when does boost hit?
when does boost hit? well i am redoing my tune and got to thinking..does my motor see any boost under 90kpa? I know it doesnt but would it. basically am trying to find out if i need to pull any timing or give any more fuel under 100 kpa? I was thinking of just adjusting 90+kpa just for safe measure.What do you think?
Joined: Jun 2004
Posts: 1,501
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From: Ft. Irwin, California (But Virginia is home)
well i am redoing my tune and got to thinking..does my motor see any boost under 90kpa? I know it doesnt but would it. basically am trying to find out if i need to pull any timing or give any more fuel under 100 kpa? I was thinking of just adjusting 90+kpa just for safe measure.What do you think?
What you need to answer for timing and fueling is how fast can the engine get into these #'s? A turbo will make some pressure even at cruise (you'll see it as reduced vacuum). So, you can be cruising at 2KRPM and have a MAP value of 70-80kPA which just doesn't happen NA. You need to add fuel/adjust timing accordingly across the board from 2KRPM up to account for this added pressure.
If you're using HP Tuners, just drive the car around/log it and set the fuel via the Ve Table. Set the "part boost (to 110kPA to around 12.0) and the WOT PE above 110kPA to 11.0-11.5 (depending what you're comfy with.) I'd dumb down the timing above 65grams/m3 and go from there. Should still have a "hump" in the Ve table showing higher numbers in the 4000-48000RPM range, as this is where the engine is making the most torque. It'll lean out a percent or two from 5K to redline.
You're not making boost at 90kPA, cause that means you're pumming vacuum. 100kPA i atmospheric pressure, and then it goes into positive boost frm there. 5PSI is about 135kPA and 210kPA is betweeen 14-15PSI.
What you need to answer for timing and fueling is how fast can the engine get into these #'s? A turbo will make some pressure even at cruise (you'll see it as reduced vacuum). So, you can be cruising at 2KRPM and have a MAP value of 70-80kPA which just doesn't happen NA. You need to add fuel/adjust timing accordingly across the board from 2KRPM up to account for this added pressure.
If you're using HP Tuners, just drive the car around/log it and set the fuel via the Ve Table. Set the "part boost (to 110kPA to around 12.0) and the WOT PE above 110kPA to 11.0-11.5 (depending what you're comfy with.) I'd dumb down the timing above 65grams/m3 and go from there. Should still have a "hump" in the Ve table showing higher numbers in the 4000-48000RPM range, as this is where the engine is making the most torque. It'll lean out a percent or two from 5K to redline.
What you need to answer for timing and fueling is how fast can the engine get into these #'s? A turbo will make some pressure even at cruise (you'll see it as reduced vacuum). So, you can be cruising at 2KRPM and have a MAP value of 70-80kPA which just doesn't happen NA. You need to add fuel/adjust timing accordingly across the board from 2KRPM up to account for this added pressure.
If you're using HP Tuners, just drive the car around/log it and set the fuel via the Ve Table. Set the "part boost (to 110kPA to around 12.0) and the WOT PE above 110kPA to 11.0-11.5 (depending what you're comfy with.) I'd dumb down the timing above 65grams/m3 and go from there. Should still have a "hump" in the Ve table showing higher numbers in the 4000-48000RPM range, as this is where the engine is making the most torque. It'll lean out a percent or two from 5K to redline.
Or go speed density.....
Doesnt the zo6 ve table go 99 or 100 at about 6000? I never thought about it before , but I think its a bit lower at the torque peak.
