mazda3 exhaust for cx5?

[MikeM.]

And if we make our CX-5 into a "full performance design" we would give up fuel economy, comfort, driveabilty, low end torque, reasonable sound levels, etc. Nobody would want the car (being a compact SUV) even if they could afford it.

It wouldn't cost any more just because the exhaust system and engine management was engineered and tuned more for the track and less for the street - it would just have different characteristics. It doesn't cost more or less to shape the header slightly differently for different design goals. But there is no practical way to achieve that on our CX-5's because there isn't a header/exhaust manufacturer out there that offers it with a chip or kit that can modify the engine management parameters.

 

[CX-SV]

It wouldn't cost any more just because the exhaust system and engine management was engineered and tuned more for the track and less for the street - it would just have different characteristics. It doesn't cost more or less to shape the header slightly differently for different design goals. But there is no practical way to achieve that on our CX-5's because there isn't a header/exhaust manufacturer out there that offers it with a chip or kit that can modify the engine management parameters.

"Full performance design" when talking about more than just exhaust header/system does cost more, when taking into account cost of high performance engines (not just exhaust system). Example: Lambo's.

 

[MikeM.]

funny read, shows how well you understand modern engines...

this is what CAN happen when you get a well designed aftermarket exhaust onto a modern engine design:
http://www.mazdatalkforum.com/viewtopic.php?f=10&t=2598&p=16207#p16207
granted, its not a civic, but it is a newer car.

What????

Are you really so naive to believe that a dyno chart uploaded by the retailer of the exhaust system is going to be an accurate representation of what you will get when you bolt their product on?

Are you aware that the dyno operator not only needs to know what he's doing but he needs to want accurate results in order for them to be comparable. There are 101 ways to make your product look better on back to back dyno runs - don't think for a minute that the lure of profitable sales doesn't make many of these "sales charts" unrepresentative of reality.

At least you didn't blatantly say "A dyno chart can't lie"!

 

[MikeM.]

"Full performance design" when talking about more than just exhaust header/system does cost more, when taking into account cost of high performance engines (not just exhaust system). Example: Lambo's.

That's obvious.

I hope you understood my point. I agree with your general position on performance headers, just saying they don't cost more to engineer and manufacture than one tuned for driveability, efficiency, longevity, etc.

 

[MikeM.]

yeah, it is funny when they 'sound' like they are going fast and yet I'm making no attempt to go fast at all and I'm out ahead of them.
But I'm not even a fan of the big V8 cars that make a ton of racket when going slow. To me a car like that should sound mellow at slow speeds and then when you really stand on it wake everyone up.

Hehe! But then the engine wouldn't sound "powerful" in normal driving, LOL!

For those who are sarcastically challenged, I fully understand and agree with your comments.

 

[CX-SV]

That's obvious.

I hope you understood my point. I agree with your general position on performance headers, just saying they don't cost more to engineer and manufacture than one tuned for driveability, efficiency, longevity, etc.

I was replying in the context of njaremka's comments obviously, "full performance design, nobody could afford". I do understand your point if we are talking only about exhaust system and cost.

 

[Suddueth13]

The CX-5 comes with an exhaust from the factory. So I'm not sure what you're saying. I was wondering what he hoped to gain with an exhaust made for a Mazda3.



LOL! Here we go again!

The exhaust systems on modern cars are not restrictive enough to reduce fuel economy. In fact, you will get lower fuel economy and worse throttle response if you change the back pressure characteristics and natural resonance frequencies of the stock exhaust without figuring how to correct the fueling. The engine is not designed to automatically adjust for a header or exhaust pipe with different characteristics - that's why your car will run worse, not better, after such a change. This is especially true in a car like the CX-5 which has a highly tuned header and exhaust system - all the operational thresholds and the tuning is designed for the characteristics of the system at various rpm's and throttle openings. Good luck finding anyone who knows how to make everything as good as it was with the standard exhaust.

I laugh at the "ricers" who pull away from the gas station with their new Honda (or insert make of your choice here) with the exhaust sounding louder and faster than a herd of wild buffaloes but the car going nowhere fast. More gutless than the stock car, many of them would have a hard time outrunning a herd of buffalo! But they have spent thousands of dollars absolutely ruining the throttle response and acceleration of their almost brand new car! Oh, and their fuel economy. They have wasted so much money that they can't even admit it to themselves that they made their car slower than ever. At least it sounds "cool" to their friends. I have to think these people have smaller than average penises. Or maybe just their brain.

But to answer your question, I was simply curious what he hoped to gain with an exhaust made for a Mazda 3. It's his car, I don't care if he wastes his money making it run worse. People do it all the time.

This shows what you know about flow dynamics in exhaust systems. Back pressure is never needed. NEVER. Anyone who thinks otherwise is misinformed. Exhaust VELOCITY is key. Keeping exhaust velocity up while freeing up flow allows the exhaust gasses to be scavenged out of the motor more effectively(in this case the header on the CX-5 does this enough). I can't speak for the CX-5 personally but the muffler on the Skyctiv 3 is very restrictive. With my Corksport exhaust I didn't lose low end torque or throttle response. I did gain mid range power/torque as well as great top end, and did in fact see better fuel economy. I averaged 32mpg before consistently and averaged 34mpg after with no other change other than the exhaust. Stock parts are almost always a compromise and not designed to be the best. (Again except the CX-5s header, that's just amazing lol)

 

[MikeM.]

This shows what you know about flow dynamics in exhaust systems. Back pressure is never needed. NEVER. Anyone who thinks otherwise is misinformed. Exhaust VELOCITY is key. Keeping exhaust velocity up while freeing up flow allows the exhaust gasses to be scavenged out of the motor more effectively(in this case the header on the CX-5 does this enough).

*Sigh*

Back pressure is not constant, it is dynamic and very complex. There are resonant frequencies that happen at certain rpm's and a well designed exhaust system is tuned to minimize the negative effects and harness the beneficial. By removing the back pressure (for example caused by the muffler) the rpm's at which a resonant frequency will happen will change and the effects of that resonance will change.

As smart as the engine management system on the CX-5 is, it is not designed to adapt to exhausts with different characteristics.

As to back pressure not being needed, all exhaust systems have back pressure and well engineered systems utilize this back pressure to great advantage. That's why the CX-5 has a 4 into 2 into 1 exhaust header. Changing the back pressure downstream of the header will mean the finely tuned header is not so finely tuned anymore.

You don't know what you are talking about.

 

[Suddueth13]

Sorry guy, back pressure is never needed. Exhaust velocity is what is needed. Those resonate frequencies are the exhaust pulses from each combustion chamber. A properly designed exhaust will increase over all flow while keeping exhaust velocity optimal by using the pulses from each combustion chamber to help scavenge the exhaust more efficiently. This is what the stock header on the CX-5 does so it can run 13:1 compression on 87 octane fuel amongst other things and get a complete combustion. The rest of the exhaust is then designed to try and maintain a high enough exhaust velocity for a given sound level that it has to meet. This is where your compromise is. I'd love to be able to cut open a CX-5 muffler and see how it's flow path is designed. This exhaust very well may be optimal since I have no experience with it personally but not all factory exhausts are optimal.

 

[MikeM.]

Sorry guy, back pressure is never needed.

Exhaust back pressure is present on all exhaust systems. And the CX-5 header and engine management system is tuned for the back pressure present with the stock muffler.

What is it that you don't understand about that?

Exhaust velocity is what is needed.

Now this is funny. Because if you want more velocity in your exhaust you simply need a smaller diameter exhaust system. This will raise the back pressure, increase the velocity and decrease the sound level. But then the flow characteristics would not match what the engine management system was expecting.

Oh, but I wish it were that simple to better the stupid automotive engineers.

 

[CX-SV]

Isn't a aftermarket exhaust now available for CX-5? (making the need to modify a Mazda3 exhaust to fit unnecessary)

 

[V8toilet]

MikeM you beat me to it. The CX5 has a tuned 4 into 2 into 1 long tube header and the Mazda 3 with the 2.0-liter Skyactive engine just has a standard exhaust manifold because the long tube header will not fit under the hood of the Mazda 3. The difference in peak horsepower is just 5 HP more for the CX5 2.0 but the torque curve for the CX5 2.0 is fatter than the torque curve for the 2.0 in the 3; both are Skyactive engines. The 2.0-liter engine in the CX5 is a highly tuned engine so good luck trying to improve its usable power. You may as well poke a hole in the stock exhaust and deal with the reduced torque and mileage and put the $1000 not spent on a new exhaust to something more useful.

 

[Gwynne_]

yeah i considered going custom and been looking into it for awhile now but it wasn't until recently when i looked under both vehicles and noticed the exhaust pattern was almost identical thats why i asked about the mazda3 exhaust fitting the cx5

CorkSport will be releasing an axle back exhaust for the CX-5 next month. Should be announcing sometime in mid Jan.

 

[V8toilet]

CorkSport will be releasing an axle back exhaust for the CX-5 next month. Should be announcing sometime in mid Jan.

If they keep the exhaust pipe diameter the exact same then they might have something that won't hurt the power.

 

[MikeM.]

MikeM you beat me to it. The CX5 has a tuned 4 into 2 into 1 long tube header and the Mazda 3 with the 2.0-liter Skyactive engine just has a standard exhaust manifold because the long tube header will not fit under the hood of the Mazda 3. The difference in peak horsepower is just 5 HP more for the CX5 2.0 but the torque curve for the CX5 2.0 is fatter than the torque curve for the 2.0 in the 3; both are Skyactive engines. The 2.0-liter engine in the CX5 is a highly tuned engine so good luck trying to improve its usable power. You may as well poke a hole in the stock exhaust and deal with the reduced torque and mileage and put the $1000 not spent on a new exhaust to something more useful.

Good points. The more I drive the CX-5, the more I am impressed with the Skyactiv technologies the Mazda engineers integrated into the engine, chassis and transmission. Some very active informational videos on the various Skyactive technologies are available here:

http://mazdausa.com/MusaWeb/skyacti...=1&s_kwcid=TC|21354|skyactiv||S|e|17275797952

I thought I was up to speed on SKyactiv but I was shocked how much I learned from what are really promotional videos.