I've searched online and couldn't really find an answer... What are the advantages to twin screw vs centrifugal superchargers? (I know how they're different, don't know why though)
ok i did!If I am correct, twin screw deliver maximum airflow at a low rpm and maintain that maximum across the rpm range. So they start at say 10 units @ 2000 rpm, and still blow 10 units at 6000 rpm. This is good for low down torque since maximum deliverable air is applied at low rpm, a figurative "+1" for screw types.
pa.....partially correct as in they flow down low yes! as to the rest i think your confused eg: @100% efficiency lets say its 100 ci per rev. @ 6000 revs its still 100 ci per rev. = 600,000ci
Centrifugal type blowers are more linear, and pressure builds as rpm do. Its a direct correlation between engine speed and pressure built. Starts at 2 psi @ 2000 rpm, ends at 8 psi @ 6000 rpm. This means that power developed due to a centrifugal blower is "peakier" than screw types. This may be a benefit at higher rpm, as this blower may be able to deliver more air at higher rpm than screw type.
pa....as per roots or the more efficient screw type charger the centrifugal too has a known displacement eg: 100ci per rpm but its efficiency varies dramatically this can be as little as 10% at 1000rpm upto 60-70% at 6000rpm
I have always seen centrifugal blowers as the mid point between turbos and roots type or screw type blowers as they contain characteristics of both F/I types. Its basically a belt driven turbo.
pa....please don't use turbo's in the same sentence!!! lol
Please anyone correct me if I am wrong, I'm just going off old memory.
akgc??? you got me lost???screw type = volume, but requires more torque/effort to spin.
centrifugal = less parasitic loss, smaller/lighter, but less CFM and harder to chang out the wheel
Why not? Many sources document that a turbocharger is a type of supercharger. Makes sense, since a supercharger is defined as "a compressor that forces increased oxygen into the cylinders of an internal-combustion engine." They are just powered differently.pa....please don't use turbo's in the same sentence!!! lol
agreedcentrifugal use less hp are easier to fit and plumb and change wheels (easier than lengthening screws anyway! so?) but totally inefficient
remember that next time an idler bearing annoys you!!! LOLWhy not? Many sources document that a turbocharger is a type of supercharger. Makes sense, since a supercharger is defined as "a compressor that forces increased oxygen into the cylinders of an internal-combustion engine." They are just powered differently.
pa...notice the all important lol at the end? IT WAS A JOKE! i was implying that he degraded / insulted turbos by mentioning them in the same sentence!!!
OP, since most of the technical stuff was covered already, the most important thing to remember here is that positive displacement superchargers sound amazing. The rest are just ok.
its all cool it just came across as 10 cfm @ 2000 rpm and 10 cfm @ 6000 rpm or units what ever you said?PA, sorry I wasn't basing my numbers off of any real math, I was being lazy and just using an example to clarify operation, but thanks for clearing that up!
Obv. turbos are mechanically very differently to superchargers, what I was saying is that characteristically a centrifugal super is closer to a turbo in operation than a screw type. Where screw type blowers have "screws" that mesh together to compound air, centrifugal supers and turbos have turbines that create pressure. Other than both using a turbine, they are completely different.
sorry went to sleep after my last reply!PA, thanks for the info. That being said, I have a few questions regarding supers that you or others might be able to answer, as it pertains to the original topic.
What type of solutions exist for cooling the intake charge when using superchargers? Can contemporary intercooler (aftercooler) systems be used with both types of superchargers? I know most turbocharger systems utilize intercooling, but lots of supercharger systems don't mention intercooling. Is this due to the lower maximum boost pressures of superchargers, or because it is simply ineffective/unattainable?
I ask because I know that screw type blowers are prone to heat soak and I am curious as to what can mitigate this issue.
me too thats why tt for me i can have both best low down torque and better power all the way up!!!Quartermaster- agreed.
Look this is one of those questions that we can all argue about "which is best" for years at a time. It all comes down to how you want to make power. Personally, I would rather have torque than horsepower.
see the beauty of turbos its a key stoke away from what ever boost you like at what ever rpm you like and inherently whatever load you like! without trying to change pulleys on the fly!!!The car has plenty of torque to spin the wheels at low speeds. Not sure why anyone would desire torque over hp in a V6 sports car. I'd enjoy more roll on power for sure but it's adequate now and I can downshift when I really need to get going.
Just an all around well balanced single street turbo set up is ideal as far as all around performance vs. cost. 400 rwhp is a real kick in the pants man!
I'm still very eager to find out how much hp Tex's 4.2 stroker makes however w/ a cam and head porting. Who knows, that might be a $5K 400hp NA solution right there which wouldn't be too shabby.
Agreed a third time. I personally think conglomerate max power and drivability would be attained by a turbo setup due to the system sapping the least power from the engine and delivering the most possible flow of compressed air by weight. However, in normal driving situation, I think max FUN will come from the instant-on torque of a twin screw. Lets face it, low end torque is almost always desirable and makes all of us grin. Yeah I like poppy fast spinning rev machines, but that's not what I bought...Twin screw or don't bother.
Centrifugal ONLY if you simply CANNOT fit a screw type in teh engine bay, or you've given up on turbos.
Back in the Tiburon days I recall RIPP Centrifugal superchargers blowing up a whole grip of 3G DSMs, Tiburons etc and ever since I learned about how peaky they can be and difficult to control, I wouldn't ever go with one unless it was the only option.