Explain please
 

Lucy, can you please 'splain the pros, cons, differences and similarities of

Turbo
Twin-Turbo
Supercharger

I have a basic understanding, but i figure if i hear it from u guys it may finally sink in...

RE: Explain please
 

Basically, any form of forced induction serves to increase the volumetric efficiency of your engine. Any increase in volumetric efficiency will increase the power output of the engine.

I'll start off with the setup for any forced induction setup for reliability. You'll need to build your bottom end VERY well. If high power output is what you are looking for, you'll also need to build FOR forced induction. By that I mean, lower than normal compression ratio (dished pistons), as well as a cam shaft with a generous overlap (turbo or blower cam).

So... Pros/Cons... Well, I'll start with a single turbo setup.

A single turbo or twin turbo will get you some good gains and is a more efficient power adder than a s/c as it doesn't use crank hp to produce the intake pressure. As with any turbo setup, there is a delay between when you stab the throttle and when the pressure builds up to make power. A TT setup generally uses two smaller turbos which means that they should spool up faster than a single larger turbo, but the additional turbo and the extra piping required increases the price.. Any turbo setup will pretty much require that a custom exhaust be made (headers right on out to the muffler). You'll also have to do a custom intake to route the air from the turbo compressor, through the intercooler, and into the intake.

Now where a turbo setup takes time to create pressure, a supercharger (centrifugal, roots, screw or hybrid) will build pressure the instant you slam on the throttle. S/C's are great for low end torque and generally require less maintenance than a turbo system. I believe that Vortech makes a centrifugal setup for pretty much any chevy v8 as well as a setup for the 4.3L v6 in a blazer. Procharger may as well. The constraints of an s-series engine compartment may limit you on the option of going with a centrifugal s/c. There are quite a few companies that make roots, screw, or hybrid s/c kits for the small block chevy, but that would require modification of the fuel system on a vortec 350. If you are considering this, it'll take a lot more time to sort out the wiring and fuel systems. Cons of a s/c setup are that they do use crank hp to make power. Pros are that the torque curve in a properly built blower motor is almost perfectly flat! Great off the line punch and good top end. A turbo will always beat a s/c at high rpm.

What you choose will be dependant on what you want to get out of it. If you are doing a v8 swap, you can build some pretty good power into a v8 and stay N/A (naturally aspirated). If you want to stay with the v6, then a turbo/csc setup is the way to go. Problem with the vortec 4.3L v6 is that the upper plenum is plastic so 10+psi shouldn't be attempted.

With either setup, engine work is necessary to make reliable hp. Mods to the bottom end would be balancing and blueprinting the bottom end. You'll also want to look into some head work to increase the flow numbers. In the case of a F/I (forced induction), you'll want to lower the static compression ratio to somewhere around 8.5:1 before adding pressure and a F/I specific cam grind should be in the budget. This will allow you to really put the screws to it reliably. With either setup, if power is your goal, you'll need fuel system upgrades as well.

I'm starting to loose track of what I've already typed... LOL. I'll leave it at that. I'm sure I've left holes in a lot of things, so I'll let others fill those holes in. Good luck and I hope you find the answers you seek!

RE: Explain please
 

crib notes :)

Turbo
makes boost by using engine exhaust
pro: less expensive
con: lots of custom work

Twin-Turbo
also makes boost by using engine exhaust, more elaborate setup.
pro: more efficient than single turbo
con: still lots of custom work

Supercharger
makes boost from belt off the crank
pro: bolt on, instant boost off the line
con: pricetag, hood clearance, not as much potential.

with any of these you can get by on a stock engine setup if you dont run much boost, but in order to make real power (and take advantage of all the work youve done) you really need to have a engine designed to handle boost. this means lowering the compression and a cam designed for forced induction.

RE: Explain please
 

As i stated in the engine thread, im looking to get and old 350 and rebuild it to w/e specs i need. I am tryin to keep cost down, but not just the here and now cost, but the cost of maintnence over time. Still dont know which i am going to go with (turbo or s/c). Hood clearance isnt an issue because i plan to put in a big scoop with an intercooler no matter which forced system i go with

Thanx all for the help...i feel like a lil kid learnin to ride a bike for the 1st time

RE: Explain please
 

no intercooler w/ a supercharger...

RE: Explain please
 

Not true, you can have an intercooler with an s/c. It's just that an air to air intercooler like what is used for turbo applications just isn't practical. S/C's use an water to air intercooler between the s/c and the lower intake manifold to cool the air charge.

Here's a pic of one that'll work on my '01 Bonneville SSEi:
http://www.intense-racing.com/images/ic_full_600.jpg
And an intercooler installed on a supercharged 3800 series 2 motor:
http://www.intense-racing.com/images/iik_800.jpg

RE: Explain please
 

Its funny you bring that up....me and a few kids from my auto school were discussing the most cost efficient wayto keep the water uber cold in a water to air cooling sytem today on one of our cigarette breaks.

RE: Explain please
 

hrmph! didnt know that... learn somethin new every day!!!

i'm assuming that will only work for fuel injected applications though, correct?

RE: Explain please
 

actually a twin turbo set-up isnt more effcient. they actually move less air on the top end then say a big single turbo set-up- but they spool much faster than the single turbocharger and are better for a daily driver, but if you do a correctley sized single turbo it can be just as responsive and still hold full boost to redline.

RE: Explain please
 

could you give web sites that sale super charger kits for a 4.3l throttle body engine?