Why not Supercharger instead of Turbo?

[v_knot]

I asked this very same question in the SE-R forum. Does anyone knows the feasibility of the supercharger application in the G20? What are the significant differences between the two, ie. pros and cons? Any feedback would be much appreciated. Many thanks.

jIm

[G-Forces]

Noone really bothers with supercharging an SR20DE because everything is basically there for a turbo already. So it's easier to setup a good turbo kit.

Personally I like turbos better. More preformance potential, no matter what anyone says!

[v_knot]

So availability is key here? I know a supercharger can put out a lot more hp and it is more efficient as well. This is the main reason why the supercharger is largely used in aerospace industry for normally aspirated piston engines. Thought same application can be applied to automotive.

[b-b00gie]

Originally posted by v_knot
I asked this very same question in the SE-R forum. Does anyone knows the feasibility of the supercharger application in the G20? What are the significant differences between the two, ie. pros and cons? Any feedback would be much appreciated. Many thanks.

jIm

Superchargers are for sissies!

[b-b00gie]

Originally posted by v_knot
I know a supercharger can put out a lot more hp and it is more efficient as well.

Sorry, that statement is full of hot air! ...no pun intended!

If you think that's true, prove it...

[frogg]

There was a huuuuuugggge thread on this not too long back.

[v_knot]

Originally posted by b-b00gie


Sorry, that statement is full of hot air! ...no pun intended!

If you think that's true, prove it...

I wish I can explain in one word but maybe this one link can help reveals some of the theoretical questions about a supercharger:
http://www.superchargersonline.com/techarticles.asp

[T4 Primera]

OH NO! Not again .........

[b-b00gie]

Know the website well...


Please prove how superchargers make more HP and are more efficient. Thousands of people would like to hear that answer.


Roots superchargers can add up to 40% power increase.
Centrifugal superchargers can add up to 100% power increase.

On an SR20DE (124whp stock) that can put you to a max of 248whp.

Do you still believe turbochargers make less power?



Turbochargers are pretty damn effecient. They use the typically wasted exhaust gas to charge the engine w/ air. Superchargers charge the air by using the engine and crankshaft. That is wasting potential HP since you need HP to make more HP.

Do you still believe turbochargers are less efficient?



BTW, there has been countless instances where supercharger companies' claims have been put to rest. Supercharger companies are notorious for publishing completely false information in order to make supercharging appear better than turbocharging.


The only down side to turbo's is lag, but guess what.. superchargers have lag too!!


Turbos win. Hands down.

[v_knot]

Me no spek Inglisss....me no nutting.....

Well, seriously I didn't know that there were previous discussions on this issue. The point that I am trying to comprehend here is the feasibility of the supercharger application. I completely agreed that the supercharger uses the engine tranny and belts to speed their impeller thereby wasting potential useful power. I suppose what "efficient" to one industry might not necessary "efficient" to the other; especially if they are almost working conversly with each other. For example, in the turbojet engine, power is produced by pressurized and burned gases whereas the typical piston engine produces power via tranny system. A supercharger would be more efficient in the turbojet engine mainly because it addes further pressurized air to the already pressurized gas before it reaches the chamber. What uses to drive the impeller of the supercharger is the same power required to drive the intake fan thus not wasting any useful thrust. Each application has its own merit. The quantity in which we measured to classify the two depends on its application. Clearly there are pros and cons for both. For instance, the supercharger have the following benefits over the turbocharger:

1) the airflow is not heated (colder air better performance)
2) higher pressures possible
3) higher and more constant flow rates possible
4) the pressures can be more controlled. ( turbocharger works off of
exhaust gas so harder to control and optimise)

In summary, the quantity in which the pros outweighted the cons is what the end benefit. The verdict has spoken. Turbo is more favourable.

[v_knot]

Supercharger VS.Turbocharger
Many people are confused about the differences between a super charger and turbocharger. Booth families of devices are basically air compressors, but they're operated' quite differently from each other. A supercharger is mechanically driven by the engine itself; usually off the crankshaft by a cogged belt andpulley system. This means that a supercharger uses up some of the engine's horsepower just to drive itself - often 60 horsepower or more! Fortunately, the airflow generated by the supercharger helps it produce far more horsepower than it requires to operate.

A turbocharger, however, is driven by the thermal energy of the exhaust
gases of the engine. With non-turbocharged vehicles, these gases are
simply discharged out of the engine as quickly and efficiently as possible, wasting a surprising amount of energy in the form of noise and heat. A turbocharger uses some of that energy (which would otherwise be wasted) to drive its compressor, without the attendant horsepower loss of a crankdriven system.

The result? The turbocharged engine stands to produce more peak horsepower than a comparable supercharged engine, mostly because the turbo does not require any power from the crankshaft. Also, the turbocharged engine will typically run much quieter than a supercharged engine since the turbo has no gears, belts or pulleys and because the turbo itself muffles the exhaust. And while many superchargers are large, heavy devices (we've all seen Roots-type blowers sticking up through the hoods of muscle cars), the turbocharger is a relatively small package - a turbo capable of producing 600 horsepower can weigh only 15 pounds and be easily held in one hand. It is for these reasons that turbocharging has become increasingly popular with both OE and aftermarket manufacturers. Automakers can produce lightweight vehicles with good fuel economy yet excellent power thanks to the turbo. The aftermarket manufacturers have jumped into the game, offering larger turbocharger "upgrades" in place of factory turbos, or even complete turbo "kits" to convert a naturally-aspirated vehicle to turbocharged configuration. (Eg. Subaru WRX is a perfect example of power to weight ratio)

The fundamentals are basically these:

* Exhaust must be routed to the turbine inlet of the turbocharger. This is
typically done with a turbo exhaust manifold, when available, or a custom adapter plate to allow you to mount the turbo to the factory exhaust manifold.

*Exhaust must be directed out of the turbine discharge of the
turbocharger. This can typically be done at a muffler shop, where a custom down-pipe will be fabricated, to connect the turbine discharge side of the turbo to the exhaust system.

*Air must be ducted from the air filter to the compressor inlet, and from
the compressor discharge to the intake manifold. This is typically done in aluminum or steel tubing which is then coupled at all joints by silicone hose couplings or nitrile rubber connectors. Flex hose is sometimes used on the inlet side of the compressor since it is only subjected to vacuum, not pressure. (Plumbing knowledge kicks in..)

*Pressurized oil must be fed to the turbocharger's bearings. The most
common place to tap into an oil galley is at the oil pressure sending unit.

*An oil drain line must be installed so that the oil used to lubricate the
turbocharger can drain back to the oil pan. This is typically done by
brazing a hose fitting to the pan and using a large diameter, oil-resistant hose from the bottom of the turbo to the side of the pan. The heart of the turbo system is of course, the turbocharger itself. The size and model of turbo that you require can vary radically depending on your application (i.e. street, track, drag). The larger turbochargers can produce tremendous amounts of power, but they will take longer to spool up (turbo lag). This is a function of the size of compressor and turbine wheels, as well as the turbine housing itself. A turbocharger applications specialist will be able to assist you in choosing the proper turbocharger for your car.

Disadvantages for turbochargers:

*With air being pumped into the cylinders under pressure by the
turbocharger, and then being further compressed by the piston, there is
more danger of knock. Knocking happens when you compress air, the temperature of the air increases. The temperature may increase enough to ignite the fuel before the spark plug fires.

*Turbo Lag. It takes a second for the turbine to get up to speed before
boost is produced. One way to decrease turbo is to reduce the inertia of
the rotating parts, mainly by reducing their weigh.

[b-b00gie]

So I guess you're starting to believe me?

[G-Forces]

Originally posted by v_knot
For instance, the supercharger have the following benefits over the turbocharger:

1) the airflow is not heated (colder air better performance)
2) higher pressures possible
3) higher and more constant flow rates possible
4) the pressures can be more controlled. ( turbocharger works off of
exhaust gas so harder to control and optimise)

1) This is incorrect. With the exception of the centrifugal supercharger (which basically uses a turbocharger turbine) the supercharges are much more inefficent in compressing the air. And will create a hotter charge at comparable boost levels.
2) I don't think that is correct either.
3) Sounds like you got this backwards too.
4) That's where a good wastegate comes into play.

Most of those points sound backwards. I'd like to hear your rationale behind 2 and 3.

[jasestu]

Hmmm, methinks someone needs to collate all these threads on superchargers vs turbochargers and put something in the FAQ section...

I think it's generally accepted that turbos are the most viable option, but I'd still like to try the supercharger thing oneday, just simply becuase it's different.

[b-b00gie]

Originally posted by G-Forces

1) This is incorrect. With the exception of the centrifugal supercharger (which basically uses a turbocharger turbine) the supercharges are much more inefficent in compressing the air. And will create a hotter charge at comparable boost levels.
2) I don't think that is correct either.
3) Sounds like you got this backwards too.
4) That's where a good wastegate comes into play.

Most of those points sound backwards. I'd like to hear your rationale behind 2 and 3.

Jason this goes back to what I was saying about supercharger manufacturers making false claims...


:frog: