Tuned Pipes and Headers, SS or Aluminum? Info Added

[Terry Heddin]

What are the pros and cons of stainless steel vs aluminum for pipes and headers?

Added info for clarification:
I have a box full of stainless steel and aluminum pipes, and need one for a Zippkit's A-Box Cracker Box with a 26 Zenoah. I am strictly a sport boater, so NO racing. Will I notice any real difference between stainless steel and aluminum? Or should I just pick the pipe that best suits the hull to start with?

 

[Dave Gilles]

I always heard aluminum absorbs the sound waves more and so the convergent wave is weaker. Who knows. Wonder if Lohring has a dyno graph?

I'd like to know if a 1" exhaust is worth the money?

 

[Mark Anderson]

The trick in both scenarios would be having pipes of the same design to test. Very small differences can make a difference in power output.

 

[Grimracer]

Years ago we started ringing them and shooting them with our radar gun.. the highest ringing (of the same pipe) was our fastest.

We were testing 3280 OPS pipes.. it was STARK!

You herd it here first and I bet ya all will be ringing pipes soon! (Christmas bells are RINGING!)
Grim

 

[Don Ferrette]

From a good number of years of testing (at the pond with radar gun and stop watch) steel pipes typically work better on gas engines than aluminum. As far as what Mike said regarding nitro and aluminum pipes smaller motors (.21 and .45s) the "ring test" did show a difference (negligible on big motors at what I saw). On the bigger motors, from what I experienced, billet pipes hit or turned on harder than a typical spun aluminum pipe which was in some cases not a good thing causing abrupt torque steer especially on twins. I did test a steel pipe on a single .90 and it was a bit of a dog, never went any further with that.

 

[shoboat]

Terry,
I think there is a lot more to tuned pipes than just the material
differences. What some don’t realize it has a lot to do with the
pipes geometry and volume of the pipes matching the volume
of our engines. Steel and Aluminum pipes have set many records
over the years, but to me and many others it is all about matching the insides of the header & pipe for a consistent high velocity return wave back into our engines. Pipe design and testing is a lot more important on our two intake engines. ️

Have Fun Testing,

Mark Sholund

 

[Terry Heddin]

Added info to original post.

 

[LohringMiller]

Material is much less important than design. Material choice has to due with heat retention in the pipe. Generally hotter gas is better, so a material that has poor heat transmission is better.
Approximate Thermal conductivity:
aluminum ~ 137 Btu/{(hr)(ft^2)(degF)/(ft)]
mild steel ~ 30 Btu/{(hr)(ft^2)(degF)/(ft)]
stainless ~ 8 Btu/{(hr)(ft^2)(degF)/(ft)]
Ti ~ 12 Btu/{(hr)(ft^2)(degF)/(ft)]

Wrapping the pipe in an insulating material can help overcome aluminum's high thermal conductivity. Of course the pipe dimensions need to reflect the higher exhaust temperatures. From the above stainless steel would be the "best" material. Other issues like weight and ease of construction are probably more important.

As a review, the article below shows what the tuned pipe is trying to accomplish. I can post methods to design pipes to accomplish this if there's any interest.

Lohring Miller





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[Timbo Whalen]

Ceramic coating of pipe and header, interior/exterior truly enhances the thermodynamics toward optimum efficiency.
Ceramic coating also removes surface tension and resonance properties from any given material in this application, and unifies such.

Weight penalties between aluminum and steel for a given pipe size is negligible....a non factor, if appropriate alloys and wall thickness are implied.

 

[Dave Gilles]

so I'll bite....what the frig is "pipe ringing"?

to answer the OP updated post ....it doesnt matter its a stock engine just go with what fits.

 

[Mark Anderson]

Ringing- tap it with something and listen to the tone.
Stock Zenoahs are the most critical for the right pipe to help scavange the cylinder.

 

[Dave Gilles]

Ringing- tap it with something and listen to the tone.
Stock Zenoahs are the most critical for the right pipe to help scavange the cylinder.

ok Im going to bite on this too. stock engines have the most base compression over a mod engine so need the least help scavenging as the pressure through the transfers is significantly higher.

 

[Mark Anderson]

Ok. If that is your finding. Cool.

 

[Dave Gilles]

Nooo you're supposed to tell me how it's wrong. Dang.

 

[Mark Anderson]

Nope. I have pipes to build and testing to do. Way too busy to argue on the internet.

 

[Dave Gilles]

You're no fun that's how we all learn. I dont claim to know what Im talking about with authority Im theorizing.

 

[Mike Bontoft]

Ringing- tap it with something and listen to the tone.
Stock Zenoahs are the most critical for the right pipe to help scavange the cylinder.

A week Sunday ago I was doing the grandkid thing in California and found myself at Legg Lake. Got to witness Don Maher's Stock Zenoah hydro run. Having no experience with Zenoahs that haven't had the guts ground out of them, I must say I was absolutely amazed at how well it ran for a stocker. Very impressive! Not sure what pipe he was running but it was steel.

 

[DON MAHER]

Hello Mike, it was great to see you and your wife last week! Thanks for the kudos. The stock rigger is a a lot of fun to play around and test different combinations of pipes and props. So far I have found the Zippkit pipe has the best bang for your buck in over all performance on a stock 26! Set at 13-1/2”just as Joe recommends and let it rip!