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Discussion Starter #1
Just thinking of new ways to lighten up my new motor and overall vehicle weight and was wondering why I havent seen anyone using aluminum headers before. I would have to say my old headers done in all steel with the 1/2" flanges are pretty heavy. Is there any disadvantages to doing this? I searched pretty good around the net and couldnt find anything or applications where this has become prevelant.
 

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first thing that comes to my mind is that headers are in a very vibration prone area, and aluminum likes to crack under those conditions.

also the aluminum would act like a giant heat sink and dump all of the exhaust heat under the hood.

Justin
 

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what is the expantion rate of alum compared to steel? dont think they would last long and beleive it would burn up the gasket
 

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The first thing that comes to mind if they didn't quickly melt, they would likely start warping like crazy and fatigue rapidly since that amount of heat would seriously increase the aging rate of many aluminum alloys.
 

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Discussion Starter #5
I'm no metalurgist. How long would it take for these things to disintegrate because of the heat? It will be in my rear engine moonbuggy with no hood. Just sides. I was thinking about making them to the same spec of my current headers, just out of AL.
 

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They will melt.

If you want light start with some thin wall stainless
If you want lighter go with titanium
If you want even lighter go with very thin wall Inconel

For the money there are many other places to start shaving weight with the exhaust being very low on the list.
 

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I think you'd be surprised how hot your exhaust really gets. I wouldn't be surprised if it was hot enough to melt/damage a header. My advise is to just build a new steel header with lighter flanges. 1/2" is just stupid thick. I think ours are 1/4" and they dont weigh very much at all.

Dallas
 

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I would worry about other things weighing more than your headers. Most steel ones are pretty light compared to a lot of other things on your engine, i.e. heads, or even the block or intake manifold.
 

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Next time you are driving up a long mountain pass at night with a load, pull over and check under the hood. Good odds your header/manifolds will be cherry red. Imagine aluminum under the same conditions.
 

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You're exhaust can get enough to get a set headers red hot, that al is going to melt in ccertain conditions (improper engine tune), i'd go thin wall stainless and a 1/4" flange if you are really concerned, or the inconel would be just sick, but then again they would probably cost more than the entire rig lol.
 

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And if the buggy was drawing in fresh water from the lake to cool them, they would probably work. :D

Only application I ever heard of using aluminum exhaust manifolds were some of the "Swiss Cheese" lightweight Super-Duty Pontiac factory drag-cars from the early-60's. Yes, the aluminum manifolds saved weight, but if staging went too long, the headers would start to melt.
 

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damn I opened this hoping I could suggest inconel... Good call Triaged. Stainless .060 wall or so would fit your budget better than inconel I'm sure; but still might be more than you wanna spend for 10 lbs or so(at most) of weight. The SS headers on our 820ci pro stock motors weigh around 30 lbs IIRC. The flanges have to be 5/16" thick to stay even remotely straight(from experience). Why don't ya just get some stainless and get to tig'ing?
 

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water jacketed....
:p

I never said they would work for him, just throwing them up there. There is a set on Ebay right now bid up to 1500 bucks.

I think there are probably hundreds of better ways to save weight if a few pounds is that big of a deal to you.
 

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Those mountain motors there tnranger probably put out enough force out of the headers to twist the flanges if the bolts come loose lol.
 

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Discussion Starter #19
Good info guys. Was wondering why I never saw anything concerning AL headers and was wondering where the melting temp was. Now I know. Thanks.
 
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