Why wouldn't this supercharger setup work?

[mkory]

Supercharger, who cares how much it flows, so long as it's more than you need.

Wastegates will dump untill they see a desired pressure.

Blow through MAF.

Wouldn't the WG on your charge pipe vent the extra air till it saw, lets say, 10 pounds of boost? I honestly see nothing wrong with this setup, and I feel I have a pretty good knowledge of how/why forced induction setups work, and what's requred to have one work successfully.

...Unless I'm overlooking something.

[Structure240sx]

the boost a supercharger makes is dependent on the size of the pulley on the supercharger. this spins it faster or slower

[TheOne]

http://auto.howstuffworks.com/question122.htm http://auto.howstuffworks.com/supercharger.htm <<that will give ya a better understanding of how a supercharger & a turbocharger work.

also, there's people that have done a supercharger on a ka, there's 2 or 3 people that post with 1 here.

[mkory]

I know that the amount of boost a supercharger makes is dependent on pulley size and engine revs. But so long as it's making more boost than you need, wouldn't it be dumped out of the wastegate? Big deal if it is, I dont see what it hurts.

[BlackHat]

Then you basically have a turbo... Unless you're going roots type or twin screw. My understanding of SC is that the centrifigal type is basically the same thing as a turbo just powered by belts instead of exhaust... meaning it's using energy that would be more usefull on the crank.

Roots type doesn't produce the psi that a centrifigal type would, but gets power at lower rpms (I still want to know how a roots SC with a big turbo would do). Twin screw is the newer technology (from my understanding) of SC'ers. It produces power at lower rpm (like roots type) but also gets pretty good boost.

I think SC's are cool and all, but I don't see how it would be any better than a turbo. All of the roots type blowers I've seen for 2.0-2.4L engines can do 10psi, but cost around $2900 new.... That's just insane. I'm pretty sure the twin screw are even worse (price wise).

Someone set me straight if I'm off anywhere.

[C-Kwik]

I know that the amount of boost a supercharger makes is dependent on pulley size and engine revs. But so long as it's making more boost than you need, wouldn't it be dumped out of the wastegate? Big deal if it is, I dont see what it hurts.

There is a very good reason why putting too large a supercharger isn't good idea. Simply, it would require more power from the motor to run. In order to boost to a certain psi, you need a certain amount of torque and engine speed. The more psi the charger will see, the more power it will generally use. This means if you are spinning it up to 12 psi and then bleeding off 5 psi, you'll still be using power from the engine to make 12 psi. Secondly, one of the things you want to try and do is match the efficiency of any charger to the motor. This will reduce the amount of power needed by the supercharger. A large charger with high flow rates are likely to be engineered to have high efficencies in the airflow and boost range for the applications they are likely to be used on. In the same way picking a well matched turbo for a car will yield more power for a given boost, the same is true of superchargers.

If you are considering a centrifugal unit, there may be some benefit to this as the boost curve could become flatter once the desired boost is reached. If you did this, I would still try to match the efficiency in an effort to keep power consumption down. Personally though, if I really wanted to have a flat boost curve and wasn't willing to turbocharge it, I'd just go with a well matched whipplecharger.

[BlackHat]

Personally though, if I really wanted to have a flat boost curve and wasn't willing to turbocharge it, I'd just go with a well matched whipplecharger.

That's the twin screw type isn't it? I think more than just whipple makes those (not 100% but thought I saw someone else selling them).

[TheOne]

whipple, kennebell, and many other companies make twin-screwed:P superchargers.

twin-screws are way more efficient than roots, twin-screws are known to have gone over 20psi in ford modular engines, and even on racing engines where they use a 3.3L twin-screw rated at up to 35psi.(there's also rumors of boat engines using a 5.0L twin-screw, but i dun believe that 1 bein true, this is the measure that the supercharger can deliver air or something like that, the bigger givin more psi)

btw are you refering the wastegate as the blow off/by-pass valve?, cause there's no wastegate on a supercharger, thats only on turbochargers to release exhaust gases when it gets to the desired psi on the intake side.

[mkory]

I know that superchargers dont have wastegates.

All the purpose of this was to ask if you could use a wastegate to vent the extra boost made. It'd open when it saw whatever boost you wanted it to run, and hold it there.

[epokh]

Well, if that was the sole purpose of the post, then the answer is yes, with the proper plumbing , I suppose a WG could be used on a SC.....but you're missing the bigger picture....it would be counter-productive like C-Kwik explained. If you want to run a SC, just run one with the proper airflow...else you're simply wasting energy. Pulleys can always be swapped if you decide to "upgrade".