will69, sorry for taking us off course, at least a little...

As seen by my sig, I have the first production week for 2003 (09/02), so I should have the 1840750281. Heck, as Matt alluded, maybe the older ones might be more desirable in some way...

If anyone has good info on differences, please share, and if not appropriate here, you can PM me. Thanks much all.

 

still waiting for new myth file

cheers

 

Just as an fyi... MINI USA "thinks" the change in the header part numbers might be due to changes in the cat design, in his words, their flow characteristics (he put me on hold to contact a fairly reliable source).

I then called a local dealership, but had to leave a vm... I called Classic MINI, and the guy there did confirm that the Cooper & MCS are the same alright. However, he too wasn't sure what has changed... He was somewhat certain that the cat is the same though, and that mabye a bolt changed, or bolt pattern etc... I then followed-up with... then getting just any MINI header might not be advisable for fitment reasons, and he agreed that I should replace my header with the same part #. Not sure I buy that, but maybe he's right...

Calling Webb next, and if I must, Tony Nuzzo!

 

if the exhaust/head gasket is the same, it will bolt right up! Also, you can check the head part number to see when that changed, if the bolt pattern changed with one, they'd have to cut the part over at the same time. I don't remember if there's a gasket between the header and the cat-back. But I'd guess there has to be..... So you can check that one as well.

I think saying just get the same part number is a way of saying.... "it's a hassle to figure out.... if you get the same part number, you surely won't have problems" which is true, but not very informative!

If the price is low, just get it and see! If you're gonna gut it like Willy69, it won't matter....

Matt

 

I hear ya Matt, and totally agree with virtually everthing you said except that I would only be gutting the precat. If the cats for the various part #'s have flow-rate differences, or desriable improvements, it would be really nice to know what those are. I have an email into Nuzzo as I'm sure he evaluated them to some degree...

 

the pre cat is the only thing i have gutted, the stock cat is of good quality and would be expensive to replace with one of equal flow and duribility.
the pic of the pre cat is posted earlier in the thread.


cheers

 

i have noticed considerably more soot collecting on the boot of the car, this was not a issue before the pre cat mod. i believe there is alot of power to be had with a apexi a/f controller, this car runs way to rich. volker at mth says their header file will help, we will see.

cheers

 

We're actually comparing the pre-9/03 header to the post-9/03 headers because apparently they have different part numbers.

So it appears the precat does perform some function after all? or do you think it has something to do with process/method that was used to construct the modified header?

 

What if one of the headers DOES flow better, but it's HEAVIER!!!! Whatever will you do!

Matt

 

*****, could this just be pre-existing soot from other areas of the exhaust that was loosened during your mod process?

 

The cars burn a lot of gas and air. Any loosened stuff should get blown out/burnt pretty fast....

But it's just a theory....

Matt

 

Just a thought.
Gases passing through the gutted pre cat will be traveling faster. This may affect how the O2 sensor reads it's values. Possibly altering A/F ratios to compensate for the new differential between the pre and post O2 sensors.

 

All of us with headers and no pre-cat may not have the same gas velocity issues, but will have the equivalent air chemistry issues... And it didn't happen for me, but I can't speak for others...

And oddly enough, they may actually be traveling slower, because of less heat released due to no pre-cat reaction.... Who knows!

Matt

 

Well, it was just a guess. Maybe bad one

 

obe wan and dr. o,

amidst the too common hype and flaming here, it's refreshing to read you guys because you both understand that in addition to data, one must have a physical principle explaining the data.

 

to hide the BS!

Matt

 

Good thought. When I examined the stock header before putting in the OBX I figured that the neck-down just after the first O2 sensor was an attempt to increase the pressure for this sensor. This would give a larger signal (higher partial pressure of O2), which is helpful in several ways for the ECU. I don't think gutting the upstream pre-cat would change the pressure at the first O2 sensor, though.

Since the OBX does not have the neck-down before the first O2 sensor, it does seem possible this could reduce the ability of the ECU to fine tune A/F ratio. But I can't say the tail pipes have gotten any blacker since installing the OBX. They are always black!

 

Do you guys actually get soot on the boots of your cars like willy69 is getting with the modified header? I only get it on my exhaust pipes.

 

small little back dingleberries on the back of my car. Much worse prior to MTH, but still present..... Clay bar type of things.

Matt

 

Guess I'm not driving hard enough. I must rectify this.

 

Yea, what he said

 

So, after looking on-line both on e-bay and at "oem" parts houses, and not finding ANY stock headers for the R53 ('04 coupe mfg'd in 9/03 or later) I called my local BMW dealer to see about a 18407533402 header availability and price. The Parts desk clerk who took my call said they can get'em and they are $775 (+tax) but they have a "core charge" of $30, too!! (meaning they want the old header assy back!!) And, BTW, the core charge applies for all header assemblies for BMW and Mini alike.

Anyone know: is this core charge deal a California thing due to the tight-a_ _ state bureaucrats, or is that nationwide?

Also, has anyone had any luck finding these in "Pick-your-Part" or other auto salvage yards? I haven't had any luck so far, but I maybe am not going about it the best way I might(?). Any help/suggestions would be appreciated.

 

no offense... but... its 30 bucks!

 

it's $805, no core charge! Or gett it from Classic, with the 20% NAM discount....

Matt

 

Points well-taken.