Supercharge systs.

Gents, I need expertise on SC systs. Currently, there are two different types of SC on the market. Can any SC experts point out the pros & cons. Driveability, reliability, etc. I am ready to upgrade my car to SC. Thanks!!!

Have you tried the search function yet? There has been many threads recently about this very topic. Lots of reading in the archives!

One uses the Vortech centrifugal system and the other uses the Eaton roots style supercharger. I had both and as far as reliability, I never had one for more than about 20k miles. I did have a different brand "roots" style supercharger (similar to the Eaton) on one car (not a Porsche) for about 100k miles with no problems. Eaton is the choice of Mercedes, Ford, and others. Here is my pros and cons for each: Eaton Pros - "instant boost" good for our low torque motors - "roots" design known for reliability - usually self contained "lifetime" oil Cons - pulsating boost, beats air into motor, doesnt compress - high heat since S/C is small - lower HP over centrifugals Vortech Pros - "coolest" discharge air centrifugal on the market - also known for reliability - lighter chassis than roots - higher HP than roots Cons - Exponential boost - low boost at low rpms, multiplies with rpm similar to a turbo - high speed impeller bearings will probably need replacing on higher mileage compressor Maybe someone who has had both on their 996 can add to this.

huh? i had a hard time reading yours.... but good info once you figure it out.... anyways, i came from a VQ engine before i got my Porsche.... and i had both the Vortech (350Z) and the Eaton style (G35 - Stillen)..... and there are differences.... Eaton will give immediate boost, and a thrill for daily drivers. the hp will be lower, and you can feel this on the higher rpm range...... Vortech on the other hand takes a little more time to build the boost but can yield a much higher hp..... so it depends on your style of driving....... if a daily run through town kind of personality, i'd go with the Eaton style, but if you want that kick, and higher rpm range, go with vortech... does anyone know the noise on these? for the VQ engine, the Vortech is 10x louder then the eaton.......?

Thanks guys!!! It's great help to me to decide which syst. is best for my car and my driving. I'm leaning toward Eaton root style, where I live there is too much traffic for any long stretch of road to go fast in high RPM.

if you don't have room to stretch your legs.... the vortech will do you no good.....

you've got it the other way around. every roots type kit i've seen on the web has a very pronounced whine and is 10x louder than the vortec and almost unbearable on the 996. vivdracing has a good video showing this. you can barely rear the aftermarket (read: louder) exhaust. if you can live with it, definitely use a water/methanol boost cooler injection system. the roots is known to push hot air into the engine. my vortec is quiet but you still hear it. on WOT you hear the engine... at idle you hear the a light whine and the trademark 996 "sewing machine" engine noise. EDIT: here's the VIDEO

If you are looking to eliminate the power curve of the flat six engine and want to maximize the level of noise coming from your mod as well as restrict high rpm power, then you should go with a positive displacement air pump. Or, you might just want to buy a mustang. The centrifuge compressor is a much better option for a flat six as it maintains the power curve and does not stop building power until you slow it down. I have yet to find any roots style modded 996 or 993 that comes close to delivering the drivable power that a well tuned centrifuge setup can. Since you are at maximum engine rpm in less than 80 feet, this argument that you need "legroom" to reap the benifits of a centrifuge system is wrong.

nope.....so you're going only 80 feet to accomplish your max engine speed to feel the effect of the supercharger...... you might as well WOT it from stop light to stop light in order for you to feel the thrill of the supercharger...... don't get me wrong, i love the vortech...... works extremely well on my 350Z..... but if you are crusing through town at stop and go, the root style is the way to go...... and the vortech for the VQ is much louder then the root style...... But i love that Whine..........READY FOR TAKE OFF!!!!!!!

IF your Vortech was louder than a roots, then the Vortech had bearing problems. The point I was making about the readline in 80 feet, was to point out the fact that the time difference for maximum power between the centrifuge and roots is only a split second, after which time the centrifuge produces more usable power, hands down. Now, if you simply want to drive around town below 4000 rpms, then why even get a blower? Anywhere above 4,000 rpm (which is shifting rpm) the roots just can't cut it against the centrifuge in a flat six. You may be like so many others that always shift at low rpms, in which case a roots would give you the thrill you are looking for. For those that drive a flat 6 for performance, a positive displacement pump just can't give you the performance delivered by a Vortech.

1999Porsche911 - I see your point but the torque is so weak I figured in the future I would get the Eaton. The problem with positive displacement superchargers on the 996 is that they are too small to make decent boost and discharge "cool"/dense air. I think if they could be bigger, you would get the high rpm hp that the centrifugals give, I could be wrong though. I had a Vortech on a '69 Camaro with about 20-22 lbs of boost and that thing would hit 8500rpm (free wrapping) before I could touch the floor board with the accelerator, thats with a 5.8 liter motor! The thing never stopped pulling in the high rpms just like you described with the centrifugals. Another '69 camaro rag top I had, had a 144 c.i. roots on 5.7 liter and that thing never liked to rev over 5000rpm, but the motor was stock compared to my other with the Vortech. I would say roots for drag racing and centrifugals for road racing, that probably sums it up best, depends on your style of playing.

It is all dependent on engine design and displacement. The flat 6 engine will perform better with a centrifuge in all conditions....drag racing or just zipping around town. If you keep the engine in the sweet spot, the roots just cannot perform as well. That is whether you are talking about the first 100 feet or the first 1/4 mile. Give yourself a taller first couple of gears and you'l get a little more out of the roots. In a larger displacement engine where the valves are larger and flow is not as restricted, a roots style pump can be advantagous, but it still limits higher rpm power.

dude you are so wrong. the eaton is soooooooooo loud. vivid racing HAD a video/audio clip of it but they REMOVED it. RL THREAD LINK TPC PROMO VIDEO gone. you definitely have bad bearings if you think the eaton is quieter than the vortec. i agree that you have the vortec is lacking in low end hp/tq on the low end. dyno plots show that the roots has a fatter curve down low.... better for lazy street driving. you just gotta ask youself if you want your 996 to have the same characteristics as oem or do you want to change it to feel like something else.

I have been doing a lot of research on forced induction lately and came across this unbiased article. There are advatages to both. I think since the 996 is somewhat lacking down low I'd rather have the eaton. BUT, for road racing the hot intake temperatures and heat soak would tend to point me in the direction of the vortech. Seems like with the vortech though you really have to be way up in the rpms to get any boost. As far as loudness goes I've heard that the eatons are really loud but they are on factory Cobras, and many other cars with no problems. It's too bad TPS doesn't take an active role in marketing this product. For me I like it silent which is why I prefer the turbos. Obviously the engine in the article is much different but the basic principles still apply to the 3.4L. Most of the people will tell you the one they bought is the best. It's too bad nobody came out with a twin screw design. These are probably one of the best since they have all the torque down low like an eaton but they don't transfer the heat, and they aren't as limited up top.

Now, let's forget a theoretical study and look at the real world and the 996. Dyno graphs, in no way accurately describe the drivability of a car. This is a once gear run which is meaningless on the street or track. First, as the graph indicates, the Vortech delivers more power over the last 15% of the rpm range AND at a substantial increase. This, alone, in the example given, will make the car with the Vortech reach 100+ mph faster (all other things equal). How is that possible with all the low end power delivered by the Eaton. It's because after the first 1 second of the race, neither car will ever visit the low rpm range again. In the case of the 996, the rpm's will never get below about 4300 for the rest of the race. This eliminate most of the torque advantage of the Eaton. Secondly, too much boost and inefficiency CAN reduce performance. This is very clearly illustrated in the dyno chart. Notice that at approximately 5800 rpm, the Vortech begins passing the Eaton in both torque and horsepower. This is when the eaton is pumping out 11 psi and the Vortech is only pumping out approximately 7 psi. That's more than 30% less boost and yet it is delivering more power. Also, if you produced 11 psi in the Vortech on the 996 at 7000 rpm, you would have a boost of 3.3 psi at 3500 rpm and of 1.8 at 1750 rpm. So the assumption that this graph translates into a better performing engine over the full range of rpms is incorrect and would easily be proven on the street or the track. In the real world, the Vortech running the same maximum boost as an Eaton will produce a faster performance. If you want your Eaton modded engine to beat the Vortech modded engine, better print out the dyno graph and wave that around instead of racing.

Now that's what I call a proper rebuttal.

I really would like a mag or somebody to do a head-to-head race (quarter-mile/roadracing) with both kits on two identical 996's with same peak boost. I am really curious which system would dominate. As far as noise, I had a '02 Ford Lightning that I had doubled the boost on (16lbs or 1.1 bar) and that thing sounded like two alley cats going at it under the hood. Those Eatons are very, very noisy.

Given the same amount of boost the Centri(Vortech) should win. The reason is because with the 6 speed you'd be able to keep it up high in the RPMs where the vortech is making more power. Also the Vortech is going to run slightly cooler so as the eaton starts heating up that also kills horsepower. I think we can all agree on this... Eaton = better power down low. Centri = better power up high. Also, you'd probably be better off with a Tiptronic with these boosted applications since you loose all your boost when you shift. Really the only place I can think the eaton would win is a 5-60mph roll on sprint. So if you want to street race it may be better. I'd take the vortech though.

This argument that the Eaton gives more power down low is irrelivent and wrong. From a dead stop, up to maybe half of maxmum engine speed, the Eaton will actually have less efficiency as it does up top. Just because you get a jump in the chart ad a substantial kick in the *** with the Eaton, do not automatically translate these things to performance. Give me an ever increasing power curve anyday againsta quick start, high power curve with a mid range plateau.

So 1999 you are saying that the Vortech makes more power below 4000 rpms?

What I am saying is that the Vortech will make your car a better (faster) performer. If you want to race from 4000 rpm to 4100 rpm, then maybe the Eaton will win.

The Roots Supercharger (aka "blower") The roots supercharger was originally designed as an air moving device for industrial buildings. The roots supercharger features two counter-rotating lobes that trap air from the intake side of the supercharger (normally at the back of the supercharger), move it around the outside casing of the lobes, and out the bottom of the supercharger through an outlet / discharge port. Like the twin screw supercharger, the roots is a "positive displacement" aka "fixed displacement" supercharger, meaning that it moves a fixed volume of air per rotation. Notwithstanding minor amounts of air-leak at low rpms, the roots supercharger cannot flow backwards like a centrifugal supercharger, and is thus nearly as efficient in its ability to pump air at low rpms as it is at high rpms. What this means is that roots superchargers are very capable of making large amounts of boost even when engine rpms are very low. This makes for great low-end and midrange power, and also makes them great for trucks and towing vehicles. The roots is also self lubricated, and is the simplest of the supercharger designs, meaning it is reasonably priced and very reliable. This is why roots superchargers have been the choice of GM, Ford, Mercedes, and Toyota for OE applications. The only real disadvantage to the roots supercharger is that it creates a lot of heat. There are two reasons for this. First, the roots supercharger does not compress air - it only moves from the intake port to the discharge port (i.e. it is the only supercharger design with no internal compression ratio). All of the compression is done in the intake manifold. Laws of thermodynamics kick in in favor of supercharger designs with an internal compression ratio (centrifugal and twin screw) because they do less work on the incoming air charge. We will leave the mathematics of this phenomenon to a later (much more boring) discussion. Another reason roots superchargers create higher amounts of heat is because they tend to carry some of the compressed air in the intake back into the supercharger because it gets trapped by the rotating lobes that are exposed to the hotter air in the intake manifold. The Centrifugal Supercharger Although the centrifugal supercharger is founded on a technology much newer than either the roots or the twin screw, it was the first supercharger to be successfully applied to automotive applications. Unlike the roots, the centrifugal supercharger is NOT a positive displacement / fixed displacement supercharger because it does not move a fixed volume of air per revolution. The centrifugal supercharger essentially operates like a high speed fan propeller / impeller, sucking air into the center of the supercharger and pushing it to the outside of the rapidly spinning (40,000 + rpm) impeller blades. The air naturally travels to the outside of the blades because of its centrifugal force created by its rotating inertia. At the outside of the blades, a "scroll" is waiting to catch the air molecules. Just before entering the scroll, the air molecules are forced to travel through a venturi, which creates the internal compression. As the air travels around the scroll, the diameter of the scroll increases, which slows the velocity of the air, but further increases its pressure. The centrifugal supercharger enjoys several advantageous characteristics that make it the most popular supercharger design in the aftermarket world. First, it is simple and reliable because it has very few moving parts - just a few gears and the impeller. Second, the centrifugal supercharger produces very little heat because of its internal compression ratio. It is also small in size and very versatile because it can "free-wheel" and allow the engine to suck air through it or even flow air backwards. For this reason it can be placed anywhere in the intake tract - it can even "blow through" the throttle body, meaning it can be mounted nearly anywhere. It is also the most thermally efficient supercharger, meaning that it produces the lowest discharge temperature. The only significant disadvantage of the centrifugal supercharger is that it must be spinning at a relatively high speed before it begins to make a significant amount of boost. For this reason, it is not helpful in creating boost (and power) at low engine rpms. Normally the supercharger only begins to create boost at around 3000 rpm, and the boost curve gradually and increasingly rises with engine RPM. Many centrifugal superchargers do not have a self-lubricating oil system, and draw oil from the engine's oil supply. The disadvantage to this is that you must tap the oil pan for the oil return line. However, in doing so, the supercharger becomes virtually maintenance free. Some manufacturers make a "self-contained" centrifugal supercharger that is self-lubricated like roots and twin screw superchargers.

Hell yeah, I wish Karlooz let me take a ride in his. That thing is a monster. Better yet I'd really like to see someone get a built motor with a forged crank rods, pistons, sleeved, and then turn up the boost. Easily make 400 - 500hp at the rear wheels with lots of boost. Let me ask you this though. Let's say they offered a Twin Turbo kit for 2 thousand dollars more. It was a more complex setup. Offered 40 more horsepower in all ranges except below 2500 rpm. But you had a little lag and may have to worry about heat. So instead of 420 you'd have 460? And it wouldn't be as linear. So at a track it may be a little bit more of a handful. Would you rather have that one?

That level of power has already been obtained. There is a maximum amount of compressed air that you can pump into an engine before it reaches the level of deminishing return. In order to acheive further compression, you would have to improve exhaust valve size and all around air flow in the engine. This is why alot of TT guys who increase boost to high levels with no other mods, actually slow their cars down.

not irrelevant for street driving or for track driving. do you only drive at 5K plus and at WOT? do you ever find yourself cruising along at 3~4Km and need/want to floor it. well at the rpm, whichever system has the most HP it will pull it along faster. this is what most people are looking for in a street system driving on the street and on the track is similar... going from part throttle in mid turn to full throttle. it also all depends on gearing too. if you have more power down low (eaton) it will pull you out a turn a lot faster than a vortec that has it mostly on top. that mean you have to always be on song to be in the meat of the powerband with the vortec. this wouldn't be so evident if the 996 had a 8500 redline so you would always be in the powerband but the eaton has a better HP curve to match the "high gearing" of the 996 transmission. given two systems with the same peak HP/TQ, ultimately the best performer is one that produces the most power in the the area under the curve. imagine nothing happens til 6K rpm with a 7k max. usable window is 1K. how drivable is that? NOT.

We all agree on which is better at what, so it really boils down into what part of the rpm do you plan on using the most. Small tracks I think the Eaton would win because of the high torque exiting a turn but Vortech for the higher rpm large tracks, but I dont race, just a theory. P.S. When I was on a Lightning forum, many guys toasted their motors when they were doing top speed runs for say, a few miles or so because of the tremendous heat generated and the intercooler heat saturation.

I completely disaggree with you Carlos. First of all, you can have a 1000 hp car and if you are in the wrong gear, your car is going nowhere fast by flooring it. Secondly, the 996 does not have "high gearing", but low gearing along with short gearing. If you are running at the track and you are ever below 4,000 rpm's in a 996, you need to step it up. Setup correctly, the Vortech produces an enormous amount of efficiency beginning at 4,000 rpm in the 996. This is why it pulls away from an Eaton in the same car running the same maximum boost. You have to get it out of your head that it is all about absolute PSI, as it is not. It's also about usable engine speed, and in this case, the low end torque produced by the Eation along with the flattening (and falling in many cases) of power at high rpms hurts the speed. Gear ratios also play an important part in your acceleration. If torque alone produced speed, your deisel cars would be winning from stop light to stop light and weight lifters who have some of the most powerfull legs around would win sprints. Take a 996 with a Centrifuge and a 996 with an Eaton and floor both at 4,500 rpm in second gear, and you will be shifting into 4th gear sooner in the centrifuge car that the Eaton one. If you are into truck pulls, then the Easton will be better. If you are looking for speed and acceleration, it is not.

1999Porsche911 knows what he's talking about (except for the Mobil water thing maybe , sorry couldn't resist ). It's hp, hp, and hp that makes your car go fast. It's pretty easy to keep our cars above 4500 rpm (when redline is 7000 grand or so and peak hp is at or close to redline) regardless of track configuration. That's what gearboxes are for. Put any supercharged car(this includes turbo cars) on the dyno and keep raising the boost and you will come to a point where the increased heat (due to lack of efficiency) of the intake air will negate the potential increased power of the increased boost and you will see less hp than you did at the previous (lower) boost level. You will reach this point much sooner on the Roots blower than with a centrifugal blower. This is the magic of turbo matching, finding the right compressor size (and style) and efficiency for you motor's displacement and powerband and gearing.

i was really referring to the street. i guess you are ALWAYS at redline on the street even cruising around and don't worry i know how to handle myself on the track ... that's road course not drag strip which i will happily give to you. BTW gears 3,4,5 are too tall for the track, too far apart. there are plenty of instances when in mid turn one gear is too high and the other is too high yes if is set up corectly and that's the rub. the evo is pretty conservative in tuning (could advance the timing a little and increase the RPMs) and the boost. as provided by evo the kit IS NOT STELLAR below 4K. power build up is LINEAR. don't even mention your car because it's supposedly highly modified you claim 500HP right? BTW what ARE your mods? i have a smaller pulley and water/meth injection and am getting rid of the intercooler because it heat soaks terribly at the track (we'll see how my little experiment goes). i haven't tuned the programming to maximize the boost cooler. i want to advance the timing a tad since now i am at a theoretical 120 octane. i wonder if giac has a race fuel tune.

only some times in his mind he is ALWASY right yup HP is make our cars go faster and if one kit has more HP under the curve then it has more USEABLE HP, right? both kits, stock SC kits, stock boost levels, peak HP is about the same HP but the eaton produces a fatter curve. better?... hell yes! i agree with everything you've said... the eaton does lose it's efficiency and fizzles out on the higher rpm ranges but it still has the same peak HP. so what's the disadvantage? higher intake temps?... then put a boost cooler on it with nozzles before and after the blower. to me the disadvantage is that damn eaton supercharger WHINE. yes it's easy to keep the engines above 4500 BUT you have a very narrow usable power band. with a fatter HP curve the usable powerband has just been lowered.

You're still not getting it. It's about velocity. If you are accelerating faster at a shift point, car slows down less which translates into even faster speed after the shift. It is also not all about power below the curve. If you hit a point of no acceleration on the back end of the curve, it makes little difference what the power is on the front side. If your engine can run another 3,000 rpm after power stops building, why waste your time in the range? A weight lifter may be able to jerk 600 pounds above his head in one movement, but not be able to lift the same if he pauses or slows down during the lift.

i understand what you are saying. i guess what i have not elaborated is that because a fatter HP curve is more beneficial for track use. eg., 2 cars, same peak HP, speed, rpm, side by side, but 1st car has fatter HP curve, exiting a turn and going onto the straight. both cars will reach the same velocity by the time they hit redline, yes? BUT the 1st car with the fatter HP curve will accelerate faster to that velocity and gain position into the next turn. beneficial? YES. does this also translate into street driving? YES

karlooz - do you have the Eaton? If you do, have you ever rode or drove in a Vorteched 996 and found any similarities or differences that are noticeable?

it sounds llike i have the eaton kit but no, i have the evo kit (check my sig). it's a great kit. can't complain other than that i wish the HP curve was fatter. i picked the evo because of the giac software flash and the fact that they use uprated fuel injectors. the tpc kit uses a piggy back system and added injectors into the intake. i haven't tried the eaton kit but i just felt more comfortable with the evo kit. i would love to try the eaton blower with the giac tuning.... if it would work. i've only heard the tpc kit from vivd racing's video clip and i don't think i could stand living with the incessant whining. deputydog has ridden in a tpc/eaton kit and he confirmed that the HP came on faster than the vortec kit. he chose the evo kit for the same reasons i did, programming and the eaton SC whine. he loves his evo kit too.

Wow, no one has spoke about parasitic drag between the two, this is a major factor too that affects performance. Eaton displays there drag on their website with given boost levels, I am not sure about Vortech, never seen one.

here's the vivid racing eaton blower video. you decide for yourself if you can live with the whine. http://www.myvividracing.com/main/996sckit.wmv

linky no worky.....

right click on link and "save as" onto your hard drive.

wow does that ever sound like crap! i see how the 2 alley cats under the hood becomes relevant!! the sound alone would push me toward EVO