T28 closing throttle at WOT...
07-06-2003, 12:59 PM
#1
Member
Thread Starter
Join Date: Apr 2000
Posts: 2,504
Likes: 0
Received 0 Likes
on
0 Posts
T28 closing throttle at WOT...
<center><img src="http://pictureposter.audiworld.com/3953/pedal_position_and_throttle_opening_vs_time_run_1. jpg"></center><p>
I knew my kit hasn't felt as strong as it did the first few days recently so I went ahead and logged a few runs today of both pedal position vs throttle body position and actual vs requested boost... As you can see from these graphs something is not right. The boost gauge on my dash is reading about 20psi while the MAP sensor is showing about 23. Also, the log of the throttle position was with the boost turned down to about 16 psi. Any ideas on how to get my car to keep 100% throttle the whole way through? I screwed up the graph for boost so it doesnt have RPM but the logs for the throttle position wouldn't log rpm properly, it stayed at about 2550 the whole time I believe, if the raw data files would help let me know and I can post them. Thanks.<ul><li><a href="http://pictureposter.audiworld.com/3953/requested_and_actual_boost_vs_time_run_1.jpg">Requ ested vs actual boost graph</a></li></ul>
I knew my kit hasn't felt as strong as it did the first few days recently so I went ahead and logged a few runs today of both pedal position vs throttle body position and actual vs requested boost... As you can see from these graphs something is not right. The boost gauge on my dash is reading about 20psi while the MAP sensor is showing about 23. Also, the log of the throttle position was with the boost turned down to about 16 psi. Any ideas on how to get my car to keep 100% throttle the whole way through? I screwed up the graph for boost so it doesnt have RPM but the logs for the throttle position wouldn't log rpm properly, it stayed at about 2550 the whole time I believe, if the raw data files would help let me know and I can post them. Thanks.<ul><li><a href="http://pictureposter.audiworld.com/3953/requested_and_actual_boost_vs_time_run_1.jpg">Requ ested vs actual boost graph</a></li></ul>
07-06-2003, 01:29 PM
#2
Elder Member
Join Date: Sep 2002
Posts: 14,366
Likes: 0
Received 0 Likes
on
0 Posts
I went over this with you steve.
Your boost gauge is measuring pressure inside the intake manifold and your boost sensor is in the IC tube before the throttle body. This means if the throttle shuts your boost level on your gauges goes down even though your boost level in the IC is still high. YOu must lower your boost level down with the boost controller till you have the throttle staying open at all times when your running wot.
Your limit at the boost sensor is 1.45 bar which is 21 psi. Your seeing 20psi in the intake manifold while the tb is closing but boost is not power, power is made by the amount of air flow being fed into the motor and if your tb is closing to 40% then your only moving 40% of your air.
BTW you told me your boost controller is way off so dont go by what your gauges say since they only read inside the manifold which is after the TB and the boost level will drop as the TB closes.
Your limit at the boost sensor is 1.45 bar which is 21 psi. Your seeing 20psi in the intake manifold while the tb is closing but boost is not power, power is made by the amount of air flow being fed into the motor and if your tb is closing to 40% then your only moving 40% of your air.
BTW you told me your boost controller is way off so dont go by what your gauges say since they only read inside the manifold which is after the TB and the boost level will drop as the TB closes.
07-06-2003, 11:58 PM
#5
Elder Member
Join Date: Sep 2002
Posts: 14,366
Likes: 0
Received 0 Likes
on
0 Posts
I think some have tried but just could not get it to work perfect.
I do know that the "throttle closing" issue was turned off on my M31/R31 GIAC chips which allowed me to run 24psi with a K03, the J31 K04 chip was also based off of the M31 chip and it ran 27psi.
07-07-2003, 03:27 AM
#6
AudiWorld Super User
Join Date: Nov 2002
Posts: 8,510
Likes: 0
Received 0 Likes
on
0 Posts
Sounds like those chips are tricking the ECU instead of working with it.
Not what I would consider "good" software, but if it works without throwing a rod or melting a piston, screw it. ;-)<ul><li><a href="http://www.moreboost.com">variable pressure transducer 0-4.0 bar</a></li></ul>
07-07-2003, 04:57 AM
#7
Elder Member
Join Date: Sep 2002
Posts: 14,366
Likes: 0
Received 0 Likes
on
0 Posts
Well the R31 K03 chip made 250 hp 300 tq on 104 octane
and ran 14.290 at 97 mph so I would have to say yes it worked great. The K04 turbo J31 chip has been dyno'd at 250+ hp and 310+ tq on 93 octane.
Trending Topics
07-07-2003, 05:45 AM
#8
AudiWorld Super User
Join Date: Nov 2002
Posts: 8,510
Likes: 0
Received 0 Likes
on
0 Posts
Like I said, it works, so screw it. ;-)
But there are 3.0 bar+ solutions out there, it's just a huge headache as far as Motronic goes. You would have to change a bunch of maps to get it to work right with the 3.0 bar. Worth the headache? Probably not, but if you're doing a custom turbo solution anyway, might be worth a shot.
07-07-2003, 07:54 AM
#9
Elder Member
Join Date: Sep 2002
Posts: 14,366
Likes: 0
Received 0 Likes
on
0 Posts
Actually I have talked to Garrett at GIAC about this.
I think they were working on a 3 bar sensor. Now on my new setup I think everything will actual be turned off, but I have had a cap on the sensor to limit its output to the ecu at 4.7 volts, the T28 chip I ran was tuned for that limit and then I just held the boost anywhere I wanted with a EBC. The most I ever ran with the T28 was about 1.6-1.65 bar, but it was on a motor that had very little compression left. I just wish I had a chance to run some real boost with the T28 on a good motor.
07-07-2003, 02:32 PM
#10
AudiWorld Super User
Join Date: Nov 2002
Posts: 8,510
Likes: 0
Received 0 Likes
on
0 Posts
3.0 bar is the way to go, my friend.
EBC's just a crutch for those that don't want to take the time and effort to learn how to program a 3.0 bar and from what you said, looks like GIAC is finally doing that.
I know it works with a boost controller, but if you're going to be working with something complex like Motronic, you can't expect it to work perfectly in the worst case scenario if you trick it.
What, may I ask, was the cause of your blown motor? Lean condition, thrown rod or just tired rings and valvetrain?
I know it works with a boost controller, but if you're going to be working with something complex like Motronic, you can't expect it to work perfectly in the worst case scenario if you trick it.
What, may I ask, was the cause of your blown motor? Lean condition, thrown rod or just tired rings and valvetrain?