what way? which would may better gains? how about the most reilable? cheapest? thanks

 

You'll have to wait to find out the costs. Superchargers are usually cheaper. Supercharger's make excellent horsepower on domestics, but on import's, not so well. The Procharger kit *claims* like 400+hp, but I highly doubt that. A supercharger would be easier to maintain, you wouldn't have to worry about boost, you just buy whatever size belt for what psi you want. Turbochargers make more horsepower than superchargers. They wouldn't be as cheap because you have to buy a lot of accessories for the turbo as opposed to the supercharger. It wouldn't be that hard to maintain, but it would be harder than a supercharger. They can be reliable depending on the kit you buy and what you do with it.

 

You are right and wrong in some sences. Turbo and SC usually run about the same prices. As for accessories, you better get them for both a Turbo and Supercharger setup so you can monitor the cars performance to make sure nothing goes wrong.

As for HP they can make the same they just make them at different parts in the RPM range. SC give a more gradual boost where as turbo's are a sudden boost at a higher RPM. This is because the SC is belt driven and turbos are excess exhaust gas driven.


Well here is a little break down of both:

A supercharger is mounted to the engine and is driven by a pulley that is inline with the crank (or accessory) belt. Air is drawn into the supercharger and compressed by either an impeller (centrifugal-style supercharger), twin rotating screws (screw-type supercharger), or counter-rotating rotors (roots-type supercharger). The air is then discharged into the engine's intake. Faster crank speed (more engine rpm) spins the supercharger faster and allows the supercharger to produce more boost (normally 6 to 9 psi for a street vehicle). Typical peak operating speeds for a supercharger are around 15,000 rpm (screw-type and roots style superchargers) and 40,000 rpm (centrifugal-style superchargers).

A turbocharger operates in much the same way as a centrifugal (internal impeller) supercharger, except it is not driven by pulleys and belts attached to the engine's crank. A turbo is instead driven by exhaust gasses that have been expelled by the engine and are travelling through the exhaust manifold. The exhaust gas flows through one half of the turbocharger's turbine, which drives the impeller that compresses the air. Typical operating speeds of a turbocharger are between 75,000 and 150,000 rpm.


Now for a head to head comparison:

Cost
The cost of supercharger and a turbocharger systems for the same engine are approximately the same, so cost is generally not a factor.

Lag
This is perhaps the biggest advantage that the supercharger enjoys over the tubo. Because a turbocharger is driven by exhaust gasses, the turbocharger's turbine must first spool up before it even begins to turn the compressor's impeller. This results in lag time which is the time needed for the turbine to reach its full throttle from an intermediate rotational speed state. During this lag time, the turbocharger is creating little to no boost, which means little to no power gains during this time. Smaller turbos spool up quicker, which eliminates some of this lag. Turbochargers thus utilize a wastegate, which allows the use of a smaller turbocharger to reduce lag while preventing it from spinning too quickly at high engine speeds. The wastegate is a valve that allows the exhaust to bypass the turbine blades. The wastegate senses boost pressure, and if it gets too high, it could be an indicator that the turbine is spinning too quickly, so the wastegate bypasses some of the exhaust around the turbine blades, allowing the blades to slow down..
A Supercharger, on the other hand, is connected directly to the crank, so there is no "lag". Superchargers are able to produce boost at a very low rpm, especially screw-type and roots type blowers.

Efficiency
This is the turbo's biggest advantage. The turbocharger is generally more economical to operate as it as it is driven primarily by potential energy in the exhaust gasses that would otherwise be lost out the exhaust, whereas a supercharger draws power from the crank, which can be used to turn the wheels. The turbocharger's impeller is also powered only under boost conditions, so there is less parasitic drag while the impeller is not spinning. The turbocharger, however, is not free of inefficiency as it does create additional exhaust backpressure and exhaust flow interruption.

Heat
Because the turbocharger is mounted to the exhaust manifold (which is very hot), turbocharger boost is subject to additional heating via the turbo's hot casing. Because hot air expands (the opposite goal of a turbo or supercharger), an intercooler becomes necessary on almost all turbocharged applications to cool the air charge before it is released into the engine. This increases the complexity of the installation. A centrifugal supercharger on the other hand creates a cooler air discharge, so an intercooler is often not necessary at boost levels below 10psi. That said, some superchargers (especially roots-type superchargers) create hotter discharge temperatures, which also make an intecooler necessary even on fairly low-boost applications.

Surge
Because a turbocharger first spools up before the boost is delivered to the engine, there is a surge of power that is delivered immediately when the wastegate opens (around 3000 rpm). This surge can be damaging to the engine and drivetrain, and can make the vehicle difficult to drive or lose traction.

Back Pressure
Because the supercharger eliminates the need to deal with the exhaust gas interruption created by inserting a turbocharger turbine into the exhaust flow, the supercharger creates no additional exhaust backpressure. The amount of power that is lost by a turbo's turbine reduces it's overall efficiency.

Noise
The turbocharger is generally quiter than the supercharger. Because the turbo's turbine is in the exhaust, the turbo can substantially reduce exhaust noise, making the engine run quieter. Some centrifugal superchargers are known to be noisy and whistley which, annoys some drivers (we, however, love it!)

Reliability
In general, superchargers enjoy a substantial reliability advantage over the turbocharger. When a a turbo is shut off (i.e. when the engine is turned off), residual oil inside the turbo's bearings can be baked by stored engine heat. This, combined with the turbo's extremely high rpms (up to 150,000rpm) can cause problems with the turbo's internal bearings and can shorten the life of the turbocharger. In addition, many turbos require aftermarket exhaust manifolds, which are often far less reliable than stock manifolds.

Ease of Installation
Superchargers are substantially easier to install than a turbos because they have far fewer components and simpler devices. Turbos are complex and require manifold and exhaust modifications, intercoolers, extra oil lines, etc. - most of which is not needed with most superchargers. A novice home mechanic can easily install most supercharger systems, while a turbo installation should be left to a turbo expert.

Maximum Power Output
Turbos are known for their unique ability to spin to incredibly high rpms and make outrages peak boost figures (25psi+). While operating a turbocharger at very high levels of boost requires major modifications to the rest of the engine, the turbo is capable of producing more peak power than superchargers.

Tunability
Turbochargers, because they are so complex and rely on exhaust pressure, are notoriously difficult to tune. Superchargers, on the other hand, require few fuel and ignition upgrades and normally require little or no engine tuning.

Overall concencious:

While the supercharger is generally considered to be a better method of forced induction for most street and race vehicles, the turbo will always have its place in a more specialized market. Superchargers generally provide a much broader powerband that most drivers are looking for with no "turbo lag". In addition, they are much easier to install and tune, making them more practical for a home or novice mechanic.

 

Well with that said I forgot some other details.. details like quality of the kit ect.

The quality of the kit makes a HUGE difference. Currently I am helping w 2000+ (3rd Generation) Eclipse owners install RIPP MODIFIED Super Chargers on their cars.

RIPP makes HIGH quality products and do not sell unless they have tested. Their stage 1 kit is putting close to 300HP to the ground on all 5spd 00+ Eclipses. They include a self tunable re-mapping box that helps the ECU read higher AIR FLOW, which is a VITAL part in the tuning buisness. Well think that is all for me now

 

I was right about most of it. Turbo's are more because you have to have a boost controller.

 

Nice posts. The thing people considering the turbo vs. supercharger decision often miss if they havn't driven turbos much is the lag issue. Even smaller twin turbos have it and it makes turbo cars harder to launch and less tractable in daily driving. And what the people who talk about 450 hp + HP numbers out of turbos arent saying is that they are not running small turbos to get it. It always amazes me to see people rant about how much they love the turbo rush that comes after the lag, but fail to mention the sluggish response until you hit 3,000 to 4,000 RPM when things start happening - and no boost controller can completely cure this. After 11 years of turbos I'm going for torque off the line this line this time so I'm going the supercharger route....

joe

 

You are completely correct. Also another oftenly missed topis is the life of the motor. Since turbos run hotter and you are going to more often have pre-detonation and mis-fires that will reduce the life of the motor quicker than a SC. But boost is boost both give 14.7lbs of air at sea level, just these 2 ways of boosting hit it at a different time. If you want to run your car over 3000-4000 RPM all the time then more power to you. But I am with you on this one Joe, the torque/low end gain is way better for daily drivers IMO.

Another thing to look into is maintnence, if you run a turbo you will mosre likley change your oil every 1500 to 2000 miles.

 

get a properly sized turbo and you wont have to worry about too much lag, i reccommend getting in touch with the manufacturer and tell them exactly what you want. theyll set you up with something that fits your description (ie. top end, mid range etc. etc.)
with my t3/t4 on my l2.8, boost is pretty much there whenever i want it.
the only reason i dont drive it everyday is because it has no power steering, and no air conditioning (hot as hell in texas!)
as far as losing traction when driving around town, its only true if you just cant keep your foot off the pedal, my car weighs about 2600-2700lbs with about 350rwt and its very easy to drive around town and not worrying about traction.
franklinz

 

But the fact is with turbos there IS ALWAYS lag. And a 2600 pound car without the drag of an AC compressor or power steering pump is hardly a reasonalble comparison to a loaded Z. It's not the issue of getting traction, its the issue of poor off the line performance unless you rev to the point the turbos kick in and then you have to worry about frying the clutch. That's what I meant about poor launch and tractability with turbos in everyday driving. My twin turbos had two small turbos that minimized lag - but the fact is it was always there. And the most noticable difference between that car and the 350 is how much more torque there is off the line in the 350 - and how much easier it makes it to launch this car than any 300TT. I'm not eager to degrade that with the lag of a turbo kit and then have to make it up on the top end.

joe

 

you can always get a spool up kit

 

What trim is your T3/T4 turbo? 60? 53? 48? sounds like it would be on the lower end. If you want low spooling I probably would not really reccoment a T3/T4 hybrid and in a car like the 350Z where room is a major issue a T3/T4 hybrid is pushing the size limit. I would look into a twin b14 or mitsubishi 16G's for that, but again you will still experiece lag, the only way around that is good old N20

 

its 60.

 

When do you hit max boost and when does it start to spool up?

 

max boost is at about 6500 redline is at 7200, and i really couldnt tell you honesly when it first starts to spool up, everytime i get to drive it im too focused on the road.

 

Wow you hit max boost WAY high in the RPM range.. Why keep your eye on the road when you can watch a pretty boost guage.. that or you must not have a pretty one LOL

 

max boost as in falling off, once i see 6500 you can feel the "pull" stop.
im not a magazine, or dyno jockey so i cant tell you when i hit peak blah blah blah, all i know is its pull-the-hairs-off of-your-***** fast. i do have dyno sheets from about 3 years ago, but dont really care to pull them out and compare them to what i have done to my car recently. (dont care) once i start a new rebuild is when ill do another pull and start with the logging.

as far as my gauges go:
sorry for the image size, and can someone flip it for me? lol its
auto meter all the way, except for two nice 350 dollar blitz exhaust and boost gauges (nice and pretty at night), youll also notice the fairly nice sds engine managment system. everythings still not done yet.
franklinz

 

http://www.superchargersonline.com/content.asp?id=19[/URL]