sure man : )
this is how i understand turbo vs sc in general:
DISCLAIMER: i do not pretend to be a mechanic, nor a true tuner, i just have a lot of general information, as well as personal experience with both a supercharged k20 and a stage2+ wrx as my DD's and this is my personal information i've "learned" so to speak and my OPINION on which is better, there are FACTS which cannot be disputed (higher dyno #'s from a turbo, but a narrower powerband also) vs SUBJECTIVE OPINIONS (i prefer the SC powerband in daily driving vs the turbo, some may not) so PLEASE take this with a grain of salt, hell a whole salt lick if you wish, knowing that this is MY OPINION gleaned from facts, i am NOT saying one is "better than the other" as both have pros and cons
-SC boosts throughout rev range, turbo does not... this leads to "turbo lag" for a turbo, wherein you hammer the gas, wait for the turbo to "spool" to make boost, and then you get a rush of power... this issue varies depending on the size of the turbo, the boost solenoid controller, and a few other things i can't think of off the top of my head, but generally a smaller turbo provides less power but a faster spool, and a larger turbo provides much more power but a slower spool (thus more lag), obviously this can be adjusted for every setup, and tuned to find a "sweet spot" where the customer prefers... in an SC it basically takes your current power curve and "lifts" it as a whole is the best way to put it...
example:
stock setup (made up #'s, just for comparitive sake) might look like this:
-1500 RPMs 75hp, 100tq
-3000 RPM's 150hp, 150tq
-5000 RPM's 175hp, 160tq
-7000 RPM's 200hp, 130tq
SC setup (again made up #'s) that gains ~50hp and ~50tq across the board
-1500 RPM's 125hp, 150tq
-3000 RPM's 200hp, 200tq
-5000 RPM's 225hp, 210 tq
-7000 RPM's 250hp, 180tq
Turbo setup (again made up #'s) peak gains of 100hp and 100tq in "spooled" ranges
-1500 RPM's 75hp, 100tq
-3000 RPM's (turbo spooling) 160hp, 160tq
-5000 RPM's (turbo spooled) 250hp, 250tq
-7000 RPM's (turbo unspooling) 230hp, 210tq
these are again MADE UP #'s just to illustrate how the power bands differ... basically a supercharger has a much wider/broader powerband than a turbo in general, but the turbo has a much higher peak, and in the ranges it makes power, it's much stronger
also for those wanting future expanadability, a turbo is the outright king. superchargers suffer from heat soak much more than a turbo, especially at higher boost levels, and it is much more difficult than just "turning up the boost" through the ECU and wastegate management, a supercharger needs a specifically calibrated set of "pulleys" to wrap the belt around which increases boost the smaller the drive pulley is. you can't just "turn the boost up" and it is a steadier boost level
ie. 3.5" pulley gives 5psi, 3.25" pulley gives 9psi, 3.15" pulley gives 13psi (set ranges per pulley size, whereas a turbo you can vary the boost)
another nice thing about the turbo is that you can vary the boost pressure based on the gear you are in through the boost solenoid ecu control and wastegate controller, so if you are putting down too much power to hook up your tires in 1st and 2nd gear, even 3rd, you can cut the boost to modulate power (so a max hp might not be reached until high 3rd or 4th gear, with say 5psi in 1st, 9psi in 2nd, 12psi in 3rd and 20psi in 4th) whereas a supercharger has a set boost throughout the gearing, so always puts down the same bonus HP, this can be problematic on a drag strip as you might just melt 1st and 2nd gear spinning
all this may point to the turbo if you are inclinded, but to me, i still prefer the SC, as in daily driving it just bumps the normal power curve up, so the car basically behaves very similar to how it would stock, only significantly faster, but the power curve is very similar, vs the "peaky" and "sharp" curves of most turbo setups
turbos have a LOT of moving parts and things to adjust/could go wrong vs a SC (or at least our mp62 design) which is just a twin screw overlapping in a chamber, a lot less parts to fail in my opinion and easier to install (pop off the intake manifold, pop the new one on, pop the blower on, put the belt on, rock and roll)
i prefer the lack of lag, the bypass valve on the blower (allowing it to free spin and not leech gas MPG driving it in lower throttle/normal driving) and the "whine" of the blower (that sound is addicting)...
one thing to know is this:
-if you are after dyno queen #'s or a 1/4 mile drag strip monster, you'll have to go with a turbo
i-f you are after a daily driver with instant power on demand, that the power curve feels similar to your stock setup, just a lot more powerful, and IMO better for autocross/twisy roads because you are never "out of boost" in the rev range then a blower is for you
-if you plan to increase HP in the future by strengthening the engine and trans, and would like a "higher ceiling" for your power #'s, go turbo
-if you plan to stick basically with what it gives you (knowing that at most, you might get 75-100more hp out of the blower) and just want a "stronger" DD go with the SC
hope that helps jonny, anybody else who wants to chime in would be appreciated too (maybe somebody who owned a turbo k20)
