Question about making boost and WOT

[Showguns]

My last vehicle was a 2006 Stage 3 Roush Mustang. The roots style superchargers for those cars only make boost at WOT. Otherwise if not WOT the boost gets dumped/bypassed.
Does the Camaro roots style superchargers work the same way? I'm guessing that snail type superchargers don't have this problem.
Or is it a problem? I thought It'd be more fun to drive with boost even at 1/2 throttle.

[YLWJKT]

The Magnacharger makes boost pretty much right off idle.

[alfie43]

Originally Posted by Wandering Scot

The Magnacharger makes boost pretty much right off idle.

Not really. The Magnacharger supercharger system incorporates a specially designed bypass valve, which is actuated by a vacuum motor near the throttle body, and re-circulates the supercharger air flow when boost is not required.

During typical driving conditions, the engine is under boost around 5% of the time, which means the remaining 95% of the time the engine is under vacuum, allowing for better fuel economy and a quieter ride.

During WOT, the bypass is closed and all h*ll breaks loose.

Alfie

[ddavis]

Originally Posted by alfie43

Not really. The Magnacharger supercharger system incorporates a specially designed bypass valve, which is actuated by a vacuum motor near the throttle body, and re-circulates the supercharger air flow when boost is not required.

During typical driving conditions, the engine is under boost around 5% of the time, which means the remaining 95% of the time the engine is under vacuum, allowing for better fuel economy and a quieter ride.

During WOT, the bypass is closed and all h*ll breaks loose.

Alfie

Bingo!
I can ease on the gas and take the rpms up to over 3k without boost coming in if I want to.

[Showguns]

Exactly what I thought, same as my previous Mustang.
Now,...how about the snail type superchargers?????

[Jon@MagnaCharger]

Alfie was very close in his description of our bypass valve. However, boost is not relegated only to WOT. You can very easily have partial throttle boost. At 3 in Hg of vacuum the bypass valve will close allowing the manifold to pressurize and give you a smooth transition to boost. This gives you the ability to modulate your throttle inputs yet still have boost. Though you can easily drive the vehicle and not hit boost if you want to, just a hair more throttle will reduce the vacuum in the manifold enough allow you to start building boost.

[old motorhead]

Boost delivery depends on how things are set up too. Smaller blower pulley (spins the blower faster) will get you into boost easier. I have 2.9" pulley on my vette maggie and it takes very little throttle to get into boost. Hitting the resume button on the cruise control will show around 2psi just for an instant. In normal driving, it's easily kept on the vacuum side though. Press the go pedal a little harder and the boost is there instantly.

[Brian@Vortech]

Centrifugals operate in a similar way. You must first overcome the vehicle's natural state of vacuum to go into boost. Therefore, in cruising or part-throttle you will not go into boost, until the engine is under load. You traditionally will not see boost from any type of compressor until around 3/4 throttle or above.

[Granatelli]

By definition, "load" unto itself creates the boost. So the more you ask of the engine via your right foot, the quicker it goes into boost.

A Maggie blower is the same in design as the Roush so their characteristics would be the same

A centrifugal (snail type) is more like the turbo. As a quick lesson in forced induction, some call the centrifugal blower a "belt driven turbo"

The turbo use exhaust flow to spin the impeller and the Vortech type uses the belt just like the Maggie and Roush