Why boost goes all the way to 18-20psi on 2,3 gears, but stays flat at 15psi on all higher gears?
03-13-2009, 01:32 PM
#1
AudiWorld Member
Thread Starter
Join Date: Oct 2001
Posts: 572
Likes: 0
Received 0 Likes
on
0 Posts
Why boost goes all the way to 18-20psi on 2,3 gears, but stays flat at 15psi on all higher gears?
Stage III: AWE K04s, ICs, fuel kit.
GIAC ship with pump mode on 92 gas...
GIAC ship with pump mode on 92 gas...
03-13-2009, 05:25 PM
#2
Junior Member
Join Date: Jan 2008
Posts: 1,679
Likes: 0
Received 0 Likes
on
0 Posts
Without data, you're not going to get much useful insight. AWE's boost curve is very RPM dependent.
If you're going WOT at lower RPMs in higher gears, that could explain the lower boost. AWE stage 3 off the shelf kits have rather conservative mid/low range boost in order to avoid any possibility of overboost.
03-13-2009, 07:19 PM
#3
AudiWorld Member
Join Date: Oct 2007
Posts: 408
Likes: 0
Received 0 Likes
on
0 Posts
My GIAC stage 1 does that
I think it has to do with the GIAC programming. I do not know if you also noticed that it is at low RPM that you are getting much higher boost levels, not at the top end.
My theory for the stage 1 setup is that because the flowrate (of air intake) is lower at low RPM than at higher RPM, it takes less turbo spin to achieve the same pressure. Consequently, if the turbo can survive with providing that nominal boost level is at high RPM, it can spin that fast at low RPM, with lower flow rate, which would result in higher pressure. So it is like keeping the flowrate into the engine relatively constant as opposed to the pressure at which air is flowing.
I hope this makes sense. But I could be dead-wrong about this.
I have noticed that the GIAC coding has a bunch more torque at low end compared to APR and EPL.
My theory for the stage 1 setup is that because the flowrate (of air intake) is lower at low RPM than at higher RPM, it takes less turbo spin to achieve the same pressure. Consequently, if the turbo can survive with providing that nominal boost level is at high RPM, it can spin that fast at low RPM, with lower flow rate, which would result in higher pressure. So it is like keeping the flowrate into the engine relatively constant as opposed to the pressure at which air is flowing.
I hope this makes sense. But I could be dead-wrong about this.
I have noticed that the GIAC coding has a bunch more torque at low end compared to APR and EPL.
Thread
Thread Starter
Forum
Replies
Last Post
SoSlow
S4 / RS4 (B5 Platform) Discussion
8
03-22-2008 10:16 AM
pitchS4
S4 / RS4 (B5 Platform) Discussion
5
10-10-2007 05:38 AM
ktnguyen
S4 / RS4 (B5 Platform) Discussion
17
08-21-2007 10:52 AM
LCP
S4 / RS4 (B5 Platform) Discussion
1
11-02-2005 06:03 AM