is it normal for boost to change?
#4
Originally posted by 4carl
no its the same. carl
no its the same. carl
Three things:
- Peak boost and your rpm/gear
- Air temp
- Diverter Valves
I'll start with peak boost:
I am not sure of the GT2's mapping, but peak boost on the stock turbo typically jumps up to .7 bar @ 2700pm in 3-6th gear and then drops off to .6 bar til 5800rpm where it climbs back up to .7 bar. 1st and 2nd really aren't in the rpm range long enough to get full boost. Also, you need to be in the higher gears as they put more load on the engine. More load = more boost per the time that you go through the RPM band. That is why you need to test in 5th/6th gear if you want consistancy.
Air temperature:
My car varies a good bit with temperature change. 70 deg might put me around .8 bar peak falling off to .7 and then .6 for a few before it peaks up to .7 at 5800rpm.
However, at 40 deg air temp, my boost climbs no higher than .7 bar while falling off to .6 rather quickly.
Cooler air is more dense with oxygen and thus, the turbos won't need to make as much boost to regulate the proper air/fuel mixture.
Diverter Valves:
If your valves are failing, that can result in lower peak boost. That is a simple fix.
Last edited by Ruiner; 02-02-2005 at 10:45 AM.
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