BeetleDragon737
Well-known member
I've been searching and reading so many threads about boost that it's getting exhausting. I still have questions, so hopefully some wise folks can chime in.
Background:
The car is a '99 Beetle, ALH engine. I'm pretty sure it was stock when I bought it. After connecting a boost gauge to the upper intercooler hose a few months ago, I saw that my boost spiked to 19 psi max and leveled off around 14 at WOT (don't know why we use that term when these cars don't have throttles). After some reading, this seems pretty normal.
After getting DLC 520s installed, my boost spikes to around 22 psi max, and levels off around 14. The turbo can only handle 18.5 psi sustained, so the increase concerns me a bit. I'm going to RocketChip to get RC3 in about two weeks, and I know the tune will increase boost, so I called Jeff. I asked about a boost valve, but he called it a band-aid and said that even if it was installed, the spring is tuned to a certain psi and can only operate in a dynamic fashion. Thus, if sustained overboost occurred, a boost valve would stop relieving boost eventually and could not adequately protect the turbo. He said I should address the underlying problems instead (ie, turbo actuator, vanes, etc).
So, questions:
1. If the boost valve is really just a relief valve with a spring that gets compressed at a certain pressure, why won't it stay open as long as overboost is still occurring? If that's true, what's the hesitation with using one? Surely installing one is far simpler than disassembling the turbo to clean out carbon from the vanes, etc.
2. If I choose to use a boost valve, where can I purchase one that does not have a vent hole? I know a vent hole is not desired for these turbos/actuators. Why?
3. If I decide to adjust the actuator, do I only adjust the stop, or is there more adjustment that can be made? Will this only affect the max boost, or will it decrease my sustained boost as well?
4. Is it straightforward to access the actuator on the Beetle's turbo, or will I have to remove things to get to it?
5. If it's carbon on the turbo vanes that's slowing the turbo response rather than a misadjusted actuator, can some of that be burned off by revving near redline and keeping the EGTs high for an extended period of time?
Thanks for any help.
Background:
The car is a '99 Beetle, ALH engine. I'm pretty sure it was stock when I bought it. After connecting a boost gauge to the upper intercooler hose a few months ago, I saw that my boost spiked to 19 psi max and leveled off around 14 at WOT (don't know why we use that term when these cars don't have throttles). After some reading, this seems pretty normal.
After getting DLC 520s installed, my boost spikes to around 22 psi max, and levels off around 14. The turbo can only handle 18.5 psi sustained, so the increase concerns me a bit. I'm going to RocketChip to get RC3 in about two weeks, and I know the tune will increase boost, so I called Jeff. I asked about a boost valve, but he called it a band-aid and said that even if it was installed, the spring is tuned to a certain psi and can only operate in a dynamic fashion. Thus, if sustained overboost occurred, a boost valve would stop relieving boost eventually and could not adequately protect the turbo. He said I should address the underlying problems instead (ie, turbo actuator, vanes, etc).
So, questions:
1. If the boost valve is really just a relief valve with a spring that gets compressed at a certain pressure, why won't it stay open as long as overboost is still occurring? If that's true, what's the hesitation with using one? Surely installing one is far simpler than disassembling the turbo to clean out carbon from the vanes, etc.
2. If I choose to use a boost valve, where can I purchase one that does not have a vent hole? I know a vent hole is not desired for these turbos/actuators. Why?
3. If I decide to adjust the actuator, do I only adjust the stop, or is there more adjustment that can be made? Will this only affect the max boost, or will it decrease my sustained boost as well?
4. Is it straightforward to access the actuator on the Beetle's turbo, or will I have to remove things to get to it?
5. If it's carbon on the turbo vanes that's slowing the turbo response rather than a misadjusted actuator, can some of that be burned off by revving near redline and keeping the EGTs high for an extended period of time?
Thanks for any help.
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