A/R in turbo's?

[GWInquisitor14]

You know i was thinking about this also today, what if you got one cermaic coated, wouldnt that help it from cracking because the ceramic material will be able to handel a lot of the heat. Cermaic matterial is heated up to 1800° just to make it solid so im sure it will be able to handle the exhaust

[duplox]

This is from corky bell's book 'maximum boost'.

yeah I think ceramic coating headers helps not only keeping them from cracking but also improves performance. I'm in the midst of an arguement on this on another one of these threads. Join in if ya like.

[GWInquisitor14]

Oh i know the design is better with the steel, i posted that before. Thats why I've been so torn between the two. Ya your definatly right though those steel ones, like the ones for 180 you see on eBay, are made of the 304 steel mig welded, i went on eBay today and sure enough thats what it said. It also said high grade steel, lol. Today I first learned how to TIG weld from my friend so that will come in handy, maybe I will consider making my own or having him help me. Hes a god when it comes to that, hes made his own bed and entertainment center. Anyways, i think the cermaic coating will help due to its structure and ability to "absorb" head (cant think of the word) What is that book that that page is from?

[duplox]

Ceramic doesnt aborb heat, it reflects it. It is a very very good insulator, so it keeps the heat in the exhaust and not in the header. Thats why you should have it ceramic coated on the inside as well as out.

[GWInquisitor14]

oh ya good point, but that would create a thinner pipe. Would it still help it not crack?

[duplox]

how would it make it thinner? its a coating that goes on the outside of the metal.

[DeleriousZ]

i think he means thinner by the fraction of the inch/cm that the ceramic would decrease the pipe size by... i'm sure it's not big enough difference to make a uh... difference.. lol

[duplox]

ceramic/aluminum coating cant be much more than .01" thick, if that. Probably less than half of that.

[DeleriousZ]

yeah that's what i was thinking.. how expensive is it to get done?

[DeleriousZ]

Originally Posted by boosted331

If you're going to build a header like that, you might as well buy a mass-produced cast one. That header doesn't have a merge collector, which right there pretty much nullifies all the benefits from a tubular header.

what type of header do you suggest constructing? and how would a merge collector be constructed.. also, where would the wastegate pipe go?

[GWInquisitor14]

Ya i was wondering that too about the wastegate flange. Would you have to use a turbo with a built in one cuz ive heard that isnt as good as having one built into the piping. Also, isn't there a collector like that \_/ shaped thing that attachs to the 4 main pipes? Couldn't you just kinda drill a whole and weld on a part for the wastegate

[DeleriousZ]

yeah, i definitely would NOT go with an internal wastegate, there are too many issues with boost creep and all that ugly stuff to even bother with it.. external wastegate is definitely the way to go. yeah that's what i was thinking, cause you defnintely want the wastegate bleeding off pressure from all 4 parts of the manifold rather than just 1 (some cast iron designs)

[GWInquisitor14]

Anyways back to that ceramic coating, isnt it like a think coating that would make the diameter of the pipes a lil smaller is what i meant by thinner

[DeleriousZ]

awright.. if i were to go with the garrett twin ball bearing turbocharger, would it be better to go with the one with the compressor a/r of .60 and the exhaust with an a/r of .64 or... with the one with the compressor a/r of .70 and exhaust .63?

is it better to have the a/r bigger on the turbine side or compressor side?

[duplox]

is that a t3 variant? If so, you should be able to buy the wheels and housings of any A/R and slap em on, and still have the benefits of ball bearing. The only problem I have with those housings is the exhaust seem a bit too big for me. You'll see more lag than neccesary. Try for a compressor around .65 and exhaust of around .50.
As for external wastegate integration, there is a nice page explaining the best way to do it in Maximum Boost, but my scanner doesnt seem to be working. Here is a crude drawing I did on my comp, but it still gets the point across:

and always put the wastegate as close to the turbo as you can - and never on the opposite side of a log type manifold, or on a primary pipe of a tube header. this will make the wastegate vent mainly one cylinder...