Rearmount cars chime in.
10-09-2008, 08:16 PM
#1
Rearmount cars chime in. I did some street testing my psi per gear. This is how it breaks down I have a manual boost controller also. My psi set range is 14 at least thats where Im tuned at. My car is a six speed car also. Im tryin to get a feel of what psi per gear every body else sees, From a roll or dead stop. Im gearing up for the mile oct 25 
and wondering if im gettin the best out my set up.
1st. 12.5 and a lot of wheel spin. dead stop
2nd.14.5 30 mph roll and a lot of wheel spin.
3rd. 14.8 30 mph roll and a lot of wheel spin.
4th 15.5 40 mph roll and a little wheel spin.
and wondering if im gettin the best out my set up.1st. 12.5 and a lot of wheel spin. dead stop
2nd.14.5 30 mph roll and a lot of wheel spin.
3rd. 14.8 30 mph roll and a lot of wheel spin.
4th 15.5 40 mph roll and a little wheel spin.
10-09-2008, 08:38 PM
#3
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You're always going to get a lower PSI in 1st and sometimes in 2nd because the engine can't produce the load needed to genreate the necessary exhaust volume to spool the turbine. Simply a matter of the efficiency from the gear ratio reducing the load on the engine by mechanical advantage. In the higher gears that advantage is less and the engine has more load, thus more exhaust gas volume to spool the compressor.
Your numbers look pretty good considering the above. Would not complain with hitting 12PSI in 1st on a 6-speed car
I could only hit 3.5 on my STS in 1st gear with the wastegate set to 5PSI........
BTW, that boost lag shoud decrease with each gear. If you're seeing positive pressure at 3.5K RPM in 1st, it should drop around 3K RPM by 3rd and as low as 2.2K by 5th gear.
Your numbers look pretty good considering the above. Would not complain with hitting 12PSI in 1st on a 6-speed car
I could only hit 3.5 on my STS in 1st gear with the wastegate set to 5PSI........BTW, that boost lag shoud decrease with each gear. If you're seeing positive pressure at 3.5K RPM in 1st, it should drop around 3K RPM by 3rd and as low as 2.2K by 5th gear.
10-09-2008, 08:57 PM
#7
You're always going to get a lower PSI in 1st and sometimes in 2nd because the engine can't produce the load needed to genreate the necessary exhaust volume to spool the turbine. Simply a matter of the efficiency from the gear ratio reducing the load on the engine by mechanical advantage. In the higher gears that advantage is less and the engine has more load, thus more exhaust gas volume to spool the compressor.
Your numbers look pretty good considering the above. Would not complain with hitting 12PSI in 1st on a 6-speed car I could only hit 3.5 on my STS in 1st gear with the wastegate set to 5PSI........
BTW, that boost lag shoud decrease with each gear. If you're seeing positive pressure at 3.5K RPM in 1st, it should drop around 3K RPM by 3rd and as low as 2.2K by 5th gear.
Your numbers look pretty good considering the above. Would not complain with hitting 12PSI in 1st on a 6-speed car
I could only hit 3.5 on my STS in 1st gear with the wastegate set to 5PSI........BTW, that boost lag shoud decrease with each gear. If you're seeing positive pressure at 3.5K RPM in 1st, it should drop around 3K RPM by 3rd and as low as 2.2K by 5th gear.
But atleats I know my system works pretty good. Trending Topics
10-09-2008, 09:36 PM
#8
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