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Discussion Starter · #1 ·
As the titles says MSDS have a Gen 3 Tri-Y Skyactive race exhaust header now in production at msdsinc.com.

1.6250″ primary ports, 2″ secondaries, 2.5″ final collector. metallic ceramic coating and 2.5″ flex downpipe. $585.00 racer net price.

MSDS - Exhaust Systems



Considering the Gen 3 skyactivs already have a race header (as explained by Dave Coleman in the vid below), will this make a noticeable difference? Is it worth ripping out the engine and replacing?

https://youtu.be/rNtS8qyjIJU?t=2m54s
 

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This header was actually designed to fit the cramped 2nd generation Mazda 3 skyactiv 2.0 engine bay. Although it would likely fit the larger 3rd generation engine bay, my enthusiasm for it went down after considering a number of factors. First off, the header is paired differently than the 3rd generation 4-2-1 header (check out the pic below). This makes it a non-sequential design which is less efficient. The other main concern I had was that the primaries are too long in proportion to the secondaries, which are just small collector pipes. The gen Mazda 3 3rd gen header has much longer secondary pipes, and a more balanced 4-2-1 design. The MSDS design is more comparable to a 4-1 design that achieves mainly in top-end gains, but may cause a loss in low-end if you already have the 3rd generation 4-2-1 header. The huge gains in low & mid range torque achieved from tuning a 3rd gen skyactiv are largely contributed by the stock 4-2-1 header:

Mazda 3 OV Tuned dyno:
http://mazda3revolution.com/forums/...us-tuned-gen-3-skyacitv-2-0-dyno-results.html

New Miata ND OV Tuned dyno:
Tuning: Mazda MX5 ND first look with GoodWin Racing - MX-5 Miata Forum

2014-Mazda3-exhaust-manifold.jpg

The 2nd gen skyactiv with the stock 4-1 header does not see such large low-end gains; instead only similar mid range & top-end gains. Finally, the O2 sensor bung was placed in one of the primary pipes, whereas it is placed in the final collector of the gen 2 and 3 skyactiv stock headers. This will likely effect 02 level reading and AFR control, which could be very detrimental for an engine that is setup for full time closed loop function (eg. closed loop control of AFR in cruise and WOT). If you already have the gen 3 stock 4-2-1 header, the advantages are that this header provides slightly larger diameter piping, cat-removal, and that header sound...But I would wait until someone releases a properly designed 4-2-1 header for the gen 3. Apparently BBR made one recently, full details not yet revealed:

http://www.bbrgti.com/product_details.php?id=11700&make=18&model=836
 

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I agree you'll lose some torque, but really not much at all. If you plan to track your car which you should if you decide to buy a header because it's kind of pointless otherwise unless you just want sound, you are rarely ever in low RPM band for torque. Usually always in 4k+ rpm range. The gains on a 2nd gen (2.0 non-sky) with an MSDS 4-1 header with removal of a 2nd cat as well was about 30bhp and 22btq this is to the crank (I have yet to dyno my car because I don't really care. I just saw gains via VDyno). You really don't lose much torque as the piping diameter is so small which helps create more torque. 8hp to tq difference is very similar to the stock difference so I'd say it wouldn't be bad to get the MSDS due to the removal of the cat alone.

Obviously this isn't the same engine, but it should not be much different.

You can see the low end torque gains between these two files (first graph is the 2nd revision of his tune. second graph is on of the last revisions)

1zdaj34.jpg

2mfq86.jpg
 

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I agree you'll lose some torque, but really not much at all. If you plan to track your car which you should if you decide to buy a header because it's kind of pointless otherwise unless you just want sound, you are rarely ever in low RPM band for torque. Usually always in 4k+ rpm range. The gains on a 2nd gen (2.0 non-sky) with an MSDS 4-1 header with removal of a 2nd cat as well was about 30bhp and 22btq this is to the crank (I have yet to dyno my car because I don't really care. I just saw gains via VDyno). You really don't lose much torque as the piping diameter is so small which helps create more torque. 8hp to tq difference is very similar to the stock difference so I'd say it wouldn't be bad to get the MSDS due to the removal of the cat alone.

Obviously this isn't the same engine, but it should not be much different
Those are some impressive gains on your MZR. I agree that a 4-1 header could make more top-end gains, but I believe it is more suited for MZR engines which differ substantially. The skyactiv engine was developed with low-end torque in mind. They gave the engine small intake and exhaust ports, and a more efficient 4-2-1 header to increase low-end exhaust velocity, and develop more low-end torque that could be achieved in previous Mazda engines.

SKY-G 2.0L Cylinder head - MX-5 Miata Forum

You could give the 3rd generation Mazda 3 a 4-1 like header, and gain some top-end while shifting the peak torque curve higher, but you are taking this engine out of its purposefully designed comfort zone. It was designed to make huge torque levels early (makes turbo like low-end torque when tuned) which is great for daily driving, as opposed to a race engine which prefers to keeps the revs high (more related to the MZR than the skyactiv). There is only so much top-end that it can develop with those intake & exhaust ports, and cams that are not race-oriented... Regarding the header, I think you would loose a lot more of that nice skyactiv low-end power by going from 4-2-1 to a 4-1 design then you noticed on your car when you went from one 4-1 to another. For example, look at the low-end power differences between a tuned skyactiv 2.0 with a stock 4-1 header and one that has a stock 4-2-1 header. Aside from 12:1 to 13:1 compression differences (which won`t change the power curve`s shape), my tuned 2nd gen skyactiv gains far less low-end with the same settings :surprise:

OV Tuned 2nd Generation Mazda 3 skyactiv 2.0:
Stock vs. Tuned- Gen 2 skyactiv 2.0.jpg

OV Tuned 3rd Generation Mazda 3 skyactiv 2.0:
OV Tuned 3rd gen skyactiv 2.0.jpg

There is also the issue of the O2 sensor position. MZRs have open loop WOT, whereas skyactiv`s now have closed loop WOT. Allowing the sensor to read O2 levels from only 1 exhaust tube compared to all 4 (stock design) can largely effect AFR control and power achieved in the skyactiv under WOT. Overall, I think this MSDS header is better suited for the MZR. Now if we ported the intake & exhaust heads, added race cams, and changed the header O2 sensor location...
 

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I don't disagree, but like I said the exhaust diameter is very small on that header. It is the same way on the MZR header. I agree about the AFR, but if you get a tune that won't matter too much.

Then again this is just about a header. Moral of the story. If you get a header, buy a tune too.
 

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Discussion Starter · #6 ·
Thanks for the input guys. I didnt realise that the header would be focused on delivering high end gains. Im not going to be tracking my car. Only looking for anything that can improve my spirited driving style. Im planning on doing a cold air intake and exhaust mod along with an OV tune. Do you guys think a H or X exhaust system would be a good upgrade over a catback/axleback (and indeed stock), or is the associated cost not worth it for what I want to do with my car?
 

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I just came across some dyno's that help support my theory for the skyactiv engine needing a real 4-2-1 header. OV Tuning just completed a dyno tune of a prototype 4-1 race header on a Miata ND (skyactiv 2.0 engine). They tuned the same car recently on the stock header with the same octane gas. You can see that the larger diameter race header moved the power curve up and caused a loss in low-end torque.

With the stock 4-2-1 header, compared to stock tune, the OV tune added 25-30 wtq gain at around 3000 rpm, reaching a peak of 162 wtq and 166 whp (blue is stock tune, red is tuned):
stock vs. OV tuned Miata ND.jpg

With the 4-1 race header, compared to stock tune, the OV tune added only ~5 wtq gain at around 3000 rpm, reaching a peak of 145 wtq and 164 whp (lowest is stock tune + stock header, blue is stock tune + 4-1 race header, red is OV tune + 4-1 race header) . That's a loss of 19 wtq in the low-end (~3200 rpm) and similar top end gains...
Race header Miata ND dyno.jpg

So the 4-1 race header offered some very slight advantage in the mid to top range (4200-5200), kept the top-end the same, and resulted in a huge low-end drop. The top-end is likely where the flow limits of the skyactiv engine kick in (see my previous post). Without doing some more engine work (eg.air manifolds, porting, etc), it seems that the stock 4-2-1 header is actually solid, and may already help pump out the limits of the engine. If an aftermarket 4-2-1 well designed header was offered (similar to Mazda design, but no cat and slightly wider), there may be some more mid range improvement, but one may question whether the cost would be worth it... As a side note, these dyno's help explain why the 2nd gen Mazda 3 skyactiv 2.0 gains much less low-end than a 3rd gen...
 
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Thanks for the input guys. I didnt realise that the header would be focused on delivering high end gains. Im not going to be tracking my car. Only looking for anything that can improve my spirited driving style. Im planning on doing a cold air intake and exhaust mod along with an OV tune. Do you guys think a H or X exhaust system would be a good upgrade over a catback/axleback (and indeed stock), or is the associated cost not worth it for what I want to do with my car?
From my last post, I'd say there is currently no skyactiv header available which would bump your mid range day-to-day driving experience. A cat-back exhaust will help pick up a few ponies across the rev range, but you won't feel the power gain (~5 whp). Axle-back, slightly less, and same story. Most people get an exhaust for the sound, and it also helps them pick-up a little extra power from a tune. Your best dollar-for-dollar upgrade that you can feel is an OV tune.
 

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Dang man, that sucks. Welp, anyways if you don't have a skyactiv get the MSDS header? lollllllll.

Hopefully the BBR company can give you all something to look forward to. The back pressure produced by the stock header must be real nice to be keeping the torque figures up that high.
 

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Most people get an exhaust for the sound, and it also helps them pick-up a little extra power from a tune.
I'm curious if this last statement is true. Because I did *not* want extra noise to interfere with my upcoming stereo upgrade I asked Mat about exhaust options. He said that the stock exhaust is "actually pretty good." So I wonder how much extra power you really get for the several hundred dollars for an aftermarket exhaust. (in addition to the noise - I mean sound) BTW, he said the same about any intake changes - more noise than improvement, except at the high end of the rev range - which I will not visit very often. I am much more interested in low-end "grunt" (read 0-60 time) and good hwy mileage.
 

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soo... where did you find that? is it 2.5 or 2.0? is it even skyactiv specific? link? or just post a picture lol
Haha...Ever the sceptic, chris sir? Look at the 4-2-1 loops....Better than MSDS, right? It's 2.0 gen3 Sky M3 specific my buddy arranged a group buy for at around $200ish. I'll share more once these get installed & dyno'd on their Ms.....
 

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Haha...Ever the sceptic, chris sir? Look at the 4-2-1 loops....Better than MSDS, right? It's 2.0 gen3 Sky M3 specific my buddy arranged a group buy for at around $200ish. I'll share more once these get installed & dyno'd on their Ms.....
Not trying to a skeptic, just trying to figure out which engine it's designed for. Can't really tell from just the picture. To be honest it really just looks like the OEM header w/o a cat on it. I'm investigating adding an up pipe to a modified oem header with a t3 flange on the end myself.
 

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Not trying to a skeptic, just trying to figure out which engine it's designed for. Can't really tell from just the picture. To be honest it really just looks like the OEM header w/o a cat on it. I'm investigating adding an up pipe to a modified oem header with a t3 flange on the end myself.
That's really just what it is...an improved version of the stock 2.0 gen3 Sky header which was already pretty optimized off the factory.:)
 

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Did ov use stock exhaust with fancy header?Why don't they dyno gen 3 with cs cat back?
On the Miata ND dyno runs with Goodwin, the first test was done on a Miata ND with stock header and aftermarket axle-back or cat-back exhaust. The second test was a long-tube 4-1 race header with a catback exhaust (full exhaust). The results showed that both configurations produces around 165 wheel hp, while the 4-1 header car lost some low-end (resulting from the characteristics of a 4-1 header). Based on the results, Mat/Goodwin racing and Long Road Racing all believe that the top-end limitation is not caused by the exhaust, rather from the air intake side. I say top-end limitation, as the top-end is where the most air flow is being pushed into the engine, and where it makes ~165 whp. They are currently testing areas of the intake system to find the limitation. They will start flow testing the small engine cylinder heads, and if that seems to be flow well, they will work their way to the air intake manifold, throttle body, intake air box, etc.

http://www.mazdatalkforum.com/viewtopic.php?f=10&t=3323&start=120

Since the Miata uses the same engine as a Mazda 3 skyactiv 2.0 (with some minor differences), if there is an air flow limitation in the Miata, there will be a limitation in the Mazda 3. Using a Corksport cat-back exhaust should not give you more top-end power on an OV tuned Mazda 3 2.0, if your tune is already causing you to hit an air flow limit (not exhaust limited). It may however, cause some gains in the mid-range power, where air flow is still not limited. With the stock tune, an aftermarket exhaust would show more top-end gains by this logic, since the stock map does not bring the engine to its air flow limit. Once the air flow limit is removed, the potential of the Miata ND 4-1 full race exhaust will be tapped into, and more top-end power should be made (that is their hope hehe).
 
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HotPipes got a good 4-2-1, guys.
This looks like a very nice header for the Gen 3 Mazda 3. Slightly wider than stock pipes, cat removal, balanced 4-2-1 length design; definitely better than the MSDS design. This may help boost low/mid-range further... but if there is an air flow limitation on the top-end, it will need to be resolved first before we see a bump in power in the top-end of a tuned car. Hopefully, the cylinder heads are not the limitation, as it is very expensive to have them ported. Also expensive to get aftermarket cams, which may help fix that problem.
 

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This looks like a very nice header for the Gen 3 Mazda 3. Slightly wider than stock pipes, cat removal, balanced 4-2-1 length design; definitely better than the MSDS design. This may help boost low/mid-range further... but if there is an air flow limitation on the top-end, it will need to be resolved first before we see a bump in power in the top-end of a tuned car. Hopefully, the cylinder heads are not the limitation, as it is very expensive to have them ported. Also expensive to get aftermarket cams, which may help fix that problem.
Totally agree. Hope limits won't need head/cam tweaking. Mat will eventually get to see how this header performs with his tune. Prototype saw promising results on stock map. Premature to share w/ these still on the way. We'll see.
 
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