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Thread: MN12 Tubular Headers (96-97)

  1. #1
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    MN12 Tubular Headers (96-97)

    Hello,

    I had a question about using the 96-97 tubular "headers" on a 95 SC. I know they will bolt up to the heads, but it doesn't seem like the EGR tube will work in the direct-fit manner. The EGR fitting on the header looks a little bit further down than the factory manifold. Does anyone have info on what needs to be done?

    I'm not going to get rid of the EGR so please don't suggest to just cap it. And I know about using ported SC manifolds and late-model Mustang headers but I already own the MN12 headers and exhaust and am not looking to spend additional money. I just want to get the best out of what I have.

    Thanks!

  2. #2
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    While they do resemble headers, sort of, I can assure you the tbird ones are complete crap, dont even look at them if u have a blower installed. I have a set of 98 mustang headers that have been cursed to death on this forum, never the less, they flow and sound 'allright', so I use them. If u want headers, get a set of 98 mustang headers or just port your stock manifolds.

  3. #3
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    Stock for stock, the 96-97 MN12 exhaust should do better than the 95 SC setup, especially where the downpipe goes into the cat. (45* bend is a lot better than 90* bend). Like I said, I know about ported SC manifolds and Mustang headers, but I'm not looking in that direction. I have all the parts for both the 96/97 MN12 system and the 95 SC system, so I don't have to spend any money. The purpose of this thread is to address the EGR tube fitment question, not suggestions about what to do with my exhaust. When I get some money, I already know where I'm going to go with the exhaust.

  4. #4
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    Your better off lwith your 95 manifolds and porting the collector to 2". Those 96/97 manifolds have a small collector. Do a search, there was flow testing done on all the manifolds/headers available for the SC and those 96/97's flow really bad when compared to the ported 95 manifolds. I would port the collector of your 95 manifolds, and get a set of dowtubes made or from SCP to get rid of those factory ones.
    SCCoA Member#: 2515
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  5. #5
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    Quote Originally Posted by rzimmerl View Post
    Your better off lwith your 95 manifolds and porting the collector to 2". Those 96/97 manifolds have a small collector. Do a search, there was flow testing done on all the manifolds/headers available for the SC and those 96/97's flow really bad when compared to the ported 95 manifolds. I would port the collector of your 95 manifolds, and get a set of dowtubes made or from SCP to get rid of those factory ones.
    Yup what he said. According to the flow test, the 95 mainfolds ported are the best thing next to going with Kooks headers. Now you don't have to worry about how you'll do the egr.
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  6. #6
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    Oh yah. I believe that a cast iron manifold with a 2 inch outlet will be close to the flow rate of a kooks header. Be real fellas. That testing method was severly flawed. You cannot flow test a header or exhaust manifold as you would an intake or exhaust port. There are way to many variables. When flowing a tube or port on an exhaust manifold or header you are getting a flow reading from port to collector. A cast iron manifold will use the entire interior area that is used for all three ports whereas the header will only use the one. With that means of testing if the manifolds had let's say a real 2.5 inch collector they would have read flowing better then a kooks header with the same size collector. Here you you would be basically comparing a 2.5 inch tube(manifold) against a 1 3/4 tube( for the header). The flor restriction in the headers case is the primary tube whereas in the manifold its the collector. Not a good comparison. Now take that area within the manifold and divide it by three and you'll soon see that all three ports flowing into that shared space can not be legitimately compared to 3 1 3/4 individual primary tubes dumping at a collector. The standard tubular factory header much like the factory manifold dumps right at the collector which is less then ideal making the collector a pretty huge restriction point. There is allot to collector lenght theory not to mention theory for proper primary tube size and lenght.

    Anyway.....I am no expert on this. I,m also not saying that any sc manifold is worse or better then the factory tubular headers. (Here are to many variables. But probably the only way to really know is to do some dyno testing, and even then it be combo specific

    My intentions here are not to stir anything up but to let you understand that we really can't say what's better or not in this regards. I do personallly feel a 2 inch collector is insaine on a supercharged performance vahicle
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  7. #7
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    I used those manifolds a long time ago. Before going to the Mustang Macs.

    I still have them in my basemant. I cannot mention on the HP increases but I enlarged the collector with a grind wheel and made the opening larger, the EGR tube was cut and welded to allow it to meet in the correct spot. I never did dyno with those so I have no idea if it was a performance gain.
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  8. #8
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    on my old 93 i put 96 OEM headers and hiflow cats and the butt-o-meter was happy with the results they allso make a good starting point for a turbo kit

  9. #9
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    Are we talking about the same headers? I went through all the trouble of welding my mustang headers in 05 because I took one look at the 96/97 tbird headers and thought they were crap.

  10. #10
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    Thanks for the replies everyone. Since I'm not looking to spend money right now (and that includes money to modify the EGR valve), I'll just stick with the stock manifolds. I'm not overdriving the supercharger, so it's not high priority for me to get the exhaust done just yet. I'll save up the money so that when I do it, I'll do it right.

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