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Modified OEM Headers


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Hi all,

 

This may have been hashed out before, but I haven't been able to find an answer.

 

Our car has cats built into the exhaust header...aka each bank goes from 3 to 1 then into a (pounded out) cat, then out of cat to another 2 to 1 where the two banks meet, then a single pipe into another pounded out cat.

 

We'd like to cut these cats out of our headers and weld in a straight pipe.

 

So the rules say exhaust free downstream of the collector - and a collector is where the individual cylinders' exhausts are merged into 1 stream.  Does this mean I can chop this header cat out and straight pipe it for zero points?

 

Pretty please?

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  • Technical Advisory Committee

This is a Tech Desk question.   Take photos and send them to the tech desk to get your official answer.

 

Unofficially, I would expect you can do precisely what you are asking with no issue.

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1 hour ago, krispykritter said:

Appreciate it.  I wasn't sure if this had come up before, so I wanted to ask ya'll prior to submitting a ticket.

There was chatter about E 36 headers and doing exactly as you described with no points..

 

Have you found any other Restrictions/issues?

Edited by Team Infiniti
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3 minutes ago, Team Infiniti said:

There was chatter about E 36 headers and doing exactly as you described with no points..

 

Have you found any other Restrictions/issues?

 

If we end up going the swap route, I'll likely chop off the current flange and build our own 2 to 1 pipe for the exhaust.  Would like to toss all three cat shells as well and have straight pipes through it instead.

 

Stock contour crossover pipe looks like this (not as pretty though, I stole this off the interwebs):

 

image.png.55e79a9b031b1f4ea2399aae112c6aba.png

 

Got that cool super tight bend in it.  I'd like to chop that off and make something straighter there but we'll just have to see how hard it is.  Mightnot be worth the effort.

 

Speaking of stock garbage, though, this is what each header looks like on the contour:

 

image.png.162b59055ec81db74070e449b45fd4da.png

 

Also may not be worth the pain to modify that as teh collector and cat entrance are all one piece and far from completely round.

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2 hours ago, krispykritter said:

 

If we end up going the swap route, I'll likely chop off the current flange and build our own 2 to 1 pipe for the exhaust.  Would like to toss all three cat shells as well and have straight pipes through it instead.

 

Stock contour crossover pipe looks like this (not as pretty though, I stole this off the interwebs):

 

image.png.55e79a9b031b1f4ea2399aae112c6aba.png

 

Got that cool super tight bend in it.  I'd like to chop that off and make something straighter there but we'll just have to see how hard it is.  Mightnot be worth the effort.

 

Speaking of stock garbage, though, this is what each header looks like on the contour:

 

image.png.162b59055ec81db74070e449b45fd4da.png

 

Also may not be worth the pain to modify that as teh collector and cat entrance are all one piece and far from completely round.

Do you have room for headers within your Points?

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If the rule says after the collector, do it.

 

It doesn't say the collector can't be welded.  Or say anything about bolted on connection.

 

That is post collector imho.  It isn't gonna turn any car into the Huggins swap car, or gbu vette...

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16 hours ago, krispykritter said:

 

If we end up going the swap route, I'll likely chop off the current flange and build our own 2 to 1 pipe for the exhaust.  Would like to toss all three cat shells as well and have straight pipes through it instead.

 

Stock contour crossover pipe looks like this (not as pretty though, I stole this off the interwebs):

 

image.png.55e79a9b031b1f4ea2399aae112c6aba.png

 

Got that cool super tight bend in it.  I'd like to chop that off and make something straighter there but we'll just have to see how hard it is.  Mightnot be worth the effort.

 

Speaking of stock garbage, though, this is what each header looks like on the contour:

 

image.png.162b59055ec81db74070e449b45fd4da.png

 

Also may not be worth the pain to modify that as teh collector and cat entrance are all one piece and far from completely round.

I'd cut that right below that "bung", weld up some straight pipe and be done. It does look a tad oval so you might have some manipulating to do. 

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16 hours ago, krispykritter said:

 

If we end up going the swap route, I'll likely chop off the current flange and build our own 2 to 1 pipe for the exhaust.  Would like to toss all three cat shells as well and have straight pipes through it instead.

 

Stock contour crossover pipe looks like this (not as pretty though, I stole this off the interwebs):

 

image.png.55e79a9b031b1f4ea2399aae112c6aba.png

 

Got that cool super tight bend in it.  I'd like to chop that off and make something straighter there but we'll just have to see how hard it is.  Mightnot be worth the effort.

 

Speaking of stock garbage, though, this is what each header looks like on the contour:

 

image.png.162b59055ec81db74070e449b45fd4da.png

 

Also may not be worth the pain to modify that as teh collector and cat entrance are all one piece and far from completely round.

 

 

The easy button would be to cut the ball and socket flange off, and plunge into that transition piece with a 2-inch hole saw. This would allow you to use a simple round pipe instead of trying to form the pipe into an oval to match the shape of the converter body. The convert body makes a nice collector shape and while having an expansion in the system is not ideal it wont really hurt your performance. Now if you had that shape before a turbo, we would do everything possible to eliminate expansions and conserve energy but for a simple NA exhaust it will be fine.

 

Replace your third converter with a nice 2 into 1 merge collector as far back as you have room. Then you can make the connection from the rear bank with a single 90deg bend instead of a 90 and then a 180 bend.

 

1819114966_IMG_20161018_19060501.jpg.bb0a2ba53c420f492a7ced69166dec9a.jpg

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15 hours ago, Team Infiniti said:

Do you have room for headers within your Points?

 

Not after a swap, no.  Could maybe make room in our points but I'd have to go over it pretty closely.  Our engine swap would add about 55 points to our TCV, and we're at around 440-445 right now.

39 minutes ago, mhr650 said:

The convert body makes a nice collector shape and while having an expansion in the system is not ideal it wont really hurt your performance. Now if you had that shape before a turbo, we would do everything possible to eliminate expansions and conserve energy but for a simple NA exhaust it will be fine.

 

Replace your third converter with a nice 2 into 1 merge collector as far back as you have room. Then you can make the connection from the rear bank with a single 90deg bend instead of a 90 and then a 180 bend.

 

This is kinda what I was thinking.  Go to a better merge between the two sides that eliminates that 180 degree bit and get rid of the third converter.  It seems like taking the 1st and 2nd out would be a ton of work and I'm not sure how strong it would be when I was done (I'm no pro welder).  Might have to be creative with the 2-to-1 bit as we can't make it much longer and still get the driveline out the top of the car.  I'm sure we could sort something out.

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1 hour ago, krispykritter said:

 

Not after a swap, no.  Could maybe make room in our points but I'd have to go over it pretty closely.  Our engine swap would add about 55 points to our TCV, and we're at around 440-445 right now.

 

This is kinda what I was thinking.  Go to a better merge between the two sides that eliminates that 180 degree bit and get rid of the third converter.  It seems like taking the 1st and 2nd out would be a ton of work and I'm not sure how strong it would be when I was done (I'm no pro welder).  Might have to be creative with the 2-to-1 bit as we can't make it much longer and still get the driveline out the top of the car.  I'm sure we could sort something out.

 

You used a magic work in your reply, swap, headers on swapped cars are covered by a completely different rule.

4.5.3.1. Any OE exhaust manifold from a vehicle on the VPI List can be used on a swapped engine for zero (0) points.

 

This means you can search for a different header that you can adapt to your car, doesn’t even have to be from a Ford. There are probably lots of decent V6 headers out there that you could search from, older cars would be unlikely to include an integrated catalytic converter. You could use 2 front, or 2 rear headers as required to get the best fit.

 

One thing I am not positive about but believe may be legal is to use a production header from a different application that may have the proper port spacing but a different bolt pattern on the flanges. Can you cut off the flanges and weld on new flanges to fit your cylinder head?

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