I'm happy with the result of removing the pre-cat, power feels better above 5000 rpm. The exh. note is a bit deeper at idle and louder WOT. Barely noticable btw, though cleaner welds would've help out even more.

When I first noticed the pre-cat and how it was pinched, I knew I had to get a hold of another stock header to try this out with. For 80 bucks, it's a worthy mod imo. I'm looking into getting a welder and redoing it myself, I'm getting more flow, but it's not the smoothest flow going by those welds.

 

First i'm glad to hear that it produced positive results. And top markes for creative thinking and experimenting. DYNO numbers would resolve my being on the fence (i.e. $120 more you can have a full header).

I hope that someone does a before and after dyno to show us the way.

 

I think that's hard since there are less than 6 people I know with this mod and they already had the mod done. So we can only hope to those who are planning to do this mod... looking forward to see the result.

 

don't worry, i am doing this mod and will post before and after results. when i started this thread i was hoping that someone had already tested this set up. i will have done by mid feb.

cheers

 

Cheers to *****!!.. I'll be waiting!

 

Bump

 

bump!

 

he'll post the results I'm sure, gonna take some time though.
When I got mine done, the dude at the shop had a harder time setting up a jig than he thought, I had to re-install and un-install that beotch like 6 times before it fit right. tricky part was leaving enough room for the Oxygen sensor.

 

Bump

 

hoping to get done by the end of feb, just finished my head project.

cheers

 

sob sob.. :(

 

Here in Europe, especially in Germany and Austria, many guys have this mod in combination with MTH. It generats in combination with adjusting the software about 10 bhp and 15Nm.
Hope I can help you.
My S produces with 15% Pulley, Denso and no Precat and MTH and fuel ROZ 98 about 215 bhp and about 244 Nm.

Hope I can help you.

 

thanks for the info, did you cut it at the flex joint? do you have a pic? if so can you please send it to me or post it if possible.

cheers

 

Post the pics here, we all are interested with this mod.. not just you *****.

 

don't worry det, i started this thread to prove the stock header design is good and i will share any info i get whether from nam or the rest of the world.

cheers

 

As soon as I can locate a used OEM header, I'll be experimenting with this as well...

 

I bought one for $25 + shipping on ebay.

 

Good deal most go for $50 or more.

When you consider that list price is somewhere North of $900 (for OEM) I'm surprised more folks don't hold onto them. The OE cat has got to be worth close to $100. ...While its only a ceramic cat the can actually has decent transitions in and out, and it doesn't have a crappy clam-shell exterior to get loose & rattle. Unless you want a metalic sport/race cat the OE ain't bad! ...No worries about law enforcement either.

 

Sorry but I have no pics of them! But you only have to cut them and then put out the cat and weld it.

 

So, what you are doing is to cut the precat tube, remove the cat material
from inside and than re weld the precat tube back together.
Is that correct?? I think that most people on this thread have planned
to replace the precat area with a new curved, round tube that has the
ox sensor port in it.

 

I think ***** should be able to guide us together with some pics, so that we can have better view and understanding.

 

I am just trying to understand what PeterKöstenberger
and the folks in Germany and Austria are doing.

 

well guys today is the day to do the pre cat removal, i will post the results sunday, again don't worry i will post the results and also will post pics of how i did it, i think you will all be surprised at the design i am going to use. it will hopefully show gains like the ones being offered from across the pond. check back sunday as i will post a new thread called test results of the stock header minus the pre cat.

cheers

 

And looking forward to the numbers...

Matt

 

Info on MINI2:

http://www.mini2.com/forum/showthread.php?t=36537

Lots of pics on page 2...

Inside the pre-cat:

http://www.mini2.com/forum/attachmen...1&d=1059448030

Restrictive "waist" above it:

http://www.mini2.com/forum/attachmen...2&d=1059448094

With a ruler for scale:

http://www.mini2.com/forum/attachmen...3&d=1059448131

And, installed - 2.5" SS pipe fitted and a new O2 bung - pic is small and kinda crappy, but you can get the general idea:

http://www.mini2.com/forum/attachmen...3&d=1060058215