Originally posted by: Eli
Originally posted by: John
Originally posted by: OS
Originally posted by: NutBucket
Sure. Afterall, you'll want to use synthetic after you bolt up that turbo
I'm more of a nitrous kind of guy.
I'm more of the S/C kind of guy.
Can you combine a supercharger and a turbocharger on the same engine?
Could they work together and produce like 30lbs of boost, or does it not work like that?
<-- blower n00b.
No, that'd be veeeeerrrrrry bad.
Personally, I find superchargers to be inferior, from an engineering standpoint. You're taking a limited resource (Crank power) and using it to generate more crank power. However, by doing so, you're actually drawing more energy than you would normally be, and are seriously stressing the engine. Superchargers typically take 35% of the power from the crank to generate the extra power.
A turbo on the otherhand works off backpressure. By increasing the backpressure, you're lowering the efficiency a bit, but the boost greatly offsets it. Typically, turbos decrease the efficiency of an engine by 20%.
Allow me to work it down to numbers to make my point more clear.
Let's say an engine puts out 200 HP naturally aspirated. We want to run 15 lbs of boost, which in theory, should increase power by 85%.
With a supercharger, amount of raw power going to the driveshaft is decreased by 35%. You then add the boost, so the engine is putting out an extra 85% of the previous net.
200 * .65 * 1.85 = 240 HP.
With the turbo, the efficiency of the engine decreases 20%, then the boost adds 85% to that net.
200 * .8 * 1.85 = 296 HP.
This is all in theory, of course, and these numbers aren't always exactly 20% or 85% and whatnot, but the fact remains - Superchargers are less efficient then turbos, and they put more stress on the drive system because they refocus its power to generate more power instead of using waste power to generate the power.
Of course, this really only applies to mild boost uses. You don't see too many dragsters using turbo systems because turbos don't scale as effectively as superchargers. But when you're dealing with less than 800 HP, I'd rather put my money on a turbo.