Mazda5 Custom 2.5 inch exhaust

[Enzo5549]

Hello Everybody,

This will be my first posting after relying on this forum for getting specs, ideas, and how-to info for my 2007 Mazda 5 for over a year now. Every time I did an Internet search on a topic for my Mazda...links to this forum would always show up. I have already used some great ideas/updates/upgrades from other forum members, and have also purchased some products from a couple of the main sponsors.

So I feel I should now contribute to this great forum, and hope this posting may help others who may want to tackle this kind of project.

I too, like many would like to squeeze out as much power from the 2.3L engine, and Im sort of disappointed that Hypertech has not found it worth their while yet to create a custom ECM profile/program for the Mazda5 as they have for the Mazda3.

So for now, Ive just decided to improve the breathing of my Mazda 5 with a K&N Typhoon Cold Air Intake, and a custom 2.5 inch cat-back exhaust. I first got the ideas after seeing these on the Internet.

http://www.srmotorsports.com/mazda5_performance_exhaust_system_parts.html
http://www.importtuner.com/powerpages/impp_1106_2009_mazda5_sport/

I found out later though that SRmotorsport has discontinued making the stainless steel exhaust for the Mazda5, and 5Zigen has closed their North American office.

Both options were not cheap, but I thought a custom made exhaust could not be any more. This is part A of a two part project, as I didnt want to do it all at once and wanted to see/feel the difference each section made. I also want to point out that this project may not be as cost effective for everybody as Im very fortunate to have a good friend who just happens to own a machine shop. I will be adding the custom axle back muffler section later, but want to mention that the work done so far has already given a noticeable increase in exhaust flow & improved in performance. Its also even given the stock muffler a burble/growl that it never had before.

We re-used the original hangers and input flange from the secondary Catalytic, but my friend insisted that we make a new outlet flange from scratch. This would be the stout connection needed when we connect Part B to the rest of this project. The rest of the parts where purchased locally. I went to Metal Mart in Port Kells to get the 5 ft T304 2.5 OD tubing at $9.98 per foot, and got all the Vibrant parts at Mopac in Langley.

Here are the links to the Vibrant parts that Ive used so far, and Ill probably continue to use Vibrant for the muffler, and mandrel bent tubing for part B, as Ive been happy with the quality Ive seen so far. Special thanks to Len at Asian Pacific Manufacturing in Surrey as he actually did all the work...I was just his helper.

http://vibrantperformance.com/catal...a5374dd4&products_id=572&cpath=1022_1065_1115

http://vibrantperformance.com/catal...0a5374dd4&products_id=46&cpath=1022_1033_1055

http://vibrantperformance.com/catal...a5374dd4&products_id=127&cpath=1022_1068_1126

 

[phunky.buddha]

Very cool! Will you be able to dyno test the results as you go? I wish you were down here in Texas- I could help you with power measurements...

Did you think about going with 3" piping? You'd gain more on the top end without losing much down low compared to the 2.5". The 240sx guys were getting pretty good gains on their 2.4L engines jumping up to 3" pipe without losing to smaller pipe at all, and their engines made about the same amount of power as our 2.3s stock.

 

[phunky.buddha]

Just got done looking through all the pictures- did you have space to put in a longer resonator? It looks like there's quite a bit of opportunity to quiet down the exhaust even more without losing flow in the straight sections if you add a longer resonator section. Just curious- I'm sure it sounds fine as is!

 

[Enzo5549]

Just got done looking through all the pictures- did you have space to put in a longer resonator? It looks like there's quite a bit of opportunity to quiet down the exhaust even more without losing flow in the straight sections if you add a longer resonator section. Just curious- I'm sure it sounds fine as is!

Hi phunky.buddha,

I wanted to make sure that we had enough clearance to make it around the bends under the car and stay close to the shape of the stock exhaust. I also didnt want the custom exhaust hanging any lower than the original height. The clearance around the rear axle is going to be tight already with the 2.5 inch pipe, but I know my buddy will able to design an awesome custom muffler setup when I get all the parts ready.

Here is what the modifications has already done to improve the sound from the STOCK muffler.

 

[phunky.buddha]

Sounds pretty good! I guess the last time I was under the car it looked like there was plenty of room to run 3" pipe, but probably not in exactly the stock routing or bends. With the sound as it is in your clip, I think I'd probably want to run a chambered muffler or something with an S-bend setup like the Dynomax Super Turbo to take out some of the higher pitch sounds- but that's just me.

 

[Silentnoise713]

Awesome. A+ for taking the road less traveled! Is the whole exhaust work Part A? Does part B include the words tubular + turbo + manifold? (yes)

A former member referenced a link to a Chinese Mz5 forum post about a custom cat-back exhaust system that dyno a gain of 17(?) WHP using 2.5 tubes. I dont recall the gains exactly but it was in the double digits and sizable for what it was. However, I also dont remember if it added headers I dont think it did. I cant read the site but it had dyno charts and I think it may have been made for retail. Unfortunately, the link is dead last time I checked back. At least this reaffirms there is noticeable gains below doing some exhaust work.

 

[Enzo5549]

Hi Silentnoise713,

No, part B will only be a custom axle back muffler section/addition . Unless Hypertech changes their mind and creates a custom program for the Mazda5, I feel that putting a turbo without some sort of engine management upgrade/control will only be asking for a reduction in engine life.

I did think about installing a header after looking at a posting from dima_rus, and is one of the reason why I decided to use Vibrant parts for this project, as his Vibrant header looked to be of high quality.

I asked Tekam Automotive in Burnaby about installing a header on my Mazda5 as they are my local Mazda Performance shop, and with a history of dominating races back in the days of the Westwood Race track....I trust their advice.

The guys at Tekam mentioned that a header would dissipate heat too fast, and that I would have to at least wrap the entire header to retain some of that heat or it would start playing havoc with the readings that the O2 sensors would be picking up/sending back to the Engine Computer Management system. These could possibly bring on the dreaded check engine light , and that the stock ECM programming would be frantically trying to compensate for all the hard work youve done putting in the header.

Thats why a custom/programmable Engine Management program is so critical for getting the most noticeable and immediate gains from any modern engine nowadays. So thats why I thought it would be best to leave the stock exhaust manifold/catalytic converter/O2 sensors alone, and just go old school and modify it downstream.

Here is a diagram of the stock exhaust layout.

 

[phunky.buddha]

Thanks for the diagram! I guess those two tunnel members might have to be modified to allow a larger pipe to pass through?

 

[rat240]

me want custom exhaust

 

[w2zoom]

Now you got me thinking of an exhaust for my 5. Can you get the weight of stock muffler please?

 

[Enzo5549]

"part b" parts

Now you got me thinking of an exhaust for my 5. Can you get the weight of stock muffler please?

I remember the stock muffler being heavier than I thought it would be, but I'll weigh it when I take it off for the last time.

Here are the parts that I've acquired for Part B. I decided to go with Vibrant parts again for the muffler and the exhaust tip, and got them at Mopac again . I went to Unified Alloys in Langley this time for the 90degree bends as they were a little cheaper at $23.00 each then getting the 180 degree mandrel bent tubing from Vibrant. I got one extra just in case, but I know I can return it if not needed.

From the U-J bend in Part A I had a small bend left and a little over a foot length from the 5foot tubing. I went back to Metal Mart in Port Kells and got an extra 2ft of 2.5 inch tubing, and 30 inches of stainless steel rod ($2.50/Ft) for the new hangers as I expect that the stock hanger will not work with the shape of the new muffler.

Len suggested that I get the double walled exhaust tip as they look and sound better than the tips with the rolled ends. He also wanted me to mention a very important safety tip when welding under or on a car, and that's to:
ALWAYS disconnect the battery terminals as the high voltages used in welding could cause damage to the electronics in the car. I also disconnected the two connectors to the engine CPU to be extra safe.

As I'm restricted to the available free time at my buddy's machine shop, Part B may not happen until the new year, but I 'm excited to see what this new freer flowing muffler section will do for the Mazda5.

http://vibrantperformance.com/catalog/product_info.php?cPath=1022_1031_1110&products_id=31

http://vibrantperformance.com/catalog/product_info.php?cPath=1022_1034_1056&products_id=86

 

[w2zoom]

Those are some nice looking parts.

 

[phunky.buddha]

Again, very nice with part B! If you have any drone when you're done you could add a Helmholtz resonator...

 

[w2zoom]

any progress on this?

 

[Enzo5549]

Now you got me thinking of an exhaust for my 5. Can you get the weight of stock muffler please?

Hi Everyone,

Getting Part B started has taken a bit as the weather has been colder than usual. To answer the question about the weight of the stock muffler section.....according to my digital bathroom scale it weighs 20 pounds.

My buddy and I have actually*just* completed the basic fabrication and installation of the new custom muffler section, and so far the power gains have been very noticeable. 2.5 inch tubing though is probably* the largest diameter* you'd want to use as there was not much extra space around the cross member.

Here are some pictures during the fabrication. I'll be uploading more pictures of the muffler in the car and some sound clips soon.* I'm very happy with how it looks, and the performance gains have been quite surprising. Throttle response has now greatly improved throughout the rev range, with stronger pull all the way to redline.

More seat time behind the wheel will be needed to get a better tally of the improvements, and how it's like now as a daily driver.

 

[w2zoom]

those are some awesome pics thankx your into made up my mind to get this done next.

 

[Enzo5549]

Hi Everyone,

Here they are. I did have to make a slight cut underneath the bumper to clear the muffler, but in hindsight I may have cut more than actually needed. Here is the sound clip of how the new muffler sounds at idle and at revs.

As an early observation, which I'm sure I was NOT able to do before....and may need confirmation from others, but while in first gear and already moving at about 10-15 mph .... I can now easily break traction and spin the front tires (even on dry pavement) if I just floor the accelerator. What do you guys think is that not normal...or am I just imagining things? I will continue to do some more testing ( when safe to do so) on the responses to throttle in the other gears and keep everyone posted.

 

[rat240]

it sounds great

 

[w2zoom]

like the sound and looks of it (rockon)

 

[foxhound1979]

oh man,that is loud aaand i like it !
great job !