Has anyone try to clean.up the flow of the std header?
I'm slightly confused why Mazda development came up with this design yet it seems the headers out the are 4 Stroke style! My point is you can't put a 4 Stroke exhaust system on a 2 strokes or it goes poop!
The 2 strokes exhaust is a thing that requires thought from the word go! Due to how the pressure waves and correcting of the expelled gas makes or breaks performance. It's not how fast you get it out!
Robin
Std. Header tune
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Re: Std. Header tune
It’s definitely not worth it, just buy a Toyo
Pete
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Re: Std. Header tune
There are long, balanced-length headers available but none work with the original cat, as there just isn't room.
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Re: Std. Header tune
Um.... why would they put a 2 stroke exhaust on a 4 stroke engine?
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Re: Std. Header tune
despite its initial appearance and its oil consumption the triangular wonder is a 4 stroke engine
one interesting thing though is the flow of the centre ports compared to the outer ports as they are smaller and won't flow as much so will need a different length primary as the effective timing is different due to different back pressure
probably not a big difference and the whole exhaust port arrangement flows so badly anyway you have your work cut out trying to find gains with it
hence the reason folks do peripheral port builds
one interesting thing though is the flow of the centre ports compared to the outer ports as they are smaller and won't flow as much so will need a different length primary as the effective timing is different due to different back pressure
probably not a big difference and the whole exhaust port arrangement flows so badly anyway you have your work cut out trying to find gains with it
hence the reason folks do peripheral port builds
Last edited by 350matt on Sun Nov 18, 2018 8:38 am, edited 1 time in total.
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Re: Std. Header tune
Yes, it's a four stroke. And yes, there are gains to be had, but not from anything you can buy off the shelf. And if you do design your own then it will come with compromises that you might not be preparred to put up with. (noise, heat, cat placement, cost).
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Re: Std. Header tune
Mid iron exhaust is completely different and much smaller yet headers don't seem to accommodate this!
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Re: Std. Header tune
the toyo manifold sold by many outlets is basically the same pattern for all of them and its made down to a price, and they are rarely flat unless you buy one of the better made ( £500+) items
if you look on the flange of it does have a smaller hole for the middle but thats about it
If you take a look at PeteH's manifold (see his build thread) you'll see its very long primaries and very little restriction at all
however for a lot of folks this isn't tenable as they need a cat to pass an MOT with and a silencer that doesn't make your ears bleed on the motorway...
the chief problem is the crap exhaust port, as there's little to be had be removing restrictions downstream of it
now if you were remaking the centre and end irons you could do something about this as I'm certain if you remove the water jacket restrictions and have a port without a 90degree turn in it and sharp edges everywhere you could uncork it quite effectively
if you look on the flange of it does have a smaller hole for the middle but thats about it
If you take a look at PeteH's manifold (see his build thread) you'll see its very long primaries and very little restriction at all
however for a lot of folks this isn't tenable as they need a cat to pass an MOT with and a silencer that doesn't make your ears bleed on the motorway...
the chief problem is the crap exhaust port, as there's little to be had be removing restrictions downstream of it
now if you were remaking the centre and end irons you could do something about this as I'm certain if you remove the water jacket restrictions and have a port without a 90degree turn in it and sharp edges everywhere you could uncork it quite effectively
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Re: Std. Header tune
Just for clarity, I have a cat, and a silencer, although your ears may still bleed.....
There is room for a larger silencer on my system.
(and, although reduced restriction is helpful, that's not the key for power).
There is room for a larger silencer on my system.
(and, although reduced restriction is helpful, that's not the key for power).
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Re: Std. Header tune
Pete can you pm or email pics of your header as my surfing abilities are useles
rob.r2rc@gmail.com
Robin
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Re: Std. Header tune
The link to my build thread is in my signature. Just scroll back a few pages and you'll find the pics.