HEY GUYS,,,,,I just bought a set off stock exhaust manifolds/headers from a member.I was going to port them and swap them with my original ones....BUT I can tell you,,, by looking at these,,,That I do not think that there is that much weld in the exhaust ports area and the collecter area welds to make a whole heck of a lot of difference....Unless, some of these production ones vary from one to another??...I am not an engineer by any means but I do know high performance engine blue printing....Yes ,I know every little bit helps...But I can see here that these welds in this set have little excess build up to cause a noticable restriction.......Like I said they may vary??..Also remember that those very hot gases are so condensed then in that area and have a lot of flow velocity that they sorta glide and shape to the contour of there path,Actually they skim ever so slightly above the surface in that state....Believe me,I did not spend the money for these and the Porsche gaskets to be second guessing this mod now........Maybe I might be missing something here,if not......I hope I helped with this info.......

 

some are worse than others, but Kevin @ UMW swears by this mod. I would clean them up a bit but not to the point of grinding through the weld.

here's a few pics of what they normally look like:
https://www.6speedonline.com/forums/...positives.html

 

HI,Thanks for your info......So,did you port yours??

 

yep! lots of other mods at the same time though so no way to know what they really did.

 

i also did mine and the main gain is at the collector, the individual runners aren't that bad but you can take a lot of the weld out at the collector. Be carefull not to go too far at the runners, i did it with my first set of headers and had to get some new Tig welds in there because i went through it. My second time was better... Lots of work, pretty time consuming.

bad pictures, sorry

 

Clean them very well before reinstall. I did mine and it does take some time but I agree there is some benefit to doing this.

 

Id try extrude hone altho may be pricey

 

Hey John, glad you got them ok.

Check on rennlist the post Kevin (UMW) made, he had some great pictures of the ones he did. I think it is a very worthwhile mod myself.

 

yup i would also swain coat them.

 

Remember, don't coat the inside. Any possible coating failure would be ingested by the turbos.

 

In answer to your question, yes, the headers I've seen are HIGHLY variable in the amount of material on the inside. I bought a pair of take-off headers from Neil at Switzer and was almost disappointed to see how clean they already looked. My buddy did his 04 headers, and they looked downright nasty compared to the ones I purchased. I've now ported and polished mine and plan to install next week. I hope the ones I have on the car look horrible so that I will see as big a difference as possible!

 

Thanks Guys,,,These ones that I got from Don look pretty clean,the collecter has hardly any weld sticking out in to it ,,,so I am hoping for mine to have more weld restriction too...I guess I will clean the ones from Don up and swap them because I am curious to see my original ones also....I will not be able to tell you guys an A B comparision because also at the same time ,I am going to remove my Cargraphics 200 cats and replace them with SpeedTechs 100 cats.......More Flow,More Go......And the disease keeps going.......lol......

 

Hey Don,Did you notice that those had hardly any weld in the collector and not to much of weld build up in the ports area?? I am comparing these to the ones in the above pictures.I measured the collector exit pipe ID,its about 1 7/16" and the weld is not even hanging in there around that ID,just afew light weld thin edges here and there........What yr.did these come off of??.......Thanks

 

I do think they got their welder fixed and the jigs redone at Porsche, the 997TT headers that I have seen look very clean compared to the early 996TT's...

I have never ported them because when it is time to run upgraded (or modded) headers, we install these:

 

I have a set of Equal Length TT headers for sale with about 5,000 miles of use for $300 + shipping if anyone is interested and a set of OEM headers too which would be $150 + shipping as part of a garage clean out, please PM me if interested