High Flow Cat Converter

Nikoman

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2014 Mazda CX-5 GT AWD
Any thoughts on a high flow cat improving MPG and/or HP?

Does the CX-5 have a second cat we can delete with a test pipe?
 
The CX-5 measures the temperature of the cat and increases the idle at speed and retards timing and makes it richer at start up to get the cat hot quick. I think if you remove the cat you will have to reprogram...
 
The CX-5 measures the temperature of the cat and increases the idle at speed and retards timing and makes it richer at start up to get the cat hot quick. I think if you remove the cat you will have to reprogram...

The second cat is not instrumented though, only the first.
 
So.... Does the 2014 CX-5 have a second catalytic converter?
 
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Years ago I read about some tests done by Hot Rod magazine where they tested a Camaro and found that the stock cat flowed better than an aftermarket high flow one and even a straight pipe didn't net much for gains. I think on a 4 cylinder you are just going to ruin a $1000 part and be disappointed with the results.
 
The cx-5 has two cats . One at the exhaust manifold (monitored) and the other is further down between the front doors. Unfortunately I don't know how restrictive they are. But just from my personal experience and thought is if there is a gain , the front (monitored) one is the one I would remove and keep the other one . As for emissions , I would run a non fowler or if one is available for our cars an o2 simulator.

For those that don't know:

-spark plug non fowler can be used to extend the o2 sensor away from the exhaust stream so that it detects less exhaust emissions . But it might still throw an internal code for the o2 sensor not being heated up enough . I know this from personal experience . But I still passed emissions.

-o2 simulator is small device you either splice or cutoff the o2 and solder in place. It will basically send the same signal/voltage to the ecu that the o2 would when everything is working as it should .
 
Well I am looking at cutting the cat on an oem mani and starting the t3 flange there. Should be enough space for the turbo
 
FWIW...

From what I remember from my B15 Sentra SE-R days, a catless header was worth around 15-16 wheel horsepower (stock header was super restrictive and the pre-cat had a tendency to break up on early QR25DE cars), while the catted Nismo header was worth around 12, so in aftermarket headers, pre-cats made a 3-4hp difference.

When Grassroots Motorsports did a Miata catalytic converter test, most of the gains were in the 1-2 hp range, and a test pipe didn't make any more power than the aftermarket high-flow cats. Thanks to that article, I ended up replacing my 1997 Miata's failing cat with a Magnaflow.

With my Mazdaspeed3, due to the downpipe being a PITA to install and the initial high-flow catted midpipe being improperly manufactured, I installed my Corksport turboback exhaust in segments, from the back to the front. By far the largest increase in sound came from the midpipe. I didn't dyno the intermediate steps because I wasn't curious enough to pay for that much shop time.

Given that info, I wouldn't expect more than a few horsepower from replacing or eliminating the first catalytic converter, and even less from replacing the secondary. We've come a long way from the days when catalytic converters robbed significant power.
 
The cx-5 has two cats . One at the exhaust manifold (monitored) and the other is further down between the front doors. Unfortunately I don't know how restrictive they are. But just from my personal experience and thought is if there is a gain , the front (monitored) one is the one I would remove and keep the other one . As for emissions , I would run a non fowler or if one is available for our cars an o2 simulator.

For those that don't know:

-spark plug non fowler can be used to extend the o2 sensor away from the exhaust stream so that it detects less exhaust emissions . But it might still throw an internal code for the o2 sensor not being heated up enough . I know this from personal experience . But I still passed emissions.

-o2 simulator is small device you either splice or cutoff the o2 and solder in place. It will basically send the same signal/voltage to the ecu that the o2 would when everything is working as it should .

the first cat (small one for warm-up purposes) you say is monitored? if you remove the cat that is monitored, you will need to tune your ECU, correct?

so the larger, main cat is not monitored? perhaps this is the one to remove because you will not get a CEL? the ECU should be able to adjust if it is not monitored.

here is a diagram: note the smaller warm-up cat is very small, no difference when you remove it so I think it's mainly a sensor or something.

sy2kd4.jpg
 
Hi, New to this forum, but have a related question. My lower catalytic converter was stolen out from under my car. Looks like they jacked it up and just sawed it off, two clean cuts. Dealership wants $1500 (Canadian) for the part which is absolutely ridiculous to me. I know they are expensive, but I feel like I could get a full custom exhaust for that! Without the cat the CEL is on obviously but it looks like the sensors are before the second cat so might just be triggering a pressure sensor? Anyone have any experience with aftermarket options that might be cheaper? I cant see this effecting the warranty as they would have to prove it was the fault of the aftermarket cat?


the first cat (small one for warm-up purposes) you say is monitored? if you remove the cat that is monitored, you will need to tune your ECU, correct?

so the larger, main cat is not monitored? perhaps this is the one to remove because you will not get a CEL? the ECU should be able to adjust if it is not monitored.

here is a diagram: note the smaller warm-up cat is very small, no difference when you remove it so I think it's mainly a sensor or something.

sy2kd4.jpg
 
Hi, New to this forum, but have a related question. My lower catalytic converter was stolen out from under my car. Looks like they jacked it up and just sawed it off, two clean cuts. Dealership wants $1500 (Canadian) for the part which is absolutely ridiculous to me. I know they are expensive, but I feel like I could get a full custom exhaust for that! Without the cat the CEL is on obviously but it looks like the sensors are before the second cat so might just be triggering a pressure sensor? Anyone have any experience with aftermarket options that might be cheaper? I cant see this effecting the warranty as they would have to prove it was the fault of the aftermarket cat?

maybe this will work for you?
http://www.magnumtuning.com/en/deta...le-specific-universal-installation/mazda/cx-5
 
Crawled under there to take a peek, unfortunately the lower O2 sensor is after the flange but before the second cat and looks like they stole that as well. Looks like it was taken off fairly clean at the plug so it should be easy to get a new one welded in.

Shawn
 
Crawled under there to take a peek, unfortunately the lower O2 sensor is after the flange but before the second cat and looks like they stole that as well. Looks like it was taken off fairly clean at the plug so it should be easy to get a new one welded in.

Shawn

Could just try cheap ebay cat, 2.5" can be had for like $20-30 USD.
 
Hi, New to this forum, but have a related question. My lower catalytic converter was stolen out from under my car. Looks like they jacked it up and just sawed it off, two clean cuts. Dealership wants $1500 (Canadian) for the part which is absolutely ridiculous to me. I know they are expensive, but I feel like I could get a full custom exhaust for that! Without the cat the CEL is on obviously but it looks like the sensors are before the second cat so might just be triggering a pressure sensor? Anyone have any experience with aftermarket options that might be cheaper? I cant see this effecting the warranty as they would have to prove it was the fault of the aftermarket cat?

My reocmendation is to buy an aftermarket high flow race cat. Just go aftermarket.
 
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