1/2" CNC MACHINED A20A EXHAUST FLANGE

[AccordEpicenter]

Woo... Guys i got sam at BMC racing (http://www.bmcrace.com/) to make me a CNC machined 1/2" steel weld flange for A20 exhaust... so all you guys who wanted to make your own manifolds/headers now you can get a flange... I paid under $30 shipped and it was well worth it, but it did take a LONG time for them to get around to making it... somthing to check out tho. It is a very nice flange esp for the money and esp considering nobody else makes one.

[A20A1]

Sure beats grinding down the stock manifold

[AccordEpicenter]

yeah you really dont want to have to use the stock cast iron one... usually weld quality can be suspect when welding cast iron to steel... Ive done it with good results but its generally not a good idea esp if youre going for a turbo manifold...

[Robs89LXi]

Have you bolted it up yet? How is the fitment?

[AccordEpicenter]

i put it on but didnt bolt it up... fits beautifully

[A20A1]

Is the ports larger or is it close to the stock port size?
How much material is left around the ports?
Can you post pics?
I'm gonna need 1.625" (1-5/8") port.

https://www.3geez.com/showthread.php?t=6466&page=2&pp=20

[AccordEpicenter]

Ok around each port there is at least .410" of material. As for ports they are stock size... maybe a few thousandths larger.

[Sean]

thats so thick that on a turbo manifold the flange will grox so much that it will litereally shear the studs off in short order. already been down this road. we use 3/8 flange 60k and 1 yrs of hard use tell me ours work good at 3/8

[A20A1]

what about 1/2" stainless does it have the same expansion as Weld Steel?


I'm going to e-mail then and ask about the stainless flange price...

If it's more expensive then doing it myself I'll try and get my friend to do a cad drawing.

[AccordEpicenter]

what about 1/2" stainless does it have the same expansion as Weld Steel?

i think stainless expands more

[A20A1]

* Does stainless expand a lot more than aluminized steel. I have heard that a stainless system will grow 1 ½” in length when it gets hot. Is this true?
o In a word, NO! If stainless systems expanded as much as some olds wives tales would lead you to believe, then how would so many OEMs use it and not have problems? The key is to look at a property of the material called the coefficient of thermal expansion (COTE-Geek terms for how much the material will grow when it gets hot). For mild steel the COTE is:

6.3 X 10-6

For stainless, the COTE is:

9.4 X 10-6

· So, to calculate the change in length we use the following formula:

=(COTE)(Length of component)(change in temperature)

Looking at an exhaust system that is 84 inches long, and whose temperature will change 600 degrees F, on average, for mild steel:

change in length=0.3157 inch.

For stainless: =0.4730 inch

As you can see, the difference over a 7-foot long exhaust system is negligible (it amounts to .0019 inch per inch).

[AccordAddict]

Sorry if this sounds like a newb quesion but what part is the flange???

[tatmark1]

look the word up in a dictionary

[A20A1]

look the word up in a dictionary

I like dictonarys, anyways the flange is something to connect two parts together, usually with a gasket inbetween, in this case the flange connects the header pipes to the cylinder head.

[tatmark1]

i recomended the dictionary as a "self help" thing

[3rdgeneration]

theres nothing on the website?but im intrested in making a purchace

[3rdgeneration]

hey anyword on these flanges?

[3rdgeneration]

i emailed the guy and he said he has none in stock and he has no time to make anymore...sorry guys

[AccordEpicenter]

shitty

[A20A1]

Look at the links here if you want the CNC flange
https://www.3geez.com/showthread.php?t=21311

[AccordEpicenter]

Hmm It looks like Weir Racing has started making custom flanges... ill see if i can get them to make them..