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Discussion Starter · #1 ·
OK I'm the first person to admit I'm far from being a engine tuning God but Have I missed something posted up about just raising the pressure that the wastegate opens ? It seems to me that all this talk about gearing up the supercharger etc etc is unnecessary when the bike obviously makes more boost than needed due to the chirping noise as the wastegate opens .

My CBX Turbo has a very simple spring and plunger to adjust the boost pressure and winding fully in makes a BIG difference , I'm sure the H2 has something more complicated than this but it must be possible to up the pressure that the wastegate releases?

Happy to be shot down in flames so fire away .
 

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Let me demonstrate my ignorance. If the waste gate is opening at some point under Full Throttle then I think you make a great point. But I'm Guessing that with the throttle wide open the boost doesn't reach adequate pressure to open the waste gate.
 

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Discussion Starter · #3 ·
Let me demonstrate my ignorance. If the waste gate is opening at some point under Full Throttle then I think you make a great point. But I'm Guessing that with the throttle wide open the boost doesn't reach adequate pressure to open the waste gate.
As I said I'm no tuning God (not even a disciple) you could well be right and I'm probably being too simplistic in my thinking in comparing a state-of-the-art modern supercharged motorcycle with my old school turbo set up.
I don't think its you demonstrating your ignorance ,it's probably me . Good answer .
 

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What your hearing is for off throttle so it doesn't pressurize system when no throttle is being asked for. It would/could be bad to mess with that Imo. You want more boost when your giving it gas not so it takes longer for pressure to release when your not.
 

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Lets get our terminology correct. The H2 uses a blow off valve which has nothing to do with letting off excess pressure, it is to let off pressure when you let off the throttle so as to prevent engine damage. It does not act as a waste gate. A waste gate is pre set to open at a certain psi and will stay open until the pressure falls below that level. If you have a turbo bike like the Honda CX650T then it is preset at 16.5 # and will release boost when it exceeds that level until it goes below 16.5. If your waste gate is sloppy it might release earlier, especially if the springs are aging. Raising the boost on the turbo is as simple as raising the resistance on the spring via some sort of hydraulic adjuster, or spring combos. Also a good way to melt pistons if you haven't thought the process through. Superchargers do not usually use a waste gate as the boost is well known at the time the system is engineered and does not vary other than by rpm.
 

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Discussion Starter · #6 ·
Lets get our terminology correct. The H2 uses a blow off valve which has nothing to do with letting off excess pressure, it is to let off pressure when you let off the throttle so as to prevent engine damage. It does not act as a waste gate. A waste gate is pre set to open at a certain psi and will stay open until the pressure falls below that level. If you have a turbo bike like the Honda CX650T then it is preset at 16.5 # and will release boost when it exceeds that level until it goes below 16.5. If your waste gate is sloppy it might release earlier, especially if the springs are aging. Raising the boost on the turbo is as simple as raising the resistance on the spring via some sort of hydraulic adjuster, or spring combos. Also a good way to melt pistons if you haven't thought the process through. Superchargers do not usually use a waste gate as the boost is well known at the time the system is engineered and does not vary other than by rpm.
Just the answer I was looking for , that all makes sense and thank you for taking the time to explane it in a way I can understand I did not appreciate that superchargers do not normally use a wastegate . My mistake was on thinking the chirping noise was the bike venting excess boost pressure like a turbo bike .
My Turbo is a aftermarket Mr Turbo kit from the early 80s fitted to a CBX 1000 not a factory CX 500 / 650 .
 

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Just the answer I was looking for , that all makes sense and thank you for taking the time to explane it in a way I can understand I did not appreciate that superchargers do not normally use a wastegate . My mistake was on thinking the chirping noise was the bike venting excess boost pressure like a turbo bike .
My Turbo is a aftermarket Mr Turbo kit from the early 80s fitted to a CBX 1000 not a factory CX 500 / 650 .

You are welcome and it is a weird concept to understand sometimes. I use both blow off valves (BOV) and wastegates on my turbo bikes. The BOV uses vacuum to tell it when to open and the wastegate uses the boost to pressure the wastegate to open. For an added feature, some people will have the BOV exhaust to the atmosphere and maybe have a horn exhaust to add to the distinct supercharger sound.
 
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