Hello I am new here, with that being said I suck at forums so if this information is elsewhere I'm sorry to make a new post.

Here is my real question I bought a 2004 rx8 probably about 4 weeks ago, it is my first rx8. I bought it already equipped with a AEM intake, Axial Flow short throw, and a Greddy cat back.

I am planning on buying a BHR midpipe because I think my cat might be going bad anyway. and I would like to know the pros and cons to having a midpipe over having a cat. Where I live they do not do emission tests so that really isn't a con for me but I have read bad things about having a midpipe like you will get excessive exhaust fumes and what not. So I would really appreciate if someone could do a short list of pros and cons, and also if the BHR midpipe will fit with my GReddy exhaust without having to purchase other things to make it work.

thanks, Badbul

 

Even if your cat isn't going bad, you should see a horsepower increase. This will be even greater if you get the ecu tuned to your setup.
You will likely get a CEL displayed on the installment panel. That will likely affect resale value.
Email BHR and ask how it fits with the Greddy. It's a common catback and he should be able to help.

 

Thanks for the reply, I have a CEL light on right now, It read a O2 censor which is getting fixed thursday. Would a bad o2 censor cut power?

 

I have the Greddy SE cat-back and a BHR midpipe and the fit up just fine you shouldn't need anything else, and if you get a CEL from not having the cat it wont cut power ( i had mine that way for about 3 months before i got the ECU tuned).

 

The CEL for not having a cat is P0420 - Catalytic converter below efficiency threshhold.

If the CEL you currently have is one of the CELs for the front O2 sensor (or Bank 1 Sensor 1, or Upstream, depending on what your reader's definition is), then you could easily be losing power from that. If it's for the rear O2 sensor (or Bank 1 Sensor 2, or Downstream) then you only lose a bit of gas mileage when cruising on the highway.


Advantages to a catless midpipe:
- More power
- Cat can no longer fail and damage sensors/engine
- Juvenile enjoyment to be had from flames/backfires (may draw unwanted attention or ire)

Disadvantages to a catless midpipe:
- More exhaust fume smell (can be mitigated heavily with tuning, and draws the ire of friends, family, and significant others)
- May throw the P0420 CEL (which can prevent you from passing emissions in OBD2 inspection states unless it's blocked with an ECU flashing option, MazdaEdit or an AccessPORT)
- Unable to pass a sniffer test in sniffer emissions states

 

Thanks guys for the responses, they have been very helpful. My next question is since a Midpipe removes the catalytic converter, which if I'm not mistaken has a O2 censor in it, would that hurt gas mileage, which doesn't matter to me really lol.

And also what are the codes numbers for bad Front and rear O2 censor?

 

Won't affect gas mileage directly. That's the front O2. You will get lower gas mileage because you want to hear your car so you give it more throttle.

 

The cat has the rear O2 sensor in it, but the midpipes typically have an O2 sensor bung to just transfer the rear O2 sensor over. The BHR midpipe does for sure. The O2 bung option on the website is to add a 2nd bung, you get 1 for free.



It's that bit sticking out to the side from the middle. Screw the O2 sensor in there.


The rear O2 sensor mileage impact is REALLY small though, maybe 1mpg if you normally get 22-23 highway.

 

Alright Thanks a lot gentlemen, I really appreciate the help on this! I think I'm gonna go with the BHR midpipe for sure. You guys wouldnt happen to know of any places around West Virginia than can properly tune the ecu? maybe in Pittsburgh?

 

There aren't many in the US. Your best bet would be to just get the AccessPORT or MazdaEdit, and then work with people here (over in the ECU tuning subforum to be more specific) and learn yourself. A few of the tuners will even give webinar classes from time to time, which is very much worth the time and money.

 

Alright sounds good thanks!

 

I've gathered from reading other threads that people don't much like him but i had MazdaManiac do my tuning when i bought the AP from him. I don't know if thats the way you want to go but for me at least it worked out fine.

 

For years he was the only real option. But he is a lousy businessman and rubbed a lot of people the wrong way. He was eventually banned from the community because of this combination.

Since he was banned, people have been far more open about discussing tuning, and there have been quite a few advancements that have shown that MM's way of tuning isn't nearly as ideal as it could be. His remote tuning service is rather good from a communication point of view (it is now anyway), but it certainly isn't king of the hill any more. He is still an option, but there are better ones available now.

Your mileage may vary.

 

I just went with him because I would like to learn to tune on my own but i wanted a new tune for the coils and to increase the OMP rates, and since i want to make damn sure i know what i'm doing before i try and tune it myself (and probably grenade my engine). His route just seemed like quickest and simplest, for the time being.

 

Yup. Just providing the reason behind your prior statement of general opinion.

 

FWIW, I don't think you can get the polished BHR pipe anymore.
Shore is purty tho.

 

I have another question if any of you guys are still around, I'm ordering my BHR midpipe; Should I get the optional Second O2 Bung?

 

That is only used for wideband tuning mods, so if you keep it stock, then you don't need it.