Titanium exhaust manifold......
No a lot of heat would get out of the TI manifold, more would be retained with Steel/Inconel. Exhaust gasses in turbo car's are supposed to be as hot as possible before the turbo to retain thermal energy, afterwards we don't give a **** we just want as little back pressure as possible.
TI manifold idea is ridiculous, this thread should be locked and another should be started. Inconel or just fancy Steel are your best options.
Scorke
TI manifold idea is ridiculous, this thread should be locked and another should be started. Inconel or just fancy Steel are your best options.
Scorke
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Joined: Jun 2006
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From: Jacksonville/Boca Raton
No a lot of heat would get out of the TI manifold, more would be retained with Steel/Inconel. Exhaust gasses in turbo car's are supposed to be as hot as possible before the turbo to retain thermal energy, afterwards we don't give a **** we just want as little back pressure as possible.
TI manifold idea is ridiculous, this thread should be locked and another should be started. Inconel or just fancy Steel are your best options.
Scorke
TI manifold idea is ridiculous, this thread should be locked and another should be started. Inconel or just fancy Steel are your best options.
Scorke
Yep. You definatly know more about materials than I do, but I do know Ti disapates heat quite fast. Inconel is where its at, but I dont want to spend 2 grand on a manifold thats not going to perform that much better than a SS on. While were on the topic, wouldnt doing a coating, which actually makes a manifold cool off much quicker, (my friends coated mani is cool enough to touch after like 10 miniutes after a drag pass) make a manifold perform in a less desieralbe way than a manifold heat wrapped?
The coatings usually retain heat.
Here is a short exerpt from swaintech they do that nice white coating that lots of people are using on there mani's,
We have thermal barrier coatings for piston, thermal barrier coatings for cylinder heads, thermal barrier coatings for valves, thermal barrier coatings for exhaust parts and thermal barrier coatings for intake manifolds. Parts that see movement and wear will benefit from Swain’s low friction coatings. We have piston skirt coatings, bearing coatings, valve stem coatings, valve spring coatings, crankshaft coatings and coatings for other parts where friction should be reduced or a solid film of lubrication can protect the part from wear or damage. Thermal barrier and heat emitting coatings for brakes should not be overlooked for race applications. A braking advantage can be as, or more important than power gains.
It seems the bulk of the coatings work to keep heat in, which in doing so increased exhaust gas performance, lower under hood tempreatures (good for water/air/oil, and just protect the piece from the environment. I am sure there are companies out there that also produce coatings to encourage heat transfer, just not sure who they are and or how they would apply.
Scorke
p.s. I don't know a lot about materials I just know a very basic amount about what applies here
If it's anything too technical its probably paraphrased from somebody who knows
Here is a short exerpt from swaintech they do that nice white coating that lots of people are using on there mani's,
We have thermal barrier coatings for piston, thermal barrier coatings for cylinder heads, thermal barrier coatings for valves, thermal barrier coatings for exhaust parts and thermal barrier coatings for intake manifolds. Parts that see movement and wear will benefit from Swain’s low friction coatings. We have piston skirt coatings, bearing coatings, valve stem coatings, valve spring coatings, crankshaft coatings and coatings for other parts where friction should be reduced or a solid film of lubrication can protect the part from wear or damage. Thermal barrier and heat emitting coatings for brakes should not be overlooked for race applications. A braking advantage can be as, or more important than power gains.
It seems the bulk of the coatings work to keep heat in, which in doing so increased exhaust gas performance, lower under hood tempreatures (good for water/air/oil, and just protect the piece from the environment. I am sure there are companies out there that also produce coatings to encourage heat transfer, just not sure who they are and or how they would apply.
Scorke
p.s. I don't know a lot about materials I just know a very basic amount about what applies here
If it's anything too technical its probably paraphrased from somebody who knows
2 nightmares when machining titanium, its terrible thermal conductivity and rapid work hardening. eg. saw thru ti too quick and you end up with a toothless saw blade
Titanium is a very poor thermal conductor, which can be a very good thing. However, I think an exhaust manifold is a poor application for the material. Plus, in an effort to keep it affordable, you have to use something like commercially-pure titanium; which is basically crap with a lot of impurities in it.
WHICH STAINLESS TO USE?
Within the 300 series of stainless steels, there are four types that are suitable, available and cost effective for the racer. These are 304, 316L, 321, and 347.
321 and 347 are known as stabilized grades of stainless. These are alloyed with either titanium (321) or columbium (347), both of which have a much stronger affinity for carbon than does chromium at elevated temperatures. This eliminates carbide precipitation leaving the chromium where it belongs for corrosion protection...remember our discussion of intergranular corrosion? Both 321 and 347 are top choices for exhaust headers, especially turbocharger systems and rotary engines. Since 321 is much more available than 347, that leaves 321 as the first choice, with no sacrifice in needed qualities.
316L is an extra low carbon (ELC) grade of stainless that has only .03% carbon, making less carbon available to precipitate with the chromium. It is used extensively in marine exhausts where salt water corrosion mixed with diesel exhaust particulates and electrolysis create such a horrible environment that even other grades of stainless cower and run away!
304 is the most inexpensive and available stainless in the 300 series. It is suitable for normally-aspirated header applications, and has been successfully used by many racing teams. It does not have the high temperature fatigue resistance that 321 does, but is considerably less costly and much more available. Most 304 tubing these days has the dual designation of 304/304L.
Practically speaking, there are overlapping applications of 304 and 321 stainless in header construction, but knowing you've got the insurance of the aircraft-grade 321 for the job is definitely worth consideration of the extra cost... if your application requires it.
Stainless steels come in both tubing and pipe sizes. Since certain pipe sizes are almost identical in dimension to tubing sizes, pipe may sometimes be substituted for tubing, and vice versa. Numerous wall thicknesses are available, but for headers, normally .049" (18-gauge) to .065" (16-gauge) is used.
Different specifications are used to meet particular requirements for the military (MIL), the American Society of Testing Materials (ASTM), and the Society of Automotive Engineers (SAE). Examples of what to look for when you order stainless tubing are as follows:
ASTM A-554 304 stainless is a welded mechanical tubing used primarily for ornamental purposes. It is not fully annealed and is work-hardened slightly in manufacturing. It has good column strength and good bendability. ASTM A-269 304 stainless is a general service commercial specification that is higher quality and is fully annealed for better ductility. It is available in both welded seam and seamless, and is a good spec for the racer to use. We have not seen any difference in longevity between welded seam and seamless stainless tubing in header use, but there is a substantial cost difference. The column strength is not as good as A-554, but it has excellent bendability with a higher cost due to the full annealing.
MIL-T-8808/8606\MIL-T-6737 321 stainless are military specifications for aircraft tubing. Suffice it to say that some MIL-specs are not necessarily better or even as good as some ASTM standards. There is no particular magic here.
There are as many uses for stainless steel as there are projects in the shop. There is nothing else that transmits an image of quality and skill to the majority of fabricators than a cleanly constructed stainless steel project. Whether it is a set of headers, intake stacks, or even a stand for one's dyno engine cooling fan, stainless steel has such great mechanical properties that its use should be considered for many projects beyond exhaust systems.
From- http://www.popularhotrodding.com/tec...d_header_tech/
Burns Stainless recommends Inconel 625 alloy for exhaust systems due to its excellent strength, corrosion resistance and fabricability. This alloy also exhibits high creep and rupture strength; outstanding fatigue and thermal-fatigue strength; as well as excellent weldability (though the guy welding it might have a different opinion!). Inconel 625 contains molybdenum and columbium, which stiffens and strengthens the nickel-chromium matrix without precipitation hardening treatments. Some hardening however does occur when heated to intermediate temperatures (1200 F to 1600 F) increasing room temperature strength. Also, this alloy retains over 75% of its room temperature strength at 1200 F. This alloy is available in a wide variety of forms including tubing, sheet, bar, plates and castings. Burns Stainless typically stocks welded and drawn Inconel 625 tubing. The tubing specification is SAE AMS 5581, Nickel Alloy, Corrosion and Heat Resistant, Seamless or Welded Tubing.
From-http://www.burnsstainless.com/TechArticles/Inconel_article/inconel_article.html
Click top link for spreadsheet comparison on the details of the metals, basically inconel pwns and is highly expensive. Second link is from burns.
If F1 uses it, it is the best, or a signifigant amount of money has changed hands to make sure it's used, either way its highly over engineered.
Scorke
Within the 300 series of stainless steels, there are four types that are suitable, available and cost effective for the racer. These are 304, 316L, 321, and 347.
321 and 347 are known as stabilized grades of stainless. These are alloyed with either titanium (321) or columbium (347), both of which have a much stronger affinity for carbon than does chromium at elevated temperatures. This eliminates carbide precipitation leaving the chromium where it belongs for corrosion protection...remember our discussion of intergranular corrosion? Both 321 and 347 are top choices for exhaust headers, especially turbocharger systems and rotary engines. Since 321 is much more available than 347, that leaves 321 as the first choice, with no sacrifice in needed qualities.
316L is an extra low carbon (ELC) grade of stainless that has only .03% carbon, making less carbon available to precipitate with the chromium. It is used extensively in marine exhausts where salt water corrosion mixed with diesel exhaust particulates and electrolysis create such a horrible environment that even other grades of stainless cower and run away!
304 is the most inexpensive and available stainless in the 300 series. It is suitable for normally-aspirated header applications, and has been successfully used by many racing teams. It does not have the high temperature fatigue resistance that 321 does, but is considerably less costly and much more available. Most 304 tubing these days has the dual designation of 304/304L.
Practically speaking, there are overlapping applications of 304 and 321 stainless in header construction, but knowing you've got the insurance of the aircraft-grade 321 for the job is definitely worth consideration of the extra cost... if your application requires it.
Stainless steels come in both tubing and pipe sizes. Since certain pipe sizes are almost identical in dimension to tubing sizes, pipe may sometimes be substituted for tubing, and vice versa. Numerous wall thicknesses are available, but for headers, normally .049" (18-gauge) to .065" (16-gauge) is used.
Different specifications are used to meet particular requirements for the military (MIL), the American Society of Testing Materials (ASTM), and the Society of Automotive Engineers (SAE). Examples of what to look for when you order stainless tubing are as follows:
ASTM A-554 304 stainless is a welded mechanical tubing used primarily for ornamental purposes. It is not fully annealed and is work-hardened slightly in manufacturing. It has good column strength and good bendability. ASTM A-269 304 stainless is a general service commercial specification that is higher quality and is fully annealed for better ductility. It is available in both welded seam and seamless, and is a good spec for the racer to use. We have not seen any difference in longevity between welded seam and seamless stainless tubing in header use, but there is a substantial cost difference. The column strength is not as good as A-554, but it has excellent bendability with a higher cost due to the full annealing.
MIL-T-8808/8606\MIL-T-6737 321 stainless are military specifications for aircraft tubing. Suffice it to say that some MIL-specs are not necessarily better or even as good as some ASTM standards. There is no particular magic here.
There are as many uses for stainless steel as there are projects in the shop. There is nothing else that transmits an image of quality and skill to the majority of fabricators than a cleanly constructed stainless steel project. Whether it is a set of headers, intake stacks, or even a stand for one's dyno engine cooling fan, stainless steel has such great mechanical properties that its use should be considered for many projects beyond exhaust systems.
From- http://www.popularhotrodding.com/tec...d_header_tech/
Burns Stainless recommends Inconel 625 alloy for exhaust systems due to its excellent strength, corrosion resistance and fabricability. This alloy also exhibits high creep and rupture strength; outstanding fatigue and thermal-fatigue strength; as well as excellent weldability (though the guy welding it might have a different opinion!). Inconel 625 contains molybdenum and columbium, which stiffens and strengthens the nickel-chromium matrix without precipitation hardening treatments. Some hardening however does occur when heated to intermediate temperatures (1200 F to 1600 F) increasing room temperature strength. Also, this alloy retains over 75% of its room temperature strength at 1200 F. This alloy is available in a wide variety of forms including tubing, sheet, bar, plates and castings. Burns Stainless typically stocks welded and drawn Inconel 625 tubing. The tubing specification is SAE AMS 5581, Nickel Alloy, Corrosion and Heat Resistant, Seamless or Welded Tubing.
From-http://www.burnsstainless.com/TechArticles/Inconel_article/inconel_article.html
Click top link for spreadsheet comparison on the details of the metals, basically inconel pwns and is highly expensive. Second link is from burns.
If F1 uses it, it is the best, or a signifigant amount of money has changed hands to make sure it's used, either way its highly over engineered.
Scorke
At the shop I frequent they have a collector from an 80's Jag F1 car sitting on the table in thier office.
I was shure it was titanium as it had 1.5~2.0 mm walls, was ridiculously light and has that ti kind of color and finish. Absolute work of art -tightest TIG work I have seen.
However when I asked them about it they confirmed it was in fact icconel.
I was shure it was titanium as it had 1.5~2.0 mm walls, was ridiculously light and has that ti kind of color and finish. Absolute work of art -tightest TIG work I have seen.
However when I asked them about it they confirmed it was in fact icconel.
ok, its good to get some info which this post was for. Inconel is what i am going to price out. Just want to have a little different products. Watch for our intake manifold with interchangable runners. You can change out to shorter of longer runners to change power.
inconnel can be made very thin as it's very strong and heat resistant. thin is better, less heat sink.
it looks different cast than it does formed in tubes.
you wouldn't want to make an intake manifold out of it... there's no real reason to. aluminum is just fine.
it looks different cast than it does formed in tubes.
you wouldn't want to make an intake manifold out of it... there's no real reason to. aluminum is just fine.
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alexyim
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Oct 17, 2005 12:26 PM
