Go Go Ghetto MSP custom exhaust

well i'm glad to know that nothing's wrong with my computer. i'll have to listen to them when i get home from work.
 
ha ha thats funny the cat is after the 2nd O2 and no MIL!hahahahahahahaha


Is that oil on the bottom of your car?
eeew!
 
Questions answered

Yeah, I talked to the exhaust guy today. He said that he put it together just like the stock exhaust. As I am quite new to aftermarket tuning I wasn't exactly sure what to make of his explanations, but I compared it with the stock exhaust (picked it up from the shop today) just to be sure. He said that you can't mess around with the position of the cat. The only thing that he didn't put on the system was a resonator which we have on the stock system. If I was going to get a "check engine" light, he said that I would have gotten it long ago, since I have been ripping around for some two weeks and 750km since I got it put on.

As for the "weird-looking flange" after the S-pipe, he said that it was not a common piece that was readily available as a result of the odd angle that the screw threads run through it. He was forced to re-use the flange that was already there in a MacGuyver sort of way. We'll be able to clean it up once I get a custom S-pipe built.

As my mechanic aptly points out in the fly-by, I really need to work on my driving skills....LOL! Hey, but that it what practice is for. And I never claimed to be an expert.....just an apt and willing student....LOL! Didn't realize till I got the video transferred to my laptop that a helicopter had gone by at the same time....doh!

Rainman

Striker187 said:
man i dunno what you people are talking about. the o2 sensor is in the right place.....before the 2nd cat. you can clearly see the o2 sensor placed right after the flexpipe section but before the 2nd cat. you're fine rainman (2thumbs)
 

Attachments

i retract my previous statement. driving home, i was thinking about your setup and i realized blkzoomzoom is right. (doh) the cat should have been before the 2nd o2 sensor. why you haven't thrown a cel yet, i have no clue.
 
Check the specs

I asked the exhaust guy about this before I replied. I also checked the MSP specs (www.autocoast.com/mazdaspeedclub/03.5_mazdaspeed_specs.pdf) just to double check what he was saying. He said that he placed the O2 sensor in the same relative position as it was on the original system. I will post pics to show you what I am talking about.

He told me that there was ony a single cat on our system. I had thought that there were 2 so I checked it out myself. The other "cat" is not actually that, but rather a resonator. That is why the volume of your exhaust goes up markedly if you get rid of it, such as with a cat-less downpipe. On my system, he eliminated the resonator for increased flow and then put the cat and the O2 sensor in the same orientation as he found them on the stock system. He also said that it was not possible (or at least not a good idea) to move the cat or the O2 sensor from where the were originally intended to be for the reason of the dreaded CEL as you suggest. So no CEL because the system is designed like the original--less the resonator. The MSP specs state that we have only a single cat on our exhaust system. The resonator is there primarily for exhaust note and volume. Believe me, the exhaust is a hell of a lot louder now than it was stock! My wife likens it to a truck exhaust...LOL! In the pics that I will post tomorrow, you can see that on the stock exhaust the resonator and cat look different and the O2 sensor is before the cat in order to provide info on pre-treated exhaust gases.

Hang tight until I post the pics tomorrow.

Striker187 said:
i retract my previous statement. driving home, i was thinking about your setup and i realized blkzoomzoom is right. (doh) the cat should have been before the 2nd o2 sensor. why you haven't thrown a cel yet, i have no clue.
 
Last edited:
sorry dude but we have a resanator yes but it is after the 2 cats. the o2 sensor was designed for only one purpose and that is to read when the cat is bad.
our exhaust goes:spipe>down pipe>cat>02>cat>resonator>axle back



Rainman said:
I asked the exhaust guy about this before I replied. I also checked the MSP specs (www.autocoast.com/mazdaspeedclub/03.5_mazdaspeed_specs.pdf) just to double check what he was saying. He said that he placed the O2 sensor in the same relative position as it was on the original system. I will post pics to show you what I am talking about.

He told me that there was ony a single cat on our system. I had thought that there were 2 so I checked it out myself. The other "cat" is not actually that, but rather a resonator. That is why the volume of your exhaust goes up markedly if you get rid of it, such as with a cat-less downpipe. On my system, he eliminated the resonator for increased flow and then put the cat and the O2 sensor in the same orientation as he found them on the stock system. He also said that it was not possible (or at least not a good idea) to move the cat or the O2 sensor from where the were originally intended to be for the reason of the dreaded CEL as you suggest. So no CEL because the system is designed like the original--less the resonator. The MSP specs state that we have only a single cat on our exhaust system. The resonator is there primarily for exhaust note and volume. Believe me, the exhaust is a hell of a lot louder now than it was stock! My wife likens it to a truck exhaust...LOL! In the pics that I will post tomorrow, you can see that on the stock exhaust the resonator and cat look different and the O2 sensor is before the cat in order to provide info on pre-treated exhaust gases.

Hang tight until I post the pics tomorrow.
 
Gotta check this out more

I will have to check this out more. I will talk to the guy again and I will also take it to my dealer to have the service guy check it out to see why there hasn't been a CEL. This guy is very experienced and does a lot of custom work for some very nice show cars, albeit he does more work on domestics than he does on imports (does that make a difference??). I'll get back to you once I get more info.

Apart from the obvious controversy that the exhaust has caused on the forum, I am very pleased with the setup. Wish it was a tad quieter so that my wife wouldn't complain about it, but other than that it is the s***!

Rainman
wicked said:
by the way he did a good job on your setup.quality work.
 
And then there was only one

Still haven't had the chance to talk to the exhaust guy again, but check out this thread which also states that nature of our single cat system.

Rainman

http://www.msprotege.com/forum/showthread.php?p=1094742

Rainman said:
Just got my custom exhaust finished for a local show last week. Got some attention at the show, but with it being my first show and only a few mods, I didn't end up placing in the Protege class.

Anyway, I had a s-pipe back 3" aluminized steel, CRUSH-bent, over axle exhaust built with a single catalytic converter and a Magnaflow muffler. The car is more reactive now and the remaining post-flash hesitation is just about gone. I tried to get a muffler that looked close to the stock, but then I ended up picking one with a 4" round opening as it had bevelled edges which looked very clean. I love the sound that it makes, although it is a bit loud for my wife. On the highway cruising at 180 km/h it sounds great.

I know that for most people aluminized steel and crush bends are taboo, but for the money ($450 CAN, all parts and labour) I think that I did alright. I have only heard 1-2 backfires after driving it all week in various different types of situations (city, highway, idling, etc.).

I will post some movie clips and pix when I have time to take them. I await the flames for my crossover to the aluminized crush-bent darkside of the MSP force.
 
Not sure on this but here is my best guess on why you only have one cat,it is because you are in canada. MSPs in the states have two.

Don't quote me on this. Like I said this is just my best guess. (uhm)
 
My mechanic agrees

My mechanic (not the exhaust guy) suggested the same thing. In one of the other posts on this earlier I put a link to the MSP specs. Those specs state that the MSP has only 1 cat. My mechanic suggested that the emissions standards are different from state to state and also province to province. He figured that the difference is a result of the different emissions standards. If this is true then the O2 sensor would be in the correct spot for our single cat system since it would provide rich/lean info about the untreated exhaust gases to the ECU. That is why I haven't had any CEL yet. The system restores the configuration that was on the car so everything checks out OK. My $0.02.

Rainman

(
armando_026 said:
Not sure on this but here is my best guess on why you only have one cat,it is because you are in canada. MSPs in the states have two.

Don't quote me on this. Like I said this is just my best guess. (uhm)
 
Terminology

I agree that there are two cat-like structures that are installed on the stock exhaust, a primary and a secondary. However, they not both cats, in the sense that, the additional unit does nothing (to my understanding as explained by my mechanic) to treat exhaust gases. Its function has more to do with the the volume and tone of the exhaust note and less to do with engine pollutants. Therefore, the placement of the 02 sensor has more to do with its position relative to the actual cat that treats exhaust gases. That is, exhaust gas-----check rich/leanness of gases via 02 sensor to adjust the engine performance----clean exhaust gases.

Alas, never fear. It is still something that I am researching.

Rainman

tekkie said:
all MSP's have 2 cats including the Canadian ones
 
Since I've been reading here and there on this forum about the 2nd cat, which looks like a cat but some say it isn't, I went and took a good look at the pipe with these two piece since I've taken them off a while ago. Well, if it's not a cat then I've no idea of what this is! It's not straight through that's for sure and definitevely has a honeycomb pattern all the way through, just like a cat. Conclusion: all MSP (Canada and US) have two cats. Why? No idea, all I know is that the Impreza has even three so two shouldn't be too surprising....
 
Last edited:
Cat or no cat?

I agree that there are two similar looking sections on the exhaust that are shaped like a cat. One is about 2/3 of the length of the other, but the overall shape is the same. However, even the MSP specs (taken from the Mazdaspeed brochure pdf file) state that there is only a single cat on our exhaust system. I too looked at the pipe as I have the stock pipe sitting i my basement. I can see how both devices look like a cat. However, the more important question is what the devices do. If they are both there for the purpose of scrubbing exhaust gases clean of their pollutants, then yes they are both cats. But if only one device does this and the other has another purpose then they are not both truly cats, regardless of how similar their appearance.

Now if we could just get a Mazdaspeed technician to add their $0.02, we could finally lay this dog to rest....LOL! (help)

Rainam
thunder said:
Since I've been reading here and there on this forum about the 2nd cat, which looks like a cat but some say it isn't, I went and took a good look at the pipe with these two piece since I've taken them off a while ago. Well, if it's not a cat then I've no idea of what this is! It's not straight through that's for sure and definitevely has a honeycomb pattern all the way through, just like a cat. Conclusion: all MSP (Canada and US) have two cats. Why? No idea, all I know is that the Impreza has even three so two shouldn't be too surprising....
 
Rainman said:
If this is true then the O2 sensor would be in the correct spot for our single cat system since it would provide rich/lean info about the untreated exhaust gases to the ECU.

That is what your FIRST O2 sensor does. The second O2 sensor (the one in question here) checks the exhaust gasses after passing through the first cat to see if the converter is doing it's job. If there is indeed only one cat in the exhaust system, it's the cat-like structure BEFORE the O2 sensor, not after it.

You basically have 2 O2 sensors measuring the same thing in your setup.
 
Last edited:
Rainman said:
Now if we could just get a Mazdaspeed technician to add their $0.02, we could finally lay this dog to rest....LOL! (help)

Rainam

That's it, maybe it's a dog after all!!! LOL ;)
On a corollary subject: why did they restrict the pipe between the cat and the dog (sorry, can't help it!) to a diameter less than 2" (4.9 cm)??? I really don't understand that move from Mazda....
 
Undercoating for winter

Just looking at my pics again. The car looks so dirty because of the rustproofing that was sprayed on before the winter. It is an oil-based product so it looks like that. Wish I was somewhere warmer so that I didn't have to rust-proof it. Hopefully, only one more winter driving it before I can start storing it.

Rainman
gboromsp said:
Looks good, but dang your car is dirty underneath. I guess winter has affected yours a lot. I think I could eat off of mine. LOL
 
Maybe, just maybe I see what you're saying

After reading all of the thread again and checking out the pics, I think I see what everyone is talking about. However, if this is the 2nd O2 sensor, then where is the first on the MSP? Is it on the downpipe? Cause I don't see it in the pics. I'll have to get my mechanic to put it up on the hoist this weekend to take another look.

Also, if the 2nd O2 sensor checks that the first is doing it's job and the cat is after the 2nd in my case (my exhaust is apparently downpipe-flexpipe-O2 sensor-cat-exhaust without resonator-muffler) then my car should read that the cat is NOT doing its job and then I should get a CEL.....which I am not. Why? Moreover, if the 2nd O2 sensor is reading untreated exhaust gases then it would think that my engine is running rich and would lean my A/F mixture corrrect? Theoretically, I should have better gas mileage (which I don't, still 400-450km on a tank of 91 octane gas depending on how I drive it) and more linear acceleration (since I would be reducing the richness-mediated hesitation of our engine). Correct me if I am wrong cause I am trying to learn something here.

Rainman

C-Bass said:
That is what your FIRST O2 sensor does. The second O2 sensor (the one in question here) checks the exhaust gasses after passing through the first cat to see if the converter is doing it's job. If there is indeed only one cat in the exhaust system, it's the cat-like structure BEFORE the O2 sensor, not after it.

You basically have 2 O2 sensors measuring the same thing in your setup.
 
Rainman said:
Also, if the 2nd O2 sensor checks that the first is doing it's job and the cat is after the 2nd in my case (my exhaust is apparently downpipe-flexpipe-O2 sensor-cat-exhaust without resonator-muffler) then my car should read that the cat is NOT doing its job and then I should get a CEL.....which I am not. Why?

Exactly why everybody is so confused :)

I'll see if I can get you a pic of the first O2 sensor.
 
Back