X51 Headers revisited
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From: Orange,Va
I'll report back. I have a set of AWE exhausts on, so YMMV as far as sound. I was thinking of having them coated. From what I understand ceramic coatings can add 40HP 
For about $175, an aluminized ceramic coating can be applied and wll match the exhausts...OK maybe that sounds ridiculous, but I like things above and below to look good.
For about $175, an aluminized ceramic coating can be applied and wll match the exhausts...OK maybe that sounds ridiculous, but I like things above and below to look good.
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From: Austin
Originally Posted by cobra06
I'll report back. I have a set of AWE exhausts on, so YMMV as far as sound. I was thinking of having them coated. From what I understand ceramic coatings can add 40HP
For about $175, an aluminized ceramic coating can be applied and wll match the exhausts...OK maybe that sounds ridiculous, but I like things above and below to look good.
For about $175, an aluminized ceramic coating can be applied and wll match the exhausts...OK maybe that sounds ridiculous, but I like things above and below to look good.
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From: Orange,Va
Originally Posted by jhbrennan
I had my AWE headers coated by Jet Hot before I installed - I went with the black coating. They did a nice job.
Some off car comparisons.
Burning Brakes
Joined: Dec 2006
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Originally Posted by cobra06
I'll report back. I have a set of AWE exhausts on, so YMMV as far as sound. I was thinking of having them coated. From what I understand ceramic coatings can add 40HP
For about $175, an aluminized ceramic coating can be applied and wll match the exhausts...OK maybe that sounds ridiculous, but I like things above and below to look good.
For about $175, an aluminized ceramic coating can be applied and wll match the exhausts...OK maybe that sounds ridiculous, but I like things above and below to look good.
Thanks for the pics...
Dave
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From: Austin
Originally Posted by Gleek48
jhbrennan-
I noticed you were in Denver. I am too. Which shop did you get your engine work done at?
Thanks!
I noticed you were in Denver. I am too. Which shop did you get your engine work done at?
Thanks!
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From: CA
If the new header is 7mm larger than the old header, I assume the exhaust port on your car will be 7mm smaller than the header flange. Is that correct? If so, won't that create a serious mismatch between exhaust port and header? I'd think that a step from the exhaust port to the headpipe would create turbulence in the exhaust flow. Does the X-51 gasket work with the standard head?
Also - if you've seen the headers on the 3.6, they look almost identical to the X-51 header style, just smaller. Only the 997S has the very short tube 3 into 1 collector design which strikes me as a very poor (spelled CHEAP $) header design, even compared to the standard 997 3.6. The X-51 header, while vastly better than the 997S header, is by no means optimized as an equal length system would be.
MC
Also - if you've seen the headers on the 3.6, they look almost identical to the X-51 header style, just smaller. Only the 997S has the very short tube 3 into 1 collector design which strikes me as a very poor (spelled CHEAP $) header design, even compared to the standard 997 3.6. The X-51 header, while vastly better than the 997S header, is by no means optimized as an equal length system would be.
MC
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From: Austin
Originally Posted by H20NOO
If the new header is 7mm larger than the old header, I assume the exhaust port on your car will be 7mm smaller than the header flange. Is that correct? If so, won't that create a serious mismatch between exhaust port and header? I'd think that a step from the exhaust port to the headpipe would create turbulence in the exhaust flow. Does the X-51 gasket work with the standard head?
Also - if you've seen the headers on the 3.6, they look almost identical to the X-51 header style, just smaller. Only the 997S has the very short tube 3 into 1 collector design which strikes me as a very poor (spelled CHEAP $) header design, even compared to the standard 997 3.6. The X-51 header, while vastly better than the 997S header, is by no means optimized as an equal length system would be.
MC
Also - if you've seen the headers on the 3.6, they look almost identical to the X-51 header style, just smaller. Only the 997S has the very short tube 3 into 1 collector design which strikes me as a very poor (spelled CHEAP $) header design, even compared to the standard 997 3.6. The X-51 header, while vastly better than the 997S header, is by no means optimized as an equal length system would be.
MC
Last edited by jhbrennan; Mar 18, 2007 at 02:46 PM. Reason: Change
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From: Orange,Va
The gaskets for the X51 and 997S non X51 are the same part numbers, which leads me to believe and sort-of know, the ports are the same size. That 7mm difference is tube diameter after the flange, not ID of the the intake ports.
Note that Europipe uses these headers for their system, as mentioned in this thread. They do their research, and don't think would include it if there were scavaging, turbulence or back-pressure issues; they found the 48 mm pipe ideal.
As far as them not being equal length, well...we're not talking about big HP differences, with or without equal length headers. The narrower stock headers may increase velocity to make up for diameter and give maybe some?? lower end torque, but then up the back pressure as well as friction of moving gases, losing it at mid-range and high end... Less then ideal. As I said before, they can't hurt.
The sum is part of the whole, as with any engine system.
Note that Europipe uses these headers for their system, as mentioned in this thread. They do their research, and don't think would include it if there were scavaging, turbulence or back-pressure issues; they found the 48 mm pipe ideal.
As far as them not being equal length, well...we're not talking about big HP differences, with or without equal length headers. The narrower stock headers may increase velocity to make up for diameter and give maybe some?? lower end torque, but then up the back pressure as well as friction of moving gases, losing it at mid-range and high end... Less then ideal. As I said before, they can't hurt.
The sum is part of the whole, as with any engine system.
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From: CA
Sounds like you've done your homework. Other than stiffer valve springs on the exhaust valves, I don't know what, if anything is different on the X51 heads. I assumed since the exhaust header was larger that the port must be as well but it sounds like that's not the case. Regardless, the X51 header seems to be the best value for a 997S owner looking for a better engineered, less restrictive system that's a straight bolt-in with the stock cats and mufflers.
It would be interesting if you did before and after dyno runs. Best of luck!
MC
It would be interesting if you did before and after dyno runs. Best of luck!
MC
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From: Orange,Va
Sure
997.111.105.00 -- exhaust manifold cylinders 1-3 (X51)
997.111.106.00 -- exhaust manifold cylinders 4-6 (X51)
The gaskets and bolts are the same as the 997S stock.
MC
I always do research before I buy or add anything. I've been at this for a while, playing with Porsche's when the internet was something you found on a fishing boat.
There are sooo many claims about bolt on parts giving wild HP claims...airboxes, 25 HP, silicone air tubes 12HP, my favorite is the Y-Plenum, a $995.00 part that gives 28HP, programing in 35 HP. I only do things that make mechanical or physical sense.
997.111.105.00 -- exhaust manifold cylinders 1-3 (X51)
997.111.106.00 -- exhaust manifold cylinders 4-6 (X51)
The gaskets and bolts are the same as the 997S stock.
MC
I always do research before I buy or add anything. I've been at this for a while, playing with Porsche's when the internet was something you found on a fishing boat.
There are sooo many claims about bolt on parts giving wild HP claims...airboxes, 25 HP, silicone air tubes 12HP, my favorite is the Y-Plenum, a $995.00 part that gives 28HP, programing in 35 HP. I only do things that make mechanical or physical sense.
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From: Austin
Originally Posted by strtswpr997
Can the X-51 headers be purchased at a porsche dealer for $550.
http://www.sunsetimports.com/