Stock Greddy turbo compressor flow
12-01-2011, 08:07 AM
#26
Yes I did .
Yes - I was saying the same thing.
Yes ,efficiency is down , but there is definitely more power there up to a point .And until you find this point where the temp/pressure increase starts to happen , you are leaving a lot of power on the table.
Backing off and running the waste-gate at a reduced setting does NOT give me more power however , FACT.
Maybe there is a point that this will happen - I'm sure I've never taken the adjustment THAT far.
And the point i made about running like this being acceptable for a street driven engine is still valid IMO. Otherwise my engine and turbo would be LONG dead .
Because a lot of our systems are practically identical and where this is the case , results can be expected to be within a few % of each-other .So you create a benchmark . If a setup runs say 10% lower power than the next at the same boost are you going to just say "it is what it is " ?
I'm certainly not , i'll look for a reason .
ad:Backing off and running the waste-gate at a reduced setting does NOT give me more power however , FACT.
Maybe there is a point that this will happen - I'm sure I've never taken the adjustment THAT far.
And the point i made about running like this being acceptable for a street driven engine is still valid IMO. Otherwise my engine and turbo would be LONG dead .
I'm certainly not , i'll look for a reason .
Last edited by Brettus; 12-01-2011 at 08:12 AM.
12-05-2011, 06:44 AM
#27
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
For laminar flows? That is not how I understand it...
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.
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.
I was wrong:
http://www.engineeringtoolbox.com/da...ion-d_646.html
The guy I spoke to first gave me a name to another guy if I wanted a better answer. He showed me this formula.
12-10-2011, 02:00 PM
#28
two gauge set-up
and 5 psi loss at 320 .
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 .
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 .
Very Poor vid, but if watched you will see a 5 psi difference.
Let the insults and BS that is so well know on this forum -- Flow.
12-10-2011, 03:13 PM
#29
SPOOLN8
iTrader: (1)
Join Date: Nov 2008
Location: Edmonton, Alberta, Canada
Posts: 2,225
Received 208 Likes
on
156 Posts
For laminar flows? That is not how I understand it...
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.
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.
You're missing a key factor here and that is hydraulic oil is a Newtonian (non-compressible) fluid and that is why hydraulics work so well..... air on the other hand is very compressible (non-Newtonian).
01-16-2012, 02:19 PM
#31
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.
.
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.
*300whp should be "possible" .
.
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.
.
.
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.
.
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.
*300whp should be "possible" .
.
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.
.
This ,I still believe, is the correct map for the stock Greddy.
01-16-2012, 03:54 PM
#33
This is what rotarymachine rx got after doing the wastegate mod 302 g/s . Without that he was around 260 .
https://www.rx8club.com/showpost.php...&postcount=358
https://www.rx8club.com/showpost.php...&postcount=358
01-16-2012, 04:03 PM
#36
Not really - maybe you are used to seeing people report ridiculously high numbers that bear no relationship to reality .
My setup sees 350g/s for 320whp which is on the low side but others on here report 400g/s yet only make 270-280whp - so maf calibration plays a big part .
My setup sees 350g/s for 320whp which is on the low side but others on here report 400g/s yet only make 270-280whp - so maf calibration plays a big part .
01-17-2012, 07:31 AM
#42
I'm not trying to get at anything, I'm just trying to understand things that's all. The flow charts utilize MAF so I was wanting to know what the g/s was on the stock greddy at WOT. I know when I did a slight boost run it was in the 300's. Not arguing the numbers just learning
01-17-2012, 08:06 AM
#44
SPOOLN8
iTrader: (1)
Join Date: Nov 2008
Location: Edmonton, Alberta, Canada
Posts: 2,225
Received 208 Likes
on
156 Posts
MAF numbers are like using a scale to measure your body weight..... They are only good if you use the same one over and over to see how your weight has changed/improved from previous measurements; but comparing your weight from one scale to another is pointless as they RARELY measure the same weight.
I was at about 285-290 g/s when I was N/A and now with the GReddy turbo I measure 300ish g/s (depending on weather and other factors); I've increased the flow of air through my MAF by about 100g/s.....
I was at about 285-290 g/s when I was N/A and now with the GReddy turbo I measure 300ish g/s (depending on weather and other factors); I've increased the flow of air through my MAF by about 100g/s.....
Last edited by RotaryMachineRx; 01-17-2012 at 08:08 AM.
01-17-2012, 12:28 PM
#45
I'm not trying to get at anything, I'm just trying to understand things that's all. The flow charts utilize MAF so I was wanting to know what the g/s was on the stock greddy at WOT. I know when I did a slight boost run it was in the 300's. Not arguing the numbers just learning
I can do numerous back to back runs and the g/s line will stay consistent within 3-4g/s on each run . It's a great tool for measuring any improvements you might make without the need to hop on the dyno each time. .
Last edited by Brettus; 01-17-2012 at 12:38 PM.
01-18-2012, 02:21 PM
#48
Set your Way-Back Machine© to December of 2006:
https://www.rx8club.com/series-i-tech-garage-22/rotary-math-106294/
https://www.rx8club.com/series-i-tech-garage-22/rotary-math-106294/
01-18-2012, 02:35 PM
#50
"Meh"? Pretty much sums-up your entire existence. Try checking out a local community college. I'm sure they have courses for "English for Speakers of no Particular Language".
In 2006, it was - it moves more air than the TD06-18g and can have the same turbine flow.
In 2006, it was - it moves more air than the TD06-18g and can have the same turbine flow.