HKS Supercharger

[Coheed]

Originally Posted by Moshpit37

Turbo lag.

Long story short: I want more power at the bottom end of the RPM range for daily driving. Turbos need to spool up more before delivering the boost.

Because waiting till 2700rpm for boost is so passe.

[sw20kosh]

Originally Posted by drifter

Eventhough I know there's another thread on tb vs. sc, please tell me why you would rather go with a supercharger. Still learning about this stuff.

The simple answer is it is less complicated thus less expensive and less chance of a breakdown somewhere in the system.

The complicated question is Roots vs. Centrifugal vs. Turbo. I will generalize below.

Roots Supercharger: Powered by the crank pulley (consumes some engine power to operate) Instant boost and response with the depression of your pedal. You get your max target boost almost instantly. This type gives you a ton of on demand torque in the lower rpm range and modest gains in the higher revs. (as with the others these characteristics depends on the size of supercharger chosen).

Centrifugal supercharger: Powered by the crank pulley so it too consumes power of the engine to operate. Has a compressor like a turbo (which is centrifugal). Linear development of boost. This means if your target is 10 psi, then you wont make 10 psi till 7,500 rpm. You will develop boost linearly through the rpm band till you hit 10 psi.

Turbocharger: Powered by the extremely hot high velocity exhaust gasses leaving the engine through the exhaust manifold. The turbo consumes what is considered "free energy" to operate and compress (via centrifugal force) air into the engine. Since more air entering the engine makes more power and makes for more high heat exhaust gasses this synergistically makes the turbo spin faster. This effect is called "spool up" or "spool up time". It means that as the turbo starts to cram more air into the engine, the engine becomes more efficient at spinning the turbo. They work synergistically. The end result is you have usually bad low end torque (~1-3k rpm) then a rapid ramp up in torque (exponential increase) somewhere in the 3-5k rpm (again I am generalizing) reaching max boost and holding that boost and torque to redline. By making the turbocharger "smaller" the spool up can be moved lower in the rpm range to achieve more low end torque but you will sacrifice torque in the upper rpm.

Turbo systems are more complicated due to the implantation of a device in the exhaust stream. One might argue the characteristics of the non-linear spool up is undesireable compared with the characteristics of superchargers but you leech off less power from the engine by going turbo.

[sw20kosh]

Originally Posted by Moshpit37

Turbo lag.

Long story short: I want more power at the bottom end of the RPM range for daily driving. Turbos need to spool up more before delivering the boost.

Then you don't want this HKS system. Not all superchargers are the same.

A centrifugal supercharger like HKS's builds boost slowly and only reaches max boost by redline.

Here is a good example of boost generation by a centrifugal s/c. Look at the bottom portion of the graph where it says boost on the Y axis.



As for Roots style superchargers (which Toyota likes to use) you get boost nearly right away like this Stillen Supercharger. Again look at the bottom portion where it says boost on the Y-axis. It holds 6-7 psi throughout the rev range.



Here is another Roots blower at ~20 psi



Here is the "spool up" of a turbo. Notice its exponential build up.

[Moshpit37]

Thanks for the info! I'll be waiting until after the factory warranty runs out before I do anything to the engine regardless, but it's awesome to see all the options coming out and I look forward to seeing what's on the market at 36,000 miles!

[sw20kosh]

Originally Posted by Coheed

Because waiting till 2700rpm for boost is so passe.

Hehe. Roots are great for street use and heavy duty towing.

If you are going for high performance on the track, you will find turbos are the best as they are more efficient by not running off the crank pulley. The turbo lag disappears (within reason) once you are moving on the track since you never want your revs to be below ~4k anyways. You want to stay in your powerband which is 4k+ and thus a turbo that makes max boost at or before 4k will be better at generating more power. There will be no spool up if you stay at the right rpm range while driving. Daily driving doesn't give you the opportunity to do this and thus car manufacturers generally place small turbos on their cars. They will spool up fast (1.5-2.5k rpm) but they will not be able to generate the kind of power a bigger turbo would in the high rpm range.

If TRD sticks to their methods, TRD's supercharger will probably be root's style and it will carry a warantee so this makes it very attractive for street warriors and track junkies alike.

[GirlyScions]

That is the hks race kit with the a/c delete. The street kit has the a/c and doesn't look nearly as sexy as the race kit.

[HKS Australia]

HKS Supercharger doesn't rob craknshaft power down low. Have a look at the design here: http://www.hks-power.co.jp/en/produc...r/feature.html and read through the brown colour tabs at the top for more info.
Cheers
HKS Australia

[sw20kosh]

Originally Posted by HKS Australia

HKS Supercharger doesn't rob craknshaft power down low. Have a look at the design here: http://www.hks-power.co.jp/en/produc...r/feature.html and read through the brown colour tabs at the top for more info.
Cheers
HKS Australia

That statement is misleading. To compress air a supercharger needs power. It gets its power from the crankshaft. Plain and simple. The power needed t turn the compressor wheel doesn't just come out of nowhere.

In regards to "down low" are you talking about the supercharger being on a clutch system where the supercharger is not engaged during low load low rpm driving? If so, roots type superchargers have been developed with the same system. Reduces the parasitic drag on the engine when boost/power is not needed. :happy0180:

[FLIPs_FR-S]

Originally Posted by drifter

Eventhough I know there's another thread on tb vs. sc, please tell me why you would rather go with a supercharger. Still learning about this stuff.

Supercharger will give your car more power faster. Turbos cause lag.

[ame="http://www.youtube.com/watch?v=lwIilncWpG8&feature=youtube_gdata_player"]HKS GT Supercharger for 86/BRZ #ft86 #lovecars - YouTube[/ame]

[wcbjr]

Originally Posted by FLIPs_FR-S

Supercharger will give your car more power faster. Turbos cause lag.

In a very general sense, yes. And it depends on the type of blower.

Also very generally, being in the correct gear eliminates that 'lag' and turbos have much more headroom for power at the top of the rpm band.

[Coheed]

Yes, unless a centrifugal charger is used. You'll have more immediate response with any direct-drive charger method. But I'll still be pulling away after 3000rpm with a disco potato. The compressor on a turbo uses a lot less power from the engine than a typical supercharger.

[ft86-UAE]

and always make more power

[Beardo]

The GT86/BRZ is sold as being all about throttle response and "purity". Turbo lag is not about waiting till 2800rpms while it builds boost it's about how quickly the turbo delivers once you get back on the throttle.

My understanding (and experience from an Audi S4) is that Superchargers have throttle response. Turbocharged cars are getting better but without an anti lag system they are not on the same page.

[boredom.is.me]

You race below 2800rpm?