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- Michigan
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- GenPu VRM MS3
so, this might be a weird question, but is it possible to port/bore out the stock mani to flow the same cfm flow as the 626? and keep the VICS/VTCS?
626 manifold
- Thread starter kachur779
- Start date
no, because the stock manifold breaks down into 8 (4 dual) runners rather than 4 single runners....you can bore out the 8 runners into 4 single runners but the passages would be huge in comparison with the 626 which, before you say it, is not necessarily better than the 626's runner diameters
I'm not too knowledgeable on the actual math to calculate the proper balance between runner size, length, etc...but I do know that there is a balance you must maintain between large and small
the 626 may not be a 'perfect' balance but from what I can tell it is a lot better than boring the stocker to 4 runners
another factor is that it would go from a large plenum, to a small runner, to a large runner, back down to a small runner, and then to the head.....which isn't necessarily optimum for airflow
I'm not too knowledgeable on the actual math to calculate the proper balance between runner size, length, etc...but I do know that there is a balance you must maintain between large and small
the 626 may not be a 'perfect' balance but from what I can tell it is a lot better than boring the stocker to 4 runners
another factor is that it would go from a large plenum, to a small runner, to a large runner, back down to a small runner, and then to the head.....which isn't necessarily optimum for airflow
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- Michigan
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- GenPu VRM MS3
well, i was just thinkin... the whole point of the 626 is to get the flow (high end/horse) right? well why not get the flow (horse) AND the low end torque? i dunno, it may just be my brain tickling and brainstorming, but it seems like a good idea to me.
you wouldn't have to calculate runner length, necessarily, but couldn't you do the same thing as cc (size) matching a cylinder head? then you wouldn't have to balance the big to small, but just take the biggest small runner, make them all of the small runners that size. then take the biggest big runner, and make all the big runners that size.
you wouldn't have to calculate runner length, necessarily, but couldn't you do the same thing as cc (size) matching a cylinder head? then you wouldn't have to balance the big to small, but just take the biggest small runner, make them all of the small runners that size. then take the biggest big runner, and make all the big runners that size.
you do not know what you are talking about
yes you have to calculate runner length in order to determine if it is going to be beneficial
no having a really large runner will not give you high end power AND low end torque
you also cannot take the smallest runner and make all of them that small AND make all of the runners as big as the biggest ones
I believe you have the way the stock manifold is designed confused....all 8 runners are the same size....the manifold opens and closes off four of the runners so as to give you low end power and high end power, because it is a viable length runner style manifold....there are sacrifices to this, mainly that you loose a cumulative amount of power in the high end and the low end (more so in the high end)
porting out the stock manifold (from the way I've seen it, and the only real way possible: turning it into a 4 single runner manifold, there isn't enough room to port all 8 runners) is pretty well useless, you'll have 4 WAY too large runners which makes the manifold inefficient
the 626 is probably the best comprimise you can get without switching to 505Zoom's manifold (which shows really promising gains)
yes you have to calculate runner length in order to determine if it is going to be beneficial
no having a really large runner will not give you high end power AND low end torque
you also cannot take the smallest runner and make all of them that small AND make all of the runners as big as the biggest ones
I believe you have the way the stock manifold is designed confused....all 8 runners are the same size....the manifold opens and closes off four of the runners so as to give you low end power and high end power, because it is a viable length runner style manifold....there are sacrifices to this, mainly that you loose a cumulative amount of power in the high end and the low end (more so in the high end)
porting out the stock manifold (from the way I've seen it, and the only real way possible: turning it into a 4 single runner manifold, there isn't enough room to port all 8 runners) is pretty well useless, you'll have 4 WAY too large runners which makes the manifold inefficient
the 626 is probably the best comprimise you can get without switching to 505Zoom's manifold (which shows really promising gains)
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- 2002 BJFW, 2007 BK3P, 1979 SA22C, 2005 BK3P
ouch, talk about blunt
we have bench tested the stock manifold VS the 626 manifold. the 626 manifold flows 40 CFM more than the stock unit with the flaps open all the way. 40 CFM, even with massive porting, is alot to overcome. at the end of the day, the stock manifold was designed the way it was to improve fuel efficiency and emissions at cold start while not sacrificing too much power. it was never designed to maximize power, and thats something that the 626 manifold simply does better.
agreed
ouch, talk about blunt
we have bench tested the stock manifold VS the 626 manifold. the 626 manifold flows 40 CFM more than the stock unit with the flaps open all the way. 40 CFM, even with massive porting, is alot to overcome. at the end of the day, the stock manifold was designed the way it was to improve fuel efficiency and emissions at cold start while not sacrificing too much power. it was never designed to maximize power, and thats something that the 626 manifold simply does better.
do you mind sharing what the stock manifold flows and what the 626 manifold flows?
also, have you bench tested the stock head?
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- 2002 BJFW, 2007 BK3P, 1979 SA22C, 2005 BK3P
200 CFM vs 160 CFM
thank you, and any chance you tested a stock head?
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- Michigan
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- GenPu VRM MS3
so, all we have to do is "bore" out the stock mani... i guess. that's what i'm going to do with my port/polish tools when i've got the time. i'm planning on upgrading everything in my car, just keeping it stock. so upgraded SMIC, upgraded "bored" (or whatever) intake mani, etc etc, and keep all the stock features like VTCS.
no it is not all you had to do to reach the same as a 626, there are airflow characteristics to take into account
just having four really large runners isn't going to give you the same gains as a properly tuned manifold (hence why 505zooms manifold shows such good gains, it's designed for a proper runner length to runner size to plenum size)
boring out the stock manifold will not see the same gains, and while you may see gains you will likely loose either a lot of low end power or a lot of high end power
just having four really large runners isn't going to give you the same gains as a properly tuned manifold (hence why 505zooms manifold shows such good gains, it's designed for a proper runner length to runner size to plenum size)
boring out the stock manifold will not see the same gains, and while you may see gains you will likely loose either a lot of low end power or a lot of high end power
Unless you've upgraded the cams/valves and done some additional headwork, I don't really see the point of swapping manifolds. Nor do I put a lot of stock in the one dyno floating around which shows no torque plot for this manifold. Potential peak power gains aside and 40 more CFM of flow is not enough to make me want to lose low end torque.
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- 2002 BJFW, 2007 BK3P, 1979 SA22C, 2005 BK3P
i think you'll find there is plenty of stuff posted that disagrees with this. any breathability upgrade for these engines is an improvement that yields results. trust me when i say this is easily the number one part i sell for mazdaspeed proteges, and not through any effort of my own. people buy it, it works well, yields noticeable results on or off the dyno and people post about it. the part has pretty much sold itself. my dealership usually has three or four on hand to meet demand. it really is a good mod for the money and if the dyno was a farce, people wouldn't be buying it because you're going to know when the car gains nothing from a part that claims X hp gain.
i'm honestly not sure you will see the same gains boring out a stock manifold.
yes it is. new from mazda as a kit.
Never said the dyno was a farce or that others should not consider the mod. I have seen plenty of threads that refer to the loss of low end torque. But the upper end gain is there for those that want that. I've only seen one post where the end user was not happy and his dyno revealed no positive results.
In no way am I saying or implying that anyone should not try this swap. Ultimately it depends on where you like your power.
In no way am I saying or implying that anyone should not try this swap. Ultimately it depends on where you like your power.
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- 2002 BJFW, 2007 BK3P, 1979 SA22C, 2005 BK3P
totally agreed
KrayzieFox
Member
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- 01 MP3 Turbo
That's exactly what it comes down to. If you don't want to lose the low end, removing the VTCS would be the closest improvement one could do. Anyone interested in removing the VTCS can feel free to check out my IM that's for sale.. all the work is already done and the price is pretty low.
http://www.mazdas247.com/forum/showthread.php?t=123727638
while you are a good seller and I got nothing against ya, I hate to go against your sale plug here....but removing either of the butterfly valves from the manifold is going to affect your low end
KrayzieFox
Member
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- 01 MP3 Turbo
No offense taken, and you are correct in that.. but it's not as much of a loss as it would be with the 626. I'm just saying that overall it's a good alternative to the 626 manifold.
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