honestly i think the oem headers are pretty good as far as stock goes on most cars out there. if you are really set on changing them out tho the most cost effective solution would be to go with something like obx or megan racing headers. i think i got mine for like 120 bucks? then cut out your existing cat and go to any muffler shop and have them weld flanges on it in the same shape that the test pipe is that came with the new headers. sure there are better headers out there but this method is going to be wayyyy cheaper then any other solution. im in the same boat you are in and didnt want to weld or cut my old cat out. so iv just got the test pipe in and come time for emissions i will just swap the oem header and cat back in. i realize you may not have the option or the will to do that but truth is if you are trying to buy some headers and then buy a new bolt on cat(that may fall apart) you are going to be spending a lot and i mean A LOT more money doing it. just my opinion tho

 

The thing is once you start making changes to your car (aka mods) it costs money. You can do it cheap, but your'll be doing it again.

 

Reading this, I think I'll take the chance of installing my Magnaflow cat and see how it goes. I already have all my components, minus some fittings, for my straight exhaust system. I'll keep the stock cat (anyway they are worth some cash) and if I destroy my hi-flow cat, I'll get the stock one modified to fit my 2.5'' exhaust.

 

that may be true in a lot of areas when changing your car but in this area i dont see how it applies. iv never heard of any of these manifolds breaking in any way and the stock cat is well known to last longer then after market cats. so really on this "mod" if you do it expensive, you may end up being FORCED to do it again. use the extra money that you save for the install or a cam or tune. then again everyone has their opinion on how they think the exhaust set up should sound and thats something you cant argue. all i can say is i love my set up and wont be changing anything about it

 

dubstepsteve I don't disagree with what you are saying (read post #11). What I'm saying is if you want to change something research it an go with the one you think is best. It might not always be the cheapest.

 

thats very true. if you dont go with your gut and get what you really want from the start and try to cut corners instead you will almost certainly find some reason to become unhappy with it. im just a guy that has been extremely happy with his "cheap" set up. i just dont think there is enough of a difference in the perfect equal length runners and the ones that are slightly off to justify spending over a grand on them. if its a track car thats different. or some rotrex or turbo conversion or someone that is just trying to make the highest numbers they can on the dyno. on a street or daily driver application i just dont see it making enough of a difference. im not tryin to hate but i just feel like i need to defend the more conservative side of modding as it seems most people jump to the conclusion that they need the expensive stuff and that if its cheap it sucks

 

hey dubstepsteve i agree whith you, i just about to buy a header and i thinking that the megan is a good choice, and i have no problem whith the polution issue because here in my country we dont have that rigusly law, b ut the idea saving the cat is good, one question do you are running any upgrade in the ecu?

 

no, not at the moment unfortunatly that and some injectors would just about be the icing on the cake for me right now. just dont have the money saved up for that yet, even with what i saved on my headers

 

OBX. Stock cat. Done.

I wouldn't have replaced my headers unless something happened. Precat housing cracked, so I went with OBX. It's built well enough for under $200, and is way cheaper than stock. I could buy two OBX headers, if not three for the price of an RMW or Mynes header. As an added bonus, you get a nice bump in horsepower, though not as much as a top shelf part like Mynes/RMW.

 

I ended up going with the milltek Header and exhuast.

Heres why.

Milltek header - No one has ever had code issues, and i didnt have to have a cat welded on. Quality built and makes power!

Exhaust - Quality built, sounds good and makes power and no drone.

If your not going to do it right the first time dont do it at all.

 

Interesting discussion but who has consistently run their system at open track or DE's w/o melting their cat? Our S/C cars run some pretty serious exhaust temps. Will the MILLTEK take the abuse/higher temps? Any others? I'm of the opinion that a test pipe is just about imperative.

 

i wouldnt say a test pipe is imperative but it is however the best solution. but think about all the millions of miles people have been running on their stock cat without much of an issue. on the track you be stupid to be running a cat in the first place.

 

I had a Rmw shorty i ran for 30k never had a single issue, i traded it out for a stepped race header with a V band and cat still haven't had a issue.
and it sounds awesome.
I don't think that steve appreciates how important a proper sized primary and merge collector is.

 

sir i definitely have appreciation for anything that is well designed. but unless your rich your wasting your money on such an expensive manifold thats only going to be on your street car. and whats the point of a race header if your just going to weld a cat to it? defeats the whole purpose of those properly sized collectors if you ask me

 

I'm curious to see a Mini dyno sheet with and without cat, pretty sure the gains aren't enough to justify not running one, even if you track your Mini! There is much more powerful cars that still run one.

 

hey beliveme is a great diference runing any engine with a cat or with out it,remember the cat is like a mesh restricting the air out of your combustion chamber, when you put a test tube on the air runs free , i have in the past remove the cat on a 300zx turbo and i have a gain of 20hp (that car was for 1/4 mile competition)and with the stock piping, now you tell me if 20hp is not worthted

 

Yeah, but.. like I've said: a MINI dyno sheet! Most cars don't produce exactly the same HP from factory, let alone with mods, so comparing it to another car make/engine isn't a good example.

As for being worth it, for a track only car, I guess. For a daily driver, I don't know, I'm not a ''ecomaniac'', but I can't think of a good reason not to run a cat on a street car, I just don't find it right. Anyway, it's my opinion!

 

well i think your right on have it remove on a street care because of the pollution issue, but on the track every hp counts and i assure you that the mini will make more hp whit ot a cat maybe been concervative it will be around 7 to 10 but it have to be proven on a dino

 

so get a dyno chart up here and show me that im wrong and i will shut up.

the way the exhaust tone sounds after the cat has been taken out is a good enough reason for me

 

I see lots of MINI's coming to DE's in street trim but, as I see it, the problem with running a cat on track is the extremely high exhaust gas temps caused by the S/C combined with a rich mixture which can melt or block the cat, then you've got "limp mode" if you're lucky.

 

i can belive nobody has a dino on a mini with out a cat , i gona order mine next month , when i get it i will dino it and prove that is worthed to run with out it, more hp people

 

I was VERY disappointed with my OBX. It broke up after only about 15000 miles. I went back to the OEM, and have never been sorry that I did. I was really glad I kept the OEM.

On the other hand, I have been VERY happy with my Milltek cat-back. great sound and decent butt dyno gain.

My car is a 2004 DD with now 112000miles. the Milltek has been on it for almost 100K. I get comments from people about the good sound. One guy I work with, in particular, who is a Vette driver says he loves it ("for a 4-banger, of course!"). =D

 

The RMW shorty is a nice header. Mine was great at first but after about 6-8 months started throwing the occasional cat codes. YMMV with mods. The cat does look like a Random Tech cat. Regarding codes, the factory ecu measures the amount of oxygen stored in the cat and uses the change between primary to secondary o2 sensors to determine if its functioning properly. Eventually my codes became more frequent so I figured out how to adjust the failure threshold in the ecu software & reprogrammed it.

 

a rich mixture runs colder then running lean
do it man! id love to see the results
that sucks how did it break? did you have any loose or broken engine mounts?
sorry, what?
it does??? i always thought it was just to be absolutely positively sure?

 

To answer your question: Your Mileage May Vary