My supercharger setup re: Huge scott update.

[FalconGTHO]

You can get aftercoolers (the correct term) for BDS setups. Its just another expensive part thats available for those who can swing it.

[Brianesff]

Many electric motors draw too much current but they do't need to run full time. They can be powered by a couple high discharge batteries.





How about reducing turbo lag?





I didn't find very much info on hydrochargers. This was some info from 2-3 years ago. Is this what was meant?





"[mr2sc]Original Garret HydroCharger Article (Long)





Eric Charnholm [email protected]


Thu, 4 Jan 2001 00:49:48 -0800





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------------------------------------------------------------------------


For all interested here is the original areticle from April 1999 Sport


Compact Car regarding the Garret HydrCharger. I got alot of requests for it


so I figured you guys wouldn't mind me just posting it here. I am going to


scan a photo of the HydroCharger itself. Just shoot me an e-mail if anyone


would like to see it. Enjoy.....





Eric Charnholm


[email protected]








"The turbocharging vs. super-charging debate has been raging for as


long


as men have associated horsepower with testosterone. Each has its


advantages and disadvantages, of course, but the natural human instinct is


to pick a favorite and then defend it with religious conviction. For those


of you prone to pre-judging a car based on the choice of air com-pressor,


Garrett is about to rock your world.





Garrett's upcoming HydraCharger blurs, the line between turbochargers


and


super-chargers, giving most of the advantages of both, and few of the


disadvantages of either. Before we go too far into the HydraCharger,


though, let's review the debate, just so we know which side we are on.


Turbocharging is usually the preference of engineering purists because it


captures wasted exhaust energy and puts it to work. Using a turbo, the heat


and horror of the exhaust stream can be used to compress the intake air,


making more power, and more heat and horror in the exhaust, which


com-presses more air, etc., etc. It's a veritable per-petual power machine.


In addition to capturing wasted energy, turbochargers tend to be the


most


efficient type of air compressors, meaning that they heat the intake charge


the least when they compress it.





The disadvantages, of course, are numer-ous, and most of them have to


do


with pack-aging. Because a turbo is driven by the exhaust, the exhaust and


intake air both have to go through it. This not only means one side of it


has to get extremely hot but a lot of plumbing has to be used to bring the


intake and exhaust systems to the same place and then back out where they


belong. Add an intercooler (a good idea with either a turbo or


supercharger) and you have more plumb-ing than a hardware store.





Finally, there is the lag. The centrifugal .compressor of a turbo has


to


be spinning quite fast before it can effectively move air. Getting the


turbo up to speed takes a certain exhaust volume, which takes a certain


intake volume, which takes a certain com-pressor speed, yada, yada, yada.


Careful siz-ing of the turbine and compressor can bring lag to a minimum,


but it still takes a certain amount of time to get the perpetual power


machine going.





Superchargers vary tremendously, and so do their strengths and


weaknesses.


Centrifugal superchargers are essentially the same type of compressor as a


turbocharger, but are driven off the crankshaft instead of by exhaust


energy. Centrifugal superchargers still need to be spinning quite fast to


be effective, but because their speed is mechanically linked to engine


speed, there is no turbo lag. At high speeds where the compressor is


effective, throttle response is immediate, but at lower speeds where the


compressor is still struggling, there is no boost available no matter how


long you wail





Positive displacement superchargers (such as roots-type blowers) are a


different story. Instead of airflow being dependent on a com-plicated


relationship between airflow, com-pressor speed, and boost positive


displace-ment superchargers simply move a certain amount of air for every


revolution, no matter what. The linear nature of positive displace-ment


superchargers makes for excellent dri-vability and instant throttle


response. The downside is that most positive displacement superchargers


either have relatively low com-pressor efficiency (in other words they heat


the air a lot) or they are just plain expen-sive or both.





Packaging tends to be easier with superchargers, since you don't have


to


deal with the exhaust system, but you still have to find enough room for


the compressor in a location where a belt can reach from the crankshaft,


and where the intake air plumbing makes sense.





The achilles heel of superchargers, though, is parasitic drag. Driving


that air compressor takes a certain amount of power, and if you take that


power from the front of the crankshaft there is less power to go out the


back of the crankshaft and down to the wheels. Power consumption depends


on what kind of compressor is used and how much air it has to move, but 10


to 15 hp is not uncommon.





Most of these turbo vs. supercharger debates eventually break down to


each


party alternately yelling "Turbo lag!" "Parasitic drag!" "Underhood heat!"


Low efficiency." Fisticuffs inevitably ensue, and if one side is unlucky,


the debate will end with a ceremonial ass kicking.


Playing mediator in this senseless battle is the new HydraCharger. The


HydraCharger con-cept is quite simple. Essentially it is a compres-sor and


center section from a conventional Garrett turbocharger, but instead of an


exhaust-driven turbine on the other side, there is a tiny (about the size


of a quarter) turbine driven by hydraulic fluid (oil, water, whatever).


That fluid is, of course, provided by a pump which is driven off the


crankshaft, so technical-ly the HydraCharger is a mechanically driven


centrifugal supercharger but one with a brilliant hydraulic transmission.





The advantages of the HydraCharger take a few moments to sink in, so


let's


walk through them. First there is compressor efficiency. Even centrifugal


superchargers seldom approach the efficiency of a modem turbo compressor.


Since any turbo compressor can be used with a HydraCharger, its compressor


is every bit as efficient. There, that shut the turbo guys up for a second.


Next there is packaging. The hydraulic pump is only about the size of a


power steering pump, so finding a place to mount it is much easier than


mounting a supercharger. The HydraCharger itself (which is about the size


of a turbo) can be mounted anywhere and unlike a turbo, which has to be


mounted horizontally, the HydraCharger can be mounted in any orien-tation.


That should keep both sides quiet





Since the HydraCharger is driven off the crank, there is no turbo lag,


but


unlike a conventional centrifugal supercharger, it can be made to work at


low rpm as well. By simply overdriving the pump and using a bypass valve at


higher rpm (like a wastegate for the fluid pres-sure) the HydraCharger can


be made to spool up to a useful sped just off idle. If required to do so,


the HydraCharger can accelerate from station-ary to 100,000 rpm in one


second, so lag needn't be a worry. That will keep the positive


dis-placement boys quiet.





Now that the bickering has quieted down, look at what we have. There


is


the responsive-ness of a positive displacement supercharger, the compressor


efficiency of a turbocharger, and ease of packaging that is unparalleled.


The downside? You've probably noticed that I didn't mention parasitic


losses. Since it is still driven off the crank, there will still be


parasitic losses, and since we have to worry about the power consumed


compressing the air, the power consumed pumping hydraulic fluid, and the


power lost due to the efficiency of the tiny fluid turbine, the power


consumption will probably be slightly more than a purely mechanical.


supercharger. The difference is small, however, and probably more than


offset by the extra power available as a result of the better compressor


efficiency.





The flexibility of the hydraulic drive system and the faster response


of


the hydraulically dri-ven turbine compared to an exhaust-driven one opens


up even more possibilities. The hydraulic bypass valve could easily be


controlled by a driver-adjustable valve-one much sim-pler than the


sophisticated controllers needed to accurately vary turbo boost. If you do


use more sophisticated controls, even more could be pos-sible. Traction>


control via variable boost, per-haps, different powerbands that can be


selected for different driving conditions, or even different boost levels


for different gears, maximizing acceleration on traction-limited cars.





The fact that a HydraCharger can be mount-ed anywhere leads to


interesting


possibilities. An engine originally designed for a HydraCharger, of course,


could integrate the hydraulic pump into the engine-much like the oil


pump--and the turbine into the intake mani-fold, for an incredibly compact,


high-output powerplant. That's all well and good, but we aren't designing


engines from scratch-think, instead, of what an eager tweaker could do.





There are a variety of reasons to do so, but no matter what your


motiva-tion, secrecy can be very valuable thing. Looking at a Sentra SE-R


engine compartment-something I do on regular basis-you could actually


supercharge the engine with a HydraCharger without leaving any visual cues


that the engine was anything but stock. First, mount the hydraulic pump on


the backside of the engine where it would be hidden under the intake


manifold. The hydraulic lines could be run in the midst of Nissan's messy


stock wiring without most people noticing, and the HydraCharger itself--now


this is where we get malicious-could squeeze into a fake battery.





Put the real battery in the trunk, and use one the hollow plastic


battery


shells used for dis-play vehicles for concealing the HydraCharger. intake


air would have to be drawn in from the fenderwell, but the battery is close


enough to fender that a black hose passing into the could easily be


overlooks. Pressurized air could feed out the back of the battery and the


air filter box behind it-they are only about an inch apart. The air filter


box would just act as a non-functional shell and the pipe feeding air from


the fake battery to the fake air mass sensor would pass right through it. A


reprogrammed ECU and stock-looking 300ZX fuel injectors would round out the


package and, again, would be invisible.





Of course, you can't go out and buy a HydraCharger just yet-it's still


under development. -The original intention wasn't even to used as a


stand-alone supercharger. Instead, it was to be used on large, turbocharged


diesel to boost low-rpm output and help the turbocharger spool up more


quickly. It wasn't until people started getting excited about shoving


-superchargers in fake batteries that Garrett started considering it as a


standalone device. When it is finally available to the aftermarket you can


bet we'll be getting our hands on one."

[FalconGTHO]

Interesting. Ill believe it when I see it in actual application. Im skeptical of the output.


Im a screw comperssor man ALL the way.