Whats the main diff. between the two besides S/C is belt driven and Turbo goes off sucking in air or something like that?....I mean performance wise, why would someone pick one over the other?

 

Ok, Youve got the S/C part, but im not os sure about the turbo part, so ill clarify it for ya.

Ok, so a turbo has two parts(and I dont know the technical name for them) but basically, one end drives it the other sucks. One half if the turbo unit runs of exhuast, so the flowing exhuast spins a turbine, and the turbine spins a shaft. At the other end of this shaft is another "turbine" that compresses air, creating boost.

The main disadvantage to a turbo is something called TURBO LAG. Basically, because you need exhaust to create the boost, once you step on the gas, the turbo effect doesnt come in until there is alot of exhuast gas flowing. The supercharger runs off a belt so it spins with the motor, and the effect is instant.

In order to eliminate turbolag, you need N2O (nitrous oxide "nos")

Turbos have wastegates, which gets rid of excess "boost"(dont know how else to put it) and that is why you sometimes hear that loud "woosh" from turboed cars.

To recap...

turbos have turbo lag, but performance principals are the same.

Jim

 

Actually... today's technology has really cut down on what used to be known as turbo lag. Also, exhaust turns turbine turns shaft turns air pump. Superchargers rely on the belt to turn, takin a little bit from the motor but in turn producing good amounts of horsepower. A lot of people on here will tell you that turbo has an advantage because it doesn't apply any parasitic loss to the motor because it runs off the spent fumes, or exhaust anyway. They are, in fact, wrong. A turbin in the middle of the exhaust causes a retriction, which means when the motor is in it's exhaust stroke, it actually has more backpressure then normal. A turbo just has simply less parasitic loss as compared to a s/c.

 

So it sounds then like a S/C would be the better investment if you were going for pure performance correct???

 

right, but the SC has parasitic loss due to being belt driven...so it technically uses some of the power that it makes.

 

But you still have some lag.

Another advantage to S/C is that you have a smooth torque band... what I mean is, with a S/C the higher the Rpms, the more air its gunna flow, but with a tubro, you need to wait for it to sool up and THEN you get the power. I dont mean turbo lag, Im talking about chitty performance at lower RPMS where bigger engines opperate. This is why you see alot of turbos on hondas and stuff... the rev higher than big V8 engines.

Another big problem with turbos is the heat. While a s/c make heet, the turbos get a little warm from all that exhaust gas, which in turn will heat up the intake side of things. thats why you need what is called an intercooler (too cool the air). Because of the need for an intercooler and having to rerout exhuast, you need to do alot of plumbing, so it enerally makes things very complicated.

What we posted here is just a basic explanation. There are many different types of superchargers... some that are clutched, some that pump air like a turbo, others that pump air with twow rotating "drums" (the kidn you see in top fuel dragsters)


Jim

 

This is true, buta turbo has its fiar share of parisitic loss as well. Turbos run off exhaust gas, and the restriction creates back pressure, and the motor has to work harder to pump the exhuast out of the motor because of the increased ambient pressure, and so your loosing hp there as well.

As far as which is better, it all depends on your aplication... a s/c car will dust a turbod car in a road race because of consistent power, where a turbo may not spool up until 1/2 way out of a turn.

Also, turbos work well for high rpm cars (4, and 6 cylinders) that get up there in the revs, where a s/c will loose efficiency.

Its all about what you are using it for.


Jim

 

from what i heard is that turbo is faster by 5 mhp than sc but smarter to have a sc.

correct me if im wrong...

 

Ok here are some links on how turbos work
http://www.turbomustangs.com/turbotech/main.htm

A turbo is better than a s/c in the aspect that with the same boost numbers you will create much more HP. S/c's are just convenient easy bolt on power. Turbos require you to reroute your exhaust and intake to conform to the turbo itself. Turbo lag isn't a very big problem at all with v8 engines simply because they produce 2x as much exhaust as a 4 cyl. The small ammount of time it takes though for your turbo to spool up and get boost is a great strategy for you to get traction. There are many workarounds to lessen the lag such as: sequential turbos, twin turbos, and ball bearing turbos. It all depends on how much time your willing spend on your car. If money nor time is an issue then I'd recommend a turbo. If your just not up to it then an s/c is still a great option.

 

Wow, I don't think i've ever read anything that was so far off on this issue in my life.

24 pieces on an external wastegate turbo.
We're in the 2000's now, that was a big issue back in the '80's
That doesn't have a big effect on lag. That has a big effect on boost threshold.
There are two sounds coming from it. One sounds like a vacuum cleaner with a small foreign object blocking PART of the suction. The other is the sound from the blow off valve or bypass valve that will either sound like a "pshhhh" or... well I can't describe the other sounds, I guess a high pitch "OOOo OOoo Ooo Ooo Oo" but it happens when the throttle plate closes & boost pressure in the intake reaches higher than it supposed to be at.
They are not the same turbo's provide more mid - high rpm power, hands down.
A little bit? Try 50hp on average as opposed to the 20hp of the turbo on average at 12psi (the higher the boost the more power robbed from both setups)
true, but in a properly built setup you will never know it was there. You should also know that some superchargers have lag aswell
Yet again it will depend on the supercharger, the supercharger that is best for high rpm power (which i might add this is where your engines peak power is) is the centrifugal type, which isn't very good at low end power. The Twin screw is going to be the flattest powerband, which if you compair it to the other 2 types & the turbo, it won't beat the others in their rpm range it's just the one with the flattest power curve.
You don't need an intercooler. You can get away with 8psi without one in some cases. I personally wouldn't recommend going above 5psi without one.
Which kind might that be?
THey are rotating lobes & the type is called the roots type. This type of supercharger is also known as a blower.
A turbocharger has NO parisitic loss. The loss on it is due to exhaust resistance. The better the design the less there is. It is true a turbo isn't free power, but it doesn't use as much as any type of supercharger.
A supercharged car will dust a turbo'd car in a race from a stop until the turbo is spooled & seeing that most turbo'd applications reach that point around 3000-3500rpm, let me ask you this, In first gear in your car, how long does it take you to reach 3500rpm? I don't know about you, but in my car the time is at the most 1/2 a second. So a supercharged car will produce more power for the first 1/2 second. From a decent roll if the person is not revving the engine right before takeoff then it is going to be producing more power for about 1.5 seconds, but when the turbo spools it's bye bye to the other car. (this is all if the boost pressure is the same, in the same car, with the same engine)
That's why there is such thing as the centrifugal supercharger out there
Stay away from sequential setups on a twin bank engine.