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Posted: 1/25/2006 5:02:50 PM EDT
[Last Edit: 1/25/2006 5:04:58 PM EDT by Zippy_The_Wonderdog]
I've wondered this for awhile...but never have done research into it. So here I go.

When it comes to getting the extra oomph out of engines, a turbocharger or a supercharger is frequently seen. Instead of searching the 'net and getting an answer, I'll just post it here. As with most inquiries here, the answers here tend to be more interesting

Given my really rough understanding of how each work....

Superchargers are belt driven and therefore force more air, and subseqently allow more fuel to be delivered. Since it is belt driven, its additional power delivery is proportional with engine rpm's and therefore allows for a smooth boost of power.

Turbochargers get their power from the exhaust, spool up to high rpm's and force air in once enough pressure is achieved, sometimes/frequently resulting in the notorious turbo lag which is a sudden surge of power.

Based upon my crude understanding, it would seem that a supercharger (aka a "blower" from Mad Max fame...) would be more desireable based upon it's smoother power delivery.

However, turbo's tend to be much more prevalent with OEM equipped turbocharged cars. Why? Is it a matter of efficiency? I understand that turbo lag has been greatly improved upon over the years and power delivery tends to be much smoother. As a reader of the car rags through the years, the biggest offender of turbo lag that I can think of was the Lotus Esprit Turbo of the 80's. From what I remember, it was a dog until you hit 25-30mph under full throttle then took off like a shot out of a rifle.

Then you throw into the mix...Twin Turbocharged cars. Does one turbocharger kick in at one pressure, then another at a higher pressure to allow for a smoother delivery.

This is my crude understanding, just wondering what is going on.

Educate me.
Link Posted: 1/25/2006 5:07:37 PM EDT

It's just easier to fit turbos under a hood than a supercharger. Plus it's easier to modulate boost with turbos.
Link Posted: 1/25/2006 5:09:18 PM EDT
[Last Edit: 1/25/2006 5:16:33 PM EDT by Planerench]
The turbos can be staged for low end and high end. The RX7 did this very well. Turbo lag is almost eliminated with a properly designed system. Very few factory systems experience much lag. Sometimes on engine configurations that have banks of cylinders very far apart ie V engines or opposed engines, two turbos are used in parallel to locate them closer to the exhaust ports and make the installation more simple to plumb.

Also, due to the high RPM of a turbo they usually take very little room compared to a conventional roots style supercharger. A positive displacement supercharger is also very unforgiving of any engine malfuction such as a backfire.
Link Posted: 1/25/2006 5:14:47 PM EDT
Turbo. Superchargers aren't used as often because they suck more power from the engine all the time, that and they're typically more expensive. The boost comes on smoother, though, I don't mind turbo lag at all (to a point).

Of course, one can't forget that turbos sound cooler (except maybe for a roots blower).
Link Posted: 1/25/2006 5:16:27 PM EDT
Well, you're pretty much right on.

There are three basic types of superchargers, in order of efficiency: Roots, screw and centrifugal. They are all driven off of a belt, and thus parasite SOME power from the engine in order to make more. These are usually better on bigger engines that already make decent power, as it takes power to drive them.

Turbochargers run in many sizes... small units that spool quickly to large honkin units for deisels and large trucks. Smaller units don't need to sap much power from the engine in order to spin up.

Twin turbo setups can be sequential - one blowing into the next - or parallel - one feeding one side of a V engine, and the other feeding the other side. Sequential lets you use different turbochargers, say, a small one to spool up quicker and give you quicker boost while a second, larger unit spools up slower, but provides more of a boost.

Link Posted: 1/25/2006 5:17:28 PM EDT
[Last Edit: 1/25/2006 5:18:22 PM EDT by Combat_Jack]
Turbos are much more efficient. Not all superchargers are equal.

Roots blowers, like on Aston Martins, Ford SVTs and the 3.8L Pontiac, are inefficient, hot running blowers that produce a lot of torque but die off at the top end. They compress air in the manifold.

Twin screw is like a roots blowers, also belt driven, but they compress air in the blower case and run cooler. They are 20% more efficient, on average, and can handle higher boost levels.

Centrifugal blowers use an impeller driven by a belt. They are essentially a turbocharger that is driven off of the engine, rather than by exhaust power. As such they tend to be more efficient that roots/TS blowers, but still don't spin fast enough to match turbos. The downside is boost lag. A subset of Centri blowers is the rotrex blower, a european development that claims to spool up as fast as a TS blower and have the top end and efficiency of a turbo. Centri blowers run cool, which is one reason they are the choice for Corvettes and other cars with high compression engines, most of the time.

Thats not organized, its a brain dump. Have at it.
Link Posted: 1/25/2006 5:20:14 PM EDT
Both have advantages and disadvantages. Dealing with heat is a problem with both, but more so with TCs. TCs are more efficient although the parasitic drag of a SC is overcome by the increased output. If you are a designer/manufacturer working with a clean sheet of paper, either can provide the performance you want. In the aftermarket, the simplicity of a SC is a big advantage for street applications.
Link Posted: 1/25/2006 5:22:38 PM EDT
It's hard to find a California legal aftermarket turbo but I've never heard of a supercharger that didn't get the green light here.
Link Posted: 1/25/2006 5:31:07 PM EDT
Isn't this ARFCOM?


GET BOTH!
Link Posted: 1/25/2006 5:37:35 PM EDT
[Last Edit: 1/25/2006 5:38:45 PM EDT by Zippy_The_Wonderdog]
I must admit something here which I am surely to get ripped on for....

For some reason, whenever I look upon a performance car that is "boosted"...either supercharged or turbocharged...or the notorious "NOx"...I turn my nose up and see it as "cheating."

My attitude is..."Well, no shit it's fast. It's got forced induction. Anyone can get that."

It's not that I don't appreciate the additional power...I just look at it as cheating as compared to power under normal aspiration.

My other problem is that with the additional stress of forced induction, you are placing additional wear on the engine and greatly reducing its lifespan and not a good idea to have for the long term, not to mention something else to go wrong.

That's just my predjudice. Forced induction is (in my mind) for wannabes, and reducing the lifespan of an engine. I suppose its a bit snobbish.
Link Posted: 1/25/2006 5:41:45 PM EDT
Another point is the fact that a roots blower is difficult to use with an intercooler. Your bigger roots style blowers creat tons of heat and adding an intercooler will result in a blower above the roofline. A turbo or centrifugal blower can be easily intercooled. But nothing beats the bottom end torque a roots blower makes. If you look at the big dog drag racers roots blowers and turbos are the only way to go. A centrifugal tends to have more belt slip issues.
Link Posted: 1/25/2006 5:43:11 PM EDT
I am not a fan of turbos for car driving. In honesty, it is all about usable power, and smooth power is the best power to have. Go to a driving school and you will see, sudden throttle movements=out of control. Supercharger>turbocharger. Best is no forced air at all.
Link Posted: 1/25/2006 5:43:31 PM EDT
Another point is the fact that a roots blower is difficult to use with an intercooler. Your bigger roots style blowers creat tons of heat and adding an intercooler will result in a blower above the roofline. A turbo or centrifugal blower can be easily intercooled. But nothing beats the bottom end torque a roots blower makes. If you look at the big dog drag racers roots blowers and turbos are the only way to go. Belt slip and failure are also a feature turbos dont have to worry about . A centrifugal tends to have more belt slip issues when they really start pounding out high boost numbers . The best way to get killer power is a single intercooled turbo.
Link Posted: 1/25/2006 5:45:01 PM EDT

Originally Posted By Zippy_The_Wonderdog:
I must admit something here which I am surely to get ripped on for....

For some reason, whenever I look upon a performance car that is "boosted"...either supercharged or turbocharged...or the notorious "NOx"...I turn my nose up and see it as "cheating."

My attitude is..."Well, no shit it's fast. It's got forced induction. Anyone can get that."

It's not that I don't appreciate the additional power...I just look at it as cheating as compared to power under normal aspiration.

My other problem is that with the additional stress of forced induction, you are placing additional wear on the engine and greatly reducing its lifespan and not a good idea to have for the long term, not to mention something else to go wrong.

That's just my predjudice. Forced induction is (in my mind) for wannabes, and reducing the lifespan of an engine. I suppose its a bit snobbish.



Yah! Go big or go home

Having said that...I'd love a big old supercharger sticking out of the hood of my Charger, all Mad Max like Something about it just screams "No, you really don't want to make your 4banger rev at the light we're both stopped at"...

Link Posted: 1/25/2006 5:45:42 PM EDT

Originally Posted By Dave15:
Isn't this ARFCOM?


GET BOTH!



it's been done. turbo magazine had a compound forced inducted mr2. s/c to help with lag and to spool the turbo down low.

Nitrous is great, but boost is free and on demand with your gas pedal. Bigger turbos on stock turbo cars can improve fuel economy as well as help lower green house gas emissions.


car's built with forced induction from the factory and engines built to withstand boost have no problems lasting for a very very long time. take a look at the 4g63 powerplant from the early eclipses, lasers, and talons. little 2 liter 4 cylinders that could be daily driven with 400+whp on a stock motor.

remember....fast, cheap, and quick....pick 2.
Link Posted: 1/25/2006 5:46:48 PM EDT
Zippy--

Might be worth going here:

forums.rennlist.com/rennforums/forumdisplay.php?f=69

The Porsche 928 is an interesting car. There are guys on that board that have Twin Turbo charged the car (V8 Engine), Supercharged it (much more frequent) and also "Stroker'd" it (Increased the displacement in normally aspirated form.

Bumps the Horsepower from 240/350 (depending on the year and emissions) to 400/500+ HP. One of the guys on the board is actively racing a Stroker (6 liter--bumped up from the 5 liter original engine), and does quite well in races--AND, he drives it on the street to the races.

Each has it's proponents--Supercharging the car is somewhat easier due to the design of the vehicle. You can get a supercharger and install it in a day for less than $3500 (of course the price goes up from there depending on intercooling, size of boost fans, etc).

Most of the guys on that board will tell you that a well made engine (even a used engine with good compression tests) can handle boost very well with no difficulty, and no excess wear. There are some of the Toyota engines in the Ricers that get 20+ PSI boost. Most forced induction cars are 5-10 psi boost, and give significant gains in horsepower.

Someday, I'd love to find an early Euro 928 and Supercharge it.

AFARR
Link Posted: 1/25/2006 5:50:06 PM EDT

Originally Posted By Zippy_The_Wonderdog:
I must admit something here which I am surely to get ripped on for....

For some reason, whenever I look upon a performance car that is "boosted"...either supercharged or turbocharged...or the notorious "NOx"...I turn my nose up and see it as "cheating."

My attitude is..."Well, no shit it's fast. It's got forced induction. Anyone can get that."

It's not that I don't appreciate the additional power...I just look at it as cheating as compared to power under normal aspiration.

My other problem is that with the additional stress of forced induction, you are placing additional wear on the engine and greatly reducing its lifespan and not a good idea to have for the long term, not to mention something else to go wrong.

That's just my predjudice. Forced induction is (in my mind) for wannabes, and reducing the lifespan of an engine. I suppose its a bit snobbish.



Where can I buy a 750 HP naturally aspirated engine for a late model Mustang that makes emissions and idles like stock?
Link Posted: 1/25/2006 5:58:55 PM EDT

Originally Posted By Zippy_The_Wonderdog:
I must admit something here which I am surely to get ripped on for....

For some reason, whenever I look upon a performance car that is "boosted"...either supercharged or turbocharged...or the notorious "NOx"...I turn my nose up and see it as "cheating."

My attitude is..."Well, no shit it's fast. It's got forced induction. Anyone can get that."

It's not that I don't appreciate the additional power...I just look at it as cheating as compared to power under normal aspiration.

My other problem is that with the additional stress of forced induction, you are placing additional wear on the engine and greatly reducing its lifespan and not a good idea to have for the long term, not to mention something else to go wrong.

That's just my predjudice. Forced induction is (in my mind) for wannabes, and reducing the lifespan of an engine. I suppose its a bit snobbish.



Nothing to be ripped about. Everyones entilted to an opinion especially in the performance world thats what makes it so much fun. I must admit beating a power adder car with a naturally aspirated car has its own unique enjoyment. But after the race i would wonder wow how bad would i ahve beat that guy if i had a power adder.
Link Posted: 1/25/2006 6:07:00 PM EDT

Originally Posted By FMJshooter:

Originally Posted By Zippy_The_Wonderdog:
I must admit something here which I am surely to get ripped on for....

For some reason, whenever I look upon a performance car that is "boosted"...either supercharged or turbocharged...or the notorious "NOx"...I turn my nose up and see it as "cheating."

My attitude is..."Well, no shit it's fast. It's got forced induction. Anyone can get that."

It's not that I don't appreciate the additional power...I just look at it as cheating as compared to power under normal aspiration.

My other problem is that with the additional stress of forced induction, you are placing additional wear on the engine and greatly reducing its lifespan and not a good idea to have for the long term, not to mention something else to go wrong.

That's just my predjudice. Forced induction is (in my mind) for wannabes, and reducing the lifespan of an engine. I suppose its a bit snobbish.



Nothing to be ripped about. Everyones entilted to an opinion especially in the performance world thats what makes it so much fun. I must admit beating a power adder car with a naturally aspirated car has its own unique enjoyment. But after the race i would wonder wow how bad would i ahve beat that guy if i had a power adder.




Normal asperation, if done right, is the way. i.e. BMW M5, McClaren F1. Then you never have to wonder...
Link Posted: 1/25/2006 6:16:25 PM EDT
You've got your answers, but I'll add that neither are particularly useful for daily drivers, except for turbos on cars with really weak engines (and possibly cars used frequently over 10,000 feet). The fact remains that most cars use only a fraction of their horsepower envelope in daily service. Manufacturers are pushing it for marketing purposes, not to address a need in the market. Only a very small segment of the market which buys performance or power, uses it as the brochure makes you think all do. It's no different than the SUV used as grocery getter thing...

Keep in mind that a Nissan Maxima right off the showroom floor, can out accelerate all bet the most hard core musclecars of the '60s. This is the golden age of the automobile...
Link Posted: 1/25/2006 6:17:01 PM EDT
Was it "mad max" where Mel Gibson flips a switch to turn his supercharger on?

But don't laugh too hard.
I just saw a car company's design for a supercharger that didn't come on until
a certain RPM range. It had seperate ducting and air dams so normal airflow could
bypass around it when it wasn't needed.

Link Posted: 1/25/2006 6:18:52 PM EDT
To draw analogies....

I see forced induction analagous to...

The chemically enhanced athlete. Sure, genetics played a part, but far more people could have performed a helluval lot better than you did if they juiced up like you did.

Fake boobies. Yeah, they look fantastic (with the right surgeon) but there's just something genuinely unsatisfying about them. I see them as the first milimeter step towards the kilometer of screwing a really hot robot with a semi-decent personality that gets me through the day and feeling hardly any degree emotional fulfillment.

A high displacement gutteral roar will take the place of a boosted whine any day. I guess I am getting old.


Originally Posted By FMJshooter:

Originally Posted By Zippy_The_Wonderdog:
I must admit something here which I am surely to get ripped on for....

For some reason, whenever I look upon a performance car that is "boosted"...either supercharged or turbocharged...or the notorious "NOx"...I turn my nose up and see it as "cheating."

My attitude is..."Well, no shit it's fast. It's got forced induction. Anyone can get that."

It's not that I don't appreciate the additional power...I just look at it as cheating as compared to power under normal aspiration.

My other problem is that with the additional stress of forced induction, you are placing additional wear on the engine and greatly reducing its lifespan and not a good idea to have for the long term, not to mention something else to go wrong.

That's just my predjudice. Forced induction is (in my mind) for wannabes, and reducing the lifespan of an engine. I suppose its a bit snobbish.



Nothing to be ripped about. Everyones entilted to an opinion especially in the performance world thats what makes it so much fun. I must admit beating a power adder car with a naturally aspirated car has its own unique enjoyment. But after the race i would wonder wow how bad would i ahve beat that guy if i had a power adder.

Link Posted: 1/25/2006 6:20:50 PM EDT

Originally Posted By intervivos:
I am not a fan of turbos for car driving. In honesty, it is all about usable power, and smooth power is the best power to have. Go to a driving school and you will see, sudden throttle movements=out of control. Supercharger>turbocharger. Best is no forced air at all.



For racing applications it comes to throttle control and mechanisms to "manage" lag associated with forced induction. I can't think of a race series that has more turbo cars and "unpredictable" road conditions than rally and they seem to do alright with small displacement motors with turbos.
Link Posted: 1/25/2006 6:21:34 PM EDT
[Last Edit: 1/25/2006 6:26:07 PM EDT by turbo_infidel]

Originally Posted By Zippy_The_Wonderdog:
I've wondered this for awhile...but never have done research into it. So here I go.

When it comes to getting the extra oomph out of engines, a turbocharger or a supercharger is frequently seen. Instead of searching the 'net and getting an answer, I'll just post it here. As with most inquiries here, the answers here tend to be more interesting

Given my really rough understanding of how each work....

Superchargers are belt driven and therefore force more air, and subseqently allow more fuel to be delivered...
not exactly true, because both superchargers and turbo chargers require the same basic air/fuel ratio to work properly, so if both units are processing the same amount of air , both are using the same ammount of fuel, also because superchargers are belt driven they require HP to work, where as turbocharger's work off the exhaust's energy making "free H.P"

"Since it is belt driven, its additional power delivery is proportional with engine rpm's and therefore allows for a smooth boost of power."...True

"Turbochargers get their power from the exhaust", ...yes

"spool up to high rpm's" ..turbos make power at all RPM ranges, depending on the application

"and force air in once enough pressure is achieved," your talking about exhaust pressure which depends on many factors, manafold design, runner diamater, A/R size on the turbine housing, and most importantly, exhaust energy
exhaust energy is what really makes it work, the heat / and pressure of the exhaust pulses get very powerful once the engine is put against a load, like accelerating a race car or on an dyno, this exhaust enrgy from the work the engine is doing makes the turbine wheel spin.


"sometimes/frequently resulting in the notorious turbo lag which is a sudden surge of power."

modern turbos act more like a naturally aspirated car than the "turbo lag" monsters of the past with the invention of dual ball bearing cartridges, and the use of exotic metal's and of course the aid of computers designing the blades and majour components of the turbos, they have come a long way, my shop car makes 5 PSI of boost when I rev the engine a little, and still makes 1070 HP to the tire at 40 pounds of boost and it is a inline 6, 3.0 litre

"Based upon my crude understanding, it would seem that a supercharger (aka a "blower" from Mad Max fame...) would be more desireable based upon it's smoother power delivery."

the mechanical losses assoiaced with a "roots" style blower like the one from mad max make it only practical for use on cars that make a few thousand H.P. they require several HUNDRED H.P to work.all tho they are BITCHIN on hot street cars..a good modern supercharger design is more like the unit from "pro-charger" which is basically a belt driven turbocharger.

"However, turbo's tend to be much more prevalent with OEM equipped turbocharged cars. Why? Is it a matter of efficiency? " yes fuel and mechanical efficiency

"I understand that turbo lag has been greatly improved upon over the years and power delivery tends to be much smoother." see above

"As a reader of the car rags through the years, the biggest offender of turbo lag that I can think of was the Lotus Esprit Turbo of the 80's. From what I remember, it was a dog until you hit 25-30mph under full throttle then took off like a shot out of a rifle." hardly the worst offender, but that POS had more to worry about than turbo lag...

"Then you throw into the mix...Twin Turbocharged cars. Does one turbocharger kick in at one pressure, then another at a higher pressure to allow for a smoother delivery." yep but most are sized different with the smaller one doing the low rpm work, and a slightly bigger one coming online when required boost and RPM dependant..keep in mind most of those twin turbo cars you are talking about loose the twins when it is time to make some power, they have fallen victim to to more efficient single and twin turbo set ups...

This is my crude understanding, just wondering what is going on

Educate me.



Link Posted: 1/25/2006 6:23:32 PM EDT
Ah yes, the Maxima and its VQ engine. Nothing smoother on the market. Takes a bit to learn how to drive it, it is so smooth. Kinda deceptive with a 6-spd manual.

Might very well be the best engine on the market today.


Originally Posted By DriftPunch:
You've got your answers, but I'll add that neither are particularly useful for daily drivers, except for turbos on cars with really weak engines (and possibly cars used frequently over 10,000 feet). The fact remains that most cars use only a fraction of their horsepower envelope in daily service. Manufacturers are pushing it for marketing purposes, not to address a need in the market. Only a very small segment of the market which buys performance or power, uses it as the brochure makes you think all do. It's no different than the SUV used as grocery getter thing...

Keep in mind that a Nissan Maxima right off the showroom floor, can out accelerate all bet the most hard core musclecars of the '60s. This is the golden age of the automobile...

Link Posted: 1/25/2006 6:36:27 PM EDT
I've never read so much silly misinformed nonsense in a single thread before...

I don't even know where to begin...

Some of you guys REALLY need get the dragstrip more often.

The rest are better off talking guns...

There's ALOT more to forced induction than just pushing air into an engine, and there ain't enough room on this website to go over it all.

All I know is... IT WORKS.
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