Stock Greddy turbo compressor flow
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I managed to find this flow chart for the 18G greddy turbo (Compressor Inducer 50.5mm Exducer 68mm) that comes with the Greddy kit for the RX8 . The chart references the TD05H housing which is smaller than the TD06H that comes with the kit but the numbers should be roughly the same.
. I have attempted to place on the chart what air flow we see in our engines at various WHP (at 7000rpm onwards) with the standard greddy kit pipework in place. https://www.rx8club.com/attachment.p...1&d=1321900368 . This chart illustrates what many of us already knew about the turbo . EG : *The compressor is too small for the engine *Even at low boost the compressor runs way outside its efficiency island therefore making a lot of hot air. *Running the engine as a 4 port (ie blocking off the aux ports)will improve the efficiency of the compressor at all boost levels.Making the compressor a much better fit for the engine. . . What the chart does illustrate also is that , as you increase the boost the turbo eases closer towards running efficiently but that there is no boost pressure (at high RPM) that you can run that allows the turbo to operate within its design efficiency range. Flame suit ready . |
again, you dont need to run the blocking plate as long as you take the time to tune the car properly
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you mentioned in one of the other threads that you found the correct 20g compressor flow map online, would be good to post for comparison.
possibly also BNR 57 trim and 60-1 upgrades? |
Originally Posted by RWD+LSD=Zoom
(Post 4129778)
again, you dont need to run the blocking plate as long as you take the time to tune the car properly
What kind of efficiency numbers lies on the right side of the map is unknown to me:crazy: So question is, what consumes less turbine power and creates lower discharge temperatures at same mass flow in this very example - higher PR with higher efficiency number or lower PR with unknown efficiency number?:suspect: |
I was simply adding on to his post, not disagreeing with it.
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Flame on!
3.5 psi loss across the system at 300 whp :SHOCKED: and you don't really 'tune' for what is described here as increasing the turbo efficiency via the block off plate. you just turn off the APV (set it to open at a point where you will not reach) in the tune. |
The Greddy turbo is a TD06-18g.
Not an insignificant distinction. I posted the flow diagram for the TD06-18g 3.5 years ago. http://www.mazdamaniac.com/images/mi...g_18g_3071.jpg |
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Yes - I have been referencing that comparison chart myself for some time . However it always bugged me that the chart you posted didn't seem to make any sense whatsoever when comparing it to what happens in reality . EG : Greddy turbos making 270+WHP regularly and one example making 293whp . At 36lbs/min which is the limit of flow for the green chart you posted - 250whp should be the absolute maximum whp - yet ...it's not . After doing some searching around I found 20g and 18g charts that actually make some sense when measured against real life performance . I believe the chart i posted above is correct and your one ..... not . Here is the TD06 20g chart that is plastered all over the net for reference - nothing like your one . https://www.rx8club.com/attachment.p...1&d=1321933909
Originally Posted by MazdaManiac
(Post 4130041)
The Greddy turbo is a TD06-18g.
Not an insignificant distinction. |
And your turbine flow as it figures into total system flow?
Oh yeah - you forgot about that. Start over. |
Originally Posted by MazdaManiac
(Post 4130212)
And your turbine flow as it figures into total system flow?
Oh yeah - you forgot about that. Start over. Tell you what ..... If you can provide any scrap of evidence that your chart is in fact correct for either the 18g or the 20g (and my two charts are not) I challenge you to post it here . |
Originally Posted by NgoRX8
(Post 4130024)
3.5 psi loss across the system at 300 whp :SHOCKED:
. If there were other people making that sort of power and measuring this stuff out there ,other than myself, I'm sure they would see the same result with this kit. A friend has a two gauge set-up . One on the uim and another at the turbo . Pressure drop early in the rpms is almost non existent . Past 6000 one gauge goes down the other goes up . Interesting to watch in real time . |
which does which
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PSI goes up at the turbo as the resistance to flow increases and the UIM gauge goes down .
It's a happy coincidence that the extra resistance from the restrictive pipework seems to actually be helping us in this scenario . As the PR increases, the efficiency of the turbo is getting significantly better. It also helps to explain why so very few people have made good power with an upgraded turbo . The resistance to flow must have an effect on the turbine side also , making the actuator ineffective , as pressure behind the turbine/wastegate increases. |
Do you even say this stuff again in your head before you post it?
Does the idea that total flow is a system make sense to you?
Originally Posted by Brettus
(Post 4131329)
PSI goes up at the turbo as the resistance to flow increases and the UIM gauge goes down .
The UIM gauge goes down? Why? You just said the "resistance" increases. Why would the pressure drop?
Originally Posted by Brettus
(Post 4131329)
The resistance to flow must have an effect on the turbine side also , making the actuator ineffective , as pressure behind the turbine/wastegate increases.
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Originally Posted by MazdaManiac
(Post 4131738)
Do you even say this stuff again in your head before you post it?
.
Originally Posted by MazdaManiac
(Post 4131738)
Does the idea that total flow is a system make sense to you?
Originally Posted by MazdaManiac
(Post 4131738)
The resistance increases? How? It is a fixed volume (if you forget about the increasing volume from the added flow paths).. Resistance to flow increases as flow increases - that is pretty fundamental . It only becomes a fixed volume at about 7000 rpm (in my case). At that point the turbo gauge appears to stabilise somewhat while the uim gauge gradually drops away as rpms climb.
Originally Posted by MazdaManiac
(Post 4131738)
The UIM gauge goes down? Why? You just said the "resistance" increases. Why would the pressure drop?
.. As for why it drops - I think It is because volume flow (from 7000rpm) is static while rpms are climbing . Therefore the engines ability to consume the available air increases . But am not 100% sure , how about you explain that one for us ?
Originally Posted by MazdaManiac
(Post 4131738)
What? So, if the flow decreases (as a result of some sort of increasing resistance, despite an increase in compressor efficiency from a higher Pr) on the cold side it increases on the inlet of the turbine? So, now the cold side is driving the hot side?!? I'm pretty sure that isn't how a turbo works
.. You know damn well what I'm trying to say here - and that garbled pile of words is not it ! |
Originally Posted by Brettus
(Post 4131800)
I think about it in a logical way - you should try it .
Originally Posted by Brettus
(Post 4131800)
Resistance to flow increases as flow increases - that is pretty fundamental .
Resistance does NOT increase as flow increases. It remains the same. It is a fixed value. If flow increases, then pressure must increase if resistance to flow remains the same (i.e. the path doesn't physically change). You are trying to invent a fourth variable. There is just volume, pressure and temperature. These are the components of mass flow. (Well, really, density, velocity and area. But, since area is fixed, velocity converts to pressure and you are left with density, which is a function of temperature. This whole relationship between velocity and area is also one of your fundamental misunderstandings, re your previous attempts at obfuscating the discussion about volute.) If you are seeing a decrease in the manifold pressure, it isn't because the "resistance" is increasing, it is because mass flow is decreasing at a greater rate than the Ve of the motor. Mass flow decreases because pressure decreases or temperature increases. That's all there is to it. The whole system is part of the volute. Changes in area convert velocity into pressure. The compressor efficiency is only part of the total efficiency calculation.
Originally Posted by Brettus
(Post 4131800)
have you not noticed that total flow increases as rpms climb ? Don't you look at your maf curve ?
"Total flow" through the engine is fixed, but modulated by velocity, which is where Ve comes from. |
Originally Posted by MazdaManiac
(Post 4131892)
Attempt and succeed are not the same thing. Don't flatter yourself.
. I'll get to the rest of your post when i have some time . |
Originally Posted by MazdaManiac
(Post 4131892)
I think this is the fundamental misunderstanding you have. (And it has been systemic since the beginning of your attempts to misdirect everyone about flow.) . That pressure vs flow argument was all about you trying to educate the unwashed masses and putting me in my place . You never actually attempted to understand the angle I was coming from . In fact - I know for certain if you could move outside of your current paradigm , that you would be a better tuner than you already are - at least in the field of diagnoses .
Originally Posted by MazdaManiac
(Post 4131892)
Resistance does NOT increase as flow increases. It remains the same. It is a fixed value. If flow increases, then pressure must increase if resistance to flow remains the same (i.e. the path doesn't physically change). You are trying to invent a fourth variable. There is just volume, pressure and temperature. These are the components of mass flow. (Well, really, density, velocity and area. But, since area is fixed, velocity converts to pressure and you are left with density, which is a function of temperature. This whole relationship between velocity and area is also one of your fundamental misunderstandings, re your previous attempts at obfuscating the discussion about volute.) . So no - i'm not trying to introduce another variable - it's just semantics .
Originally Posted by MazdaManiac
(Post 4131892)
If you are seeing a decrease in the manifold pressure, it isn't because the "resistance" is increasing, it is because mass flow is decreasing at a greater rate than the Ve of the motor.
Mass flow decreases because pressure decreases or temperature increases. That's all there is to it. . Secondly : I didn't say the decrease in manifold pressure was because resistance was increasing . Re-read my previous post . Thirdly : my explanation for why pressure goes down and flow stays the same actually makes some sense - see if you can come up with a better one .
Originally Posted by MazdaManiac
(Post 4131892)
Uh, you are forgetting about time. Remember, RPM is a description of an event over time. "Total flow" through the engine is fixed, but modulated by velocity, which is where Ve comes from. |
I think i got what MM and Brettus means.
Here's my criterias, forgive me for any ignorance; - Resistance is mostly given by intercooler, right? - Flow is not turbulent(laminar in english?). What Maniac means regarding flow resistance As long as flow is not turbulent, flow resistance will be a certain factor for all flows, meaning that if you have 5psi drop @200g/s, you will have 10psi@400g/s. Pressure drop = factor * flow. By that resistance is fixed, not increasing. It is flow that is increasing. What Brettus means To keep a certain pressure AFTER intercooler, you need to increase pressure from turbo to compensate. At a higher pressure you get a better efficiency. Or have I got it totally wrong? Trying hard to educate myself regarding turbo, but feel like progress rate is like pulling barbwire out of my ass.... |
Originally Posted by Brettus
(Post 4132157)
OK - I think it was actually you that said " pressure IS resistance to flow " . I have probably bandied that term around in the wrong way when what i should be refering to actually is Pressure.
Originally Posted by Brettus
(Post 4131329)
PSI goes up at the turbo as the resistance to flow increases and the UIM gauge goes down .
Originally Posted by Brettus
(Post 4131329)
PSI goes up at the turbo as the pressure increases and the UIM gauge goes down .
No, I'm sure that is not what you mean. So, it is NOT "semantics". It is physics. What you are observing is pressure decreasing because flow is increasing while the temperature remains constant OR pressure decreasing because temperature is decreasing while the flow remains constant. Obviously, the latter is the least likely - even if the turbo is becoming more efficient, the lower temperature will be offset by the increased flow. So, pressure is decreasing in the manifold because engine demand is increasing faster then compressor output. Total system flow is decreasing as a function of time (RPM). The MAF is showing increasing input flow, but this is below demand, so pressure decreases. In a system where compressor efficiency meets demand, this will not happen.
Originally Posted by Brettus
(Post 4132157)
In fact - I know for certain if you could move outside of your current paradigm , that you would be a better tuner than you already are - at least in the field of diagnoses .
So - enlighten me. Where have my "diagnoses" failed me? So far, all you have done is try to force-fit improperly correlated data points into equally malformed conclusions. This would be somewhat understandable if the proper correlations and conclusions weren't already extant. But they are and evidenced in abundance. |
Originally Posted by MazdaManiac
(Post 4132647)
Then, when you say
What you are actually saying is The UIM cannot "go down" if pressure is increasing in it. No, I'm sure that is not what you mean. So, it is NOT "semantics". It is physics. Yet you too are getting confused … PSI goes up at the turbo as the resistance to flow increases and the UIM gauge goes down . And it was you who said “pressure is resistance to flow” not me . That statement is not strictly true but I knew what you were getting at and ran with it , so you turning that around on me is kinda ironic.
Originally Posted by MazdaManiac
(Post 4132647)
What you are observing is pressure decreasing because flow is increasing while the temperature remains constant OR .
Originally Posted by MazdaManiac
(Post 4132647)
So, pressure is decreasing in the manifold because engine demand is increasing faster then compressor output. Total system flow is decreasing as a function of time (RPM).
The MAF is showing increasing input flow, but this is below demand, so pressure decreases. In a system where compressor efficiency meets demand, this will not happen. .
Originally Posted by MazdaManiac
(Post 4132647)
I am continually adding to my repertoire. So - enlighten me. Where have my "diagnoses" failed me? So far, all you have done is try to force-fit improperly correlated data points into equally malformed conclusions. This would be somewhat understandable if the proper correlations and conclusions weren't already extant. But they are and evidenced in abundance. How ? By recognizing that pressure is a useful parameter for comparison purposes. Yet You constantly berate me for insisting that pressure is useful . |
Originally Posted by Brettus
(Post 4132842)
Did you really mean that or are you getting confused ?
As flow through the system increases, pressure will decrease if temperature remains constant.
Originally Posted by Brettus
(Post 4132842)
Great we have got that one sorted and put to bed .
Originally Posted by Brettus
(Post 4132842)
On a couple of occasions where you have dynoed turbo cars that have had piss poor results , I have later diagnosed what the issue was .
I don't really offer diagnostic services at dyno events. There isn't the time and I don't think the customer - or those that are waiting - would like to go through the time or expense that such diagnostics would require. I am quite happy to have people like you that do that for others free of charge. I simply do not have the luxury of being so charitable. |
Originally Posted by MazdaManiac
(Post 4133032)
No, but you not understanding this principle is fundamental.
As flow through the system increases, pressure will decrease if temperature remains constant. . At the turbo ( rpm past 7000): we see pressure increase flow is staic Temperature increase So the increase in pressure (at the turbo) would best be explained by the fact that the compressor moved over its choke line and became less efficient. Correct ?
Originally Posted by MazdaManiac
(Post 4133032)
So, now you are agreeing with the very premise you were disagreeing with in the previous admonishment? .
Originally Posted by Brettus
As for why it drops - I think It is because volume flow (from 7000rpm) is static while rpms are climbing . Therefore the engines ability to consume the available air increases . But am not 100% sure , how about you explain that one for us ?
Originally Posted by MazdaManiac
(Post 4133032)
I haven't had any cars with "piss poor" results that weren't mechanicals.
I don't really offer diagnostic services at dyno events. There isn't the time and I don't think the customer - or those that are waiting - would like to go through the time or expense that such diagnostics would require. I am quite happy to have people like you that do that for others free of charge. I simply do not have the luxury of being so charitable. I still say you miss a key ingredient by dismissing pressure the way you do. |
Originally Posted by AAaF
(Post 4132253)
if you have 5psi drop @200g/s, you will have 10psi@400g/s.
Originally Posted by Brettus
(Post 4131800)
As for why it drops - I think It is because volume flow (from 7000rpm) is static while rpms are climbing. But am not 100% sure , how about you explain that one for us ?
Maybe you meant actual mass flow?:scratchhead:
Originally Posted by Brettus
(Post 4131800)
Therefore the engines ability to consume the available air increases.
So only reason why your manifold pressure drops while flow remains same is because, as Mazdamaniac already pointed out, compressor can´t keep up with engine demand.
Originally Posted by Brettus
(Post 4133052)
So the increase in pressure (at the turbo) would best be explained by the fact that the compressor moved over its choke line and became less efficient. Correct ?
Originally Posted by Brettus
(Post 4133052)
I still say you miss a key ingredient by dismissing pressure the way you do.
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Originally Posted by 999miki
(Post 4135409)
Pressure drop is squared function of flow. If you really would have 5 psi drop at 200g/s, it could be 20 psi drop at double flow:crazy:
http://en.wikipedia.org/wiki/Reynolds_Number http://en.wikipedia.org/wiki/Pressure_drop I had to check with one of the hydraulic eng at my workplace, and he also said that in an ideal system, pressure drop will be linear. When flow is turbulent it goes exponential. Then, of course, you have factors like what kind of material your tubing is made of etc. |
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