Buschur Ported exhaust manifold, how much was YOURS ported?
Evolving Member
Joined: Mar 2007
Posts: 272
Likes: 0
From: In front of a Catia screen
if one of the vendors could do a simple test using a flow rate indicator or a velocity meter like the man in the vidoe below is doing then that would be great. Just a suggestion!
http://www.youtube.com/watch?v=nnctm9def8y
http://www.youtube.com/watch?v=nnctm9def8y
This does not mean you will make more power!
if u try to dyno the two which the vendor did, people would start asking why the second one wasn't retuned............etc it would just be easier to measure the physical properties between the two and prove which one delivers the highest flow rate. DONE!
[QUOTE=Bob@MAPerf;7627745
The rest of the portwork that everyone is missing, are the transitions from runner to the turbo flange, and they are definitely not straight beveled like the BR version.....[/QUOTE]
AH! That's the answer I have been looking for....
Few people know how to make a transition, most murder it or leave a point on the top, or just leave it.
I don't totally disagree on making the exhaust manifold bigger then the port, Just not as big as the gasket. We do that on our intakes, fight reversion by making the intake manifold a tad smaller.
The rest of the portwork that everyone is missing, are the transitions from runner to the turbo flange, and they are definitely not straight beveled like the BR version.....[/QUOTE]
AH! That's the answer I have been looking for....
Few people know how to make a transition, most murder it or leave a point on the top, or just leave it.
I don't totally disagree on making the exhaust manifold bigger then the port, Just not as big as the gasket. We do that on our intakes, fight reversion by making the intake manifold a tad smaller.
Former Sponsor
Joined: Feb 2009
Posts: 45
Likes: 0
From: Minnesota
AH! That's the answer I have been looking for....
Few people know how to make a transition, most murder it or leave a point on the top, or just leave it.
I don't totally disagree on making the exhaust manifold bigger then the port, Just not as big as the gasket. We do that on our intakes, fight reversion by making the intake manifold a tad smaller.
Few people know how to make a transition, most murder it or leave a point on the top, or just leave it.
I don't totally disagree on making the exhaust manifold bigger then the port, Just not as big as the gasket. We do that on our intakes, fight reversion by making the intake manifold a tad smaller.
j/kI agree that there are way to many people that pretend they can port, but very, very few can port well, and even fewer still have any idea the specific science behind what they do.
Former Sponsor
Joined: Feb 2009
Posts: 45
Likes: 0
From: Minnesota
On the exhaust side, I can hog out all the runners to the max I feel safe, flow significantly more than stock, to achieve what? Some higher flow #? It's not all about that. By hogging it out you effectively change the system's AR (think of the mani as an extension of the turbine housing) and while it's possible you can make more up top, you generally induce more lag, and can sometimes sacrifice a bit of mid range power. Make sense?
Essentially I would rather have a port/runner as small as possible, with the highest velocity. That would be your best performer.
A good example of this is I have a competitor in another market, selling a head that flows 310 on the intake side, and mine flows 308. Would you buy his just based off the number? Or would you want more pertinent information like his is about 6mm larger than stock ports, with no guides (cut to the roof), and mine is stock sized with guides scalloped into the bowl....
Well there is airflow quantity, and airflow quality, and they don't always seem to appear together.
On the exhaust side, I can hog out all the runners to the max I feel safe, flow significantly more than stock, to achieve what? Some higher flow #? It's not all about that. By hogging it out you effectively change the system's AR (think of the mani as an extension of the turbine housing) and while it's possible you can make more up top, you generally induce more lag, and can sometimes sacrifice a bit of mid range power. Make sense?
Essentially I would rather have a port/runner as small as possible, with the highest velocity. That would be your best performer.
A good example of this is I have a competitor in another market, selling a head that flows 310 on the intake side, and mine flows 308. Would you buy his just based off the number? Or would you want more pertinent information like his is about 6mm larger than stock ports, with no guides (cut to the roof), and mine is stock sized with guides scalloped into the bowl....
On the exhaust side, I can hog out all the runners to the max I feel safe, flow significantly more than stock, to achieve what? Some higher flow #? It's not all about that. By hogging it out you effectively change the system's AR (think of the mani as an extension of the turbine housing) and while it's possible you can make more up top, you generally induce more lag, and can sometimes sacrifice a bit of mid range power. Make sense?
Essentially I would rather have a port/runner as small as possible, with the highest velocity. That would be your best performer.
A good example of this is I have a competitor in another market, selling a head that flows 310 on the intake side, and mine flows 308. Would you buy his just based off the number? Or would you want more pertinent information like his is about 6mm larger than stock ports, with no guides (cut to the roof), and mine is stock sized with guides scalloped into the bowl....
I guess to me, I like seeing more of this data rather than just dyno #'s and that is just a personal preference simply because the type of tune, air conditions, fuel, elevation, heat saok from multiple runs....etc that could effect it. ur an ME so iam sure u have thought of this
anyways this was just a suggestion.
cheers!
Former Sponsor
Joined: Feb 2009
Posts: 45
Likes: 0
From: Minnesota
I totaly agree with you, but how would u collect this data if ur only relying on the dyno #'s where there are many variables that keep on changing from run to run?
I guess to me, I like seeing more of this data rather than just dyno #'s and that is just a personal preference simply because the type of tune, air conditions, fuel, elevation, heat saok from multiple runs....etc that could effect it. ur an ME so iam sure u have thought of this
anyways this was just a suggestion.
cheers!
I guess to me, I like seeing more of this data rather than just dyno #'s and that is just a personal preference simply because the type of tune, air conditions, fuel, elevation, heat saok from multiple runs....etc that could effect it. ur an ME so iam sure u have thought of this
anyways this was just a suggestion.
cheers!
How much is there total to be gained over a stock manifold?
Ok, since we are talking some level of fluid dynamics, I want to ask about your approach on a couple issues I noticed while porting my exhaust manifold.
1. Pulse converter technology
The stock manifold seems to have a pulse converter type shape in the runners at the turbo collector area. For those not familiar, a pulse converter in a manifold is a shape in the port that basically the cross section tapers down to increase velocity in the forward direction. Thus, when the air hits the collector area, it's been smoothly accelerated and leaves the smaller port in a fast and organized manner. The exhaust in the collector however is not moving nearly as fast and is much less organized. It just sees a smaller hole so it has less potential to flow back up the runner.
This is used pretty extensively in diesel manifolds where air velocities and temperatures (both forms of energy) are lower. Everything I have found has suggested it doesn't work on high RPM gasoline engines though since there is a lot more available energy to force backflow. I find it interesting in the first place the Mitsubishi used it, but the stock evo really was targeted for a peak torque at a low RPM, so it's not THAT out there.
It seems like A LOT of this shape gets messed up on the stock manifold just by simply putting a smooth radius from the floor of the runner into the collector. It changes the cross sectional area a noticeable amount. Are you guys trying to maintain some of this pulse converter shape while reducing separation of the boundary layer?
2. Anti-reversion at the head flange
Now, I get the idea behind this, I actually built a tubular manifold and used this large change in cross sectional area approach at the head specifically to implement it. But after I built the manifold, I started to question my approach. Airflow can go from a larger crossection to a smaller cross section with very little turbulence. The airflow merely builds up small separation zones that smooth the transition and then because the air velocity and momentum is increasing, it keeps the boundary layers from entering into the flow path. Air can, to a large extent, create it's own radius inlet, particular in pipe flow cross sectional area changes.
The opposite is the case though going from small to large cross sections. The air tumbles heavily at the cross section change and because the air velocity is dropping, it causes the boundary layers to expand further into the flow path.
Effectively this could potentially cause a higher flow loss coefficient in the small to large configuration then in the large to small. This is the exact opposite of what we want for anti-reversion.
I can see it going either direction, and I’ve been meaning to do some CFD work just to look at this issue. Has anybody done actual testing on just this one change to see if it actually does produce any meaningful gains?
1. Pulse converter technology
The stock manifold seems to have a pulse converter type shape in the runners at the turbo collector area. For those not familiar, a pulse converter in a manifold is a shape in the port that basically the cross section tapers down to increase velocity in the forward direction. Thus, when the air hits the collector area, it's been smoothly accelerated and leaves the smaller port in a fast and organized manner. The exhaust in the collector however is not moving nearly as fast and is much less organized. It just sees a smaller hole so it has less potential to flow back up the runner.
This is used pretty extensively in diesel manifolds where air velocities and temperatures (both forms of energy) are lower. Everything I have found has suggested it doesn't work on high RPM gasoline engines though since there is a lot more available energy to force backflow. I find it interesting in the first place the Mitsubishi used it, but the stock evo really was targeted for a peak torque at a low RPM, so it's not THAT out there.
It seems like A LOT of this shape gets messed up on the stock manifold just by simply putting a smooth radius from the floor of the runner into the collector. It changes the cross sectional area a noticeable amount. Are you guys trying to maintain some of this pulse converter shape while reducing separation of the boundary layer?
2. Anti-reversion at the head flange
Now, I get the idea behind this, I actually built a tubular manifold and used this large change in cross sectional area approach at the head specifically to implement it. But after I built the manifold, I started to question my approach. Airflow can go from a larger crossection to a smaller cross section with very little turbulence. The airflow merely builds up small separation zones that smooth the transition and then because the air velocity and momentum is increasing, it keeps the boundary layers from entering into the flow path. Air can, to a large extent, create it's own radius inlet, particular in pipe flow cross sectional area changes.
The opposite is the case though going from small to large cross sections. The air tumbles heavily at the cross section change and because the air velocity is dropping, it causes the boundary layers to expand further into the flow path.
Effectively this could potentially cause a higher flow loss coefficient in the small to large configuration then in the large to small. This is the exact opposite of what we want for anti-reversion.
I can see it going either direction, and I’ve been meaning to do some CFD work just to look at this issue. Has anybody done actual testing on just this one change to see if it actually does produce any meaningful gains?
Former Sponsor
Joined: Feb 2009
Posts: 45
Likes: 0
From: Minnesota
So just radius the top will add that much to a mani? I know we can pick up 50 or so over someone else's ported head..just can't wrap my head around there being that much power in a manifold that is against another that is ported.
How much is there total to be gained over a stock manifold?
How much is there total to be gained over a stock manifold?
Former Sponsor
Joined: Feb 2009
Posts: 45
Likes: 0
From: Minnesota
Ok, since we are talking some level of fluid dynamics, I want to ask about your approach on a couple issues I noticed while porting my exhaust manifold.
1. Pulse converter technology
The stock manifold seems to have a pulse converter type shape in the runners at the turbo collector area. For those not familiar, a pulse converter in a manifold is a shape in the port that basically the cross section tapers down to increase velocity in the forward direction. Thus, when the air hits the collector area, it's been smoothly accelerated and leaves the smaller port in a fast and organized manner. The exhaust in the collector however is not moving nearly as fast and is much less organized. It just sees a smaller hole so it has less potential to flow back up the runner.
This is used pretty extensively in diesel manifolds where air velocities and temperatures (both forms of energy) are lower. Everything I have found has suggested it doesn't work on high RPM gasoline engines though since there is a lot more available energy to force backflow. I find it interesting in the first place the Mitsubishi used it, but the stock evo really was targeted for a peak torque at a low RPM, so it's not THAT out there.
It seems like A LOT of this shape gets messed up on the stock manifold just by simply putting a smooth radius from the floor of the runner into the collector. It changes the cross sectional area a noticeable amount. Are you guys trying to maintain some of this pulse converter shape while reducing separation of the boundary layer?
2. Anti-reversion at the head flange
Now, I get the idea behind this, I actually built a tubular manifold and used this large change in cross sectional area approach at the head specifically to implement it. But after I built the manifold, I started to question my approach. Airflow can go from a larger crossection to a smaller cross section with very little turbulence. The airflow merely builds up small separation zones that smooth the transition and then because the air velocity and momentum is increasing, it keeps the boundary layers from entering into the flow path. Air can, to a large extent, create it's own radius inlet, particular in pipe flow cross sectional area changes.
The opposite is the case though going from small to large cross sections. The air tumbles heavily at the cross section change and because the air velocity is dropping, it causes the boundary layers to expand further into the flow path.
Effectively this could potentially cause a higher flow loss coefficient in the small to large configuration then in the large to small. This is the exact opposite of what we want for anti-reversion.
I can see it going either direction, and I’ve been meaning to do some CFD work just to look at this issue. Has anybody done actual testing on just this one change to see if it actually does produce any meaningful gains?
1. Pulse converter technology
The stock manifold seems to have a pulse converter type shape in the runners at the turbo collector area. For those not familiar, a pulse converter in a manifold is a shape in the port that basically the cross section tapers down to increase velocity in the forward direction. Thus, when the air hits the collector area, it's been smoothly accelerated and leaves the smaller port in a fast and organized manner. The exhaust in the collector however is not moving nearly as fast and is much less organized. It just sees a smaller hole so it has less potential to flow back up the runner.
This is used pretty extensively in diesel manifolds where air velocities and temperatures (both forms of energy) are lower. Everything I have found has suggested it doesn't work on high RPM gasoline engines though since there is a lot more available energy to force backflow. I find it interesting in the first place the Mitsubishi used it, but the stock evo really was targeted for a peak torque at a low RPM, so it's not THAT out there.
It seems like A LOT of this shape gets messed up on the stock manifold just by simply putting a smooth radius from the floor of the runner into the collector. It changes the cross sectional area a noticeable amount. Are you guys trying to maintain some of this pulse converter shape while reducing separation of the boundary layer?
2. Anti-reversion at the head flange
Now, I get the idea behind this, I actually built a tubular manifold and used this large change in cross sectional area approach at the head specifically to implement it. But after I built the manifold, I started to question my approach. Airflow can go from a larger crossection to a smaller cross section with very little turbulence. The airflow merely builds up small separation zones that smooth the transition and then because the air velocity and momentum is increasing, it keeps the boundary layers from entering into the flow path. Air can, to a large extent, create it's own radius inlet, particular in pipe flow cross sectional area changes.
The opposite is the case though going from small to large cross sections. The air tumbles heavily at the cross section change and because the air velocity is dropping, it causes the boundary layers to expand further into the flow path.
Effectively this could potentially cause a higher flow loss coefficient in the small to large configuration then in the large to small. This is the exact opposite of what we want for anti-reversion.
I can see it going either direction, and I’ve been meaning to do some CFD work just to look at this issue. Has anybody done actual testing on just this one change to see if it actually does produce any meaningful gains?
For the anti reversion feature, by the manifold and head's design, you have to incorporate more anti reversion that is there in stock form (IMO). This is why I nearly gasket match, then smooth taper to the runners. Yes, it is possible that some flow may be compromised in the process, but what is gained by way of less reversion, lower cylinder temps, therefore more timing, and ultimately more power, more than offsets the negative.
Some of this is more speculative, and we don't have full NASA type data proving, or disproving these applications, we always rely on the dyno or other real world tests to show where the work is going. Thus far we have been doing well, performance wise too.
-Bob
BOB, have you guys considered doing any casting work?
http://store.forcedperformance.net/m..._Code=EMFPRace
If FP can offer up an investment cast manifold for under $300 on the DSM, it seems reasonable to believe it could be done on the EVO as well?
It seems like you've made some decent improvements on the EVO manifold, but as mentioned, you are still heavily limited by the factory casting. If there is lots of room left for improvement, starting from (almost) scratch and building a replacement manifold that maintained the factory mounting location should pay off, especially considering the HUGE interest in stock-framed turbochargers lately.
Just about everybody makes or is working on a stock frame based evo turbo.
http://store.forcedperformance.net/m..._Code=EMFPRace
If FP can offer up an investment cast manifold for under $300 on the DSM, it seems reasonable to believe it could be done on the EVO as well?
It seems like you've made some decent improvements on the EVO manifold, but as mentioned, you are still heavily limited by the factory casting. If there is lots of room left for improvement, starting from (almost) scratch and building a replacement manifold that maintained the factory mounting location should pay off, especially considering the HUGE interest in stock-framed turbochargers lately.
Just about everybody makes or is working on a stock frame based evo turbo.