jet coating hardpipes?

[pb4ugoout]

is this something i might want to do? would it be beneficial? i want to buy pipes soon but have no idea which i want. steel or aluminum? i have no clue. not really looking for advice on what i should get, don't want this to be a "this one is better than that one" thread but i'm wondering if jet-coating some steel pipes would be just as good as aluminum pipes. i really have no clue. just trying to toss around some ideas. flame wars over who's product is better are just lame and not what i'm looking for. all other input is appreciated

[Captain KRM P5]

mental addiction does this if i am not mistaken

[jurgs01]

Aluminum has better heat dissapation properties than steel, doesn't corrode like steel, and is lighter than steel. Manufacturers use mild steel because it is cheaper and thus they can give you better prices.

You will never be able to claim that mild steel is as good as aluminum for the intake piping. Is this enough of a difference to justify the price difference. For me it is. For others it is definately not. It's up to you.

[Striker187]

ok check me if i'm wrong on this but if the piping material conducts heat better/faster (i.e. better heat dissipation properties) then you do NOT want to use that as your material if you're trying to keep the inside cool. your heat sink is the interior of the pipe, not the engine bay. aluminum will simply dissipate (conduct) the heat it absorbs from the engine to the piping interior.

now i know jet-hot coating insulates piping so i imagine this will keep heat out as well as it does keeping heat in. sounds like a good idea for the hardpipes.

[kicker22705]

my ic pipes are ceramic coated mild steel. as far as rust, dont' worry about it, its coats it both inside/out.

[pb4ugoout]

now i know jet-hot coating insulates piping so i imagine this will keep heat out as well as it does keeping heat in. sounds like a good idea for the hardpipes.

^^thats what i was thinking....and can you jet-coat aluminum pipes???

[kicker22705]

^ maybe for the turbo-ic pipe, but from ic-tb pipe, it would keep the cooler air in and the hotter engine bay heat out.

[Striker187]

and can you jet-coat aluminum pipes???

not a clue. i don't see why not.

[Rainman]

ok check me if i'm wrong on this but if the piping material conducts heat better/faster (i.e. better heat dissipation properties) then you do NOT want to use that as your material if you're trying to keep the inside cool. your heat sink is the interior of the pipe, not the engine bay. aluminum will simply dissipate (conduct) the heat it absorbs from the engine to the piping interior.

now i know jet-hot coating insulates piping so i imagine this will keep heat out as well as it does keeping heat in. sounds like a good idea for the hardpipes.

^^^Yep, aluminum is less favourable in terms of heat conduction and thus dissipation. Mild steel is better in this regard. However, aluminum is substantially lighter than is mild steel and with aluminum piping you get a reduction in weight. Now, does weight reduction and corressponding increase in performance from aluminum piping (due to the improved power-to-weight ratio) outweigh the loss in performance (due to less favourable heat-dissipation/thermal protection) associated with aluminum piping. That all depends on the length of tubing used, the diameter of the tubing, the wall thickness of the tubing, and the design of the tubing (which affects the turbulence of the flow of the enclosed gases). Not to mention, aluminum is harder to weld and more expensive to purchase. For all of these reasons mild steel is acceptable for most people. Once powder/jet-coated, you get the performance aspects as well as the durability.

For the record, aluminum corrodes just like mild steel. However, aluminum oxide, the byproduct of aluminum rust, is super-hard and near-colourless. This means that once aluminum starts to rust it gets covered with a microscopic layer of super-hard aluminum oxide which ironically protects the piece of aluminum and effectively stops the rusting process from progressing any further.

R

[Striker187]

i thought aluminum oxide dulls the surface? good info though. the same happens with ss and titanium.

[pb4ugoout]

so maybe coated steel parts are just as good/maybe better than aluminum pipes? i really don't think the weight gain from the steel would be enough to make a difference in movement numbers so weight isn't really going to be a factor in my decision. i simply like the look of aluminum much better. however the price of steel is mighty tempting

[Striker187]

well u could always chrome your pipes instead....:)

[jurgs01]

ok check me if i'm wrong on this but if the piping material conducts heat better/faster (i.e. better heat dissipation properties) then you do NOT want to use that as your material if you're trying to keep the inside cool. your heat sink is the interior of the pipe, not the engine bay. aluminum will simply dissipate (conduct) the heat it absorbs from the engine to the piping interior.

now i know jet-hot coating insulates piping so i imagine this will keep heat out as well as it does keeping heat in. sounds like a good idea for the hardpipes.

The metal steel gets hot and retains heat. Thus, it is constantly heating up the inside constantly. The heat dissapation from the aluminum pipes allows them not to get hot (as much), thus the inside air isn't as affected. Do you think firefighters use steel equipment? You can do what you want, but that is just basic materials.

[pb4ugoout]

maybe aluminum pipes and jet coat the cold pipe to keep the heat out of the pipe. leave the hot pipe alone. i guessing that keeping the heat in the hot pipe isn't a good idea either cuz then the air wouldn't get as cool when it goes through the intercooler

[Striker187]

The metal steel gets hot and retains heat. Thus, it is constantly heating up the inside constantly. The heat dissapation from the aluminum pipes allows them not to get hot (as much), thus the inside air isn't as affected. Do you think firefighters use steel equipment? You can do what you want, but that is just basic materials.

ok we need to clarify something here....what is the temperature of the intake charge? if it is cooler than the engine bay temperature, you want to use the best insulator to keep the intake charge cool.....thus you want the poorest conductor of heat. if the intake charge is hotter than the engine bay temperature, you want to conduct as much heat away from the intake as possible....thus you want a good conductor of heat.

besides, if the aluminum pipes dissipate heat so they don't get as hot, where do you think that heat is going? to the engine bay? only if the engine bay is cooler than the intake charge (which i hope it is not). but otherwise, you can look at the system as a double wall heat exchanger. sure the aluminum will dissipate heat, but it will do so by dissipating heat into the intake stream since this is the cold stream. that's just basic heat transfer mechanics.

[jurgs01]

Heat also dissipates out to. This is most important AFTER the turbo. The air is moving too fast for the heat coming in to significantly heat it up. The air from the turbo-IC is HOT. It is better that some of that heat energy is dissipated.

[pb4ugoout]

this is good stuff...didnt think i would get this many responses. although i still don't know what i want to do

[Striker187]

Heat also dissipates out to. This is most important AFTER the turbo. The air is moving too fast for the heat coming in to significantly heat it up. The air from the turbo-IC is HOT. It is better that some of that heat energy is dissipated.

ok i'm with u on the turbo to ic piping if the air is indeed at a higher temp than that of the engine bay. if that is the case, it would be best to use aluminum to dissipate this heat....however, the length of this pipe is very short so i don't think there would be much of a difference in intercooler inlet temperatures. however, the length of the piping from the intercooler to the throttle body is longer so insulating this air charge would be beneficial, thus steel would be best.

so i guess the ideal setup would be aluminum from the turbo to the intercooler and steel from the intercooler to the throttle body. i managed to talk with my materials prof today about it and he is in agreement with me :). glad to know i'm not going crazy.

[peepsalot]

How hot is the average engine bay? Depending on how much you boost, and how efficient your IC is, the air in the "cold" pipe may still be hotter than the engine bay (shrug).

[jurgs01]

ok i'm with u on the turbo to ic piping if the air is indeed at a higher temp than that of the engine bay. if that is the case, it would be best to use aluminum to dissipate this heat....however, the length of this pipe is very short so i don't think there would be much of a difference in intercooler inlet temperatures. however, the length of the piping from the intercooler to the throttle body is longer so insulating this air charge would be beneficial, thus steel would be best.

so i guess the ideal setup would be aluminum from the turbo to the intercooler and steel from the intercooler to the throttle body. i managed to talk with my materials prof today about it and he is in agreement with me :). glad to know i'm not going crazy.

I agree with you there wouldn't be much difference either way. I personally wouldn't use mild steel, but that's just my preference. SS would be a decent choice for that pipe, but it's heavy (relatively). My ideal conclusion would be both pipes aluminum with the IC-TB pipe coated. All exhaust piping and manifolds SS.

[jurgs01]

this is good stuff...didnt think i would get this many responses. although i still don't know what i want to do

We're arguing about something that isn't going to make you see a few degrees of difference either way (the air speed keeps it from absorbing much heat). I would go with either SS or aluminum for the pipes (corrosion resistance), and getting the IC-TB pipe coated would help, but I'm not sure it's worth the price.

[peepsalot]

We're arguing about something that isn't going to make you see a few degrees of difference either way (the air speed keeps it from absorbing much heat). I would go with either SS or aluminum for the pipes (corrosion resistance), and getting the IC-TB pipe coated would help, but I'm not sure it's worth the price.
Header wrap is cheaper than jet-hot, if you don't mind the look of it.

Or maybe just get CF hardpipes, I imagine they wouldn't conduct heat well. Someone just came out with a CF CAI and SRI, so maybe hardpipes are not far away...

[Striker187]

We're arguing about something that isn't going to make you see a few degrees of difference either way (the air speed keeps it from absorbing much heat). I would go with either SS or aluminum for the pipes (corrosion resistance), and getting the IC-TB pipe coated would help, but I'm not sure it's worth the price.

indeed. at the very least, use mild steel that's been coated.

[pb4ugoout]

after thinking about it i also saw the ideal setup as both aluminum with the IC-TB pipe coated. anyone know how much it costs to get something jethot coated? i want to do my heat shield as well

[jurgs01]

http://www.jet-hot.com/pages/getestimate.php

[jurgs01]

That's gonna be expensive, but if you can afford it... I may even do it to when I send some other things to be coated.

[RyanJayG]

one thing to think about is expansion of the pipes. Aluminum expands a lot more than mild or stainless steel. Cast Aluminum isn't so bad and this is why ceramic coating cast pistons is a good idea, but I've always felt coating forged pistons is a bad idea because the expansion can cause the ceramic to crack and flake off. that being said, make sure you get a ceramic coating with a high flexability so it doesn't crack off.... that could kinda look crappy.

*edit*

one more thing, I would suggest you try someone local. Jet-Hot is SOOOOO SLOW!!!! simply because they are the most famous and are usually backed up for work.

[pb4ugoout]

i wasn't aware that other people did this...who would i look for to get it done

[RyanJayG]

http://www.google.com/search?hl=en&lr=&q=%2Bceramic+coating&btnG=Search

or you could narrow the search to South Carolina.

honestly there are HUNDREDS of places that do ceramic coatings, usually with a few options for color.

[jurgs01]

True. The thermal expansion for basic aluminum is ~ 24ppm/degree C while steel is ~13ppm/degree C. So, with pieces of steel and aluminum heated to the same temperature the aluminum will expand roughly twice as much. I don't think you will get it hot enough to crack the coating though.

[pb4ugoout]

i'll have to see about this stuff. i just dropped 1000 on new tires and brake rotors so i'm spent for a while. but when i get around to hardpipes (next large purchase) i think i'll have the coldpipe coated. does anyone know if there is any kind of finish i can put on the hotpipe to make it match the finish of the ceramic coating on the cold pipe? just don't want to have mismatched parts under the hood

[Rainman]

Although this is probably heresy I have wondered about mild steel hard pipes, but with a single layer of CF surrounding them. Riles has just come out with his CAI and SRI out of CF and is planning to do the hardpipes in the future, however it will be some time before he does this. I imagine that CF hardpipes will be somewhat more costly since longer runs of piping are necessary and the path is more convoluted...thereby requiring a more complex mold. In addition, since multiple layers of CF are needed for structural rigidity, the cost of the product is increased with each layer of CF added to the structure.

In considering this problem (and in constructing my own mold for a CF CAI) I thought about the "ideal" mold. The ideal mold would be the actual piping itself. This way you get the best conformity between the mold and the cast. However, what would happen if you used the mild steel piping as both the final product AND the mold. This is to say, what if the final product was a mild steel hardpipe with only a single layer of CF bonded to the outside. This would have several benefits.

First, cost would be lower than that of a a completely CF hardpipe. Second, structural rigidity would be maintained by the mild steel so that only a single layer of CF was required. Third, the conformity of the CF would be at its best since it was to the actual piping itself, and since it didn't need to be cut off the pipe. Fourth, you would obtain some of the heat conduction resistance that the CF provides to counteract the conductivity of the mild steel.

Downsides are only few as I see it. First, the cost would be higher than mild steel pipes only, albeit lower than that of CF pipes only. This could be offset somewhat by using a thinner guage of mild steel since the CF contributes to rigidity. Second, the weight of the final product would be higher than the weight of both mild steel and CF piping. However, using the same tactic as mentioned above, weight savings could be won back by using a thinner guage of hardpiping for the mold or core of the piping. Those are the major issues as I see it.

What do you think? This could be an alternative to jet coating which could achieve the same end at a fraction of the price while looking bad-ass doing it.

Thoughts?

R

[jurgs01]

Insides still rust, especially if you have a CAI. Plus they are heavier than other options. There are some ceramics (plastics) out there that would be the best material, but are WAY too expensive.