CF Intake Tubing?

[Shoeless]

Hey guys,

Random question for the group. I don't see a lot, or really any, people using carbon fiber tubing for their air intake setups. Is there any particular reason or am I missing something? Too much heat in the engine compartment?

I'd like to piece together a nice 4" diameter CF tubing setup for my air intake and figured I'd pose the question while I'm getting rather bored working from home.

Thanks

[jamesfr58]

Sean,

Heat can be an issue if the CF is not designed and manufactured to take a high heat environment. Here is what I found a while back looking at construction materials aluminum vs carbon fiber...

Carbon fiber is a material with low heat conduction characteristics.

Carbon fiber thermal conductivity

Heat conduction mainly depends on transfer/conduction of energy from areas of high temperature to areas of low temperature. Highly heat conductive materials transfer temperature more easily than materials with low heat conductivity.

Composite made from carbon fiber and epoxy resin is a material with heat conductivity x 40 times less than aluminum and 10 times less than steel. Therefore, the assumption may be made that carbon fiber is a particularly good insulator.

This table compares heat conductivity of different materials– including carbon fiber (Unit W/m*)

Material Heat conduction
Carbon fiber– epoxy composite 5-7
Steel 50
Aluminum 210

Resistance to temperature

Aluminum is a material with resistance to high temperatures, and in this regard, it offers advantages over carbon fiber composites.

Carbon fiber performance and resistance to high temperatures depends on the composite structure and baking technology. It is true that carbon fiber composite is resistant to high temperature, but unfortunately that is often not the case. It results from improper materials, improper baking of the composite or insufficient know-how and experience in this regard by many composite suppliers.

To ensure resistance to high temperature, only materials may be used during manufacture that demonstrate such resistance, provided that composite baking is carried out properly in the range of temperatures like the desired resistance of the composite. Use of resins resistant to high temperatures, without additional hardening inside the oven, will not provide the required resistance.

Standard epoxy carbon fiber composites that underwent proper baking feature resistance up to 70-100 °C (160-210 °F).
If resistance is required to temperatures over 100 °C, most often carbon fiber prepreg is appropriate, often along with hardening of the composite at temperatures around 150°C/300°F, which enables improved resistance up to temperatures of 200°C/400°F. For example, Prepreg Gurit EP127 features resistance up to 230°C/445°F.

If resistance is required to higher temperature, phenol resins are used and these composites feature momentary resistance up to 500°C/930°F.
Resistance can be ensured for composites, note that these special materials are costly and require not only hardening in a furnace at high temperature, but know-how as well. Therefore, all of this results in a high price for composites that are resistant to remarkably high temperatures.
Long term performance

When used for construction, the carbon composite should be manufactured with the vacuum method – resin infusion or prepreg. Such technology ensures long service life of the carbon composite. Carbon composite made manually with “a roller and brush” has poor strength and short service life.
Carbon fiber has corrosion resistance, which offers another advantage compared to aluminum.
Carbon fiber– epoxy composite has disadvantage that relate to reduced resistance to UV radiation, and therefore the composite exposed to UV radiation should be protected by top coat application, which, as an additional process, makes for higher production costs.

Production implementation

Why is carbon fiber is not widely used in production runs although it offers many advantages over immensely popular aluminum?
Most often it is caused by price: carbon fiber elements cost more than aluminum ones because carbon fiber costs more and the manufacture of carbon products is more time consuming.

On the other hand, when comparing costs related to implementation of aluminum and carbon fiber production, in many cases it is the production of the carbon fiber element that will be cheaper and, more importantly, affordable in case of a small run, for which implementation of aluminum element production would not be cost-effective.

With time, more and more design engineers will make use of this material, as carbon fiber offers many advantages including light weight, practically zero heat expansion, easy machining and high rigidity.

[Perkster029]

I wonder if there's any possibility of the clear coat yellowing with the high temp exposure?

Would you do the entire intake tubing system, elbows included? That sounds like a whole sub-project of its own.

[HardRocker]

Maybe try some stainless exhaust tubing then skin it with CF using a high temp epoxy. btw I’ve seen a bunch of CF air cleaners. Google for images.

[Shoeless]

James,

Wow that was a hell of an answer and exactly what I was looking for. I was going to reach out to several suppliers and start with what temps they are rated to. I'm figuring a reputable company would easily have this available and shoot that right over to me. From there I'll be able to determine if it will be cost effective for what I'd like to go for.

Ryan,

Yup, looking at the entire intake tubing system. I was looking at doing a dual 4" full CF setup, but I can't seem to locate anyone that does a "Y" split. I assume tooling to make that would be significant. So I'd have to work with everything up to 90 deg.

If you think this is a large sub project, you should see the engine harness I'm building LOL. My pool table in the house is currently home to inventorying all the needed components. Although I have a rough idea of what I have spent so far, I don't want to add all the receipts up. It's STAGGERING to say the least.

[HardRocker]

I was looking at doing a dual 4" full CF setup, but I can't seem to locate anyone that does a "Y" split. I assume tooling to make that would be significant. So I'd have to work with everything up to 90 deg.

There is a YouTube channel called Easy Composites Ltd that has a few videos on making CF tubes in odd shapes. Takes alot of mold making but they show you step by step. Which is why I mentioned doing the intake in SS tubing (which is very heat resistant) and for the CF look to simply skin it.

Or, if you really wanted to go there, you could form your shape in SS tubing, slice it in half lengthwise, and use that for the split mold.

And, another thought. Ping Easy Composites and ask about them about making it for you. If you do, retrieve the molds you pay for so you can have them used for making more sets. https://www.easycomposites.co.uk/#!/composites-tutorials/split-mould-carbon-fibre-tube for the CF tube making video.

[beeman]

I remember watching a Koenigsegg YouTube video, beyond our abilities but pretty cool. He talks about the CF tubing around the 2:00 mark...


https://youtu.be/504I_hJDFck

[Shoeless]

This is all some really cool stuff. Give me plenty of videos to watch and some reading to catch up on.

So what temperature limit do you guys think I would have to work with? I've found a vendor with offerings in the 250-275 deg temp rating range with reasonable prices. There may be one spot where the intake comes close to my Kook exhaust.

[beeman]

I think the bigger issue than the carbon getting damaged by heat is the thermal conductivity increasing your AITs and you losing power? I'd probably stick to aluminum tubes with CF skin.

[HardRocker]

There may be one spot where the intake comes close to my Kook exhaust.
My heads are coming off for inspection and rocker upgrade but I have the kooks with the y shaped cai. If it was running I’d laser shoot the temps for you. So who is around with the setup that can take some readings?

btw that Easy Composites place has resin good to 338f. There has to be a place in the US with the same or an even higher temp aerospace type material.

Beeman and I agree on skinning but I’d use stainless exhaust tubing since the mandrel bends are available for you to make your shape and have someone weld it together for you. Tack welds from a mig would work then ground down flush to be CF skinned which would seal the tubes.

[Shoeless]

Am I interpreting James' post on thermal conductivity of CF 40x less than aluminum tubing incorrectly? Sounds like the CF would outperform aluminum tubing with respect to thermal conductivity.

Hardrocker, thanks for the tip on Easy Composites. I'll have to read up on the specs some more. There are all kinds of acronyms I'm not familiar with here. Especially "To achieve 170°C HDT, follow post cure cycle in TDS."

[beeman]

Am I interpreting James' post on thermal conductivity of CF 40x less than aluminum tubing incorrectly? Sounds like the CF would outperform aluminum tubing with respect to thermal conductivity.



Yeah, I read that backwards, sorry

[Shoeless]

Yeah, I read that backwards, sorry

No worries.

[aquillen]

Carbon fiber intake in my 818 project here:

https://thefactoryfiveforum.com/showthread.php?20434-Art-s-818-build/page2
starting at #67

and more at:

https://thefactoryfiveforum.com/showthread.php?20434-Art-s-818-build/page3
starting at #95

and at:

https://thefactoryfiveforum.com/showthread.php?20434-Art-s-818-build/page6
entry #238

The resin used - FibreGlast 309 (System 3000). Rated for 300F service after proper baking. Clearcoated for appearance with Duplicolor engine clearcoat. Aluminum to resin interfaces bonded with 3M '2214 Hi-temp new formula' 1 part epoxy, service temp up to 350. This is also bake cure cycle. Vacuum formed parts except for the upper air filter plumbing - hand layup there. The intake is designed with "blow off poppet valves" in case of intake back-fires, and is not suited to forced air - natural asp only.

No previous experience with the products but probably did about 100 hours research using mfr data and general WEB reading which I consider anectdotal only - I don't trust blog data unless the info is intuitively obvious or properly referenced. For bonding, I did rather extensive testing with 6 epoxy glues claiming higher temp performance, JB Weld, Loctite and others. The 3M above excelled over the others. It is expensive but the project warranted the cost.

I've had the engine up to temp a number of times with no issues apparent in the intake to date. Only time and use will prove this one way or the other.

By the way - Beeman - read your project a couple days back - love your work. Hooser's rock !

[Shoeless]

Aquillen,

Thanks for sharing, I’ll have to read up on your post and gain some knowledge on this.

[HardRocker]

Very very nice work Art. I too am a fan of the Falcon F7 episode of Dream Cars. I’ve got all of them archived. I imagine Falcon can have those made now for pennies on the dollar since all the r&d and molds are all done.

[Jake From State Farm]

Is it funny that I was going to post the Koenigsegg video until I saw bee’s post, and I’m not at all surprised that Art already went there on his 818 build? I love the brain trust here!

Shoeless, you don’t see this as often because it requires a greater knowledge (and capability) to do correctly. This almost always means working with a two part mold and pre preg cured in the autoclave. That combination can quickly exceed or overwhelm the average enthusiast. James nailed it.

[beeman]

Carbon fiber intake in my 818 project here:.

Somehow I have missed your build thread! Amazing stuff, love the fabrication! I'll be reading through the entirety of it ASAP!

[beeman]

Maybe you have seen this


https://youtu.be/bBbOUDDJv4Q

[Shoeless]

That was an excellent video on how to make complex tubing. I've got to check out there other rolled tubing video as well. The part that hangs me up is the vacuum oven to cure the pre-preg parts in. I'm sure I could jimmy something together to make it work, its just the size and availability of space in my garage. I've got to read up on Art's process, maybe he has something figured out that's pretty straight forward.

I'm thinking for my intake tubing, I'll just buy some already done up that are rated at 250-275 deg F and just let it ride and see what happens.

I'd still love to tackle a rear hatch piece to replace the rear hatch glass all out of CF one day. Now that I'd be willing to put some serious time and money into to make a one off piece. Not sure if I'm too ambitious on this, but I'm sure with enough research, practice, and a solid plan, I can make it happen.

[Perkster029]

That was an excellent video on how to make complex tubing. I've got to check out there other rolled tubing video as well. The part that hangs me up is the vacuum oven to cure the pre-preg parts in. I'm sure I could jimmy something together to make it work, its just the size and availability of space in my garage. I've got to read up on Art's process, maybe he has something figured out that's pretty straight forward.

I'm thinking for my intake tubing, I'll just buy some already done up that are rated at 250-275 deg F and just let it ride and see what happens.

I'd still love to tackle a rear hatch piece to replace the rear hatch glass all out of CF one day. Now that I'd be willing to put some serious time and money into to make a one off piece. Not sure if I'm too ambitious on this, but I'm sure with enough research, practice, and a solid plan, I can make it happen.

I know Shane has a spiffy looking version of that... http://vraptorspeedworks.com/rear-hatch-glass-replacement-panel/

[Shoeless]

I know Shane has a spiffy looking version of that... http://vraptorspeedworks.com/rear-hatch-glass-replacement-panel/

Not going to lie, Shane's hatch replacement is a sharp piece for sure.