vraa

I'm adding on to my web mastering project of German Automobiles Museum and adding a few exhibits and a whole new Japanese Car Museum sector.

For one of the exhibits it's the pros and cons of Supercharging and the pros and cons for turbocharging. So far what I have is just a bare minimum and I was wondering if yall could correct me and or add onto my list

Turbocharging - Pros
-Low range Torque

Turbocharging - Cons
-Turbo Lag
-Engine go boom

Supercharging Pros
-Less stress on the engine

Supercharging Cons
-Not as much power for bigger engines

As yall can see I have pretty much zero information on each one, what I'm thinking is maybe turn it into a Venn Diagram, but the list will look better. School is tedious but so fun

dswildfire

a turbocharger is a supercharger, but not vice versa. the low range torque on a turbo is related to the size of the turbo. smaller trubo will be more low end because of less airflow creating backpressure, shorter spool times, and a result, less lag. bigger turbos have more air flow, so more high end hp, and longer spool up times so more lag. they can both stress the engine equally, depending on boost pressure. superchargers or small turbos are more linear in power delivery. more power loss associated with running a supercharger versus a turbo.

that should be a start. anybody, feel free to correct mistakes i have made.

JBrady

HUGE range of variables. Ultimately, turbocharging has the POTENTIAL to make the most power of any engine ehancement... period. Back before Formula One outlawed turbocharging it was not uncommon for a qualifying engine to be making in excess of 15 horsepower per CUBIC INCH!!!

Turbochargers ARE superchargers. Supercharging means to feed the engine HIGHER than ambient air pressure. To do this you need a compressor. There are MANY different types of compressors but turbocharger compressors are almost exclusively centrifugal compressors. These are generally highly efficient compressors but need to be spun at a pretty high RPM to be effective. If the turbocharger is sized to reach this RPM at a low engine speed... the turbo will in fact make fantastic low speed power. If it is size too large it will make poor low speed power. Also, a poorly designed turbosystem can create a dramatic thermodynamic load on the engine both on the intake and exhaust sides.

Superchargers (as generically termed) uses a direct power takeoff from the crankshaft, usually in the form of pullies and a drive belt. A well designed supercharger system can make great power all the way from idle to redline. Most supercharger systems are not so well designed. Many superchargers do not make usable boost below say 2500 or 3000rpm and the boost climbs to peak at redline. Because and engine is most vunerable to detonation at its torque peak... this can actually protect the engine... but power will be down.

If you are getting the idea this is really requires book length answers to clearly define the pros and cons of the various choices mentioned.

rlh006

turbocharging would be alot better than supercharging. endless possibilities!!!just to bad noone wants to make any turbo kits for us gasoline cars...hint.

E55AMG99

Hey vraa, sounds like a cool project. Like JB already said, there are a huge number of variables. A lot of builders use superchargers (belt driven) to generate big boost at a low cost. They are generally simpler to manufacture, maintain and produce less stress on the engine. They can produce more boost at a lower RPM quickly but they max out early too. A similar argument can be made for a turbo (exhaust driven) on the last point too but turbos are generally more efficent at higher RPM.

I think someone like Smokey Yunik wrote a book on the pros and cons of forced induction. You should look for it.

Greg

E55AMG99

Deciding which is better is a difficult proposition. It all depends on what your goals are. Making such a blanket statement is foolish. How many dragsters do you see with turbochargers? Same is true for your last comment.

Richard Galing

Corky Bell's "Maximum Boost" also present a wealth of knowledge on modern supercharging & turbocharging.

An ideal situation would be, of course to have all (3) turbo, supercharger & nitrous adding power to your car...Unfortunately that maybe an unrealistic dream slightly out of reach for the common performance enthusiast.

dNA3D

Turbocharging - Pros
More power than Supercharging possible
More efficient setup (runs on essentialy useless exhaust gases)
Usually lag free on large, well tuned engines
Large turbos require wastegates, BOVs etc. sometimes makes fantastic noises

Turbocharging - Cons
Sometimes does not make so fantastic noises
Large turbos lead to turbo lag, not very linear torque curve
Turbo Surge
More expensive and complex than supercharging
Quite laggy on smaller engines

Supercharging - Pros
Usually flattens and heightens the torque curve
Cheaper, simpler
Almost (note: Almost) lag free
Whine noise can be exhilarating

Supercharging - Cons
Whine noise can be annoying
Relatively inefficient (not good for smaller engines)

E55AMG99

I saw a Pro Street style car like that several years ago and he was ridiculed by others for having an unrealistic setup. Funny thing is, that car probably had the best street setup around! The turbo fed the supercharger which helped lessen the high RPM pumping inefficiencies and the shot of N20 removed any low RPM lag. Too bad you need a boat sized car to put it all in not to mention the boat load of cash!

vraa

Thanks a lot yall! I'm editing and revising and restating a lot of things said here, I'll make sure I direct link this thread for more information.

For the belt driven superchargers.. the belt is connected from the main pulley to the supercharger pulley correct? I remember Ben explaining a lot of the pulley stuff to me recently.

I'm not really understanding the exhaust driven turbocharging thing here, you can have a turbo that isn't exhaust driven?

So is that kind of recycling spent fuel?

James F. Cannon

vraa,
You could have a turbocharger running on another fuel source altogether, although not practical. And yes, turbocharging is recycling exhaust energy (heat and pressure) to compress air into the engine. Turbochargers are very much like turbine engines. Wrapping the hot side of a turbocharger along with the exhaust piping feeding the turbo not only protects other components from the heat but also increases the efficiency (heat is energy). The heat and velocity involved with a turbocharger are responsible for the higher costs of components. Most metals rapidly weaken with the elevated temperatures involved therefore turbocharger turbine blades are made of the same or similar alloys used in jet engines (stainless steel and crome alloys). Hope this helps your understanding of turbochargers.

rlh006

Deciding which is better is a difficult proposition. It all depends on what your goals are. Making such a blanket statement is foolish. How many dragsters do you see with turbochargers? Same is true for your last comment.

E55AMG99
i was just going to make a simple statement. also ther are alot of dragsters running turbos. they even used them in indy. also have you ever driven either one? maybe but i bet you havent driven both. i have i know the pros and cons of both. to tell you the truth im not knocking superchargers but i dont think ill never pick a supercharger again unless i have a honda civic that power doesnt kick in until 5500 rpm. any properly tuned will give you great increases of power. since mercedes have v-blocks the thing to do would be put twin-turbos on it for almost NO LAG. and get outstanding performance out of it. and also have you ever heard the air going through the turbo? sounds almost as amazing as when the blow-off valve opens and lets off a big scream letting everyone know not to mess with you!

Steve Clark

stop and realize that what counts is the total engine package,and
simply whether or not it does what you want it to.
Turbocharger or supercharger?.Depends on how well you do it...
Done right=broad powerband,huge grins and fun.
Done wrong= fussy,unfriendly and probably short-lived.
Quit worrying about forced-induction flavors and just go have fun.

Usually he who makes the most power also has the deepest pockets.

E55AMG99

RLH, I've driven dozens of engines with turbos, supercharges, N2O and combinations thereof in anything from one cylinder to 16. I've even built several. In my experience, you cannot make simple statements about "forced induction" engines. A properly tuned (pick from list) will result in a great performing engine. My comments about the benefits of superchargers explain why MB chose them instead of turbos for their "55" motor. The latter would require more cost and engineering for things like custom plumbing and intercooler fitment. As far as lag is concerned, in order to reduce (remove) it to the point of their supercharger setup, it would require 2 small turbos. My guess is that it would add 4-5X the cost of the supercharger mods and top end could still suffer. They could have used 2 stagered turbos like the Porsche 959 but that would probably add 10x the cost and complexity.

The last motor I modified was the 6.0 Liter GM engine in my Denali. There were few choices for turbo but many choices for superchargers. Why is that? The reasons are in my first post but I'll give you a hint. It has to do with HP/$. Prior to that, I built a 620HP 496 cubic inch Chevy with a pair of Garret turbos similar to the setup Gale Banks used on his 600HP 350 cubic inch small blocks back in the 80's. Gale actually helped me design the wastegate system. After running the setup for a year or so in a 6500 pound Suburban 2500, I redesigned the whole thing around a custom B&M roots style blower. Why? Not enough low end power. The turbos were sized to provide peak power at 6500 RPM but could not spin up fast enough. After the change, the motor lost 25HP at its new redline of 6000 RPM but it gained over 100 lbs of torque from 2000 to 3500 RPM. The result on the street was nothing less than scary and almost a half second faster to 60 than the turbo motor. Even though the supercharged motor made less power, it had more power "under the curve" and that is why it was so much faster.

What I'm trying to show is that there is a strong argument for street driven supercharged vehicles.

BTW, there are very FEW dragsters running turbos. Nearly every class that allows pressurized induction, superchargers dominate 99% of the engines. How many AA/Fuel cars run turbos? ZERO.

Indy Cars are a completely different situation. They don't need to accellerate quickly. Since they run wide open at Indy, they only need to make high peak horsepower. On road courses, they were allowed more boost among other things to give them more accelleration. If you have ever driven an Indy Car (I have albeit only up to about 100 MPH) you will immediately realize that they have no low end power at all. Starting off in first gear requires reving the engine to about 9000 RPM (15,000 is redline) and massively slipping the clutch. I think I staled it 5 times before I was able to get out of the pit box.

USAC/IRL rules outlawed turbos and all forms of forced induction about 6 years ago in an effort to control costs but then again, Indy Cars are NOT dragsters, now are they?

Greg

VRAA,
One more thing to think about when comparing exhaust driven superchargers (commonly called turbos) to belt driven is that the ones on the exhaust are turbines (I think Ed Conroy might have said it already) and 99% of the belt driven more are like positive displacement pumps. They can be shaped like lobed paddles or twin screws that mesh together. As they turn, they squees the air into a smaller space to create boost. There was one manufacturer that used a belt driven turbine. It might have been Granatelli or Vortech. I'm not sure.

E55AMG99

aint that the truth!

rlh006

E55AMG99

My guess is that it would add 4-5X the cost of the supercharger mods and top end could still suffer.
top end for turbos will alway exceed superchargers

turbocharging done right cost no more money than superchargers. to prove my point www.4redlinemotorsports.com makes one for a camaro
http://www.4redlinemotorsports.com/a...ochargers.html
585whp 601wtq for $6400.00
http://www.4redlinemotorsports.com/a...rchargers.html
compared to the vortech supercharger they sell 470hp 462tq for $6365.00.
notice the supercharger is not wheel hp so autos can deduct 20% due to drivetrain loss.
one other thing since turbos dont run boost all the time they dont use as much gas. turbocharging takes a little more time developing but when developed right it will always make more power than a supercharger. turbos take longer to spool-up than superchargers but if you think about it, its just helping you because you dont have to worry about spinning out all over the place. it makes no sense putting either one on a 6500lb suburban.

i repeat
it makes no sense putting either one on a 6500lb suburban.

if you plan on running 1/8th miles get a supercharger
if you plan on running 1/4's get a turbo done right.

rlh006

In theory, a turbocharger is more efficient because it is using the "wasted" energy in the exhaust stream for its power supply. This means more overall power from the same amount of boost. Another advantage to turbochargers is the incredible number of units available. This means the size of the turbo can be easily matched to the demands of the engine. This can allow instant boost, and peak levels over thirty pounds of boost.

thats it
no more
E55AMG99

E55AMG99

Zero to 60 in 5.5 seconds. Ask the guys in 911 Turbo's (1988-91 era) that got their butts smacked by my truck and they'll tell you that a supercharger on a Suburban makes PERFECT sense! Ask guys like Al Unser, Bruce Canepa, Danny Sullivan, Andre Agasi, Ryan Falconer, and other racer/builder/go fast guys if it makes sense. They all drove or still drive supercharged suburbans.

You obviously have never driven one before and after. Drive a late model with a Whipple or Magnacharger and come back to me. $5500 installed nets 100 plus peak HP (more at low RPM) and improved gas mileage (if you have self control), street legal and a full waranty through GM. If all that could be done with a turbo, don't you think somebody would have?

You are either missing the point or trying to fool everyone with the peak HP claims. Just because in your example the turbo puts more power to the wheels at its peak does not necessarily mean it will make the car faster than the supercharger will. See my last post for the proof.

FYI - the Vortec unit is a belt driven TURBINE like the exhaust driven turbocharger. Not exactly like a positive displacement supercharger. Also, is the turbo kit street/emissions legal? Doesn't look like it. Again, not exactly a fair comparison. Much of the cost of the Vortec is R&D to make it street legal. I'd like to see the performance and cost numbers after they try to make the turbo street legal.

You comment about turbo lag helping to keep the tires from spinning is laughable. You are joking, right? If you fully believe that and your 1/8 vs. 1/4 mile statement, tell it to Kenny Bernstein. He'll get a good laugh out of that one!

Tell you what- build a few cars and race them competitively. Maybe then you will understand when and why each method of forced induction makes sense.

E55AMG99

Now we are talking theory. Well in theory, a supercharger is more efficient becasue it doesn't heat the intake charge as much as a turbo so it can make more power from the same amount of boost.

When have you ever seen a turbo provide "instant boost" AND peak over 30 pounds?

rlh006

E55AMG99

your kidding me right?
Zero to 60 in 5.5 seconds. Ask the guys in 911 Turbo's (1988-91 era) that got their butts smacked by my truck and they'll tell you that a supercharger on a Suburban makes PERFECT sense!
you dont race a suburban. you race cars or small trucks.

also ive driven both. ive helped build both
like i said before im not knocking either. i just prefer turbo.

Just because in your example the turbo puts more power to the wheels at its peak does not necessarily mean it will make the car faster than the supercharger will.
my 99 eclipse gsx 0-60 in 3.4 can your suburban beat that? probably not. also i bet you dont have any car that could do that.

also turbos get better gas mileage because they are not always under boost unlike superchargers

pros---superchargers get boost as soon as you hit the throttle.
cons---superchargers are limited and cannot make the same hp with the same amount of boost as a turbo

pros---turbo can make more hp per pound of boost.
cons---turbo have spool-up most tuned right takes 1-1.5k in a small powerband to boost. 2-2.5k in a larger powerband.

E55AMG99

Not kidding at all. John Lingenfelter (RIP) built the bottom end and ported the heads for me. I went to Gale Banks first because street superchargers were not available at the time (1984) and I didn't want an 8-71 Jimmy sticking out of my hood! With a massively ported and pressureized Holley 850 I was close to 6.0 seconds to 60. After 40,000 miles and talking to some other engine builders and a couple of insane racers like Al Unser, they were playing with the new "street" superchargers coming on the market. I went to Chatsworth to talk to my friends at B&M and they balanced and blueprinted an oversized version of their roots type street blower for me. Since the motor was in need of rebuild (you don't make 620 HP without increased wear and tear), I went with a Comp Cams 282 instead of the 292 it had before and I topped it off with Holley's new FI unit. The truck was much more drivable in town because of the increased low end boost and HP. I was even able to go back to a 2200 stall TC to help my gas mileage and still crack off the occasional 5.5 second blast to 60. My stock 1989 911 Turbo was no match to 60 until I dropped another $6K in the motor. The best it could do stock was about 5.7 and even if the suburban was running poorly, it would still holeshot the 911 EVERY time. Remember, we are talking PRE 1990 here. Performance technology as come a LONG way since then.

No car in my current stable can touch your eclipse but give me a few more months. I'm working on some upgrades (most importantly to the rear tire area) to an '03 E55 that should give it a run for it's money

So, in your last paragraph (pro/con), you contradict your earlier posts. I guess you do understand that there is a place for both.

rlh006

E55AMG99

im glad we found a little bit of a comprimise.

what do you plan on doing to the 03 e55 if you mind me asking?

James F. Cannon

Hey vraa,
Sounds like you are getting an automotive history lesson!! By the way, happy belated birthday!!

E55AMG99

I was just thinking that my '32 Ford Model B Coupe might do it. It hasn't been down the track yet but it weighs about 3000 pounds and puts out 540HP at the crank. I rebuilt the big block motor from the suburban after it went 100,000 miles and stuffed it under the hood. The blower is gone but with 12:1 compresson, throttle response neck snapping! C5 Corvette suspension, rear end and a 4L80E 4 speed automatic round out the package. I can't wait to get that beast out this summer! I think it still needs the 200HP N2O system but I'm just too freeking busy (OK lazy) these days. It sure would help!


I've been listening to the guys here about poor traction and narrow tires on the E55 for about a year and studying the car physically only for a few days. My friends in the tire biz think that with a custom rim, some minor suspension mods and fender rolling they can get a 305 out back. If the suspension mods don't work, they still think they can squeeze a 295. That is a huge improvement over the stock 265. Another guy is working on some mods to the electronic part of the suspension to transfer more weight to the rear. Again, he thinks it's possible but not yet developed. Other areas I'll be addressing are a lower ratio LSD rear end, intake cleanup, less restrictive exhaust (race cats), reprogrammed ECU and pulleys. Guys like stephens are already getting 100HP without any exhaust mods. If the planets are in alignment, this could be a low to mid 11 second 4100 pound 4 door, five passenger luxury car.

vraa

James: Thank you so much! I love debates because it always brings out ten fold more information!

I think I might have to do an exclusive section on my project all about your Suburban and Model B and E55 Greg!

rlh006: I will also try to get my partner to add your speed demon into the site also under the Japanese Cars part!

Don't spread this link around please.

http://vraa.gotdns.com/mainproject/t...al/default.htm

That's the site so far, I work on the main page and exhibits and the German car part, my partner works on the Japanese cars part.