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Old 10-22-2010, 06:17 PM   #51
stav05sti
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btw since we're talking about header design is it feasable to talk about EGT location or is this off topic? I'm asking because my Internet research has led me to be able to support either point of view, with the EGT giving a better reading for tuning on a per head basis and on a collector/uppipe basis. To give my point of view/educated guess, it seems that unless you are worried about having any one cylinder performing bad, then EGT location is best at the collector/uppipe.
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Old 10-22-2010, 07:28 PM   #52
KillerBMotorsport
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First run witht he car stock, except for cat-back are the solid lines. Last run of the day, with stage II parts (intake, catted downpipe, fuel pump, Killer B Header) added and custome tune are the dashed lines.

So Peak gains at the wheels were:

92ft/lbs

54hp
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Old 10-22-2010, 08:32 PM   #53
Concillian
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Quote:
Originally Posted by KillerBMotorsport View Post
That's interesting. Does anyone know the difference (typically) in 91 vs 93 power levels, and conversion factor beween Mustang & Dynojet readings? Too many variables to comapre? Maybe I'm getting too off topic here.
Dynos read different. Dynojet to mustang is as much as 20% different. Nothing is really gospel though. 91 to 93 is fairly dramatic too, close to 10%.

You really need a baseline on each dyno to tell one from another.
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Old 01-25-2011, 04:15 AM   #54
berdugo
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I decided to have another custom made headers with a machine chop fabricated flanges, here are some pics of the flanges made by a local machine shop here



heads to headers gasket inner diameter



primary pipe inner diameter



primary pipe wall thickness





flange to pipe welding will be done outside (not inside the flange) to avoid turbulance due to ugly welds and to maintain inside smoothness of the flange - pipe connection



flange is tappered to allow very smooth gas flow and avoid turbulance


Last edited by berdugo; 01-25-2011 at 04:24 AM.
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Old 01-25-2011, 04:31 AM   #55
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Grimmspeed exhaust manifold to Headers gasket







flange is tappered





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Old 01-25-2011, 08:47 AM   #56
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Which way are you tapering the flange?

please say in terms of flow direction that it's smaller to bigger, thus being stepped...so smaller at the gasket and opening to the ID of the primary tube.

Nice looking flanges by the way
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Old 01-25-2011, 09:56 AM   #57
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Quote:
Originally Posted by Homemade WRX View Post
Which way are you tapering the flange?

please say in terms of flow direction that it's smaller to bigger, thus being stepped...so smaller at the gasket and opening to the ID of the primary tube.

Nice looking flanges by the way
thanks

I hope I can tell/explain what's really on my mind with the direction of the tapper.

in this flange

the bigger inner diameter is the gasket side, so from the cylinder head then the oem gasket then the header flange, the gasket side of the flange has the same inner diameter with the gasket (around 1.85inch), then the flange narrows down to match the inner diameter of the primary pipe (which is around 1.6695 inch).

The exhaust gas from cylinder head -> gasket -> flange (1.85in) -> primary pipe (1.6695in), that's the flow for the heads to headers flanges.

The headers to UP taper is reversed since the secondary pipe's inner diameter is a bit larger than the inner diameter of the gasket, the flange is tappered from 2.136inch to 2.0615 inch matching the inner diameter of the gasket going to the up pipe. Exhaust gas flows from the collector -> secondary pipe (2.136inch) -> flange going to up pipe (2.0615 inch)

The "canal" or groove on the other side of the flange is where the pipes should be inserted and to be welded outside the flange not inside like some headers does. Hopefully the flange is thich enough and won't crack. If I ever crack it, I'll have a 1inch thick flange custom made with about 1/2 for the pipe to insert into.


My explanation might be confusing and I'm having a very hard time explaining it in english, I hope is good enough to convey what I mean.
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Old 01-25-2011, 11:59 AM   #58
KillerBMotorsport
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IMO your flange should match the port and tubing ID, not the gasket. Let the gasket be inset. That tiny ridge won't add up to anything as long as the flange and port are matching and concentric.
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Old 01-25-2011, 12:02 PM   #59
KillerBMotorsport
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Oh.. another thing. Be very carefull inserting a tube into a counterbore and only welding on one side. It makes it nearly impossible to get decent penetration and no one wants to put a header on that has built in cracks This is less important at the head flanges than it is at the 2-bolt where you'll see much more heat.
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