by Bottoz » Thu Oct 26, 2006 5:04 pm
I thought the Brammo 300 was a 7k redline. Either way, the M62 Recomended Max Continuous Blower Speed = 16,000 rpms. With a 2.8, blower speed is 14,000 rpms at 6,250 rpms.
The Stock ECOTEC does have an ECU controlled bypass valve. Here's some info on that:
The boost bypass system on our superchargers has three parts: the solinoid, the actuator, and the butterfly valve (normally closed). The actuator is a diaphram/piston that has two chambers and a small metal shaft that connects to the buterfly valve. When the ECU triggers boost bypass, it opens a soliniod allowing charged air (in the range on 12+ psi stock to about 18+ with a very small pulley) to fill one of the chambers of the actuator. When this happens the piston in the actuator pulls on the shaft which opens the butterfly valve allowing charged air back into the inlet side of the supercharger instead of forcing that air into the engine.
The ECU uses boost bypass to bleed off some of the boost just before you hit the rev limiter to prevent damage from the engine getting fuel (or spark) cut off at maximum boost. The problem with this is that if you change the pulley, the computer detects that you are hitting the "maximum boost" (near 13 psi) and opens the bypass while you still have a lot of RPM's left to climb.
The idea of boost bypass is that if you allow the computer to open the solinoid, but do not allow the charged air to reach the piston chamber on the actuator, the butterfly (bypass) valve will never open. Many people on this board have this mod done, and it is considered a 'safe' mod, but remember that you are disabling an engine protection feature.
The following statement is true for a stock or near stock setup, but with signifantly smaller pulleys the boost bypass opens earlier:
The boost bypass valve opens up at 6,000rpm and bleeds boost off untill redline. The bypass mod disables it keeping it closed all the way up untill redline. You will see no difference in power under 6,000 rpms if you disable it. They only increase in power comes after 6000 rpms where you will see an additional 10hp gain in peak hp.
I thought the Brammo 300 was a 7k redline. Either way, the M62 Recomended Max [b]Continuous[/b] Blower Speed = 16,000 rpms. With a 2.8, blower speed is 14,000 rpms at 6,250 rpms.
The [b]Stock[/b] ECOTEC does have an ECU controlled bypass valve. Here's some info on that:
[i]The boost bypass system on our superchargers has three parts: the solinoid, the actuator, and the butterfly valve (normally closed). The actuator is a diaphram/piston that has two chambers and a small metal shaft that connects to the buterfly valve. When the ECU triggers boost bypass, it opens a soliniod allowing charged air (in the range on 12+ psi stock to about 18+ with a very small pulley) to fill one of the chambers of the actuator. When this happens the piston in the actuator pulls on the shaft which opens the butterfly valve allowing charged air back into the inlet side of the supercharger instead of forcing that air into the engine.
The ECU uses boost bypass to bleed off some of the boost just before you hit the rev limiter to prevent damage from the engine getting fuel (or spark) cut off at maximum boost. The problem with this is that if you change the pulley, the computer detects that you are hitting the "maximum boost" (near 13 psi) and opens the bypass while you still have a lot of RPM's left to climb.
The idea of boost bypass is that if you allow the computer to open the solinoid, but do not allow the charged air to reach the piston chamber on the actuator, the butterfly (bypass) valve will never open. Many people on this board have this mod done, and it is considered a 'safe' mod, but remember that you are disabling an engine protection feature.
The following statement is true for a stock or near stock setup, but with signifantly smaller pulleys the boost bypass opens earlier:
The boost bypass valve opens up at 6,000rpm and bleeds boost off untill redline. The bypass mod disables it keeping it closed all the way up untill redline. You will see no difference in power under 6,000 rpms if you disable it. They only increase in power comes after 6000 rpms where you will see an additional 10hp gain in peak hp.[/i]