aluminium exhaust, a good idea?

[oldcorollas]

I wouldn't say that. In dyne testing we have a bigger exhaust than standard, which flows alot better, we control backpressure with a valve at the end of the exhaust. Anyway point it we would easiler get the manifold glowing red/orange and also a good almost 2 meters of the exhaust too. Obviously this is at sustained peak revs tough,a good 7,200 from a V6 for say 2 mins. The colour does stay for the majority of the test though, just not as intense.

little side note that I find interesting is when we test some of the v6 turbo you can literally see though the exhaust side of the Turbos. now that was really cool the first time I saw that!

if you don't control backpressure does it still heat up so much?
i guess in the real world. you will not be sitting on limiter for 2 minutes (except for burnout comps )

i wonder about that claim of seeing thru the exaust side of turbos...
i have furnaces here that go up to 1800 or 2000 deg, which is well into white hot region.... and i have never "seen thru metal" yet...
how does it work? the matel does not magically become translucent....

hmm

(big pic)http://img.photobucket.com/albums/v2.../TurboGlow.jpg
(edit, second pic is same as first, but someone has "hottified" it )

[wombat]

We control the backpressure beacause we don't run the full car exhaust we have a shorter modified version. So the backpressue is controled so that it matches the pressure the standard exhaust in the car would produce.


Don't get me wrong its not like looking through glass, and it is generally about 2 mins before it blows. mainly on proto type parts, also if I remember the engineer messed up the ecu program and instead of the normal 8psi he ran somwhere near 30psi out of the turbo.

It goes white then if you look closely you can see the blades rotating inside the turbo.

[oldcorollas]

We control the backpressure beacause we don't run the full car exhaust we have a shorter modified version. So the backpressue is controled so that it matches the pressure the standard exhaust in the car would produce.


Don't get me wrong its not like looking through glass, and it is generally about 2 mins before it blows. mainly on proto type parts, also if I remember the engineer messed up the ecu program and instead of the normal 8psi he ran somwhere near 30psi out of the turbo.

It goes white then if you look closely you can see the blades rotating inside the turbo.

rotating? but they are spinning like maybe 70,000-100,000rpm??? all you should be able to see if a blur if anything..
at that temp, heat loss is fast so if there are any relative cool spots inside, it will show up on the outside....

anyway, i am yet to see a translucent metal
when white hot, it looks different, but aint see thru (but i would like to see what you have tho )

edit, read this http://www.physicsforums.com/archive...p/t-99658.html

That illustrates a two pretty major flaws in the reasoning of the guys on that site, btw: If heating metal made it translucent, it would still require an intense source of light behind it to see through it - you wouldn't even see it through a micrometer solar filter, so how could you see it through a centimeter of steel? And, any metal parts inside the turbo wouldn't be putting out much more light than the casing, so they wouldn't be visible even if it was completely transparent but emitting light itself (which, as the pics of hot glass showed, isn't really possible anyway).

[oldcorollas]

hey i just did a quick test.... i put two bits of metal in furnace (mayne 3mm thick nickel?)

one was in centre at 1200C, the other was a bit closer to me at 1100C..

this is hotter than you get in a turbo

metal aint transparent .. the bit of metal closer to me still looks 1100C... and when i look from the other side, the 1200C one still looks like 1200C.....

so how is this turbo thing meant to work?


edit, however the surface of the metla DOES "look glassy" but this is due to the light being emitted and the reflection that still occurs....
also..when i use the arc melter (it must go above 2500-3000C cos it melts stuff like niobium and tungsten)) that shit is HOT, btu it aint see thru..

[wombat]

Don't take the "see it rotating" so literal. its like sayig you can see an engine on a big ass plane, you can see the engine rotating, but not literally see the blades and stuff spining, you just know it is and can see the blur.

Anyway no idea how it works, after all I'm just a mechanic. who knws could have been a shit quality turbo cos is was proto, only saw it once though.

I ike that you can just throw metal in a furnace, thats so cool. lol

[Billzilla]

It's just heat shadows that you're seeing.
Makes it look like you're seeing the turbine but you're not.

[wombat]

And all this time I thought I wasn't delusional. Lol.
Fair enough though.

[4DaDrift]

Edited Post.

[oldeskewltoy]

edit, aluminium boat exhaust manifolds for V8's? water cooled no? but they have zinc anode (due to water... not the exhaust)
http://www.boatstoreonline.com/glmexhaust.html
http://www.boatstoreonline.com/images/c6_12_1_.jpg

Hmmm, so in theory you could make a copy of the OEM manifold(NOT header)... but in whatever alloy these were cast from???
How hard would it be to include a cooling jacket around the manifold? Could you use a laminova cooler, or would you use the cars cooling system?

[oldcorollas]

well, the main issue is having a constant stream of cold water.. ie.. river, lake, ocean.. that sort of thing.
the manifold might be a pre-heater fro water that goes into the block also, but it all depends on having a constant stream of cold water..

i don't think any form of radiator etc would be enough to reject that amount of heat?

[river]

Hi,

i am yet to see a translucent metal

Yeah, it was in one of the Star Trek films, where Scotty gave the formula to some dude so they could make transparent aluminium. They made a big tank inside the space ship, where they beamed up some whales and water.

Then they went forward in time and dumped the whales into the ocean, which stopped some manically modified Voyager space probe from destroying the earth.

Well... I think that's how it went.

seeyuzz
river

[oldcorollas]

i remember that episode

i was cringing...

[Billzilla]

Here ya go.
http://www.ingentaconnect.com/conten...00001/05106962

(Unless the word 'translucent' is being used in some other way that I'm not familiar with)

[oldcorollas]

no cigar that is aluminium nitrides... ceramics...

[Moppitt]

*Snaps fingers* that explains why Aluminium Oxide as Sapphire hasn't shown up in this discussion yet... Was wondering why that was...