Well Ross finally made it to the shop.....a couple hours late. His system is as follows, JDM ITR Header, 2-1/2" Car Sound Cat, Type One B pipe and N1 Axle Back. Before his trip over the western pond I ported his header and cut out the anti reversion chamber. He brought the Type One and N1 pieces with him and we noticed a few bottle necks. Today he came down to remove the worst one.

Here is the inlet flange of his N1 after it lost to the saw. The ID is 2". I must say, with the exception of the flange, this N1 axle back is a very nice piece. The tip is actually smaller than stock I believe the tubing used to be 60mm but this one is 63.5mm (2-1/2" OD). It's built to bolt on to the stock B pipe and hence the flange. The muffler/resonator is very short so I would think that it could be on the loud side, but I didn't ride in the car at all.


Here are 2 pictures of the Type One where it bolts to the axle back. It too is built to bolt to the stock axle back so that's why it necks down.


The outlet is 2.0" OD/1.88" ID



The Type One also lost it's fight with the saw. Here's a side by side of the 2-1/2" tubing and the flange that was cut off.



Here's a pic of the Type One 2 bolt flange right after the resonator, the ID is 2.25". The 3 bolt flange at the cat is also 2.25" ID.



The Type One tubing measures 63.5 mm OD (2.5") and has a wall thickness of 1.5mm.

N1 Axle Back with new 2-1/2" flange welded up.



Type One B pipe with new 2-1/2" flange and tube extension



I think Ross' next mod should be removal of the mismatch at the cat (2-1/2" ID) and B pipe (2-1/4" ID), but we didn't have the time to do it today.

Just one last picture for you guys. Ross asked for the camera and took it into the bathroom with him (got me worried a bit) and took this shot for all of you.



Which is typical for this board


[Modified by SMSP, 8:45 PM 6/22/2002]

 

Nice

 

Which N1 was it?

Thanks for the writeup

 

SMSP,
For posterity, can you tell me why you cut out the anti-reversion chambers on the header? Just curious!

 

Because the ID of the chamber (true collector outlet) is only around 2-1/8" versus 2-3/8" on other JDM headers. Don't worry though, the way the primaries come into the collector provides some anti reversion characteristics.

 

Nice work Dave

Hope to get your B-pipe derestrictor thingy put in next week...

BTW, any noticeable results from porting the JDM 4-1 ITR header?

 

I took this picture for the NC dudes:

 

Yeah, which N1? Spoon? A'pex-i?

 

Spoon.

It's so damn loud...like sitting in a sport bike.

 

 

nice writeup and pics,
one question though, alot of ex systems have those bottlenecks at the flanges, even very high quality brands, is it possible that those would increase ex velocity (like the spoon venturi plate), and therefore be planned and beneficial?
just a thought.
nice welding work

-steve

 

I saw it at Midnight..

Wil
-who would rather not be at Summit

 

But we all like it!

 

THe only reason I can come up with is why they do it, is for interchangability. The Spoon N1 will bolt up to the stock B pipe for the person who just wants to have a different look and sound at the rear. The same goes for many of these systems that are bolt on, they are made to attach to stock connections. What gets me is there is more work to build the systems with these bottlenecks versus using flanges that have IDs equal to the tubing OD. The manufacturer of these systems (even stock) need to crunch the tube ends for these smaller flanges.

I like using all one size of tubing from the cat back. As for George's statement on the early Porsche's, I don't have any experience with them but it sounds like something else in the package, i.e. cam lift/overlap may have required it. I don't know of modern day races that try to induce back pressure in their exhaust systems.

 

[buttcoin] Hell YEAH! [/buttcoin]

Looks good

 

And just think, you get to see it this coming weekend, too! At least your duties will be limited to wrench turning and elbow bending.

Dave - As always, nice work! Hows that E39 header coming...LOL...

 

NIce rework on the exhaust

 

I checked but I can't find the car in my shop, where are you hiding it?

 

Must have been that little POS I rolled over on my way to the shop...

 

Are you sure that wasnt a blue trash can?

 

Oh no, don't tell me you have lost it AGAIN...if you were still in Charlotte....

 

man we're glad that the saw wins everytime Dave !

wanna do the kakimoto?