openings and definitly flow better than the old log type most boaters have been use to. They will definitly make more power and torque than the old log manifolds.

3. The tubular stainless and special cast units with long 18" to 24" semi-equal length with good merge collectors, like CMI, IMCO Super Powerflo, Stellings, Eichert Bassett, Dana, etc. will generally flow exhaust more efficiently than either of the two other types.

The real question here is the 496 engine. The stock 496 Merc (GIL) aluminum manifolds (type 2) are really pretty good units when compared to other (type 2) manifolds. Their individual runners and merge into the stainless steel round big radius risers with merge collectors can do a very good job of helping the 496 develop its great torque and good power. ESPECIALLY WHEN THEY ARE GIVEN EVER SO SLIGHT MODIFICATONS! If you were to take the turbulator plates alone out of the 496HO and dyno the motor you will see about a 15HP increase alone! So if you compare certain aftermarket manifolds (not type 3 tube headers) you will in most cases see no significant power increases from stock 496 manifolds.
If you are looking for more Bling, polish or paint the Mercury 496 manifolds, polish the stainless risers and you have some good look'in aluminum manifolds that work well and you will save yourself about $1500 minimum.
If your 496 is stock and you choose to step up to a good (type 3) header system you will probably see about 25-40HP net increase over the stock exhaust manifolds and risers with the "turbulators" removed, depending on your boats riser to transom configuration and muffler use if applicable.

Trust me when I say that Raylar has probably made more dyno pulls on stock and modified 496's with many combinations of exhaust than probably anybody in the industry short of GM and I have the dyno sheets to prove it! We have made over 525HP on a normally aspirated 496 with stock Mercury 496 exhaust manifolds (turbulators removed and manifold riser openings lightly ported.) This is about the limit, normally aspirated, for these stock manifolds.

If your plans are to go above 525HP with a 496 either normally aspirated or supercharged 496, then invest in a good set of (type 3) real headers or manifolds, you won't get there without them.
I am not trying to endorse or critisize any aftermarket exhaust manufacturers here, I am just trying to get the real world results of their use on stock 496's where I have my expertise.
Remember engines increase power from increased breathing and efficent use of fuel. The 496's need to breathe better on the intake side to make more power above 450HP and this will only come from improvements in heads, cams and intake manifolds, supercharger or turbo charger addtions . You are not going to get a 475HP from a stock 496 from just installing any set of headers and especially not from a set of $2000 manifolds. If you do, let me know how you did it.

Just some real world facts!

Best Regards,

Ray @ Raylar

Harper220 01-01-2006 02:32 PM

Re: Eddie Marine Exhaust = 10%+ HP/Tq gains!
 
Thanks Ray. That helps a lot.

Too Old 01-01-2006 04:31 PM

Re: Eddie Marine Exhaust = 10%+ HP/Tq gains!
 
Good post Ray.

Currently the CMI 496 system is the only system that I know of that has a good sampling of systems on a variety of boats to provide real world results from customers.

As more manufacturers bring systems to the market, there will be more data available from end users on those systems. Right now, it's pretty early in the development and sales of these systems.

I have sold more sets of CMI headers for the 496 than anyone. I have yet to have a disappointed customer when it comes to performance gains. It's not an inexpensive product, but I'm comfortable with the gains that my customers have experienced.

I can sell anyones exhaust. But I try to give people all the information available so they can make an informed decision.

Semper Fi 01-01-2006 06:08 PM

Re: Real gains with exhaust changes on 496's
 

Originally Posted by Raylar
You are not going to get a 475HP from a stock 496 from just installing any set of headers and especially not from a set of $2000 manifolds. If you do, let me know how you did it.

Just some real world facts!

Best Regards,

Ray @ Raylar

Raylar,
Thanks for taking the time to point out some great info. I am wondering (correct me if I read you wrong) but I thought the CMI's were adding approx. 60hp to a stock 496HO. Are you saying this can't be done?

Just trying to clarify. The next boat I buy might have 496Ho's and I would want to have some info to get more power from them.

Gerard

dyno 01-01-2006 07:41 PM

Re: Eddie Marine Exhaust = 10%+ HP/Tq gains!
 
running the thunders on my 454's with the dry stacks, 10% is a bit over the top maybe closer to 5%.I'd buy the Lightnings much better bang for the buck and I've ran both......my .02

Too Old 01-01-2006 09:23 PM

Re: Real gains with exhaust changes on 496's
 

Originally Posted by Semper Fi
Raylar,
Thanks for taking the time to point out some great info. I am wondering (correct me if I read you wrong) but I thought the CMI's were adding approx. 60hp to a stock 496HO. Are you saying this can't be done?

Just trying to clarify. The next boat I buy might have 496Ho's and I would want to have some info to get more power from them.

Gerard


Gerard,

The dyno sheets I have show a bit over 55 hp.

Semper Fi 01-02-2006 01:41 PM

Re: Real gains with exhaust changes on 496's
 

Originally Posted by TRICK
Gerard,

The dyno sheets I have show a bit over 55 hp.

That's impressive!


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