Carbon Fiber Exhaust...

GreenPlease · 10-06-2008, 10:32 PM

Has anyone considered a carbon fiber cat-back exhaust? I did a

but found nothing. I have to think that there is potential for ~70lbs of weight saving by switching from SS to CF.

Anyone know the limits of the resin used for CF? I want to say 350C....

Thoughts?

GreenPlease · 10-06-2008, 10:35 PM

As an addition, the CF exhaust could be made in this manner:

1. Take a normal cat back exhaust
2. Wrap in CF, apply resin, let set
3. Cut the CF in half length wise
4. Put the CF pieces back together and wrap again with CF, apply resin

Probably missing some stuff as I've never worked with CF before, but its a start.

Amir87 · 10-06-2008, 10:36 PM

I don't know about CF but Titanium exhaust is a great alternative to save weight.

CF mainly used for looks on exhuast ie: tips.

Sniz · 10-06-2008, 10:40 PM

wow that would be expensive

GreenPlease · 10-06-2008, 10:43 PM

@Amir87

Titanium cat-back? I'd think that would actually be heavy... strong, but heavy. Aluminum's number on the periodic table is 13, Ti's is 22.

The exhaust isn't a load bearing structure, so as long as it can hold up to the pressure and heat of the exhaust gas (and occasional shock) you should be able to make it out of whatever is lightest.

Mr. 5 · 10-06-2008, 10:50 PM

I'm really curious with why someone would spend a good amount of money to dress up the underside of a car that nobody will see.

Scine CF is generaly used for weight savings, it's a little ironic how one would be adding weight to their car by adding the CF-not much weight but you get the idea.

wj4 · 10-06-2008, 10:51 PM

Quote:

Originally Posted by GreenPlease

@Amir87

Titanium cat-back? I'd think that would actually be heavy... strong, but heavy. Aluminum's number on the periodic table is 13, Ti's is 22.

The exhaust isn't a load bearing structure, so as long as it can hold up to the pressure and heat of the exhaust gas (and occasional shock) you should be able to make it out of whatever is lightest.

Titanium exhausts are thin and light..the downside is that they're pretty loud. I remember seeing a Titanium catback for an Evo getting weighted and it came out to be around 8 lbs.

GreenPlease · 10-06-2008, 10:58 PM

@Mr. 5

I think you misunderstood. My intent was for the exhaust to be exclusively CF, not a CF wrap, thus allowing for weight savings.

Mr. 5 · 10-06-2008, 11:01 PM

Quote:

Originally Posted by GreenPlease

@Amir87

Titanium cat-back? I'd think that would actually be heavy... strong, but heavy. Aluminum's number on the periodic table is 13, Ti's is 22.

The exhaust isn't a load bearing structure, so as long as it can hold up to the pressure and heat of the exhaust gas (and occasional shock) you should be able to make it out of whatever is lightest.

Are you serious?
What exhaust is made out of aluminum?

One would save an easy 50 pounds by changing out their Stainless cat back exhaust with a titanium exhaust.

An e46 M3 rear muffler in SS is bout 40 pounds.
The same exact muffler is 20 pounds in TI.

Mr. 5 · 10-06-2008, 11:02 PM

Quote:

Originally Posted by GreenPlease

@Mr. 5

I think you misunderstood. My intent was for the exhaust to be exclusively CF, not a CF wrap, thus allowing for weight savings.

Whoops, I re-read the process.
I jsut can't see it holding up though.
Is it possible?

EOE90 · 10-06-2008, 11:04 PM

what about louis voiutton wrapped exhaust?

LOLrance · 10-06-2008, 11:06 PM

Quote:

Originally Posted by GreenPlease

@Amir87

Titanium cat-back? I'd think that would actually be heavy... strong, but heavy. Aluminum's number on the periodic table is 13, Ti's is 22.

The exhaust isn't a load bearing structure, so as long as it can hold up to the pressure and heat of the exhaust gas (and occasional shock) you should be able to make it out of whatever is lightest.

i stopped reading after that. You really think titanium exhaust are heavy....

GreenPlease · 10-06-2008, 11:06 PM

I'm not sure, that's why I'm asking. Once again, I'm pretty sure the resin can hold up to 350C heat and I doubt corrosion or fatigue would be an issue. My biggest ? is to whether the exhaust gases are >350C after the cat.

BoostedBMW · 10-07-2008, 08:33 AM

Quote:

Originally Posted by wj4

Titanium exhausts are thin and light..the downside is that they're pretty loud. I remember seeing a Titanium catback for an Evo getting weighted and it came out to be around 8 lbs.

+1... we are talking about an exhaust that would most likely weigh less than 15lbs (dual mufflers for the 335) if it were made out of titanium. This car is a pig to begin with so to have to go through all of the trouble of making a custom CF exhaust (I have never heard of this to be honest) seems like it wouldn't be worth the trouble. BTW, what happens when a rock hits the undersite of your CF exhaust? I know that the CF diffuser on my s2000 took a whole month to crack.

In any case, does anyone even produce a full Ti exhaust yet for this car? I can't remember if it was JIC or some other JDM brand that I think produced one.

roadkillrob · 10-07-2008, 08:59 AM

I would worry about the heat after the CAT - cat's operate at internal temperatures of about 1300 degrees as the chemical reactions inside the cat are made to generate heat as it takes a lot of heat to break up the molecules in the emissions. I would also worry about turbulance as the inside of the carbon piping is pretty rough.

Rob

J.P. · 10-07-2008, 09:04 AM

U can buy Carbon fiber tubing. Most Aerospace wholesalers have them
just google it. Now the muffler may be a problem...

thegeneral101 · 10-07-2008, 09:05 AM

Quote:

Originally Posted by BoostedBMW

+1... we are talking about an exhaust that would most likely weigh less than 15lbs (dual mufflers for the 335) if it were made out of titanium. This car is a pig to begin with so to have to go through all of the trouble of making a custom CF exhaust (I have never heard of this to be honest) seems like it wouldn't be worth the trouble. BTW, what happens when a rock hits the undersite of your CF exhaust? I know that the CF diffuser on my s2000 took a whole month to crack.

In any case, does anyone even produce a full Ti exhaust yet for this car? I can't remember if it was JIC or some other JDM brand that I think produced one.

i agree with you, the cost would not "outweigh" the benefits

J.P. · 10-07-2008, 09:08 AM

http://www.dragonplate.com/

http://www.composite-resources.com/o...s/default.html

http://www.onlinemetals.com/merchant.cfm?id=1057&step=2

uberschnell · 10-07-2008, 10:00 AM

I'm not too sure how CF would handle the high-freq vibrations over the long term. Plus, the weight savings would be at the base of the car. Better to remove weight working your way down from the top, bigger bennefits.

Andras · 10-07-2008, 10:19 AM

Quote:

Originally Posted by Sniz

wow that would be expensive

+1, just think about the price of a Gruppe M air intake and how small such intake is in comparison with a 335i exhaust

NMS335 · 10-07-2008, 02:49 PM

Quote:

Originally Posted by BoostedBMW

In any case, does anyone even produce a full Ti exhaust yet for this car? I can't remember if it was JIC or some other JDM brand that I think produced one.

Does any one know who it was that produced one? The only one that I have seen is the Erricsson (Amuse) exhaust for the e92 m3.

Leebro61 · 10-07-2008, 09:02 PM

Just run an aluminum exhaust if you are interested in weight savings. You'll still need to run steel mufflers (if you plan on running any), so traditionally we do this by using mixed material V-band clamps. No, it won't melt and how long it will last will depend on the quality of the fitment and the welding. My brother ran an Aluminum downpipe on his SFWD car for a while without issue.

10-06-2008, 10:32 PM	#1
GreenPlease Lieutenant Colonel 146 Rep 1,629 Posts Drives: BMW 335i e92 Join Date: Feb 2008 Location: Orlando Florida iTrader: (2)	Carbon Fiber Exhaust... Has anyone considered a carbon fiber cat-back exhaust? I did a but found nothing. I have to think that there is potential for ~70lbs of weight saving by switching from SS to CF. Anyone know the limits of the resin used for CF? I want to say 350C.... Thoughts?
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10-06-2008, 10:35 PM	#2
GreenPlease Lieutenant Colonel 146 Rep 1,629 Posts Drives: BMW 335i e92 Join Date: Feb 2008 Location: Orlando Florida iTrader: (2)	As an addition, the CF exhaust could be made in this manner: 1. Take a normal cat back exhaust 2. Wrap in CF, apply resin, let set 3. Cut the CF in half length wise 4. Put the CF pieces back together and wrap again with CF, apply resin Probably missing some stuff as I've never worked with CF before, but its a start.
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10-06-2008, 10:36 PM	#3
Amir87 Gruppe Titan 279 Rep 2,839 Posts Drives: 08 E92 SG/Coral Join Date: Sep 2007 Location: NC iTrader: (37) Garage List 2008 E92 335i [10.00]	I don't know about CF but Titanium exhaust is a great alternative to save weight. CF mainly used for looks on exhuast ie: tips. __________________
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10-06-2008, 10:40 PM	#4
Sniz Lieutenant General 682 Rep 10,584 Posts Drives: e92 335 - gone // e36 M3 turbo Join Date: Mar 2007 Location: Ellicott City, MD iTrader: (1)	wow that would be expensive __________________
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10-06-2008, 10:43 PM	#5
GreenPlease Lieutenant Colonel 146 Rep 1,629 Posts Drives: BMW 335i e92 Join Date: Feb 2008 Location: Orlando Florida iTrader: (2)	@Amir87 Titanium cat-back? I'd think that would actually be heavy... strong, but heavy. Aluminum's number on the periodic table is 13, Ti's is 22. The exhaust isn't a load bearing structure, so as long as it can hold up to the pressure and heat of the exhaust gas (and occasional shock) you should be able to make it out of whatever is lightest.
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10-06-2008, 10:50 PM	#6
Mr. 5 Modder Raider 802 Rep 8,633 Posts Drives: M3 Join Date: Apr 2007 Location: Surf City, HB iTrader: (31) Garage List 2007 e90 335i [8.00]	I'm really curious with why someone would spend a good amount of money to dress up the underside of a car that nobody will see. Scine CF is generaly used for weight savings, it's a little ironic how one would be adding weight to their car by adding the CF-not much weight but you get the idea. __________________ e36 M3 Coupe, e36 325i Sedan e90 335i--SOLD Best 60-130-------------9.15 Seconds------------------WWW.MR5RACING.COM
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10-06-2008, 10:58 PM	#8
GreenPlease Lieutenant Colonel 146 Rep 1,629 Posts Drives: BMW 335i e92 Join Date: Feb 2008 Location: Orlando Florida iTrader: (2)	@Mr. 5 I think you misunderstood. My intent was for the exhaust to be exclusively CF, not a CF wrap, thus allowing for weight savings.
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10-06-2008, 11:04 PM	#11
EOE90 Colonel 135 Rep 2,427 Posts Drives: F15 Join Date: Mar 2006 Location: Laker City iTrader: (0) Garage List 2006 3 [0.00]	what about louis voiutton wrapped exhaust? __________________ E90 M3 -> F15 X5 M-Sport
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10-06-2008, 11:06 PM	#13
GreenPlease Lieutenant Colonel 146 Rep 1,629 Posts Drives: BMW 335i e92 Join Date: Feb 2008 Location: Orlando Florida iTrader: (2)	I'm not sure, that's why I'm asking. Once again, I'm pretty sure the resin can hold up to 350C heat and I doubt corrosion or fatigue would be an issue. My biggest ? is to whether the exhaust gases are >350C after the cat.
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10-07-2008, 08:59 AM	#15
roadkillrob Major General 892 Rep 5,475 Posts Drives: 08 335i,22 X3M, 2012 C63 Black Join Date: Jul 2007 Location: NH iTrader: (15)	I would worry about the heat after the CAT - cat's operate at internal temperatures of about 1300 degrees as the chemical reactions inside the cat are made to generate heat as it takes a lot of heat to break up the molecules in the emissions. I would also worry about turbulance as the inside of the carbon piping is pretty rough. Rob __________________ 2025 X5 Msport 2008 E93 335i FBO 2012 Mercedes C63 Black Series Alanite Grey
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10-07-2008, 10:00 AM	#19
uberschnell Brigadier General 680 Rep 4,077 Posts Drives: Wide Body 1 Join Date: Mar 2007 Location: Bay Area iTrader: (48)	I'm not too sure how CF would handle the high-freq vibrations over the long term. Plus, the weight savings would be at the base of the car. Better to remove weight working your way down from the top, bigger bennefits.
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10-07-2008, 09:02 PM	#22
Leebro61 Private 1 Rep 58 Posts Drives: e92 335i Join Date: Jan 2008 Location: Greenville, SC iTrader: (0)	Just run an aluminum exhaust if you are interested in weight savings. You'll still need to run steel mufflers (if you plan on running any), so traditionally we do this by using mixed material V-band clamps. No, it won't melt and how long it will last will depend on the quality of the fitment and the welding. My brother ran an Aluminum downpipe on his SFWD car for a while without issue.
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