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AutoSpeed - The Audi's DIY Boost Control - Part 1
Like this? Yep makes sense. Cant find part 2 where they perfect it, but yeah I did do this a year or two ago. In part 2 they found that the pressure regulator was not exhausting residual boost fully and was trapping boost between itself and the wastegate. They ended up running a circuit (with a one way valve) back to the front of the pressure relief to sort this. I raided the pneumatics part bins at work and set it up and it worked great, but it was very bulky and hard to find the real estate to mount it. There will be a relic post I did on this forum maybe 2 years ago somewhere. Yeah you're dead right re the restrictor. That's what I was taught - that its ability to restrict is dependent on the rate of change of flow. That might be why it works so well at clipping the over boost peak when flow is fastest and changing rapidly but then has a diminishing effect later in the boost curve/load range/rev range where I guess it sort of hands ful control back the solenoid. I guess there is no reason why a pressure relief valve couldn't be placed in series before the boost control solenoid to guarantee that there is no premature wastegate cracking before the solenoid is absolutely needed.
No I'd rather the boost curve that the 10psi spring gave any day. Such a little turbo and such small turbine boost will always fall away but the stiffer spring did help. The 7psi spring still has improved things over the diabolical stock one though. But until I learn how to log/tune with Nefmoto I'm bit of a prisoner of my generic flash tune and had to use hardware to match the software ie getting my actual boost to resemble the tunes specified/expected parameters. Tomorrow if its not wet i'll get out and start to add timing.
Like this? Yep makes sense. Cant find part 2 where they perfect it, but yeah I did do this a year or two ago. In part 2 they found that the pressure regulator was not exhausting residual boost fully and was trapping boost between itself and the wastegate. They ended up running a circuit (with a one way valve) back to the front of the pressure relief to sort this. I raided the pneumatics part bins at work and set it up and it worked great, but it was very bulky and hard to find the real estate to mount it. There will be a relic post I did on this forum maybe 2 years ago somewhere. Yeah you're dead right re the restrictor. That's what I was taught - that its ability to restrict is dependent on the rate of change of flow. That might be why it works so well at clipping the over boost peak when flow is fastest and changing rapidly but then has a diminishing effect later in the boost curve/load range/rev range where I guess it sort of hands ful control back the solenoid. I guess there is no reason why a pressure relief valve couldn't be placed in series before the boost control solenoid to guarantee that there is no premature wastegate cracking before the solenoid is absolutely needed.
No I'd rather the boost curve that the 10psi spring gave any day. Such a little turbo and such small turbine boost will always fall away but the stiffer spring did help. The 7psi spring still has improved things over the diabolical stock one though. But until I learn how to log/tune with Nefmoto I'm bit of a prisoner of my generic flash tune and had to use hardware to match the software ie getting my actual boost to resemble the tunes specified/expected parameters. Tomorrow if its not wet i'll get out and start to add timing.
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