Brettspeed cast manifold with G30-660 - info thread
11-23-2023, 01:08 PM
#276
11-23-2023, 02:14 PM
#277
Were you sitting stationary when it happened or in motion? I just bring that up because if you were crawling along for 3-4 hours and constantly slipping the clutch, I know my left foot would be getting tired, could it possibly have been stalled due to a bad start when you were leaving from a stop? Yeah it sounds silly, but sitting for that long in traffic doing the same motions over and over can kind of distort a person's perception of what actually happened when it stalled.
11-28-2023, 06:20 AM
#278
^^ let me correct you both; it depends on the fuel being used because obviously the difference between straight gasoline and E85 is not going to be a simple ratio as you did there. Most people don’t even recognize that stoichiometric for E10 pump gas is 14.1, not 14.7. Whereas stoich for E100 is 9.0. The reason being that ethanol is a highly oxygenated fuel. Which the calculations above don’t account for. And also why there’s more to the “E30 gets most of the benefit” fake news schtick for those who understand how to extract all of the performance benefit that a higher ethanol content has to offer.
Came here to post something else though, so will do that separate to avoid the inevitable argument likely to ensue from this one …
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Came here to post something else though, so will do that separate to avoid the inevitable argument likely to ensue from this one …
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, than it doesn't change for the mixture of the fuel (which is annoyingly not constant through the seasons in the year - less E in colder times)...the calc'ss and comment above were as written about mass of gas being flown
assuming same fuel before/after
11-28-2023, 05:40 PM
#279
true, but he wasn’t speaking lambda, and then other factors have to be considered that still support my position it has to be determined as a whole without errors of assumption.
You’re not a dummy, so stop acting like one and use your head to the potential I can see that it has.
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You’re not a dummy, so stop acting like one and use your head to the potential I can see that it has.
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MilosB (11-29-2023)
11-29-2023, 01:50 AM
#281
would be interesting to define/measure the ignition timing vs emap (can be aproximated by egt , the one before the turbo, not after it thought)
but the biggest problem with all these is accumulation / snowballing effect. a % here and there grows quickly to large changes.
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MilosB (02-27-2024)
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MilosB (02-29-2024)
02-29-2024, 04:15 PM
#286
I'll just answer this incorrect assumption and you can see how it might change your thinking.
The Siamese port flows approx. the same (or slightly more) than either of the side ports. I know this to be true .. absolutely no question!
How do I know ?
1/Years ago a video was posted showing an NA Renesis with headers on an engine dyno...... only one of the header tubes glowed red - the Siamese . For that to happen the Siamese would need to flow more than either front or rear.
2/That video gave me confidence to try something unusual. My previous manifold design used the Siamese port exclusively to supply the wastegate (See Brettus turbo 111 thread). Set up like that I was able to run at boost pressures down to about 7-8psi at peak rpm. Plugging into matchbot reveals that the siamese would have to flow more than 40% of the total engine output to achieve that!
As far as why my manifold works so much better :
1/Straight shot into the turbine from the rear port preserves the pulse energy from that port.
2/Lower volume
3/Better heat retention
4/Less bends all round
5/You run a T25 flange (vs T3) which is just too small and restrictive
6/More efficient turbo (compressor similar but turbine flows more and is more efficient ) BTW - looks like a T04b compressor housing in the pics - I found that housing to be quite inefficient on my GT35 setup .... adds 2-3 psi emap on it's own.
7/More efficient intercooler
8/ Exhaust post turbo is more free flowing
9/Possibly more free flowing intake ...is yours 76mm minimum diameter with a large filter ? The intake can make a huge difference if it's in any way restrictive.
All of those are making a small difference with perhaps 1/ being the biggest, but all combined it's a BIG difference.
I suggested years ago that you should start playing around with Matchbot because it will give you a better understanding of how each aspect of a setup affects things .
The Siamese port flows approx. the same (or slightly more) than either of the side ports. I know this to be true .. absolutely no question!
How do I know ?
1/Years ago a video was posted showing an NA Renesis with headers on an engine dyno...... only one of the header tubes glowed red - the Siamese . For that to happen the Siamese would need to flow more than either front or rear.
2/That video gave me confidence to try something unusual. My previous manifold design used the Siamese port exclusively to supply the wastegate (See Brettus turbo 111 thread). Set up like that I was able to run at boost pressures down to about 7-8psi at peak rpm. Plugging into matchbot reveals that the siamese would have to flow more than 40% of the total engine output to achieve that!
As far as why my manifold works so much better :
1/Straight shot into the turbine from the rear port preserves the pulse energy from that port.
2/Lower volume
3/Better heat retention
4/Less bends all round
5/You run a T25 flange (vs T3) which is just too small and restrictive
6/More efficient turbo (compressor similar but turbine flows more and is more efficient ) BTW - looks like a T04b compressor housing in the pics - I found that housing to be quite inefficient on my GT35 setup .... adds 2-3 psi emap on it's own.
7/More efficient intercooler
8/ Exhaust post turbo is more free flowing
9/Possibly more free flowing intake ...is yours 76mm minimum diameter with a large filter ? The intake can make a huge difference if it's in any way restrictive.
All of those are making a small difference with perhaps 1/ being the biggest, but all combined it's a BIG difference.
I suggested years ago that you should start playing around with Matchbot because it will give you a better understanding of how each aspect of a setup affects things .
I know what you mean by the glowing siamese tube, but i'm reminded of how when our cats get clogged, they also glow red, and it's because of the opposite effect - lack of flow...
Has anyone taken measurements of the siamese port? It would seem to me that consisting of two ports funneled into one, the outlet of the port could flow as much as either of the sideports, but each individual inlet in the port would not. in fact, given that it's divided inside, with the divider taking up room, it should flow a bit less than half of the regular port. So each half of the siamese being more restrictive than each side port, more flow would come out of the port with the lesser restriction - the side ports.
I absolutely welcome any correction to my logic here, just thinking out loud.
02-29-2024, 08:05 PM
#287
On a more topical note -
Has anyone taken measurements of the siamese port? It would seem to me that consisting of two ports funneled into one, the outlet of the port could flow as much as either of the sideports, but each individual inlet in the port would not. in fact, given that it's divided inside, with the divider taking up room, it should flow a bit less than half of the regular port. So each half of the siamese being more restrictive than each side port, more flow would come out of the port with the lesser restriction - the side ports.
I absolutely welcome any correction to my logic here, just thinking out loud.
Has anyone taken measurements of the siamese port? It would seem to me that consisting of two ports funneled into one, the outlet of the port could flow as much as either of the sideports, but each individual inlet in the port would not. in fact, given that it's divided inside, with the divider taking up room, it should flow a bit less than half of the regular port. So each half of the siamese being more restrictive than each side port, more flow would come out of the port with the lesser restriction - the side ports.
I absolutely welcome any correction to my logic here, just thinking out loud.
When I say CAN flow ----- I'm alluding to that fact that it does change if the backpressure is varied between the ports.
Also, the latest engine was performing better than anything else so far which I'm putting down to minimising flow from the Siamese and maximising flow from the side ports via porting changes.
Last edited by Brettus; 02-29-2024 at 08:23 PM.
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MilosB (02-29-2024)
03-02-2024, 12:11 AM
#288
wrt to the siamese port claims, seems to me that you forgot it sees twice the pulses than the end ports due to being on both rotors with 180° pulse spacing.
It might be worth considering going back and re-evaluating the situation taking this into account.
As one example, the visible temperature difference of an exhaust pipe is much less likely to be determined by flow rate as compared to exposure/contact time.
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It might be worth considering going back and re-evaluating the situation taking this into account.
As one example, the visible temperature difference of an exhaust pipe is much less likely to be determined by flow rate as compared to exposure/contact time.
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Last edited by TeamRX8; 03-02-2024 at 01:46 PM.
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MilosB (03-02-2024)
03-02-2024, 01:44 PM
#289
If we said for each rotor the siamese flows slightly over half what the side port does. For the front rotor we have say 64% out the side and 36% out the siamese and the same for the rear rotor. But considering the engine as a whole we have to halve those numbers so we get 32 + 18 + 18 + 32 for each of the four internal ports. Giving externally the sides flowing 32% each and the Siamese flowing 18+18= 36%.
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MilosB (03-02-2024)
03-02-2024, 03:55 PM
#290
Imho there is no issue in running more flow to the siamese port.. My car when purchased was remaped (without my knowledge of such) and uppon logging some i flund that at WOT and high rpms, the AFR was 14.5:1 and EGT being 950+°C...
the map got corrected and engine in the end died due to oil cooler rupture...
long story short, the front and rear irons were blue as hell in the area of exhaust port where it is not cooled (transmission side, and front cover side) while the middle was completely normal looking with 0 signs of overheating. Also, there was no damage on the rotors either.
based on that, my hypothesis is that the water cllling on all sidesof siamese port makes it much more resilient to heat than the other two.
the map got corrected and engine in the end died due to oil cooler rupture...
long story short, the front and rear irons were blue as hell in the area of exhaust port where it is not cooled (transmission side, and front cover side) while the middle was completely normal looking with 0 signs of overheating. Also, there was no damage on the rotors either.
based on that, my hypothesis is that the water cllling on all sidesof siamese port makes it much more resilient to heat than the other two.
03-03-2024, 07:00 AM
#291
my intent is not to say if it flows more or not, just that assumptions like 32/18 aren’t proof of anything. It’s just a guess.
why would it even be more than 1/2 of the end port? The end port is wider with more availability for flow to make the 90° turn, while the siamese port is not only narrower, but also has a divider plate in the middle choking off the turn even more. It’s less than 1/2 the width of the end port in that sense.
the siamese port could easily flow more just by the conditions that may result in more backpressure on the end ports compared to it
flow always takes the path of least resistance and wrt a wastegate valve, bias and other factors matter.
you have to go back to why there is a siamese port. Mazda found that too much combustion remained at the middle iron side with only end ports on the front & rear iron plates. So they added the siamese port to help address that. It didn’t have to flow a lot to achieve the desired emission result and they didn’t want to redesign the basic 13B configuration to accommodate a wider middle plate.
That the siamese port flows more sort of goes against basic logic, and even Mazda’s own discussion about it, but again this is without knowing the actual parameters, so I can’t say if it flows more or less. It doesn't add up in my mind is all I can say with any confidence.
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why would it even be more than 1/2 of the end port? The end port is wider with more availability for flow to make the 90° turn, while the siamese port is not only narrower, but also has a divider plate in the middle choking off the turn even more. It’s less than 1/2 the width of the end port in that sense.
the siamese port could easily flow more just by the conditions that may result in more backpressure on the end ports compared to it
flow always takes the path of least resistance and wrt a wastegate valve, bias and other factors matter.
you have to go back to why there is a siamese port. Mazda found that too much combustion remained at the middle iron side with only end ports on the front & rear iron plates. So they added the siamese port to help address that. It didn’t have to flow a lot to achieve the desired emission result and they didn’t want to redesign the basic 13B configuration to accommodate a wider middle plate.
That the siamese port flows more sort of goes against basic logic, and even Mazda’s own discussion about it, but again this is without knowing the actual parameters, so I can’t say if it flows more or less. It doesn't add up in my mind is all I can say with any confidence.
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Last edited by TeamRX8; 03-03-2024 at 07:14 AM.
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MilosB (03-03-2024)
03-03-2024, 07:31 AM
#292
Im not saying its one or another, just givjng an argument as to why the Siamese could flow more than the basic size would suggest.
since there is more continuous flow the max flow can be larger even for lower area.
just as a figure to try to get a "picture" of what I am saying.
You need almost twice the area to flow the same volume/time if the flow is pulsed at lets say 50% interval. Perhaps even larger area as pulses create resistance.
Another point might be that one rotors negative pressure pulse creates bigger pressure diferential on the port opening, resulting in higher flow rate
These are obviously just hypothesis I share, not a statement that it does results in higher or lover flow
since there is more continuous flow the max flow can be larger even for lower area.
just as a figure to try to get a "picture" of what I am saying.
You need almost twice the area to flow the same volume/time if the flow is pulsed at lets say 50% interval. Perhaps even larger area as pulses create resistance.
Another point might be that one rotors negative pressure pulse creates bigger pressure diferential on the port opening, resulting in higher flow rate
These are obviously just hypothesis I share, not a statement that it does results in higher or lover flow
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kevink0000 (03-03-2024)
03-03-2024, 03:41 PM
#294
Well we woukd need MAF sebsors in easmch exhaust port to quantity the exact flow. All the rest is just speculation.
03-12-2024, 06:54 AM
#295
the part you don’t seem to get in your usual thought process that leaves the thinking it through part out is that blocking the end ports will make the center port 100% but the total flow rate is going to tell the tale, i.e the path of least resistance is easily influenced in that regard. That won’t happen unless it’s being forced to, which is what’s going on in those instances.
when you get down to it, the one manifold design being peddled on here is essentially a log manifold with the WG on one end and the turbo on the other. It’s never been that great at lower rpm spool, because the flow path balance is anything but until the WG has to open. The Greddy is also poorly configured that way except 100% of the time. When an engine has equally spaced intake/exhaust events the optimum system in a 13B is going to equalize the flow paths for both rotors in every instance.
anything short of that isn’t fully optimized, which is my position since forever, but generally either not recognized as such, or easily dismissed being the convenient cop out.
at least cipriani is breaking the mold some, he deserves credit for that, and slash128 as well hasn’t gotten enough credit for his efforts to achieve 450 whp either.
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when you get down to it, the one manifold design being peddled on here is essentially a log manifold with the WG on one end and the turbo on the other. It’s never been that great at lower rpm spool, because the flow path balance is anything but until the WG has to open. The Greddy is also poorly configured that way except 100% of the time. When an engine has equally spaced intake/exhaust events the optimum system in a 13B is going to equalize the flow paths for both rotors in every instance.
anything short of that isn’t fully optimized, which is my position since forever, but generally either not recognized as such, or easily dismissed being the convenient cop out.
at least cipriani is breaking the mold some, he deserves credit for that, and slash128 as well hasn’t gotten enough credit for his efforts to achieve 450 whp either.
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03-12-2024, 07:47 AM
#296
well its not all about equalizing flow.. its also about minimizing the path of it to disperse as little pulse energy as possible..
For fastest spool, you need the minimal volume and not equal length.
The pulses might be not equally timed, but even that assumption that equal timing is best for turbo boost is false. 2 (or more) consecutive pulses with longer pause before the next one gives better spool than a perfectly spaced pulses. simmilar to why a divided twin scroll has better spool than merged. If merged is a necessity due to space ect...
"Banana" manifolds are beautiful, but most often it is not the best..
For fastest spool, you need the minimal volume and not equal length.
The pulses might be not equally timed, but even that assumption that equal timing is best for turbo boost is false. 2 (or more) consecutive pulses with longer pause before the next one gives better spool than a perfectly spaced pulses. simmilar to why a divided twin scroll has better spool than merged. If merged is a necessity due to space ect...
"Banana" manifolds are beautiful, but most often it is not the best..
03-12-2024, 02:46 PM
#297
when you get down to it, the one manifold design being peddled on here is essentially a log manifold with the WG on one end and the turbo on the other. It’s never been that great at lower rpm spool, because the flow path balance is anything but until the WG has to open. The Greddy is also poorly configured that way except 100% of the time. When an engine has equally spaced intake/exhaust events the optimum system in a 13B is going to equalize the flow paths for both rotors in every instance.
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Better than the Greddy system with a smaller turbo and better than the top mount EFRs that you used to claim would outperform it.
I have heard of small low mount EFRs that possibly spool quicker but struggle to make any kind of decent power.
I've tried to light a fire under you in the past to actually accomplish something yourself but it's been SIX YEARS since you started pedaling your equal flow design and still it's just bluster!
Get off your **** and do it already!
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