04 3800 supercharged wastegate?
#1
05-22-2016, 11:36 AM
04 3800 supercharged wastegate?
So I was talking with one of my friends and he brought up that supercharger has kind of a waste gate and that would hinder me being able to get more boost. Is that true and if it is how do I get rid of it. My friend went to school for automotive mechanics at University of northwestern Ohio. So she does know what is talkIng about.
#2
05-22-2016, 12:54 PM
No offense, but if your auto mechanic friend thinks that your roots supercharged car has a wastegate and that it is holding you back from making more boost, then they must've skipped a few classes, lol.
Wastegates are nearly exclusively used on turbo cars. The waste gate is placed in the exhaust piping before the turbo's hot side, and it is used to bypass exhaust gas around the turbo to control the amount of boost the turbo makes (more accurately, it controls how much air goes through the turbo which controls how fast it spins which controls how much air is moved on the intake side).
There is one exception to this that is used on very rare occasions and that is on centrifugal superchargers. Because centrifugal superchargers build boost over the rpm range, and don't hit peak boost until peak rpm, people will put a much smaller pulley on the blower to add boost across the rpm range and then will use the wastegate to limit boost to some preset value. The intent is to get the centrifugal to come on much stronger on the low end, like a roots blower while still keeping max boost under a maximum threshold for the octane limits of the engine.
With that said, your engine does have a way to limit boost, the boost bypass valve. The function is different from a wastegate though as it really only has one main function, to bypass the supercharger at idle and low throttle positions. This increases fuel mileage and reduces stress on the blower. As soon as you hit the throttle hard, the bypass valve instantly closes, and the engine starts making full boost (as dictated by whatever size supercharger pulley you're running). The pcm has a few other oddball uses for it, but they're not things you'll normally run into.
Short story is, if you want more boost on a roots supercharged engine, you need to decrease the size of the supercharger pulley (or increase the size of the crank pulley). There is no sort of wastegate on your car that you can adjust to magically gain more boost. You could theoretically lock your bypass valve closed all the time, but IMO there's no reason to bother with that, if you want boost, just press the throttle harder.
Of course you need to keep in mind that although you can easily add more boost with a pulley change, it must be accompanied by supporting mods to make sure you get the most power out of the change and to make sure you don't grenade the engine.
Wastegates are nearly exclusively used on turbo cars. The waste gate is placed in the exhaust piping before the turbo's hot side, and it is used to bypass exhaust gas around the turbo to control the amount of boost the turbo makes (more accurately, it controls how much air goes through the turbo which controls how fast it spins which controls how much air is moved on the intake side).
There is one exception to this that is used on very rare occasions and that is on centrifugal superchargers. Because centrifugal superchargers build boost over the rpm range, and don't hit peak boost until peak rpm, people will put a much smaller pulley on the blower to add boost across the rpm range and then will use the wastegate to limit boost to some preset value. The intent is to get the centrifugal to come on much stronger on the low end, like a roots blower while still keeping max boost under a maximum threshold for the octane limits of the engine.
With that said, your engine does have a way to limit boost, the boost bypass valve. The function is different from a wastegate though as it really only has one main function, to bypass the supercharger at idle and low throttle positions. This increases fuel mileage and reduces stress on the blower. As soon as you hit the throttle hard, the bypass valve instantly closes, and the engine starts making full boost (as dictated by whatever size supercharger pulley you're running). The pcm has a few other oddball uses for it, but they're not things you'll normally run into.
Short story is, if you want more boost on a roots supercharged engine, you need to decrease the size of the supercharger pulley (or increase the size of the crank pulley). There is no sort of wastegate on your car that you can adjust to magically gain more boost. You could theoretically lock your bypass valve closed all the time, but IMO there's no reason to bother with that, if you want boost, just press the throttle harder.
Of course you need to keep in mind that although you can easily add more boost with a pulley change, it must be accompanied by supporting mods to make sure you get the most power out of the change and to make sure you don't grenade the engine.
Last edited by bumpin96monte; 05-23-2016 at 04:16 PM.
