prob dumbest question ever... how do you control/change boost?
- Thread starter Scuffler
- Start date
Bescurred
BOOSTED SHAMU v2.0
- Joined
- Jun 10, 2001
Right under the turbo is the wastegate. Its that skinny rod down there and on this turbo picture it is actually disconnected from the rod. It's suppose to be connected up but this one is threaded. Turning it in or "shorting" the rod makes the boost go up and making it longer turns the boost down. Also on the compressor side of the turbo is a vacuum connection. You can get a manual boost controller for that part too. Not sure what that on is called but I've always just called it a RJC style boost controller because that is where I got mine from.
If you wastegate is stock you won't be able to turn up or down the boost until you mod it or buying an adjustable one.
If you wastegate is stock you won't be able to turn up or down the boost until you mod it or buying an adjustable one.
we should also discuss how the wastegate works, and how the stock ECM controls boost, so that the OP understands the hardware and can take appropriate caution when fiddling with this.
The wastegate is a little flapper valve that allows exhaust gases to bypass the turbine wheel. by limiting the amount of exhaust that hits the turbine wheel, we limit the amount of boost the turbo makes.
The wastegate "actuator" in the picture above is pressure operated, pressure from the turbo compressor causes the rod to extend when it overcomes the actuator's internal spring's "preload". By shortening the rod (in the case of an adjustable actuator) more preload is applied to the spring, so it takes more boost pressure to overcome it.
The stock system includes a special set of hoses and a solenoid that the ECM pulses to raise the boost level. This pulsing of the solenoid bleeds off part of the pressure that is being fed to the actuator. By bleeding off some of the pressure in the little hoses, more boost pressure is required to make the wastegate open, so you wind up with more boost. The solenoid is controlled by the ECM, and therefore the chip. The chip programming can be changed to change your boost, and some chips have "parameters" the user can adjust to set their boost.
The easiest thing to do is to adjust the actuator, however.
Now, a word of caution, the wastegate hoses are a common failure item, they degrade from age and heat and if they fail you will get a bunch of boost (probably too much) which could damage the engine if you don't catch it. So, now, today, check the condition of those hoses where they connect to the turbo and the wastegate actuator. If they look dried out or cracked, cut them back and re-attach them. Install tie-wraps to ensure they stay on, and order a new set now, today.....
Clear as mud?
Bob
The wastegate is a little flapper valve that allows exhaust gases to bypass the turbine wheel. by limiting the amount of exhaust that hits the turbine wheel, we limit the amount of boost the turbo makes.
The wastegate "actuator" in the picture above is pressure operated, pressure from the turbo compressor causes the rod to extend when it overcomes the actuator's internal spring's "preload". By shortening the rod (in the case of an adjustable actuator) more preload is applied to the spring, so it takes more boost pressure to overcome it.
The stock system includes a special set of hoses and a solenoid that the ECM pulses to raise the boost level. This pulsing of the solenoid bleeds off part of the pressure that is being fed to the actuator. By bleeding off some of the pressure in the little hoses, more boost pressure is required to make the wastegate open, so you wind up with more boost. The solenoid is controlled by the ECM, and therefore the chip. The chip programming can be changed to change your boost, and some chips have "parameters" the user can adjust to set their boost.
The easiest thing to do is to adjust the actuator, however.
Now, a word of caution, the wastegate hoses are a common failure item, they degrade from age and heat and if they fail you will get a bunch of boost (probably too much) which could damage the engine if you don't catch it. So, now, today, check the condition of those hoses where they connect to the turbo and the wastegate actuator. If they look dried out or cracked, cut them back and re-attach them. Install tie-wraps to ensure they stay on, and order a new set now, today.....
Clear as mud?
Bob
GNcollectables
Member
- Joined
- Dec 12, 2005
these videos might help:
http://buickturboregal.com/turbo-wastegate-settings-basics-preload-actuator-videos.html
.
http://buickturboregal.com/turbo-wastegate-settings-basics-preload-actuator-videos.html
.
Rafs-T-Type
Not so Senior Member
- Joined
- Mar 8, 2009
Dumb would be a person that is too embarrassed to ask the question in the first place. We all started at the bottom. No one is born with the knowledge of how cars work. Use the search feature and fire those questions away!
Well if your car is stock it will NOT have the adjustable screw actuator that can be an aftermarket or a home made mod. The very early days we used a bleeder valve tee'ed into the little hoses to "fool" the system into thinking there was less boost. Some guys still use these but they are hard to dial what amount of boost is raised and lowered.
groumoutis
Active Member
- Joined
- May 1, 2009
I am using the iPhone app so I can't see your sig and don't know what all you have so bear with me.
I highly recommend that you get to know your way around the engine very well before adjusting the boost. Make sure you have the scan tool to monitor the engine and have a good boost gauge to know how much boost you are running. Find a guy in your local area and have him help you. I always tend to be a little cautious when turning up the boost. I am running Alky and only go up to 20psi just to be on the safe side.
Posted from the TurboBuick.Com mobile app
I highly recommend that you get to know your way around the engine very well before adjusting the boost. Make sure you have the scan tool to monitor the engine and have a good boost gauge to know how much boost you are running. Find a guy in your local area and have him help you. I always tend to be a little cautious when turning up the boost. I am running Alky and only go up to 20psi just to be on the safe side.
Posted from the TurboBuick.Com mobile app
chris kirk
Active Member
- Joined
- Jun 1, 2013
If you can do some research to find an expert on the GN's where you live. Hence the words "EXPERT ON GN'S." There's a lot of smart, talented techs out there but the GN's are a different kind of beast... Six cylinder turbos that beat the big blocks.... And not everyone can understand them. I've been around these cars for 25 years, this is my second one and it's the third motor that I've done and I still would not be comfortable doing something like that. There's a lot of factors to consider when turning up your boost. Be careful and good luck. Oh, and welcome to the GN's. The few and the proud...
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