20G LT, 1st. day review.
Jan 10, 2007, 05:29 PM
#32
On the stock 04 turbo I would see ~2017 HZ at 28-29 psi on race gas. Most of the time it was ~1980s HZ.
On pump gas at 24.4 psi I would see ~1700's-1850's HZ. I really never made pics of the AFC with this info. It never dawn on me it could help later!
Last edited by 04AWDTURBOEVO; Jan 10, 2007 at 05:34 PM.
Jan 10, 2007, 07:54 PM
#33
EDIT- So here is the point to consider, it moves more air now on Pumpgas than he was able to move at high boost on race gas with the 9.8 and then he made 359whp. Dang.
Last edited by JohnBradley; Jan 10, 2007 at 08:16 PM. Reason: thought of something
Jan 11, 2007, 09:30 AM
#36
The Hz value is just a value that is used by the ECU to calculate mass airflow with other variables, such as barometric pressure, intake temperature, and the MAF curve.
I've been working with the MAF tables in the ECU and coming up with equations that will relate the Hz value to a mass airflow, that includes the air density calculated from the logged baro and intake temp, along with the stock MAF curve.
I'm not saying that this turbo doesn't flow more air...I'm just saying that you can't compare the two Hz values to come to that conclusion. The Hz values could have more easily been changed by changing intakes that alter the MAF calibration, resulting in an incorrect Hz reading.
The turbo definitely seems impressive, though, from the data so far. But don't rely on Hz measurements. If you have mass airflow measurements, like kjewer posted in one of the threads, that is a much better comparison. If you do need to use Hz values, you will also need to know if anything was changed pre-post MAF that could have altered the MAF curve, baro, and intake temp for both runs.
Eric
Jan 11, 2007, 10:41 AM
#37
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got mine today also...cant wait to get it on and tuned I have current mods: Pauter rods,Wiseco pistons,Supertech vales springs retainers 1mm over,Turbo Trix ported race/street head,HKS 264/272 cams downpipe exhaust intake,Buschur 680 inj.,Alchy kit. Hope it runs hard
I got the new 20G LT Turbo installed yesturday. First, I will comment about the turbo. By comparison, my stock 9.8 turbo is a much smaller unit. The 20G LT is a jewel. Once you got it in your hands, you can't stop to look at it. It is got a much biger compressor housing, a biger compressor wheel, then it is got a larger 10.5 hot side, and a much larger turbine wheel. Plus, the waste gate flapper is single and much improved. Add the porting option like I did, and get the upgraded 18 psi actuator, and you got a monster for a turbo.
Anyway, I installed the turbo and started the car for the morning work commute yesturday. Turned the boost controller off to verify the actuator was set properly. It was. I adjusted it a few turns at the time of install. With the controller off, I was geting 19.6 psi. Perfect. To make a long story short, I got to miss with it tonight. Tuned the mid-range as it was a bit leaner between 5000 and 6500 rpms. Made a few more logs, adjusted turbo gain and wastegate setting, and made sure I was at around 11.5 -11.6 A/Fs.
This Turbo pulls hard. At 23.4 psi, I am reading 2100 plus HZ on my SAFC at 68 percent throtle. I am posting a pic of the reading. The RPMs clime very fast. All clues that this unit is flowing much more air. I took my friend Manny for a ride tonight, and he was saying it was ridiculous. He drives a IX that has gone 12.05@114.67, and my car has gone 11.8@116. So it take a little to impress us. We both think this turbo made a big difference in my car. It is only been a day, but so far, so good! Here are a few pics of my VIII turbo next to the 20G LT. Both compressor and exhaust shots. A big tumps up for Buschur Racing and FP. In my opinion, great product that does what it was made for, stock spool up and much more top end. Pulls all the way to 8000. And, you better be looking, because it gets there quick. I used the stock manifold with a very nise and nasty port job. I will continue to update this thread on track and dyno runs in the next few weeks. I am thinking of dialing in the cams and crank and a may be also adding Meth injection. For sure, the 1st. few tests will be on C16 and 28 to 29 psi.
Manie
Anyway, I installed the turbo and started the car for the morning work commute yesturday. Turned the boost controller off to verify the actuator was set properly. It was. I adjusted it a few turns at the time of install. With the controller off, I was geting 19.6 psi. Perfect. To make a long story short, I got to miss with it tonight. Tuned the mid-range as it was a bit leaner between 5000 and 6500 rpms. Made a few more logs, adjusted turbo gain and wastegate setting, and made sure I was at around 11.5 -11.6 A/Fs.
This Turbo pulls hard. At 23.4 psi, I am reading 2100 plus HZ on my SAFC at 68 percent throtle. I am posting a pic of the reading. The RPMs clime very fast. All clues that this unit is flowing much more air. I took my friend Manny for a ride tonight, and he was saying it was ridiculous. He drives a IX that has gone 12.05@114.67, and my car has gone 11.8@116. So it take a little to impress us. We both think this turbo made a big difference in my car. It is only been a day, but so far, so good! Here are a few pics of my VIII turbo next to the 20G LT. Both compressor and exhaust shots. A big tumps up for Buschur Racing and FP. In my opinion, great product that does what it was made for, stock spool up and much more top end. Pulls all the way to 8000. And, you better be looking, because it gets there quick. I used the stock manifold with a very nise and nasty port job. I will continue to update this thread on track and dyno runs in the next few weeks. I am thinking of dialing in the cams and crank and a may be also adding Meth injection. For sure, the 1st. few tests will be on C16 and 28 to 29 psi.
Manie
Jan 11, 2007, 02:53 PM
#39
You can't really compare Hz values from different times/conditions.
The Hz value is just a value that is used by the ECU to calculate mass airflow with other variables, such as barometric pressure, intake temperature, and the MAF curve.
I've been working with the MAF tables in the ECU and coming up with equations that will relate the Hz value to a mass airflow, that includes the air density calculated from the logged baro and intake temp, along with the stock MAF curve.
I'm not saying that this turbo doesn't flow more air...I'm just saying that you can't compare the two Hz values to come to that conclusion. The Hz values could have more easily been changed by changing intakes that alter the MAF calibration, resulting in an incorrect Hz reading.
The turbo definitely seems impressive, though, from the data so far. But don't rely on Hz measurements. If you have mass airflow measurements, like kjewer posted in one of the threads, that is a much better comparison. If you do need to use Hz values, you will also need to know if anything was changed pre-post MAF that could have altered the MAF curve, baro, and intake temp for both runs.
Eric
The Hz value is just a value that is used by the ECU to calculate mass airflow with other variables, such as barometric pressure, intake temperature, and the MAF curve.
I've been working with the MAF tables in the ECU and coming up with equations that will relate the Hz value to a mass airflow, that includes the air density calculated from the logged baro and intake temp, along with the stock MAF curve.
I'm not saying that this turbo doesn't flow more air...I'm just saying that you can't compare the two Hz values to come to that conclusion. The Hz values could have more easily been changed by changing intakes that alter the MAF calibration, resulting in an incorrect Hz reading.
The turbo definitely seems impressive, though, from the data so far. But don't rely on Hz measurements. If you have mass airflow measurements, like kjewer posted in one of the threads, that is a much better comparison. If you do need to use Hz values, you will also need to know if anything was changed pre-post MAF that could have altered the MAF curve, baro, and intake temp for both runs.
Eric
It does not matter, you need to buy it, try it yourself so you too can be a believer. Guess work is that, just guess work. I am speaking from experience, less than 1 week of it, but non the less.
Great review and pointers as well. Look forward to seeing you open up some cans of whopp as$ on the streets and the track! 
Jan 11, 2007, 03:47 PM
#41
To get a mass airflow from a Hz number, you need to use baro and intake temp as well, not to mention any compensation changes for the maf table due to the mods.
For example, a colder day will produce much more mass airflow from the same Hz number, or vice versa, on a hotter day, you will need a much higher Hz number to achieve the same mass airflow. The same goes for barometric pressure. Lower pressure will result in lower airflow.
I'm not saying that the new turbo isn't giving your more airflow, I'm simply stating that you cannot use Hz alone for comparison. You need a mass airflow, which the Hz number is not.
For example, I am still developing this equation, but this will get you close. To find the mass airflow from your Hz number, you need the to do the following:
First to find L/s, or air volume:
y = -4E-09x3 + 1E-05x2 + 0.1234x - 1
where y is L/s and x is Hz
Then you multiply L/s by air density. You can find air density if you log your baro and intake temps from your logger with this equation:
airdens=Atmospheric_Pressure /14.6956/.08026/(Intake_Air_Temp +273.15)*28.9
Then to find the mass air, you multiply this air density by the air volume:
massaircalc=(-4*10^-09*AirFlow^3 + 1*10^-05*AirFlow^2+ 0.129*AirFlow - 1) *airdens
This will give you your mass airflow, in g/s.
Like I said, I am still developing this based off the maf tables in the ECU and dissembly being done, but this gives you an idea what the ECU is doing to calculate mass airflow. I hope your understand now why you simply can't look at Hz alone.
Eric
Last edited by l2r99gst; Jan 11, 2007 at 03:53 PM.
Jan 13, 2007, 12:13 PM
#42
Up Date
Update 1-13-2007
I got around to making a log of the boost curve on the 20G Lt.
The following was a 3rd. gear run from about 2,300 rpms to about
7,500 rpms. At 3,710 rpms the boost was right at 20.0 psi. On
the picture, you can see the boost was at 20.9 at 3,850 rpms, and
at 5,100 rpms it peak’d at 25.5 psi. Then, at 7,450 it held
boost at 23.0 psi.
As the graph shows, the dark tall line is the boost curve. You can
See how fast the turbo spools. You can also see that there is a
Very minimal spool lag between 4,000 rpms and 5,100 rpms, but the
Car is reving so fast, this can only be seeing on this graph.
This is just a graph to show the stock like spool up of the 20G LT
Turbo and that it can hold good boost to redline.
Manie
I got around to making a log of the boost curve on the 20G Lt.
The following was a 3rd. gear run from about 2,300 rpms to about
7,500 rpms. At 3,710 rpms the boost was right at 20.0 psi. On
the picture, you can see the boost was at 20.9 at 3,850 rpms, and
at 5,100 rpms it peak’d at 25.5 psi. Then, at 7,450 it held
boost at 23.0 psi.
As the graph shows, the dark tall line is the boost curve. You can
See how fast the turbo spools. You can also see that there is a
Very minimal spool lag between 4,000 rpms and 5,100 rpms, but the
Car is reving so fast, this can only be seeing on this graph.
This is just a graph to show the stock like spool up of the 20G LT
Turbo and that it can hold good boost to redline.
Manie
