Difference between a SuperCharger and a Turbo???

[Vegeta]

This might sound like a newb question but i really don't know and want to get a little more educated. I know it isn't specifically a celica question but I want to know what the difference is between a supercharger and a turbo charger if any and what are the pros and cons of each..

Thanks
Vegeta

[Keyshawn]

Check it out: http://www.howstuffworks.com/question122.htm

[Da Kine Guy]

You should probably post this in the forced induction forum. Both turbos and s/c's fall under that category. They both shoot more air into the cylinder to achieve more compression I believe.

[ND4SPD]

so wouldn't a turbo charger be more efficient then? i would think that you would lose hp with a super charger because it derives it's power straight from the engine whereas the turbo gets the power from a turbine in the exhaust stream.

[MarkyMark]

turbo's "die" and have to be replaced...I dont think s/c's do

[ND4SPD]

how and why do turbo's die?

[BoyRacer]

Well they dont necessarily die. they need to be rebuilt. they can get oil leaks,water leaks, the turbine can get messed up(which can mess up the housing). id imagine carbon buildup would be an issue when it comes to performance as well..............

[BoyRacer]

Oh and the turbo is more efficient because unless you are getting on it they arent really being used a whole lot, and dont use alot of energy. unlike the S/c which you can never turn off. so its always beging used. benefits of the s/c is there is no lag or spool up time.

[Pitlab77]

Originally posted by BoyRacer
Oh and the turbo is more efficient because unless you are getting on it they arent really being used a whole lot, and dont use alot of energy. unlike the S/c which you can never turn off. so its always beging used. benefits of the s/c is there is no lag or spool up time.

lag is overrated. there really is no "lag" lag like people think it is.

[BoyRacer]

i am just say becuase its the term people are originated with. basically the spool up time.

[GTS LAID]

with a large turbo on a car like the celica which has very little exhaust volume, you'd have plenty of lag... which is why they opt for smaller turbo installations in our cars (the ones who've done it at least)

[BoyRacer]

my sentiments exactly! i wrote that then erased it. lol weird.

[Tien's 00celica]

S/C is more for torque at low end revs where as a turbo will help out at higher speeds.
hope that helps:)

[Oo DaRk StAr oO]

Turbochargers are better because they use energy that is wasted by the car. The supercharger requires energy to run. The thing about a Supercharger is you feel it right away whereas a turbo you feel after 3000rpm. Ive rode in a Supercharged Civic and I had a turbo Civic and my turbo was way better. Slower off the line but caught up and burnt it with the beautiful sound of PSSSHTTT!!!

[My2ktoy]

[QUOTE]Originally posted by Tien's 00celica
S/C is more for torque at low end revs where as a turbo will help out at higher speeds.
hope that helps:) [/QUOTE

actually that depends on the type of supercharger. your standard roots-type blower pumps out a fixed amount of air per rpm, regardless of how high or low the rpm is. the centrifugal supercharger is designed like a turbo, except its turned by the belt instead of the exhaust. the centrifugal design compresses more air per rpm at high revs than at low. so you get a large amount of high-end horsepower, but not as much low end torque. so a centrifugal supercharger would have the same high-end power as a turbo. and you don't have to wait for 3000 rpm.
go to http://www.eaton.com/supercharger/M45.html for a roots-type blower and http://www.powerdyne.com/new/pcs.htm for a centrifugal.

[greg]

So about how long is the "lag", or spool up time, on the turbos being made for the celica?

[BoyRacer]

hmm with a t-28 which is a smaller turbo. id say 2800-3000 rpm. essentially there is no lag. regular driving you take your foot off the the clutch from nuetral to first betweeen 1500-2000 rpm's (most drivers).......so assume 1k rpms from there is nothing till you are boosted. so its really the perfect size for the car.....

[Vegeta]

I appreciate all the help guys this has been very informative :)... but another question... which is easier to up your PSI a turbo or a SC or are they the same.. Also if a car came with a SC stock.. then would you have to do any mods to up the PSI or would you just have to get a boost controler?? i'm not even sure how those things work.. i'm kinda new to the turbo/SC world and am just trying to figure it out... thanks again guys you have been more then helpfull :)

[My2ktoy]

turbo is easier to up the PSI, you set the amount of boost you want on your boost controller. with a turbo, you have to change the size of the pulley on the supercharger. smaller pulley = more rpm = more boost. supercharger is probably easier to install (easy meaning 8 to 10 hours), since you don't have to change the exhaust manifold, or connect oil to it since most s/c are sealed. with a stock supercharger, just using a smaller pulley will up your boost.

[celicauk]

How much of the above is wrong? Most of it.

1 - SC is more efficient than a turbo. Reason, well there are a few I know of. SC runs colder so the air output doesn't require quite as much cooling. SC actually compresses air(unless its centrifugal), a turbo merely accelerates the air flow via a turbine. An SCs output power is measured differently to that of a turbo, in reality the output from an SC should be 1.5 to 2 times greater than that of a turbo, so if you run both units at 6 psi, the SC could be equivalent to turbo output of up to 12 psi. This is a generalisation as some units are not that good.

2 - An SC is easier to fit. There is no manifold to construct, no big heat problems to concern yourself with. Usually, and especially on our cars, the routing of pipework is simplified by the intake being on the front of the engine, its always a good idea to keep all pipework lengths to a minimum, and the run to the FIC and back to the throttle intake should also be as straight as possible, try that with a turbo on our cars, difficult isn't it Matt/Dave ? Of course it can be difficult to find a decent mounting point for the SC which requires a direct drive from one of the main belts or pulleys.

3 - Changing the output power on an SC is easier as all you need to do is change the pulley diameter. The only restriction will be the maximum rotational speed of the compressor rotors, spin them too fast and they will break up, and they go very very fast. If you fit a bigger turbo you will incur higher heat problems and possible mismatch between manifold and exhaust mounting points.

4 - An SC can be underrun to allow power to be constant to the top end of the rev range. And in case this all seems a little biased, an SC will present a direct load to the engine, you don't get the power for nothing, these are usually called parasitic losses and get greater as the output pressure increases (ie engine revs go up), eventually you reach a point where the output of the SC is eroded by its own load on the engine. This is when you fit a turbo on the back to take over and have some real fun!

I am biased towards SC as it is kinder to the engine, easier to fit, cheaper to maintain and I am getting one :)

I am sure someone will argue the toss on a minor or trivial point (oldster :rolleyes:).

[My2ktoy]

Originally posted by celicauk
How much of the above is wrong? Most of it.

1 - SC is more efficient than a turbo. Reason, well there are a few I know of. SC runs colder so the air output doesn't require
quite as much cooling.

shouldn't the heat generated be around the same? the heat is generated by the compression of the air, which will happen regardless of s/c or t/c. which is why both use intercoolers.

SC actually compresses air(unless its centrifugal), a turbo merely accelerates the air flow via a turbine.


actually i'm pretty sure thats backwards. thats why a roots-type s/c is called a blower, because it blows the air, it doesn't compress it. the actual compression occurs simply because of the increased amounts of air. the design of the turbine in a t/c or centrifugal s/c actually compresses the air as it is forced to the edges of the turbine. which is why a turbo generates more boost/rpm at high revs than at low.


An SCs output power is measured differently to that of a turbo, in reality the output from an SC should be 1.5 to 2 times greater than that of a turbo, so if you run both units at 6 psi, the SC could be equivalent to turbo output of up to 12 psi. This is a generalisation as some units are not that good.


hmm...never heard about this. why would the same amount of psi give you different amounts of power? i mean, once its past the throttle body i don't think the engine would know the difference. (besides temperature)


2 - An SC is easier to fit. There is no manifold to construct, no big heat problems to concern yourself with. Usually, and especially on our cars, the routing of pipework is simplified by the intake being on the front of the engine, its always a good idea to keep all pipework lengths to a minimum, and the run to the FIC and back to the throttle intake should also be as straight as possible, try that with a turbo on our cars, difficult isn't it Matt/Dave ? Of course it can be difficult to find a decent mounting point for the SC which requires a direct drive from one of the main belts or pulleys.


i definitely agree here. luckily there's a nice spot in front just waiting for one.


3 - Changing the output power on an SC is easier as all you need to do is change the pulley diameter. The only restriction will be the maximum rotational speed of the compressor rotors, spin them too fast and they will break up, and they go very very fast. If you fit a bigger turbo you will incur higher heat problems and possible mismatch between manifold and exhaust mounting points.


true, but for simply adjusting the amount of boost you want, a turbo is easier (up to the max boost of the turbo)


4 - An SC can be underrun to allow power to be constant to the top end of the rev range. And in case this all seems a little biased, an SC will present a direct load to the engine, you don't get the power for nothing, these are usually called parasitic losses and get greater as the output pressure increases (ie engine revs go up), eventually you reach a point where the output of the SC is eroded by its own load on the engine. This is when you fit a turbo on the back to take over and have some real fun!

I am biased towards SC as it is kinder to the engine, easier to fit, cheaper to maintain and I am getting one :)

kinder? it is running all the time, even if its not always boosting. (hmm, is that the proper term? lol) and you forgot to mention its completely sealed, no outside oil necessary. ;)



I am sure someone will argue the toss on a minor or trivial point (oldster :rolleyes:).

naw...i'd never do that. actually, i agree with you. i'd personally prefer a supercharger, but since there isn't one available for the GT in the near future, i'm going turbo.

[BigJuiceGTS]

SC actually compresses air(unless its centrifugal), a turbo merely accelerates the air flow via a turbine. An SCs output power is measured differently to that of a turbo, in reality the output from an SC should be 1.5 to 2 times greater than that of a turbo, so if you run both units at 6 psi, the SC could be equivalent to turbo output of up to 12 psi. This is a generalisation as some units are not that good.
Actually Both Superchargers and Turbos Compress Air, hence them both being measured in "PSI". And in the "REAL" reality the output from a turbo, on average, is greater than the output from a Supercharger, given they are both running the same "PSI".

[2000 XYR]

Superchargers are good. :D ;)

I've owned 2 supercharged vehicles. The other was a '88 MR2 SC. (which by the way violates the note above that said that the SC is running all the time. In the MR2 it did not. It engaged when needed and disengaged when it wasn't. Kinda cool. Also, it's the only one that know of that does that. The Eaton in my truck runs all the time. But it is also completely sealed (as was mentioned above). In my MR2 I had to check the oil occasionally (a pain in the @SS BTW) and add SC oil as needed.)

But all in all I still think I prefer Supercharged over turbo. But maybe that's just me. I've got no top end power but I can toast you off the line. :D :)

[oldster]

Originally posted by celicauk
I am sure someone will argue the toss on a minor or trivial point (oldster :rolleyes:).

See, I didn't have to say a word, although minor & trivial are very subjective terms. :chuckles:

[celicauk]

The heat generated by a urbo or sc is not the same. The turbo works by using the exhaust gases to turn the turbine, those gases are damn hot, I have seen a trubo and manifold glow from the heat, nice cherry red, and sometimes they get so hot you can see the vanes, however, I have neither seen nor heard of an SC getting that hot.

This is where the efficiency thing comes in, as the air from a turbo is nice and hot, it doesn't burn as efficiently (not as oxygen rich I think), whereas the SC runs cooler, gives out much colder air and therefore the burn is more efficient. I don't think its the SC or FI thats more efficient, I think its the air passed in to the engine that burns better due to be colder on an SC. Therefore, to get the same amount of oxygen into the engine from a turbo as with an SC, it stands to reason that the turbo is going to have to put out a lot more air, to do this it has to run faster and therefore the pressure goes up. So in efficiency terms the SC should require a lot less PSI than a turbo to acheive the same power increase.

I may have generalised on the SC being a compressor, but I think I am fairly right on that one.

As for it being totally sealed, I am going to have to disagree here. That is definitely down to the type. For example, the SC I am using (Rotrex 3084) has an integral oil pump which is connected to either the engine oil system or to its own oil cooler system. In my case I will be using a seperate cooling system with its own tank and inter cooler, I think it runs on ATF fluid too. I don't think theres much difference here as my friends turbo bug has an oil feed for cooling as well as an optional water feed, that uses a Turbonetics T3 btw.

I believe its kinder on the engine because the power is gradual from low revs right through the range, unlike a turbo where the power comes in a big rush at around 2/3k. Its the sudden bursts of power that are doing damage to the engine and transmission, once its up and running its ok, but that initial hit of power can't be a good thing, except for being great fun that is :)

[dfess1]

If turbos are so good (in terms of power output), why do you always see that big thing poking up under the hood of Top Fuel Funny cars and Dragsters??? Simply curious...

[celicauk]

Read everything I posted above and you'll get a good idea.

Superchargers RULE!!!!!! :D

[Arghman]

I don't know why VTEC and VVTL-i owners are so worried about turbo lag when they have to wait til 5 or 6K RPM for their powerband...

[dfess1]

Originally posted by Arghman
I don't know why VTEC and VVTL-i owners are so worried about turbo lag when they have to wait til 5 or 6K RPM for their powerband...

Good point.

Originally posted by celicauk
Read everything I posted above and you'll get a good idea.

That was sarcasm. However, I would disagree with you on the heat issue. The s/c suffer from heat soak as much as the turbo's do. Perhaps not glowing red, but they still benefit emensly from an aftercooler, or water injection system.

[celicauk]

Thanks for pointing that out ;)

Interesting on the heat thing though, I think I will get an air temp meter and measure the air flow from the SC once its up and running.

[oldster]

Originally posted by celicauk
Interesting on the heat thing though, I think I will get an air temp meter and measure the air flow from the SC once its up and running.

Your car should be up and running soon, not? Don't forget the pictures. :)

[celicauk]

Should be, the SC finally arrived at the shop, slightly damaged in transit, the oil cooler got squished :rolleyes: no biggy though as its nothing special.

The shop have promised me they will get it in the car on Tuesday and Wednesday so hopefully by next weekend I'll be ready to run in.

I'll be going over to get some pics of the SC before they start though so I'll post them up so you guys can flame me for taking pics of things on a bench :D

[BigJuiceGTS]

If turbos are so good (in terms of power output), why do you always see that big thing poking up under the hood of Top Fuel Funny cars and Dragsters??? Simply curious...
More than likely this has to do with power delivery...it is also much easier/cheaper to mate a supercharger to a "V" engine's intake than it is to design a twin turbo or single turbo setup for it.

Also, I'm not trying to hate on superchargers...in fact if this Blitz kit is priced reasonable (~$4500), I'll be one of the first in line to pick one up.

[dfess1]

Originally posted by BigJuiceGTS

More than likely this has to do with power delivery...it is also much easier/cheaper to mate a supercharger to a "V" engine's intake than it is to design a twin turbo or single turbo setup for it.

Also, I'm not trying to hate on superchargers...in fact if this Blitz kit is priced reasonable (~$4500), I'll be one of the first in line to pick one up.

Ok, again, it was sarcasm. But more importantly, these professional race teams have enough money to do what they need to do to get the power. In fact, they have too much power in these cars. It all comes down to traction and how agressive the clutch setup is. So if it were more advantagous for the t/c, don't you think you'd see them on these setups?