It seems to me that most of the time, diesels are turbo charged, but gassers are supercharged. I.e. you rarely see a supercharged diesel, and turbo gassers really arent as popular as supercharged ones (good grief, even Chevy is SCing the Monte Carlo and Impala SS's)

Is there a reason for this? I can understand the benefits of supercharging, i.e. no turbo lag. If this is the reason, why no supercharged diesels?

__________________
-Matt

EPA Section 609 Certified MVAC Technician
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Oil Burner Kartel Member #10

Ahh the smell of Diesel Fuel, it's like coffee in the morning!

My Car:

1982 300SD Turbo Diesel (231,500 miles!) RIP

1984 300SD Turbo Diesel Custom (235,500 mi on driveline.) - On Road!!

www.icsrepair.com

Supercharging a motor is much cheaper and easier than turbocharging an engine.

Perhaps because diesels have an abundance of low end torque but run out of breath at higher RPMS, maybe a turbo would be better applied to solve this issue rather than a supercharger. Just a guess though.

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1985 CA 300D Turbo , 213K mi

Don't know if supercharging is more popular for gassers. Think of Saab, Porsche, Mitsu, Subaru, Mazda, and Mercedes. That is all the turbos I can think of off the top of my head; I'm sure there are more. There is a Euro VW that is to have both systems.

__________________
Lawrence Coppari

2002 SLK32 AMG
2005 Acura TL
1987 328GTS
1986 944T

Supercharges have parasitic power losses as they use the engine to drive it...

Turbocharges use exhaust gas to power them and have no parasitic power losses.

sometimes that is enough to offset the pros and cons of each....

__________________
Proud owner of ....
1971 280SE W108
1979 300SD W116
1983 300D W123
1975 Ironhead Sportster chopper
1987 GMC 3/4 ton 4X4 Diesel
1989 Honda Civic (Heavily modified)
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Section 609 MVAC Certified
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"He who fights with monsters might take care lest he thereby become a monster. And if you gaze for long into an abyss, the abyss gazes also into you." - Friedrich Nietzsche

I think you just mentioned it there - supercharging has no lag. However, the lag time is an issue only on sport-oriented vehicles, where you want the power NOW.

On big utilitarian diesels, this is not an issue, and it gives them an opportunity to harness the exhaust energy that would otherwise go to waste.

This also applies to small diesels (e.g., commuter cars), where the intended application is more on fuel economy rather on sportiness.

That's not exactly true. The backpressure created by the turbo does cost the engine in terms of flow and heat build-up; however, the flow is quickly offset by the force of the air that is being blown through the engine once the turbo makes boost but the heat remains a serious issue. The turbo is much more efficient at making power because it does not cost the engine nearly as much hp as spinning a supercharger. They are also more reliable, if built well, and can create much more power than a supercharged engine.

Superchargers do have some nice features. They can be added much easier and cheaper than a turbo. The underhood heat is much less. Exhaust gas backpressue on the heads is much less. Since the heat is not there, it doesn't cook your exhaust valves and heads. They can be added or removed relatively quickly.

I like both systems. Superchargers are great for an aftermarket power adder and turbo's are great when they come from the factory. Positive displacement blowers make instant boost and are great for street cars that want instant response. Turbo's are more suited for the long race and superchargers are more suited for the short race.

Supercharger use by manufacturer:
Mazda, Ford, Jaguar, Aston Martin(not sure if the newer models are supercharged), GM, Mercedes, and Toyota.

Turbocharger use by manufacturer:
Mercedes, Porsche, VW, Saab, Volvo, Mitsubishi, Subaru, GM, Bently(VW engines), and Bugatti.

This is not an all inclusive list. Many manufacturers have used turbos in the past and I'm sure there will be more in the future. In general, I think turbos are generally the preferred power adders by most manufacturers.

This sounds like the right answer to me. Since manufacturers seems to use both systems about equally, I am guessing their cost is similar. So the choice would come down to the different characteristics. Turbo is probably more suited to Diesels for the above reason. I don't know why the manufacturers of gas cars have not gone predominantly one way or the other. IMHO.

Mike

__________________
1998 C230 330,000 miles (currently dead of second failed EIS, yours will fail too, turning you into the dealer's personal human cash machine)
1988 F150 144,000 miles (leaks all the colors of the rainbow)
Previous stars: 1981 Brava 210,000 miles, 1978 128 150,000 miles, 1977 B200 Van 175,000 miles, 1972 Vega (great, if rusty, car), 1972 Celica, 1986.5 Supra

You really need to engineer a turbocharged engine but just about any engine can take a supercharger. A turbocharged engine creates a lot of heat and pressure on the exhaust valve that is not there in a supercharged engine. A turbocharged engine also needs a lower compression ratio than you do in a supercharged engine.

A supercharged engine is cheaper to manufature than a turbocharged engine. You can also adapt a supercharger to an engine easier than you can adapt a turbocharger. The same goes for a manufacturer.

Totaly wrong...Turbochargers require no more engineering than a supercherger does....in in many ways far less.

Inside the motor boost is boost...the same fuel compenstation is required either way.

Turbochargers are most efficient...followed but positive displacement superchargers...IE whipple and roots being two examples..

the least efficient being centrifugal...

Turbos are far simpler and cheaper....require no fancy machined mounts that keep it aligned or drive belt systems...

A positive displacement supercharger IE Roots or whipple has the advantage of strong low rpm boost adn a fairly linear progression...but parasitic drive losses mean fewer crank HP...

Turbos make higher peak boost with lower charge heating rates but suffer a small degree off idle due to boost lag...

Cetrifugal superchargers suffer the worst of both...but see use in certain cars without room for a roots, or whipple ( these are usually on TOP the engine with a V-8 or V-6)....or lack of space makes using a more efficeient turbo impracticle due to space limitations.

Any Inline application or car with sifficient underhood space will make more power far easier and cheaper with a turbo setup.

__________________
Proud owner of ....
1971 280SE W108
1979 300SD W116
1983 300D W123
1975 Ironhead Sportster chopper
1987 GMC 3/4 ton 4X4 Diesel
1989 Honda Civic (Heavily modified)
---------------------
Section 609 MVAC Certified
---------------------
"He who fights with monsters might take care lest he thereby become a monster. And if you gaze for long into an abyss, the abyss gazes also into you." - Friedrich Nietzsche

unlike what the other guy seems to believe the supercharged cars GM, Ford adn Benz produce use Roots type positive displacement superchargers. these are low total boost units that provide boost from idle on up...they make les pwer than a turbo setup but to your average loose nut behind the wheel they would trade less power for the smoothness.

__________________
Proud owner of ....
1971 280SE W108
1979 300SD W116
1983 300D W123
1975 Ironhead Sportster chopper
1987 GMC 3/4 ton 4X4 Diesel
1989 Honda Civic (Heavily modified)
---------------------
Section 609 MVAC Certified
---------------------
"He who fights with monsters might take care lest he thereby become a monster. And if you gaze for long into an abyss, the abyss gazes also into you." - Friedrich Nietzsche

Let's keep this to the most basic of systems.

Turbocharger:
Turbo, new exhaust manifold and modified exhaust to fit the new exhaust manifold, oil lines for the turbo, water lines for many turbos, blow-off valve, wastegate, air filter, plumbing from the turbo to the intake. If you want your turbo to last, you need to add a turbo timer or be very dilligent as not to turn the car off immediatly after running the car extremely hard.

Positive displacement blower:
New intake, supercharger, belt, and air filter.

Centrifugal supercharger:
Mounting bracket, supercharger, belt, air filter, and plumbing from blower to intake. A Vortech blower will require oil lines but an Eaton, Whipple, and many centrifugals are self contained and do not need an oil source.

Yeah, lot's easier and fewer parts with the turbo!

True, however, it's easier to tune the fuel for a supercharged engine vs a turbocharged engine due to the delivery of the boost. This statement would not apply for newer EFI systems that are capable of adjusting the air/fuel ratios very quickly.


Some turbos have better adiabatic efficiency than superchargers but many do not. Whipple superchargers rates their blowers at 70% to 80% adiabatic efficiency. Turbo's range frm 60% up to the most efficient and modern/up to date turbo at 80%. Centrifugal are right in line with the very efficient turbos at 60% to 78% and roots blowers have the least adiabatic efficeincy at around 40% to 65% with the newer Eaton's at 65%.

I don't know the last time you were in a fabrication shop but from all the work I've done a centrifugal supercharger wins hands down for ease of installation and low R&D costs. A turbocharger would have been more than four times the cost of my custom supercharged application. I would prefer a turbo but the cost to engineer a turbocharged system for a large displacement V8 was too high.

A positive displacent blower produces the same boost off idle to redline. If you hate turbo lag and need instant throttle response, a positive displacement blower is for you. http://www.whipplesuperchargers.com/content.asp?PageID=68


It depends on many factors and you can't just throw a blanket statement out there like this. Small degree? Depending on your turbo it's more than a small degree of suffering when you refer to boost lag.


In 2003 this 350 Z equipped with a centrifugal supercharged V6 beat out many turbocharged cars and won Sport Compact's 2003 ultimate streeet car challenge: http://procharger.com/gallery/showtemp.php?market=5&idx=1102
http://www.sportcompactcarweb.com/uscc/0312scc_challengers/
http://www.procharger.com/350z_profiles.shtml
I think there are plenty of guys running in the 6 -7 second 1/4 mile that may want to argue your position.
http://www.procharger.com/racing-news/05update-jul.html

There are few examples that I can think of where a turbo application will be cheaper than a supercharged application when constructing from scratch. However, I will agree that pound for pound of boost that the turbocharged application will make more power than a supercharged application due to the power robbing aspects of a crank driven supercharger.

I prefer turbocharging to supercharging on a vehicle with a manual transmission but for an auto equipped with an automatic tranny I'd rather have a positive displacement blower. However, you have to weigh all the aspects of both types of forced induction and see what system meets your driving style and budget. I prefer forced induction over normal aspiration any day of the week.

If you run a Mustang...its clear why you chose what you chose... they have very tight engine bays...you are more limited by what you can fit than you are by what you might want.

Fabricating a manifold for a supercharger is not a small task on a one off basis....since we are discussing one to one basis then the economy of scale for the intake manifold will not be assumed...but on a one off basis its far harder to make that than a turbo mainifiold for a car..again we are assuming inline engines. and also joe public is not an experienced machinist with a well equiped shot at his disposal.

Turbos.....you don't need a turbo timer..the average person doesn't bast into his driveway rev the engine just before stutting it off...

I've owned several turbo cars...never had a turbo fail ....and did well over 100K not very easy miles...it just takes comon sense driving...

many cases you dont need a special exhaust manifold..and adapter plate is suppicient in man cases..but yeak custon exhaust manifold will make more poer just as it would un a supercharger of any type.

plumbing is easy to make using off the shelf aluminum mandrel bends., difficulty is purely dependent on the car...IE some will be easier than others.

Many turbos have built in wastegates..., blow off valve..the need for this will vary with the amount of boost planned..., plan on more than 10 psi then yeas its a good idea to have...these go into th intake plumbing path...minimal work is needed. oil and water lines are nothing...they tap into lines already present in the engine bay area. and again low cost items.

THe tubo hangs off the exhaust manifold, a far easier piece to fabricate. than an intake manifilold , or custome mounts a centrifical needs...you have the same pluming with those that you have with a turbo.

Turbo systems are far simpler and lower cost than a supercharger setup..

Take an application where no kit exists....you take your bare supercharge of choice...(mo mounting kit...I take a T-3 turbocharger...I can make it fit an earlier car (pree ODB2 ) and work for less money than you could for the supercharger. Now I am talking with whats availible to the average hobiest/mechnic.... with access to a welder and basic tools. no freebie machinist time.. I can part together a turbo system for less than $500...and have...Its just not installed yet. Thats a project for this winter or spring.

Your comment about positive displacement blowers I mostly agree with they do well from idle up...however they have a downside with charge heating on he upper end thats worse than a turbo...you see these used bacasue they do so well off idle....and for 90% of people who by factory supercharged cars thats why..they preffer the smoothness and are willing to accept the downside to have it.

The turbo lag comment....I'm talking a properly sized unit...you can have big boost will acceptible turbo lag.....but of you are after monster boost levels (that call for racing fuel) then yes bottom end lag is the price you pay.

At either of those boost leverls I am talking up 15+ psi for pump gas 20+ psi for racing fuel you are going to want and need an intercooler...regardless of if you supercharge or turbo charge. Rule of physics...compress air and it gets hot.....

we all you you are a procharger spokesman.....or at least should be...but you have locked yourself into that choice and wish to defend that choice irregardless....

Do I think its the best thing out there? no by a longshot...but it has its purpose as none of this is really a one size fits all situation.

A supercharger is no easier or harder to tune the fuel to match......

Most EFI cars use MAF sensors and manifold pressure (or Vacuum) sensors.. these are tuned equally....so much air requires so much fuel.....there are different ways to achive that..at the fuel map...(best way) or you can key fuel pressure to boost levels...(the most common method used)

Using those applies the same...becasue for X amount of air you need X ammount of fuel...turbo or supercharged.

this is not 1965 and we are not talking turbocharged corvairs...materials and quality are far better today..carberettors didn't meter fuel well enough to work as they need to.

I preffer turbochargers...hoever you do have to look objectively at what you really need, VS what you really want..they all have strengths and weaknesses...you have to decide which matter more to you and which least...any of them will be a bit of a comprimise. Like you were fond of saying you can't toss out a blanket statement....most supercharger kits I see are upwards of $3K some upwards of $4K...thats hardly chump change for many people. I can fabricate a turbo setup at home with the tools I have at home...

I can't do that with a supercharger.

Are either going to improve the power of the car? certainly.

__________________
Proud owner of ....
1971 280SE W108
1979 300SD W116
1983 300D W123
1975 Ironhead Sportster chopper
1987 GMC 3/4 ton 4X4 Diesel
1989 Honda Civic (Heavily modified)
---------------------
Section 609 MVAC Certified
---------------------
"He who fights with monsters might take care lest he thereby become a monster. And if you gaze for long into an abyss, the abyss gazes also into you." - Friedrich Nietzsche

That's a BS comment. I'll leave it at that.

Get some lexan and create a bracket then have it taken to a machine shop for cutting and or welding. Cheap and easy. In fact, it's much much easier than creating a new manifold. Not to mention, most superchargers are CARB certified. You can't do that with a non CARB certified turbo unless it is purchased as a kit and it goes through the certification process. A supercharger does nothing to trip a failed emissions inspection. A turbo on a non turbocharged car will trip an emissions inspection and it will fail USEPA inspection as well as CARB unless it has received approval.


I don't know how you drive but I don't drive like a granny.


Joe Public, good luck!

You would need a very short manifold and it would need to be on an engine mounted sideways; ie, front-wheel drive car. You can't escape making new manifolds for a V8 or a V6. It's not cheap to have done nore is it easy in tight spaces.

Correct!

However, you will need to tap into lines and not everyone is skilled enough to do that task. A blower mounts up to existing mounting points with no tapping or drilling needed. Vortech blowers are the exception.


Yes and no. Yes it's usually easier to fabricate a manifold than an intake but in some circumstances where space is tight it can be the other way around. No, a bracket is quicker and easier to make than a manifold. That's even more aparrent on V6's and V8's.

Not for the vast majority of V6's or V8's on the market.


Only on an Eaton as compared to a very efficient turbo. however, the newer Eaton's adiabatic efficency is as high as most turbos on the market. A Whipple has greater adiabatic efficency than most turbos on the market and is equal to that of the highest efficiency turbo on the market. Joe Blow will not likely be using that turbo for his budget project.

Yep, the lag can be very substantial. I love the way it feels when it kicks in though. Kind of like the hand of God kicking you in the arse!


Correct! That or methanol/water injection.

I'm not defending anything. In fact, if you read my comments, I clearly say that I prefer turbocharging. However, on a V8 and in my application, a supercharged system was much much cheaper than a turbocharged system. Not to mention, I can take it back to stock in less than 1 hour with no evidence of ever having a supercharger on my car.

Yeah, I already said that I don't completely agree with that comment but the exception was modern EFI systems.

A MAP(manifold air pressure sensor) is the best sensor to use for aftermarket turbocharged applications.

Correct!

True, but, you can't assume everyone is installing an aftermarket EFI system. There are many many forced induction cars that use carbs. I'm running CIS on my SEC and it's only a step away from a carb. However, I will install an EFI system to get maximum hp from my system.

Yeah, but compare those same vehicles and try to buy a turbocharger for the same price. The cost for an aftermarket turbocharged system on V8 and V6's can be more than 3x the cost of a supercharged system on the same car.

I couldn't do that with a turbocharger on my V8.

Yep, at least we can agreee on somehting.

That's a BS comment. I'll leave it at that.


BS to you, not to anyone who understands these things. , and I know enough Mustang guys that feel the same way, these guys run everything between them



Get some lexan and create a bracket then have it taken to a machine shop for cutting and or welding. Cheap and easy. In fact, it's much much easier than creating a new manifold. Not to mention, most superchargers are CARB certified. You can't do that with a non CARB certified turbo unless it is purchased as a kit and it goes through the certification process. A supercharger does nothing to trip a failed emissions inspection. A turbo on a non turbocharged car will trip an emissions inspection and it will fail USEPA inspection as well as CARB unless it has received approval.

Thats BS....Boost is boost...a superchrger will trip a code just as fast as a supercharger will....and as far as carb goes.....you are also wrong...the kit has to be certified by application....adn CARB has not one damned thing to do with the EPA requirements either....you better do some reading up...California doesn't dictate to everyone else..much less whats EPA legal or not...a car has to meet emissions standards applical for the year it was manufactured....and a properly tuned job will do exactly that, and get that plate just a tiny bit off on alignment and wait till you kick belts all the time.

I don't know how you drive but I don't drive like a granny.


drive any car like an idiot and its not going to last....I ran my car hard...wore out two transmissions but the stock turbo and engine was still going strong



Joe Public, good luck!

Funny...Joe Public does well with turbos....



You would need a very short manifold and it would need to be on an engine mounted sideways; ie, front-wheel drive car. You can't escape making new manifolds for a V8 or a V6. It's not cheap to have done nore is it easy in tight spaces.

Wanna bet.....Civic EX or HF manifold is short enough and inch thick abafter is all you need to hang a T-3 or whatever you want off and D series Honda...and you have only a small loss over a well designed turbo manifold.

V-6 or V-8 that depends...on many you only need one manifold with the other feeding it...but like I orriginally stated..we are commenting on inline engines...not V-8 engines...

Correct!



However, you will need to tap into lines and not everyone is skilled enough to do that task. A blower mounts up to existing mounting points with no tapping or drilling needed. Vortech blowers are the exception.


Well you really aren't tapping...you are using T-pittings at the existing ends...and using lines as is...anyone doing either a supercharge or a turbocharger will be able to handle that or they have bigger issues to worry about.



Yes and no. Yes it's usually easier to fabricate a manifold than an intake but in some circumstances where space is tight it can be the other way around. No, a bracket is quicker and easier to make than a manifold. That's even more aparrent on V6's and V8's.

That depends..bracket rigidity and alignment are mighty important issues, or thing break and belts get thrown...but if its easier than in exhaust manifold or not really is a case by case issue....some are easy, others hard.


Not for the vast majority of V6's or V8's on the market.




Only on an Eaton as compared to a very efficient turbo. however, the newer Eaton's adiabatic efficency is as high as most turbos on the market. A Whipple has greater adiabatic efficency than most turbos on the market and is equal to that of the highest efficiency turbo on the market. Joe Blow will not likely be using that turbo for his budget project.



Yep, the lag can be very substantial. I love the way it feels when it kicks in though. Kind of like the hand of God kicking you in the arse!


But thats a choice in sizing the system ...minimal lag or maximum boost, if you chose the former its not very noticible..(but yes you can feel it) if you chose the latter you get exactly what you describe...and thats part of deciding what you want before you set out to decide how you plan to do it...if you are realistice and objective you may end up either going turbo or supercharged...like I have said they each have their own pro's and con's.....




Correct! That or methanol/water injection.


Fine for a track car but not the best setup for a daily driver....if that spray becomes a stream you will hydrolock th eengine...If yo uneed that boost of the street take the time and intercool it.



I'm not defending anything. In fact, if you read my comments, I clearly say that I prefer turbocharging. However, on a V8 and in my application, a supercharged system was much much cheaper than a turbocharged system. Not to mention, I can take it back to stock in less than 1 hour with no evidence of ever having a supercharger on my car.



Yeah, I already said that I don't completely agree with that comment but the exception was modern EFI systems.



A MAP(manifold air pressure sensor) is the best sensor to use for aftermarket turbocharged applications.


I did mention that one only not directly by name...we agree there....



Correct!



True, but, you can't assume everyone is installing an aftermarket EFI system. There are many many forced induction cars that use carbs. I'm running CIS on my SEC and it's only a step away from a carb. However, I will install an EFI system to get maximum hp from my system.

People use carbs...but as we both know fuel management is even more critical on a boosted system...lean out under boost and you lunch the engine...those people using carbs typicall run excessively rich to avoid that.

Not just EFI but mechanical systems can beinfit from the same shortcuts using a fuel pressure regulator referenced to boost pressure. Thats how many of these "Kits" do it.



Yeah, but compare those same vehicles and try to buy a turbocharger for the same price. The cost for an aftermarket turbocharged system on V8 and V6's can be more than 3x the cost of a supercharged system on the same car.


Provide some examples there...becasue the average kit I see for the centrifical units varies from $3,500 -$4,500 and up....

I've never seen a turbo kit at triple that price. But comparison will be rough...don't know any companies that built both...



I couldn't do that with a turbocharger on my V8.



Yep, at least we can agreee on somehting. [/QUOTE]

Yes we agree on the last point.


There are people who are so stuck on one way they won't look at the other....these are usually the very same people who can't sit down , be honsts with what they want, with what they need and therefore can't pick the right system for them..becasue in the end it could be either one based on needs...

Personally hearing and seeing a 502 chevy with EFI and 4-71 or 6-71 sitting on top of it running is almost as good as sex....it just isn't the most practical route to power at all times.

__________________
Proud owner of ....
1971 280SE W108
1979 300SD W116
1983 300D W123
1975 Ironhead Sportster chopper
1987 GMC 3/4 ton 4X4 Diesel
1989 Honda Civic (Heavily modified)
---------------------
Section 609 MVAC Certified
---------------------
"He who fights with monsters might take care lest he thereby become a monster. And if you gaze for long into an abyss, the abyss gazes also into you." - Friedrich Nietzsche