Turbochargers vs Superchargers

[oilpan49]

I wasn't sure if I were to post this here or in the Racing Engines forum but here goes.

I'm just posting this to try and learn something. I was watching something on the Travel channel last night and they were doing an episode about the Early to mid 80's Buick Grand Nationals. This made me think about the differences between superchargers and turbochargers. About the only differences I know between the 2 are is Superchargers force air down the intake thus providing muchas more HP and torque. As far as there HP and Torque gains are concerned they usually range between 60-100 HP am I right??

turbochargers connect with the exhaust and they seem to lag and provide about 50-70 extra horses and seem to be more reliable than superchargers.

Like I said this is what I know, am I wrong on some things, yea probably. I'm just looking for honest facts between the 2 chargers and some pros and cons. Please no flamming or bashing

Thanks,,,,,AR

 

[SteveD2]

They both create extra HP by forcing air down the intake. The supercharger gets its power from the drive belt, a turbocharger gets its power from the exhaust stream. Turbos create more HP with the same amount of boost, because they are less of a parasitic loss on the engine. If it's done right, there shouldn't be much of a lag problem with a turbo. Turbos and superchargers generally create about 30-50% more HP.

 

[jhnrckr]

Both super chargers and turbo chargers are designed to force air into the cumbustion chamber allowing the addition of more fuel which equals more hp. They both have their pros and cons. Superchargers are basically an air pump that runs off of your motor, just like your power steering pump or alternator. The draw back is that it takes some hp to run the supercharger in order to make hp. You can easily double baseline hp with a supercharger and you can increase boost by changing pulley size.


Turbo chargers are turbines that are spun off of exhaust gases and do not run off of the motor like a supercharger so they do not rob hp as much as a supercharger but they do require a somewhat restrictive exhaust manifold. The turbo charger needs to spin up and the more engine RPM you give it the more boost you get, this is where the turbo lag comes in. The wifes Volvo is turboed and you don't really feel it until 2500 RPM and then it comes alive and hauls all the way to red line.


They both require lower compression ratios, less timing advance and high octane fuels. I am a fan of building a motor for hp, less complication and much easier to tune. Factory turbo and supercharging is reliable but it is pretty tame and usually doesn't add huge hp numbers.

 

[JohnBrowning]

It is cheaper and easier for an OEM to control a supercharger. Superchargers are more idiot proof then a turbocharger. Most modern superchargers have their own self contained oil supply and are not affected by poor maintence and extended oil change intervals with cheap 5w30 conventional oil! A properly designed turbocharger system can all but elimanate lag. You have twin segential setups, variable venturi setups and some new electrical driven setups that keep it spooled up. Any combination of the above will elimanate most any lag issues. The problem is that most engines runing a turbo are very small displacment engines and most people mistake the engines peaky power band for turbo lag. The spooling of the turbo is dependent on EGT more then anything else. THe hoter you get it the more power it makes. Intercoolers are reqiured on all serious applications.

Oh you can also play all kinds of throtle plate and came passing games in relation to the turbo chargers output. It is also in vogue now to put a shot of NO2 into the exhaust gas's to get a quick spool up!

Turbochagers are much more effecient and can produce more power but cost and complexity is greater as well!

 

[cryptokid]

to say that turbos or supers generally put out 30-50% more power isnt really valid. the numbers can be pretty astronomical.

i have seen turbo front wheel drive honda civics with over 800 horsepower and still be (barely) streetable. thats quite a bit more than 30-50% and is admittedly not the utual turbo setup.

iirc, the blowers on top fuel cars add many thousand horses.

theres turbo kits designed for miatas which DOUBLE the power and are designed to be on a daily driver car that maintains a high degree of reliability.

so it really comes down to what you want to do. from my stile of driving, i like a turbo better than a super for the high rpm power and efficent low rpm fuel economy. my dad likes superchargers low end grunt. my buddy jeff is a nitrous guy!whatever floas youre boat i guess.

 

[ChrisW]

quote:

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Originally posted by jhnrckr:


They both require lower compression ratios, less timing advance and high octane fuels.

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I respectfully disagree with this statement. With proper tuning (and fuel, 100 octane which is the highest non-leaded yu can get; this is assuming streetability), you can boost high, and keep the compression up. Lowering the compression makes it easier to add more boost, but bumping the compression is one of the best ways to add power, imo. The higher octane fuel is there so it doesn't pre-detonate when you turn up the boost or raise the compression.

This is of course talking about gasoline fueled cars, diesel is slighty different.

Edit: I also want to add, with proper engine internals too, like a forged crank, rod, and pistons, and a sleeved block, ARP studs and bolts, the works.

 

[Virtuoso]

In the words of Carroll Shelby - "If you've got turbo lag, you ain't driving it right!"

 

[1 FMF]

I have an 02 Camaro SS, had a 1999 before that, and have been pondering the forced induction idea since day 1. Everything said thus far is pretty much correct I think, even the arguments. Either way has it's advantages and disadvantages.

My .02, from reading everyone in the LS1 communities experiences, is neither one is more or less reliable than the other.
From a lube standpoint, the disadvantage of a turbo is motor oil must be routed from the motor under pressure to provide good oil flow to the turbo to lube it's bearing. With exhaust gases of 1200-1400F I think for gasoline motors (800-1300 for diesel) passing through the turbo housing it doesn't take a genius to understand the impact it has on the motor oil. Some superchargers (vortech) tap oil from the motor to lube itself, others have their own oil sump, but neither see the heat like a turbo does. In the case of a turbo, because of heat from the exhaust would have a greater need to have an intercooler (to cool intake air going to motor) although that probably depend more on the boost levels (compressing a gas heats it up).

FYI, compression ratios don't necessarily dictate the minimum fuel octane and maximum boost levels to prevent preignition. It's the cylinder pressures seen at piston top dead center. Because of valve timing (intake/exh valve overlap and how long the intake valve stays open on the upward power stroke) cylinder pressures can be all over the place. I've read that the rule is no higher than 200psi cylinder pressure for 93 octane gasoline, and it didn't mention motor operating (coolant) temp. The LS1 chevy (all-alum 346) motor in the Camaros, Firebirds, Corvettes have a 10.1 compression ratio. Cylinder pressures run is the 170psi range I think. Vendors selling supercharger & turbo kits for it claim the stock motor can handle up to 8psi of boost with no worries. The worry actually, is tuning the computer properly to account for boost and preventing a lean mix. Guys that build these motors with forged pistons (can handle heat better) and lower compression claim to run anywhere from 10-14 psi boost pressures on 93 pump gas.
Some good sources of info are the forced induction forums at ls1.com, ls2.com, ls1tech.com and the ATI and vortech websites.

 

[Ryan00TJ]

Both have their advantages @ disadvantages IMO. For a street car driven on the road I prefer a roots style blower that is run off the engines' crank. These blowers make instant torque right off idle and are a blast to drive due to that fact. The downside is that they make alot of heat, take power to spin them and depending on design start to fall off in higher rpms 5500rpms+.

 

[HOndaGuy]

Put it this way, do you want your boost on all the time(supercharger), or do you want the motor to do the low end and feel a good midrange kick(turbo)?

Me personally, Id take either one in a car, but when it comes to a 4 stroke watercraft, it has to be a turbo because I can go wot all the time wheras a car you cant go over 70mph in the u.s.

 

[2003TRD]

I think it is easier and a little cheaper to upgrade a turbo than a supercharger. You can control boost with a cheap 80dollar turbo xs boost controller (limited by fuel mods) so you can fine tune your boost level a little cheaper than buying pulleys that are 5, 6, 7 lbs etc. Also, If you want to change the whole power curve of the car you can replace the whole turbine (anywhere from 500-1500.00) This will give you a little more latitude in power. A small turbine has minimal lag but looses out in the high hp numbers. Switch to a bigger turbine and voila you have a completely different beast( more lag but greater top end)
The most important thing though is the sound of a a turbine spinning up and a blow off valve, ooohh its musical...