EVO Green/20g-LT airflow numbers
Dec 8, 2006, 03:31 PM
#1
EVO Green/20g-LT airflow numbers
The other threads on this turbo have become quite cluttered, so I'm putting this info here. This is not meant to be a perfect comparison of the stock turbo and this new turbo, or even a review of this turbo. I have done some testing, looked at the data, and drawn some conclusions; and I encourage you to do the same for yourself. I have also not included all of the data I collected, just a few tidbits that illustrate certain points. I'm far too lazy these days for big writeups. 
Also, questions and discussions around this subject matter are encouraged, but I would like to see this thread stay a little cleaner than the others that have gone to complete ****. If you're a donkey raping porksword swallowing beanbag hugger, please move along. That being said...
I put up this page on my site, but here is a copy of it. I will continue to update that page as I continue this process. It is supposed to be warmer again next week and I have another set of tests planned. I am also putting links to the charts and pics despite the inconvenience to the reader in an effort to keep my limited bandwidth from getting raped.
Turbo installed pretty easily. I ordered some EVO9 parts to make life easy, and I'm glad I did. The EVO9 compressor outlet seems to be angled a little differently than the 8, I had a hard time getting the LICP to fit satisfactorily. Not much else to say about installation.
First pull on the street and there was a clear increase in power even while still at 21 psi. More than I would have expected. 60-80 times on pump gas have never been below 2.1 seconds, no matter how much tuning I do. I've spent whole days on it. First pull last night ended up too lean on the AEM (first hint at more airflow) . Added 10% fuel just to get it safe, it ended up too rich in the mid 10s, but comfortable. Logged two quick pulls and 60-80 times dropped to 1.8 seconds. That's quite an improvement for the same boost and still a little rich, with no other changes.
The car also feels stronger, and if lag has increased I'll have to get some low rpm logs to catch it. It feels just about the same. Quarter throttle at 2500-3k rpm still builds usuable boost. The turbo sounds different too, it's a lower pitch whine, which was interesting. The car also is much stronger from about 6k rpm and up, as others have mentioned. I'm sure the larger turbine wheel plays a role in this, but I also wanted to check boost taper. It's nearly non existant. At the actuator pressure of 19.x psi, there is no taper. Nice flat boost curve. With the HKS set at 30% resulting in just under 21 psi, it tapers to 19.5 by 7500. A little over 1 psi drop, better than the stock turbo.
Fast forward to the next day. Swapped back to DSMlink and made some pulls. Comparing to a previous stock turbo pull with the same boost, I come up with this chart. Don't use it to compare spool though, it's not scaled against RPM. I am within 1 psi of full boost by 3500 rpm in third gear. That last psi takes a few hundred rpm to get there thanks to the EBC trying to avoid the spike, so naturally that doesn't count.
http://www.posracing.net/files/Stock...reen_small.JPG
Airflow has increased from ~38 lbs/min to ~43 lbs/min. That's a pretty nice increase for the same boost. Part of this is due to the fact that boost holds better at higher rpm, by about 2 psi. Boost is set to 21 psi in both cases however. There is also about a 40 degree difference in intake temp. In the chart above the top lines are airflow, the middle are boost, and the bottom lines are airflow/rev. The Green-LT is the higher is all three data sets.
When I first saw results of this turbo, I predicted that it would hit 49 lbs/min despite being rated to 47, and then estimated from that that it would hold 26 psi to redline. After swapping in some race gas, pulling the line to the WGA, and pulling the Gus line off the 1g BOV, this was the result:
http://www.posracing.net/files/Green-LT_max_boost.JPG
Boost peaked at 30.1 psi in both gears and tapered to 26.1. Airflow peaked at 48.9 lbs/min. I was unable to get a clean pull in third gear, but this 2nd to third shift managed to not knock. Thinking about it later, wondering why I was getting knock on 117 octane fuel and hardly any timing, it occured to me that I forgot to remove the tailpipe silencer. So I was basically trying to flow ~49 lbs/min through a 1.5" exhaust. Oops, that sucks. I'll get some more logs next week without the silencer when it's not so damn cold...
Also, questions and discussions around this subject matter are encouraged, but I would like to see this thread stay a little cleaner than the others that have gone to complete ****. If you're a donkey raping porksword swallowing beanbag hugger, please move along. That being said... I put up this page on my site, but here is a copy of it. I will continue to update that page as I continue this process. It is supposed to be warmer again next week and I have another set of tests planned. I am also putting links to the charts and pics despite the inconvenience to the reader in an effort to keep my limited bandwidth from getting raped.
Turbo installed pretty easily. I ordered some EVO9 parts to make life easy, and I'm glad I did. The EVO9 compressor outlet seems to be angled a little differently than the 8, I had a hard time getting the LICP to fit satisfactorily. Not much else to say about installation.
First pull on the street and there was a clear increase in power even while still at 21 psi. More than I would have expected. 60-80 times on pump gas have never been below 2.1 seconds, no matter how much tuning I do. I've spent whole days on it. First pull last night ended up too lean on the AEM (first hint at more airflow) . Added 10% fuel just to get it safe, it ended up too rich in the mid 10s, but comfortable. Logged two quick pulls and 60-80 times dropped to 1.8 seconds. That's quite an improvement for the same boost and still a little rich, with no other changes.
The car also feels stronger, and if lag has increased I'll have to get some low rpm logs to catch it. It feels just about the same. Quarter throttle at 2500-3k rpm still builds usuable boost. The turbo sounds different too, it's a lower pitch whine, which was interesting. The car also is much stronger from about 6k rpm and up, as others have mentioned. I'm sure the larger turbine wheel plays a role in this, but I also wanted to check boost taper. It's nearly non existant. At the actuator pressure of 19.x psi, there is no taper. Nice flat boost curve. With the HKS set at 30% resulting in just under 21 psi, it tapers to 19.5 by 7500. A little over 1 psi drop, better than the stock turbo.
Fast forward to the next day. Swapped back to DSMlink and made some pulls. Comparing to a previous stock turbo pull with the same boost, I come up with this chart. Don't use it to compare spool though, it's not scaled against RPM. I am within 1 psi of full boost by 3500 rpm in third gear. That last psi takes a few hundred rpm to get there thanks to the EBC trying to avoid the spike, so naturally that doesn't count.
http://www.posracing.net/files/Stock...reen_small.JPG
Airflow has increased from ~38 lbs/min to ~43 lbs/min. That's a pretty nice increase for the same boost. Part of this is due to the fact that boost holds better at higher rpm, by about 2 psi. Boost is set to 21 psi in both cases however. There is also about a 40 degree difference in intake temp. In the chart above the top lines are airflow, the middle are boost, and the bottom lines are airflow/rev. The Green-LT is the higher is all three data sets.
When I first saw results of this turbo, I predicted that it would hit 49 lbs/min despite being rated to 47, and then estimated from that that it would hold 26 psi to redline. After swapping in some race gas, pulling the line to the WGA, and pulling the Gus line off the 1g BOV, this was the result:
http://www.posracing.net/files/Green-LT_max_boost.JPG
Boost peaked at 30.1 psi in both gears and tapered to 26.1. Airflow peaked at 48.9 lbs/min. I was unable to get a clean pull in third gear, but this 2nd to third shift managed to not knock. Thinking about it later, wondering why I was getting knock on 117 octane fuel and hardly any timing, it occured to me that I forgot to remove the tailpipe silencer. So I was basically trying to flow ~49 lbs/min through a 1.5" exhaust. Oops, that sucks. I'll get some more logs next week without the silencer when it's not so damn cold...
Last edited by kjewer1; Dec 8, 2006 at 03:57 PM.
Dec 8, 2006, 03:48 PM
#4
did i miss somthing.
you saidBoost peaked at 30.1 psi in both gears and tapered to 21.1. Airflow peaked at 48.9 lbs/min. I was unable to get a clean pull in third gear, but this 2nd to third shift managed to not knock. Thinking about it later, wondering why I was getting knock on 117 octane fuel and hardly any timing, it occured to me that I forgot to remove the tailpipe silencer. So I was basically trying to flow ~49 lbs/min through a 1.5" exhaust. Oops, that sucks. I'll get some more logs next week without the silencer when it's not so damn cold...
and right befor that you said it can hold 26psi at redline. well here your saying 21psi. what did i miss
what does this turbo or is able to hold boost at red line?
you saidBoost peaked at 30.1 psi in both gears and tapered to 21.1. Airflow peaked at 48.9 lbs/min. I was unable to get a clean pull in third gear, but this 2nd to third shift managed to not knock. Thinking about it later, wondering why I was getting knock on 117 octane fuel and hardly any timing, it occured to me that I forgot to remove the tailpipe silencer. So I was basically trying to flow ~49 lbs/min through a 1.5" exhaust. Oops, that sucks. I'll get some more logs next week without the silencer when it's not so damn cold...
and right befor that you said it can hold 26psi at redline. well here your saying 21psi. what did i miss
what does this turbo or is able to hold boost at red line?
Dec 8, 2006, 03:58 PM
#6
Actually I missed something, that was a typo. It did in fact hold 26.1 psi, as seen in the chart directly above that paragraph. Thanks for pointing it out.
For comparison, on my car, the stock turbo would only hold 20 psi to redline, with airflow maxed out at 41-42 lbs.
For comparison, on my car, the stock turbo would only hold 20 psi to redline, with airflow maxed out at 41-42 lbs.
Dec 8, 2006, 03:58 PM
#7
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Good work!
It'd be nice to see some track times also.
Maybe someone in a warmer climate can slap one of these on and go down the 1320.
And EvoDan, my 20g-LT peaks @ 31lbs and tapers to 27-25lbs at redline.
It'd be nice to see some track times also.
Maybe someone in a warmer climate can slap one of these on and go down the 1320.
And EvoDan, my 20g-LT peaks @ 31lbs and tapers to 27-25lbs at redline.
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Dec 8, 2006, 05:11 PM
#13
LMAO, no problem. 
I had a feeling that 47 lb figure was a little light and had to test it myself, even if I decided not to keep the turbo in the end. The unfounded speculation about the boost to redline was driving me nuts too, and I had to test my prediction about that. It's a sickness, there is something wrong with me... But after seeing the performance gain and the neglible increase in lag (turbo feels very much like the stocker in this regard) I think I will keep it. Combined with the nitrous kit I should be able to reach my goals for the 07 season. I've run my share of big turbos and learned some hard lessons. I'm less motivated to ruin the theme of this car for some reason.
I had a feeling that 47 lb figure was a little light and had to test it myself, even if I decided not to keep the turbo in the end. The unfounded speculation about the boost to redline was driving me nuts too, and I had to test my prediction about that. It's a sickness, there is something wrong with me... But after seeing the performance gain and the neglible increase in lag (turbo feels very much like the stocker in this regard) I think I will keep it. Combined with the nitrous kit I should be able to reach my goals for the 07 season. I've run my share of big turbos and learned some hard lessons. I'm less motivated to ruin the theme of this car for some reason.
