Shopping for headers.. Advice needed..
#17
06-24-2008, 01:52 PM
just thinking out loud, but if the tubes are equal length then how much mixing of the gases will occur at the collector? It seems that there would be not much? Unlike unequal design there exhaust gases may run into each other.
Last edited by gmoney; 06-24-2008 at 01:55 PM.
#18
06-24-2008, 01:56 PM
the pulses of exhaust gas probably travel in a spring/slinky type fashion so the main/peak waves should not hit at the same time but there will be some mixing of the lesser concentrations
#20
06-24-2008, 02:04 PM
I always try my best to get the point across to the companies that are selling/installing the stuff. Unfortunately most end users really don't know what they are looking at. To them it's just some shiny pipes.
We build our products with shop owners and installers in mind. Those are the people that can appreciate the details.
#23
06-24-2008, 02:28 PM
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#25
06-24-2008, 03:35 PM
So I emailed this link to our lead Engineer, Chris. He said he would review all of the data logs from the header testing.
Not only did he inform me that there was zero difference in EGT's, he gave me further info as well.
Here is a quote from his email.
Our headers do not change EGTs. Past the exhaust ports, peak EGTs are influenced primarily by turbine geometry and post turbine exhaust design.
Header design however can have a significant impact on EGTs during transient load conditions, i.e. during turbo spool. In this situation it is important that the header transfers as much heat energy to the turbos as possible to minimize delays in turbine acceleration. Primary length and geometry, material selection, wall thickness and interior surface finish all influence the header's thermal behavior. We tailored our design to ensure good dynamic response, as well as peak power.
If you have questions, please let me know.
Not only did he inform me that there was zero difference in EGT's, he gave me further info as well.
Here is a quote from his email.
Our headers do not change EGTs. Past the exhaust ports, peak EGTs are influenced primarily by turbine geometry and post turbine exhaust design.
Header design however can have a significant impact on EGTs during transient load conditions, i.e. during turbo spool. In this situation it is important that the header transfers as much heat energy to the turbos as possible to minimize delays in turbine acceleration. Primary length and geometry, material selection, wall thickness and interior surface finish all influence the header's thermal behavior. We tailored our design to ensure good dynamic response, as well as peak power.
If you have questions, please let me know.
#26
06-24-2008, 10:40 PM
Join Date: Jan 2008
Location: Singapore
Posts: 75
Rep Power: 20
1)each primary tube should have a port matched to the size of the exhaust port on the head
2)each merge collector should have a proper design and the flange should be matched to the turbine inlet
3)tubes should have smooth bends and no kinks, preferably have equal length tubing
2)each merge collector should have a proper design and the flange should be matched to the turbine inlet
3)tubes should have smooth bends and no kinks, preferably have equal length tubing
1. Flycut flanges. When the transition (the initial tube that goes from oblong to round) gets welded to the header flange, a small amount of warpage takes place. This is just a byproduct of the heat from welding. To combat this we then take that flange and put it in a custom fixture in our CNC machine. We then run a fine cutting tool across the flange on the side that will meet the cylinder head. It will take down any high spots from the warpage and even it out so it is perfectly FLAT. This means a perfect fit, no leaks, and no stress to the head studs.
Try taking a straight edge to a competitors product and tell me if it is flat. I am confident that it will not be. How do we know this?
Seventeen years of experience...
2. Cracking is always a concern on a Porsche exhaust. The runners are short and there is intense heat. That is why we use 321 stainless over 304.
Why? Seventeen years of experience...
3. If you notice our headers are made up of small pieces of tubing and welded together. This for some reason has been a topic of debate. We are not sure why, because many custom exhaust builders for upper echelon motorsport teams use this same technique. You are probably asking yourself how we avoid weld slag on the inside of the pipe in an area that cannot be ground down.
Simple, we "back gas" or "purge weld" during construction. We have an intricate jig system that allows us to fill the tube with Argon. This accomplishes two things. One, there is no oxygen penetration which results in a stronger cleaner weld. Second, that weld slag does not build up on the inside so it remains perfectly smooth.
Did we learn this overnight? No, from seventeen years of experience...
4. These headers have been carefully designed to assure that there is equal resistance on each runner.
A quote from our website:
In order to equalize flow across all the cylinders, careful study of the available space was in order. Also in order to provide adequate road clearance while not taking any shortcuts with tubing arrangements, we painstakingly digitized the interface between cylinders heads and turbos and then CAD designed a primary and secondary tube solution that far exceeds in quality any other design currently on the market.
Seventeen years of experience...
5. Each port is hand finised to assure no weld slag disrupts flow.
Try taking a straight edge to a competitors product and tell me if it is flat. I am confident that it will not be. How do we know this?
Seventeen years of experience...
2. Cracking is always a concern on a Porsche exhaust. The runners are short and there is intense heat. That is why we use 321 stainless over 304.
Why? Seventeen years of experience...
3. If you notice our headers are made up of small pieces of tubing and welded together. This for some reason has been a topic of debate. We are not sure why, because many custom exhaust builders for upper echelon motorsport teams use this same technique. You are probably asking yourself how we avoid weld slag on the inside of the pipe in an area that cannot be ground down.
Simple, we "back gas" or "purge weld" during construction. We have an intricate jig system that allows us to fill the tube with Argon. This accomplishes two things. One, there is no oxygen penetration which results in a stronger cleaner weld. Second, that weld slag does not build up on the inside so it remains perfectly smooth.
Did we learn this overnight? No, from seventeen years of experience...
4. These headers have been carefully designed to assure that there is equal resistance on each runner.
A quote from our website:
In order to equalize flow across all the cylinders, careful study of the available space was in order. Also in order to provide adequate road clearance while not taking any shortcuts with tubing arrangements, we painstakingly digitized the interface between cylinders heads and turbos and then CAD designed a primary and secondary tube solution that far exceeds in quality any other design currently on the market.
Seventeen years of experience...
5. Each port is hand finised to assure no weld slag disrupts flow.
#27
06-24-2008, 10:49 PM
Join Date: Jan 2008
Location: Singapore
Posts: 75
Rep Power: 20
come to think of it.. are there any reason(s) NOT to change to aftermarket headers. Other than fuel consumption going up, any other disadvantages when using aftermarket headers? I have tubi exhaust now..
#28
06-25-2008, 07:13 AM
I can show you my present headers.
They came from very small German company and they are hand made of course.
I paid for a set 2000euro netto.
One more important thing I know some famous people from Porsche motor sport department responsible for preparing racing cars electronics etc.
They all say that original headers are fine up to 700ps.
My car in ex set up with headers, race exhaust without catalytic converters and custom made ecu on dyno generate 550ps and 680Nm measured on the dyno.
I believe that with standard headers would be the same.
I also measured performance using race logic box
0-100km/h -3,4s
0-160km/h-7,1s
0-200km/h-11,1s
one more thing fvd headers are from china.
They came from very small German company and they are hand made of course.
I paid for a set 2000euro netto.
One more important thing I know some famous people from Porsche motor sport department responsible for preparing racing cars electronics etc.
They all say that original headers are fine up to 700ps.
My car in ex set up with headers, race exhaust without catalytic converters and custom made ecu on dyno generate 550ps and 680Nm measured on the dyno.
I believe that with standard headers would be the same.
I also measured performance using race logic box
0-100km/h -3,4s
0-160km/h-7,1s
0-200km/h-11,1s
one more thing fvd headers are from china.
#30
06-25-2008, 10:37 AM
Mike/A.W.E. I have a question: I have the Champion Motorsport rear diffuser on my 997tt, have you seen clearance problems going from stock to AWE headers with the diffuser? After all my research you guys have the best headers bar none! (Although there is a set of headers used in the Champion Werks K1 (997TT) that are about $4000k made of a light rear metal that has very high heat dissipation (probably more a racing app.see pic).