New BW EFR Turbo Thread
Jan 21, 2011, 03:52 PM
#31
***********Anybody interested in how to use the Matchbot Turbo matching software - watch this youtube video, It's a thorough and detailed walk-thru + info on the ins and outs of the software as well as proper values to target: YouTube - Part 1: BorgWarner MatchBot Turbo Matching Tutorial
A few weeks ago we posted up the Sierra Sierra Evo EFR 8374 dynochart making 700lbft Tq at 5000rpm with a 2.2L 4G63:
since then we've had a lot of questions about the Sierra Sierra car, and why does the 8374 drop in torque, while their 9180 does not? Do they run small cams? is it true that twinscroll chokes up? The answers to these questions are in the data of course, and can be seen in the matchbot software. Dont forget: a dyno is only a tool and the outputs are dependant on the inputs just like the matchbot shows. Looking at Sierra Sierra: they run a mustang dyno (heartbreaker as many call it) and are located in Minden, Nevada at 4800ft elevation. It is important and valuable to compare data, but this is truly a worst case scenario for internet bragging rights.
Two huge bits of data that most people overlook when comparing dyno charts are the turbo's speed and the ratio of compressor:turbine pressures. The EFR turbo makes it easy to get the speed sensor data, and it's very simple to monitor compressor:turbine pressure differentials.
^^CAD image showing the speed sensor in the compressor housing
^^^ sierra sierra's 9180 with shaft speed sensor installed
the EFR shaft speed sensor allows you to log exactly how fast the turbo is spinning, and that tells us where on the compressor map we are operating. So let's take a look at the 8374 compressor map:
you will see that the highest line shows "128.1" this means 128,100 is the recommended max speed for this turbo, and it can push a maximum airflow rate of approx 79 lb/min. Of course you can spin the turbo faster than this, but that will generate more heat without increasing airflow. Anything over 130,000 rpm is going to be choke flow and not going to be beneficial for power or healthy for the turbo.
compare that to the 9180:
for the 9180, 116,000 rpm is max wheel speed and it is capable of 95 lb/min airflow at that speed... anything much over that speed is not going to make more power
Sierra Sierra runs a time attack motor so it does not have a crazy drag race port job or cams/intake manifold. They use an off-the-shelf Full-Race twinscroll manifold (small runner, a/c compatible) and the turbosmart WG's 32psi boost (~3 atmospheres).
Dave "Emp" Empringham, driver for SSE, is a complete animal on the track as anyone whos watched him drive can verify. He pushes that car and turbo as hard as it can be pushed, full boost 32psi on an EFR 8374 for lap after lap. Their datalogs showed their EFR 8374 had higher intake pressure than exh pressure from idle to 7500rpm, then slightly over 1:1, just about perfect for a time attack car. The lightbulb for this came on when looking at the turbo speed logs: shaft speeds approaching 135+k rpm and in some cases it came close to 150k!!!! - this means their wastegates are being shut while Emp is pushing that turbo all the way to the limit and asking for more... lap after lap. With shaft speeds this high, the compressor is moving every ounce of air that it can, and it is trying for more (and heating charge air in the process). Sierra/Cosworth development continues on the cyl head, cams, etc in the search for more power - So what is the solution when you are out of airflow on the most advanced compressor out? Install the next larger turbo - the 9180.
With the 9180 you can clearly see that the torque is not dropping, instead it carries. The dyno's power output is not astronomical since we are at 4800ft on a mustang dyno - bu the data tells the story. they saw Intake:Exhaust pressure was under 1:1 the entire time and peak shaft speeds were ~105k with this turbo, clearly within the "safe" window for efficient operation. Unfortunately everything in life has compromise, so with the spoolup being considerably later the driver was no longer pleased with the boost transition in low speed turns. For that reason this turbo went slower on the circuit. (It will be faster for a drag race application of course). The 8374 remains
Lightening up the car will make a HUGE difference going forward and they continue to find new ways to gain power and response, while increaseing downforce and better tuning the susp.
Cliffnotes:
Street setup that sees light weekend track days: 7670
Time attack or Street/Strip: 8374
Drag Racing: 9180
I hope this makes sense, have a good weekend everyone
A few weeks ago we posted up the Sierra Sierra Evo EFR 8374 dynochart making 700lbft Tq at 5000rpm with a 2.2L 4G63:
since then we've had a lot of questions about the Sierra Sierra car, and why does the 8374 drop in torque, while their 9180 does not? Do they run small cams? is it true that twinscroll chokes up? The answers to these questions are in the data of course, and can be seen in the matchbot software. Dont forget: a dyno is only a tool and the outputs are dependant on the inputs just like the matchbot shows. Looking at Sierra Sierra: they run a mustang dyno (heartbreaker as many call it) and are located in Minden, Nevada at 4800ft elevation. It is important and valuable to compare data, but this is truly a worst case scenario for internet bragging rights.
Two huge bits of data that most people overlook when comparing dyno charts are the turbo's speed and the ratio of compressor:turbine pressures. The EFR turbo makes it easy to get the speed sensor data, and it's very simple to monitor compressor:turbine pressure differentials.
^^CAD image showing the speed sensor in the compressor housing
^^^ sierra sierra's 9180 with shaft speed sensor installed
the EFR shaft speed sensor allows you to log exactly how fast the turbo is spinning, and that tells us where on the compressor map we are operating. So let's take a look at the 8374 compressor map:
you will see that the highest line shows "128.1" this means 128,100 is the recommended max speed for this turbo, and it can push a maximum airflow rate of approx 79 lb/min. Of course you can spin the turbo faster than this, but that will generate more heat without increasing airflow. Anything over 130,000 rpm is going to be choke flow and not going to be beneficial for power or healthy for the turbo.
compare that to the 9180:
for the 9180, 116,000 rpm is max wheel speed and it is capable of 95 lb/min airflow at that speed... anything much over that speed is not going to make more power
Sierra Sierra runs a time attack motor so it does not have a crazy drag race port job or cams/intake manifold. They use an off-the-shelf Full-Race twinscroll manifold (small runner, a/c compatible) and the turbosmart WG's 32psi boost (~3 atmospheres).
Dave "Emp" Empringham, driver for SSE, is a complete animal on the track as anyone whos watched him drive can verify. He pushes that car and turbo as hard as it can be pushed, full boost 32psi on an EFR 8374 for lap after lap. Their datalogs showed their EFR 8374 had higher intake pressure than exh pressure from idle to 7500rpm, then slightly over 1:1, just about perfect for a time attack car. The lightbulb for this came on when looking at the turbo speed logs: shaft speeds approaching 135+k rpm and in some cases it came close to 150k!!!! - this means their wastegates are being shut while Emp is pushing that turbo all the way to the limit and asking for more... lap after lap. With shaft speeds this high, the compressor is moving every ounce of air that it can, and it is trying for more (and heating charge air in the process). Sierra/Cosworth development continues on the cyl head, cams, etc in the search for more power - So what is the solution when you are out of airflow on the most advanced compressor out? Install the next larger turbo - the 9180.
With the 9180 you can clearly see that the torque is not dropping, instead it carries. The dyno's power output is not astronomical since we are at 4800ft on a mustang dyno - bu the data tells the story. they saw Intake:Exhaust pressure was under 1:1 the entire time and peak shaft speeds were ~105k with this turbo, clearly within the "safe" window for efficient operation. Unfortunately everything in life has compromise, so with the spoolup being considerably later the driver was no longer pleased with the boost transition in low speed turns. For that reason this turbo went slower on the circuit. (It will be faster for a drag race application of course). The 8374 remains
Lightening up the car will make a HUGE difference going forward and they continue to find new ways to gain power and response, while increaseing downforce and better tuning the susp.
Cliffnotes:
Street setup that sees light weekend track days: 7670
Time attack or Street/Strip: 8374
Drag Racing: 9180
I hope this makes sense, have a good weekend everyone
Last edited by Geoff Raicer; Jan 24, 2011 at 11:27 AM.
Jan 22, 2011, 09:14 AM
#34
Thanks Geoff, I found it to be very interesting. However I wished he used the 8374 & the 9180 for his examples, to make life easier for me.
I had to watch the darn thing several times already, and yes I watched all 4 segments. 
I had to watch the darn thing several times already, and yes I watched all 4 segments.
Jan 22, 2011, 10:31 AM
#35
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After playing around with the BW matchbot some more, it looks like a 7670 will pretty much fit all of my criteria in either the 1.05 or .92 AR.
So I have a couple of questions, Geoff. Apart from the packaging/feature difference, what kind of difference would I see between the two trims? I'm assuming that the .92 will spool slightly faster and make a little less power up top, but at my target of 30psi on a built 2.0L, either option seems to be viable.
How difficult will it be to fit the .92AR 7670 onto an Evo? I hate open dumps and the integrated wastegate and BOV appeals to me greatly.
l8r)
So I have a couple of questions, Geoff. Apart from the packaging/feature difference, what kind of difference would I see between the two trims? I'm assuming that the .92 will spool slightly faster and make a little less power up top, but at my target of 30psi on a built 2.0L, either option seems to be viable.
How difficult will it be to fit the .92AR 7670 onto an Evo? I hate open dumps and the integrated wastegate and BOV appeals to me greatly.
l8r)
Last edited by Ludikraut; Jan 22, 2011 at 10:34 AM.
Jan 22, 2011, 05:11 PM
#40
Is it possibly due to the combo of very little head work, small cams, & high altitude ?
I think the reason for mild head work & small cams is to keep as much low & mid range performance as possible.
I'm also interested in what's the spool difference between the 8370 & the 9180 ? Judging from the dyno it appears like the 9180 spools similar to a single scroll HTA 3586 on a 2.0 set up.
I think the reason for mild head work & small cams is to keep as much low & mid range performance as possible.
I'm also interested in what's the spool difference between the 8370 & the 9180 ? Judging from the dyno it appears like the 9180 spools similar to a single scroll HTA 3586 on a 2.0 set up.
Jan 22, 2011, 05:15 PM
#41
Is it possibly due to the combo of very little head work, small cams, & high altitude ?
I think the reason for mild head work & small cams is to keep as much low & mid range performance as possible.
I'm also interested in what's the spool difference between the 8370 & the 9180 ? Judging from the dyno it appears like the 9180 spools similar to a single scroll HTA 3586 on a 2.0 set up.
I think the reason for mild head work & small cams is to keep as much low & mid range performance as possible.
I'm also interested in what's the spool difference between the 8370 & the 9180 ? Judging from the dyno it appears like the 9180 spools similar to a single scroll HTA 3586 on a 2.0 set up.
Jan 22, 2011, 05:25 PM
#42
Jan 22, 2011, 05:27 PM
#43
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Is it possibly due to the combo of very little head work, small cams, & high altitude ?
I think the reason for mild head work & small cams is to keep as much low & mid range performance as possible.
I'm also interested in what's the spool difference between the 8370 & the 9180 ? Judging from the dyno it appears like the 9180 spools similar to a single scroll HTA 3586 on a 2.0 set up.
I think the reason for mild head work & small cams is to keep as much low & mid range performance as possible.
I'm also interested in what's the spool difference between the 8370 & the 9180 ? Judging from the dyno it appears like the 9180 spools similar to a single scroll HTA 3586 on a 2.0 set up.
