Stainless Marine headers

[DeltaDog]

I've got an older 22' Donzi Classic, 454 with a Bravo 1 drive. It's stock except it has an Edelbrock intake and carb. The boat probably runs in 60-65 mph range. I've found a set of Stainless Marine Hi-Torque Exhaust System (slightly used but like brand new) that I could buy for half of what a new set would cost. Even at that they are pricey and I wonder if the performance increase would be worth the investment.
I know that performance increases don't come cheap and it's usually not just ONE thing that makes a boat faster. It's usually a combination of things that makes a real difference. The manufacturer makes claims that tests revealed increases of 3.2 to 6.5 MPH on MerCruiser Big Block powered 22'-24' boats. Now, THAT got my attention. To me, I would be very happy to get a 5 mph increase on just exhaust alone!
Question: Does anyone run this exhaust and did you experience this kind of increase in performance by just bolting these on or are they just blowing smoke?

[MOP]

The gain is very slight with with no other mods, some say barely noticeable on stock applications.

[DeltaDog]

Thanks for the reply MOP. I think you're probably right. I figured they might be exaggerating at 3.2 to 6.5 mph increase.

[gcarter]

I think the main advantage of the SM products is the reduction in weight and the risers won't ever leak at the joint like stock manifolds can.
Beside the marginal improvement in performance these other two items are worthwile.
They will improve the quality of your boat.
They are a good investment.

[craigdskilling]

It starts with the exhaust then you might think of msd thats good for a few more hp if you still have the points.

[DeltaDog]

It's got a stock Thunderbolt pointless distributor. Unfortunately I'm not in a position to trick out the motor right now but thought if I could get 5 mph from the exhaust system alone, it would be worth the investment.

[zelatore]

Short of a blower, I can't think of much you'd bolt on that would give you 5 mph.

Still a good exhaust though, and a good starting point should you want to make mods down the road. If it's in the budget I wouldn't hesitate to go for it, just don't expect big gains. Think of it as laying the foundation for future mods. Plus, it should out-last the stock manifolds by a good bit - they just looooove to rust!

[joseph m. hahnl]

[/URL][URL="http://www.danamarineproducts.com/ProductDetails.cfm?group_id=10&catid=75&productid=3670&CFID=1131517&CFTOKEN=34854ed-f518a67c-f4f8-4080-bb7d-b67527e85739"]http://www.danamarineproducts.com/images/interface_assets/ACF5AFF.gif (http://www.danamarineproducts.com/ProductDetails.cfm?group_id=10&catid=75&productid=3670&CFID=1131517&CFTOKEN=34854ed-f518a67c-f4f8-4080-bb7d-b67527e85739)

[zelatore]

A- he's got a 454, not a 496/8.1
B- I question the '48 hp' gain
C- even if it was a true 48 hp gain, I don't know if that would be enough to go from 60-65 to 65-70

But they sure are pretty...

[BUIZILLA]

48 ain't happenin'....... :bonk:

[IpanemaSports]

http://www.danamarineproducts.com/images/interface_assets/ACF5AFF.gif (http://www.danamarineproducts.com/ProductDetails.cfm?group_id=10&catid=75&productid=3670&CFID=1131517&CFTOKEN=34854ed-f518a67c-f4f8-4080-bb7d-b67527e85739)

Wow, those look nice.

Been reading on offshoreonly about how a lot of guys had problems with some of the tube design headers cracking welds, but these units look thicker.

http://www.danamarineproducts.com/Images/ProductDetailsImages/productimage3_PG_31.gif

Do any of you have experence with these?

[VetteLT193]

One of the magazines many years ago did the SM swap on a 22 and it picked up considerable speed all things considered. That may be where the speeds come from.

That said, it probably depends mostly on your existing system. If your current exhaust is a rust pile that is about ready to fail it could really help. If it is new or near new, not so much.

[zelatore]

48 ain't happenin'....... :bonk:

I have to agree. I'm sure they have a dyno sheet somewhere that supports that, but I find it hard to believe Merc would leave that kind of power on the table. If you figure the delta between the stock manifolds and the Danas at a bulk wholesale price I would think Merc would have just upped the engine price by a few hundred bucks and claimed a huge power advantage over their rivals.

And yet they didn't.

I don't doubt they're a decent part. I just question the claims.

[Pismo]

Ask Carl what he got out of his $5000 CMIs on his old 496...Zero.

[mrfixxall]

Wow, those look nice.

Been reading on offshoreonly about how a lot of guys had problems with some of the tube design headers cracking welds, but these units look thicker.

http://www.danamarineproducts.com/Images/ProductDetailsImages/productimage3_PG_31.gif

Do any of you have experence with these?

Howee bolted a set of thease on his 22 and he got 48 +


Gallons of water in his engine..(reversion)

[joseph m. hahnl]

A- he's got a 454, not a 496/8.1
B- I question the '48 hp' gain
C- even if it was a true 48 hp gain, I don't know if that would be enough to go from 60-65 to 65-70

But they sure are pretty...

Dana Makes them for all the Merc V8's


48 ain't happenin'....... :bonk:

Play on words here, up to 48HP


Howee bolted a set of thease on his 22 and he got 48 +


Gallons of water in his engine..(reversion)

He bought the wrong risers


They state that the short riser can cause reversion and Cam overlap is a critical element in there application.

Statements in their literature

Short aluminum risers do have a camshaft limitation to prevent reversion

Econo risers do have a camshaft limitation to prevent reversion



Here's a good read on selecting the proper headers http://www.carcraft.com/techarticles/header_basics/index.html

[DeltaDog]

Thanks for all the input guys but I screwed around too long thinking about it and they sold.:frown: He who snoozes....looses

[mrfixxall]

Dana Makes them for all the Merc V8's



Play on words here, up to 48HP



He bought the wrong risers


They state that the short riser can cause reversion and Cam overlap is a critical element in there application.

Statements in their literature

Short aluminum risers do have a camshaft limitation to prevent reversion

Econo risers do have a camshaft limitation to prevent reversion



Here's a good read on selecting the proper headers http://www.carcraft.com/techarticles/header_basics/index.html


he has the long risers and the motor is almost stock..the exhaust ports were over 1/4'' off,the boat is zimm's old bloat??? and they were on the 454 with the whipple in the boat that granaded a piston which i think caused it to blow up after seeing the reversion..he sent them back to dana and they gave howey a new set of manifolds and extended the inner tube on the risers and howee put them back on and they still reverted..

last post you can see them and hear how stock the engine sounds..last i spoke to howee he still had my old exhaust on his boat..

http://www.donzi.net/forums/showthread.php?t=60022&highlight=zimm

[farmer tx]

he has the long risers and the motor is almost stock..the exhaust ports were over 1/4'' off,the boat is zimm's old bloat??? and they were on the 454 with the whipple in the boat that granaded a piston which i think caused it to blow up after seeing the reversion..he sent them back to dana and they gave howey a new set of manifolds and extended the inner tube on the risers and howee put them back on and they still reverted..

last post you can see them and hear how stock the engine sounds..last i spoke to howee he still had my old exhaust on his boat..

http://www.donzi.net/forums/showthread.php?t=60022&highlight=zimm

Thats exactly what happened to Zimms engine!!