Only read the first page and literally skimmed through the rest. Noticed the usual thing that goes on where everyone has a few details correctly, but posts a few incorrect things as well. But I'm glad to see that, at least those I read, did it the right way of stating at the end that they weren't sure and to allow others to correct them. Good job.
So, I'll give a brief explanation on this, since there is a lot that goes into these manners of forced induction.
Turbos, as far as how they work, is simple. They are mounted on the exhaust manifold or turbo manifold, or turbo headers, whichever way to call it is just fine. The exhaust gases, instead of going directly through the exhausts to the back (like in a naturally aspirated engine), it goes through the back (hot side) of the turbo. They hit the turbine blades inside the shell, making it spin, and via a shaft that connects that turbine to the front turbine (the one in the front part, the cold side of the turbo) it makes the front turbine spin. The front one causes a suction effect, which then feeds the pipes that eventually end in the engine. As for the exhaust gases, they follow the housing from the hot side which eventually vents into the exhaust pipe, and then exits the car. I know I had a cut out picture of one, but I can't find it at the moment, since I'm taking a short break from something while I write this.
As for those myths of turbos working better on Japanese engines, and not so good on American engines, ALLLLL of that is simply: not true. Any engine can be fitted with either a turbo or a supercharger. No discussions, no "oh but my older brother said....". Yeah well, your brother is retarded  .
The problem with turbos is this. First, what is called turbo lag. Turbo lag is what happens when the turbo is spooling up, but not creating any actual boost (not sending any extra pressure beyond atmospheric pressure, 14.7psi below a certain height above sea, I forget the height above sea level where the atmospheric pressure starts to decrease). The greater the margin between the size of the turbo and the engine, the more lag it should have.
As for the different turbo set ups.
1) Single turbo: easy to comprehend, don't need to explain.
2) Sequential twin turbo: for examples, take the MK4 Supra and the FD RX-7. The point of this set up is to have a smaller turbo for lower rpm's, and a bigger turbo for up top. Since a reasonably small turbo shouldn't have much lag, it allows the vehicles to accelerate from a stand still, or from a low rpm level, without having that annoying lazy feel. The big turbo... well, you're smart. It's obvious.
3) Parallel twin turbo: found in Sledgehammer Corvette, and MANY European, top model cars. Both turbos will be the same size, and will be run at the same time to give extra power at all times.
4) Misc set ups: Some people customize their cars to have 3 turbos at once, others have run 8 turbos (can't find the picture to the old chevy with the 8 turbos in the trunk, all operational, but not that big of a deal at only 800rwhp). Why do they do this? Heck of it. The Bugatti Veyron has a quad, sequential turbo set up. It has 1 small and 1 large turbo on each bank. Same purpose as a twin sequential, but with twice the turbos.
Usually, turbos are great from mid-high end power and torque.
As for superchargers. There are a few types of superchargers, such as the twin screw, roots type, centrifugal (the one that looks like a turbo), and I don't think there are any extra types (ignore all of those electric supercharger ads, they don't work, don't bother asking, hush it).
The screw type and roots type are both damn similar. On the outside, they look the same. Find a picture of a Ford GT engine bay, and there you'll have one. The thing is that they both use (cheap description following) 2 long shafts, each with their own shape. Screw types use shafts that look like worm gears, sort of.... while the roots type uses long shafts with 3, round edges of some sort. Hard to explain, look it up in Google images. Anyhow, the roots type is the least efficient cuz it pretty much just can't maintain a steady stream of air flow feeding the engine, while the screw type can.
Centrifugal superchargers are those that look like the front side of a turbocharger. In essence, it's a turbo powered by the engine's crank instead of exhaust gases.
The problems with SC's? First of all, the parasitic loss of the engine having to use up some power to run the supercharger. Secondly, screw and roots type are generally big if you want some extra power by using one of them, which add more weight than a single turbo set up. Screw and roots types are good at lower rpm levels, but tend to lack at the high end. Centrifugal superchargers offer boost depending on the engine speed. In other words, you will get your desired max psi most possibly at the end of the shift, when the engine is spinning hard (disappointing, eh?).
Advantages? The "no lag" factor, compact size (mainly centrifugals), and sometimes, durability.
Why are SC's used more in V engines, instead of turbos? Less space required, less heat than twin turbos, ease of installation compared to turbos, less weight, probably less cost (depending on sizes), and it looks interesting. Doesn't mean it's better though. A proper twin turbo set up might be just as good, or even better, but it can go either way.
And I am now tired of typing. So I'll post a bit more later, with pictures, or just simply answer any questions. |
Yah, I jes got a medium sized turbo to compensate for this. A nice GReddy 20G, the TD06-SH I think it was called...can't remember, it's been a while...but the turbo that seems perfect for the MR2 was GReddy's TD06 Level II kit...stainless and polished tubular exhasut manifold and an external wastegate for the boost creep. Guy @ ATS Racing is running w/ this set up (the guy I bought my car from) and he's putting 400 down to the wheels. Not too shabby eh? If you wanna check it out hit up their http://www.atsracing.net 
Hehe, but those are the salt flat specials ;P. Top speed for a Supra in Salt Flats 249, 18 wheeler 300+ Haha...strange strange world that we live in. 
Jes makes it that much more interesting. Pz. 
Make sure youre applying astro-glide as you bend over or that shit will hurt. 
My 'S doesn't build any boost til 2500, has about 5 psi by 3k, then at 3k it hammers full boost. Well, when it's running right anyway lol.
