I have a comment on the placement of the exhaust temp probe. The temps are going to be hotter the closer the probe is to the exhaust port. You need to know the temps coming off of the exhaust ports to prevent piston damage. The turbo is going to see cooler temps as the turbo is downstream on the exhaust manifold or header. I think this header will allow the turbo to see cooler temp than a cast manifold. From test we have done with diesel engines in farm tractors, you can see about a 300 degree drop from pre-turbo to post-turbo exhaust temps. In short, weather the probe is installed closer to the exhaust port or turbo, there will not be enough of a temp change to save pistons and not the turbo.
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Stainless Header
- Thread starter gitchesum
- Start Date
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I'll take two! They sure look good! Maybe after the cummins turbo header is complete a similar setup on Jeep's inline 6 could be in the works? I have tried copying the twin sequential turbo setup from twin turbo supras with no luck!
That header is looking good. Are there any updates?
gitchesum said:
why?
why not just use mild steel if you're going to ceramic coat... mild expands/contracts less than 304 and is much less brittle... you would have a better product and lower cost if you went with ceramic coated mild steel vs. ceramic coated 304!!!
the ONLY reason to run stainless is because stainless is sexy when it blues up!
Forrest Nearing said:why?
why not just use mild steel if you're going to ceramic coat... mild expands/contracts less than 304 and is much less brittle... you would have a better product and lower cost if you went with ceramic coated mild steel vs. ceramic coated 304!!!
the ONLY reason to run stainless is because stainless is sexy when it blues up!
Who said it was going to be ceramic coated stainless??
CJ
Cummins Thunder said:Who said it was going to be ceramic coated stainless??
CJ
sorry, I got confused by the title of the thread and the pictures inside it
Forrest Nearing said:why?
why not just use mild steel if you're going to ceramic coat... mild expands/contracts less than 304 and is much less brittle... you would have a better product and lower cost if you went with ceramic coated mild steel vs. ceramic coated 304!!!
the ONLY reason to run stainless is because stainless is sexy when it blues up!
I don't want to start a "header alloy war" but here is my two cents worth.
Stainless has the goodness that Mcarcerano stated 4 pages back. One issue is that the perception that one flavor stainless isn't that different than another flavor. You basically get what you pay for. 304 is cheap and available and will crack in a pre-turbo application as it will fatigue faster due to the heat and turbo weight and overall vibration levels. The key is how many cycles you get before its fatigue life is used up. 321 is better as it is/was used on APU exhausts on aircraft from the early 60's up to about the mid to late 80's. 347 became the preferred alloy as it is much more receptive to welding and the rod used has better properties in leaving the weld a bit ductile (I believe it's called Hastelloy or something. ) Looking around, it is probably hard to find 347 tubing in any standard sizes and most small shops don't want to buy a mill run for small projects like this. Will mild steel work? Not even close to how long stainless' life will be. Will 304 work? Yup, but gitchesum has a lot of work to do to validate the product or else the feedback here will have repercussions due to the speed and reach of internet news.
Most commercial ceramic coatings help on applications where the temps don't exceed 1300F regularly. At or above that temp, the coating turns from the shiny nickel appearance to a really dull gray. At least this is my experience with snowmobile exhaust systems that use HTC's process. Using plasma applied thermal barrier coatings will withstand some obscene temps but are not practical for this stuff. They don't look purty either.
Will added wall thickness help fatigue life? You bet, in a big way. Stresses go down by a factor of 1/diameter difference^4. Difficulty in forming goes up to keep wrinkles out of the inside ofthe bends.
Mass air flow (kinetic energy) and heat energy are big players in spooling up a turbo. Feed more energy in and results are guaranteed to change. The hard part is measuring what you actually changed, or in this case, has the "energy in" to the turbine housing appreciably changed.
maybe try swaintech coatings, ceramic header stuff which nascar and f1 cars use.
Many thanks to RKerner for an awesome, clear and precise explanation.
Let the alloy holy war begin.....
Mild steel is NOT a superior metal when it comes to high heat cycling. This metal will become brittle and fatigue much earlier than any grade stainless steel. That is the reason why stainless is used on the majority of OE exhaust systems today. The only real benefit mild steel has over stainless is that it is much cheaper to purchase and easier to work with using regular tools and welding equipment - making the final product cheaper to purchase.
The purpose of ceramic coating it is to extend its service life. The ceramic coating's purpose is to insulate the metal and keep the heat away from metal and in the exhaust flow - an insulator. The big benefit is that you can not only coat the outside of the pipe but the inside as well. The process can also be performed to stainless steel.
There are matt ceramic coatings that will withstand 2000 degrees.
The only other way to avoid "bluing" of the pipes is to take a trick from the motorcycle world: double pipes.
The big issue for most of us here is that we all want the best but are unwilling (or unable) to step up and pay the price it takes.
I would love to have an equal length 321 (or better) stainless steel header on my 05; but reality is that this unit will cost somewhere around $1,200-1,700 dollars, and I am not willing to drop that amount of cash on that part at this point for the marginal power/performance/drivability improvements it will yield with out other major mods (like ported/polished head, better cam shaft, lightweight rods, knife edged crank, twin turbos, HUGE intercooler and improved injectors... . the list goes one and one).
So - it'll be the crappy looking cast iron exhaust manifold for me for a little longer... ...
Let the alloy holy war begin.....
Mild steel is NOT a superior metal when it comes to high heat cycling. This metal will become brittle and fatigue much earlier than any grade stainless steel. That is the reason why stainless is used on the majority of OE exhaust systems today. The only real benefit mild steel has over stainless is that it is much cheaper to purchase and easier to work with using regular tools and welding equipment - making the final product cheaper to purchase.
The purpose of ceramic coating it is to extend its service life. The ceramic coating's purpose is to insulate the metal and keep the heat away from metal and in the exhaust flow - an insulator. The big benefit is that you can not only coat the outside of the pipe but the inside as well. The process can also be performed to stainless steel.
There are matt ceramic coatings that will withstand 2000 degrees.
The only other way to avoid "bluing" of the pipes is to take a trick from the motorcycle world: double pipes.
The big issue for most of us here is that we all want the best but are unwilling (or unable) to step up and pay the price it takes.
I would love to have an equal length 321 (or better) stainless steel header on my 05; but reality is that this unit will cost somewhere around $1,200-1,700 dollars, and I am not willing to drop that amount of cash on that part at this point for the marginal power/performance/drivability improvements it will yield with out other major mods (like ported/polished head, better cam shaft, lightweight rods, knife edged crank, twin turbos, HUGE intercooler and improved injectors... . the list goes one and one).
So - it'll be the crappy looking cast iron exhaust manifold for me for a little longer... ...
PToombs said:
The latest prototype lives! Ceramic coating and all...
Hammer
TDR MEMBER
Hmmm. .
I have been watching this thread since it started and yet no one has asked how much air the header will flow over the already proven ATS,High Tech and B-D Power exhaust manifolds. See,this header design goes against all known header design and airflow characteristics and I'd be willing to bet once its strapped on a flow bench its design flaws would show easily. To make a header that flows correctly and follows what is known about exhaust air flow,you would have to relocate our turbos. Any header that is designed with bends following bends will never flow properly and create more turbulance inside costing HP and raising egts.
Another thing inquiring minds would like to know here is cost. See while most would just jump on the bandwagon due to it being different,normal owners would like to know what they stand to gain for their money. They would also like to know what they would gain by buying this as compared to the money spent for the proven other manifolds out there. The old theory "bang for your bucks" is what is needed to be known or simply,tell us what we stand to gain for the added price of this show piece or is it simply nothing more than a show piece for the money?... ... ... . Andy
I have been watching this thread since it started and yet no one has asked how much air the header will flow over the already proven ATS,High Tech and B-D Power exhaust manifolds. See,this header design goes against all known header design and airflow characteristics and I'd be willing to bet once its strapped on a flow bench its design flaws would show easily. To make a header that flows correctly and follows what is known about exhaust air flow,you would have to relocate our turbos. Any header that is designed with bends following bends will never flow properly and create more turbulance inside costing HP and raising egts.
Another thing inquiring minds would like to know here is cost. See while most would just jump on the bandwagon due to it being different,normal owners would like to know what they stand to gain for their money. They would also like to know what they would gain by buying this as compared to the money spent for the proven other manifolds out there. The old theory "bang for your bucks" is what is needed to be known or simply,tell us what we stand to gain for the added price of this show piece or is it simply nothing more than a show piece for the money?... ... ... . Andy
If you want those things to take the heat and not crack, go Titanium. Hang on to your wallet,though!
Curtis. . keep up the good work testing, and trying new stuff
hope it works for ya !
Gary
hope it works for ya !
Gary
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Issue 128 – Digital Version
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Subscribe
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Back Issues
Subscription Status
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Ram Diagnostic Trouble Codes
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