To re-confirm, the 496 kits include the Vortex style risers. The picture is due to be updated. The dyno sheets are available for the 496 HO, 496 Mag, and the Raylar 525 converted engine.

The risers are specifically designed to be a Merc replacement. Silent Choice or "S" pipes are not a problem.

There is alot of different systems out there, and I can't say a word about any of them.

What I can say is that we went to great lengths to make our kit make good HP and be easy to install. We had several well known people involved in the development of this kit. We spent alot of $$$ to have accurate dyno numbers and water testing.

There's always going to be questions, but I can tell you, it was not my intentions to spend all this money and time to produce inaccurate or twisted dyno numbers.

Full Throttle Marine has recently purchased two kits and is conducting his own dyno testing. Once completed he will report his results. We're confident his results will be very similar to ours. Hopefully this independent testing will prove that we're not stretching the facts.

Here's one thing nopt mentioned - the effect taking the turbulator ring out has on estimated hp gains. I understand that is about 10-15 hp an that the manufacturers include this in their overall publication.

I took mine out and it sounds better, but did not notice much - MAYBE another 100 rpm but who knows. Sound was a little better through. I heard this in another thread so if a manufacturer claims 50hp increase over stock - maybe it's more like 35 to 40?

Has anyone dyno'd a stock manifold with the rings out? They do restrict by about an inch on each side.

Very well said, can not wait to get mine installed and the boat in the water to do some testing.

Jaime is my boat done yet....LOL


Undertaker

I was told taking the turbulators out gives you nothing noticeable. Jaime sent me a great picture showing the minimal restriction with the tubulators in......

Undertaker

I have read many threads saying that taking the turbolators out is good for 10-15 hp, most boats require 10-15 per extra mph, so you may gain 1mph or so. If these exhausts claim 45 or so hp, your really only getting 30 or so because of removing the turbolators.. so like most real time numbers I have seen an exhaust change will net about 3 mph...

I would much rather have a CMI setup but I have heard the 496 exhaust is made by Gil and they are very good for stock. I polished mine and removed the rings. They say that they are more for colder climates - I'm in Fl.

Here are pics of the tubulators that some one else here had posted a while back in some other thread.. The turbulator removal on its own really wont net much Hp at all on this 496 set up. The manifold & riser are tapered & machined out to accept a turbulator that wont really restrict the flow. The problem is however that the actual exhaust exits could be a little largetr overall & The biggest thing is the need for longer & tuned runners. On the Gil offshore systems that were used on the 500hp's the turbulator removal may net you a little more hp in some circumstances, but still nothing like the DMP units or CMi set ups will do. ;) :)

Jamie / Lakeside

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Nice job on polishing the factory risers.. :) It looks good.. :)

Yes the stock Merc exhaust is not bad on the 496, BUT it can be improved upon as mentioned earlier.. One of the reasons that many say it is good for a stock system is that compared to the old full cast iron manifold & cast iron riser it is an improvment in weight & performance..

:) Jamie / Lakeside

Agreed,

I was taking off the riser to polish them, if not I would have left the rings alone. When it comes time for a rebuild, I'll be doing the full monty - along the lines of a Raylar along with pipes.

:D I need to clone myself.. lol..:drink:

You are on the list ;) .. Didnt you also get snow & ice last night & today as well??.. Maybe we should install a set of skates or skis on the thing.! :drink: :evilb: Jamie / lakeside

Sounds like a good plan.. I think you would be happy with that BK 103kit & an exhaust.. :) Jamie / Lakeside

real nice set up. im going the same route this year. im ordering the polished cowling and we will see what exhaust i go with. i even got the polished battery box.

Here's a better view of all the diamond plate and polished stuff... (sorry - don't want to hijack the thread)

Getting the bling on!! :D It should look nice.. :) Jamie

Not at all.. It looks good! :) Jamie

donzi33. pm sent your way.

Yeah, but it is going to be in the 50's this weekend.........I'll give you a call tommorrow....

Undertaker

Although not for everyone, CMI Headers have proven performance gains and great looks. There are alot of decent exhaust systems out there and many have been mentioned in this thread. If we can help you out with product information or a quote on CMI's, please give us a call. Exhaust systems are expensive, make sure you choose something that performs to your expectations and looks like you mean business!!

Kirk
Ateco Engine and Dyno Shop - Your CMI Source

Nice job Shooter!

Got it.. Back at ya ;) Jamie / Lakeside

Sounds good.. Catch ya later.. :D Jamie

Kirk,
I agree CMI is also a good system & has its place in the market without question. It's just good to also have more than one option.. On tighter twin applications the Cmi is the only other good way I know to go when looking for more bling & power.. I also cant say anything bad about the quality of their pipes, every set we have sold or installed to date has been "A ok".. :) It's just too bad the pricing is not a little bit better on their products, Although everything everywhere is expensive anymore.. :) Jamie / Lakeside

.

At this point if I was buying today, it would be Dana. BUT this thread was asking about headers (not my thread though). Anyway, wouldn't it be great if we could see a comparison between all 496 headers - Stellings, Lightning, CMI, Bassett (any I forgot).

CMI's are around $4500 per set and I believe the Stellings to be similar. Not enough bang for the buck IMO. Lightning can be had for $2000 (mild steel) or $3500 for all stainless polished. Getting a little more realistic IMO. I wonder about the performance in comparison to the others. Bassett, I really don't know anything about including the price.

Anyone with anything further or corrections?

With all due respect, it absolutely does affect other points of running, perhaps not to the point where you are noticing it with soot. It will richen it by the square root of the pressure ratio.

Michael

I'll agree that the fuel pressure increase is changing the curve through out the range. I think that's a given. From my experience it does not change it to any negative affect.

We had 3 full days on the dyno with three different 496 engines, and have installed and ran this exhaust on two different boats. By "ran" I mean we've installed and ran for extended periods of time with Mercury scan tools and portable O2 sensor kits installed.

At no time did we have any reason for concern with the 3 pound increase.

This increase was a neccesity on the late model 496 HO's. Without the change, the engine will run dangerously lean.

I personally think it is great that Dana Marine has done enough research to know that more fuel is necessary.

I would think that their manifold must be doing something to require more fuel. Either they are producing more HP or TQ (or both) somewhere than others, or the others are running lean. I sure wish we had O2 and EGT sensors with a more sophisticated computer....

The dyno sheets I have seen around here from CMI seem to have some funny things going on with pressure and humidity plus I see it states 92 octane. Maybe those were misprints and sensors not hooked up or whatever,but ?????:rolleyes:

Dana Marine Products, can you go ahead and post a dyno sheets of stock versus your manifolds for us (any of the engines)? I have seen other posts where you clearly state the increases along with the baselines. I am not doubting your claims.

I will see if I can dig up somemore info on them like dyno sheets.. I will post it if I can ;) Jamie / Lakeside

[QUOTE=Bill 3;2040669]I sure wish we had O2 and EGT sensors with a more sophisticated computer....
[\QUOTE]



Are you sure of that? Get ready for big brother to make it much harder to increase HP....IMO

I agree!! As I stated there are alot of nice products on the market. Just hope people make the right decision the first time. We have several customers that bought a lesser brand and ended up paying twice. Looks like you guys rep some nice products Jamie. Hope you have a great season!!!

:rolleyes: I am not sure about that, you may be right, and I think we already have enough big brother.

I would guess that we could make more efficient power if the computer could have more info on what it going on with the motor. Almost like tuning on a dyno. It could get rid of a lean condition, or bad fuel. I don't know, maybe air flow, temp and knock sensors are enough:rolleyes:.

And then if we could tune our own motors with the likes of HP Tuners or EFI-Live to make up for small changes such as exhaust instead of going with an across the board fuel pressure increase.

Thanks.. You too.. :) Jamie

BTW.. You are correct cheaper is not always better.. Quality & purpose should be important concerns.. Price in a perfect world should be second.. :)

Ok guys here are the Dyno sheets from my rep @ Dana Marine .. They were on an independent facilities' dyno.. Hopefully it will help some of you.. :) Jamie / Lakeside


Click the link below.. :)

Dana 496 Dyno sheets / Flyer


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Jaime looks good... :drink: Tried to call you this evening, give you a call tommorrow..

Undertaker :drink:

Very true....thats what I use on my chevy truck motor. Very interesting stuff you can tweek. I just dont want to get to the point where the motor begins to work for emissions. Although a properly running motor shouldnt trip any emission sensors.

Beautiful....proof is in the pudding. Sign me up for a set.

Notice that the A/F ratio is much leaner with the headers. On the right bank at 4800 rpm, we've gone from 13.15 to 13.87. What happens if we just lean the engine with the stock manifolds?

Michael

Will This Exhaust Work On A 2004 31 Sonic With Corsa Silent Choice? Also The A/f Ratios On The Dyno Sheets Of 14 ++ Are Too Lean At Those Rpms!!! Looks Like A Ecm Flash Might Be Necessary With This Exhaust System......

From the graphs it looks like Eikert is the way to go.

Just to clarify, that lean condition is the result of only adding the exhaust. No ECM modifications were done. That lean condition is exactly what we've being talking about in this thread. The 3 pound fuel pressure increase brings that number back down to 13.5.

As previously stated, I find it amazing that no other exhaust company is suggesting the fuel pressure increase.

Anyways, we've done the testing and make the suggestion to do the fuel upgrade.

GRS Fast - The system is compatible with the Silent Choice System. BUT PLEASE NOTE: your engine will not require the fuel pressure upgrade. That change is only necessary on late model 496HO applications. The 2004 and earlier engines have a different computer program that is much richer than the later model engines. You can add the exhaust to your engine with no fuel modifications.