# Parasitic losses of supercharger vs. turbocharger...



## jasonyates (Nov 23, 2000)

Ok, so the crank pulley having to turn a supercharger takes away some power, and the exhaust having to turn a turbocharger also uses some power. I am inclined to think that more power is robbed by a supercharger, but I am just curious if anyone has done any comparisons or anything??


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## JettaRed (Aug 14, 2000)

*Re: Parasitic losses of supercharger vs. turbocharger... (jasonyates)*

You are correct. This chart shows the amount of hp required to build 5 or 10 psi at a certain charger rpm. Depending on your crank and charger pullies sizes, the charger spins about twice as fast as your motor.


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## 2DoorFury (Jun 23, 2002)

*Re: Parasitic losses of supercharger vs. turbocharger... (JettaRed)*

Is that a roots or centerfugial(sp) charger on that chart?


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## JettaRed (Aug 14, 2000)

*Re: Parasitic losses of supercharger vs. turbocharger... (2DoorFury)*

Roots. It's from the Eaton site.


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## mrkrad (Nov 9, 2000)

*Re: Parasitic losses of supercharger vs. turbocharger... (JettaRed)*

along time ago we talked about this subject (pre current forums).
on a g60 at nominal boost levels,
the g60 robbed 18ft/lbs of torque
the lysholm like 38ft/lbs
and eaton nearly 60ft/lbs for the same amount of cfm/boost.

Abiaditc efficiencies can easily get shot in the wind with parasitic loss.
Centrifugals are massive torque-eaters too.
Probably why my turbo pegged 239/ftlbs of torque at 200whp, and most blown cars see a more even spread (like 200/200) because of the parasitic losses. 
Also your rod bearings take a severe punishment based on the blower type too. Especially ones not setup correctly that constantly place drag on the crank even when idling.. This is a problem that affects most crank driven cars, the rod bearings need a 60-80K interval service before the rod bearing rattle comes to play..


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## VW97Jetta (Sep 5, 2002)

*Re: Parasitic losses of supercharger vs. turbocharger... (mrkrad)*

quote:[HR][/HR]Also your rod bearings take a severe punishment based on the blower type too. Especially ones not setup correctly that constantly place drag on the crank even when idling.. This is a problem that affects most crank driven cars, the rod bearings need a 60-80K interval service before the rod bearing rattle comes to play..[HR][/HR]​Interesting.......never knew that....wonder how the new VF charger will shape up...


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## 84turboGTI (Sep 26, 2002)

*Re: Parasitic losses of supercharger vs. turbocharger... (jasonyates)*

The theory on a turbo, as explained to me a long time ago. It is simply using energy from your exhaust gases that would normally be wasted, to turn the turbo, rather than using power from the engine to create boost, therefore making it more efficient and popular. This is very basic, there is more to it I think, but it gives the idea.


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## mrkrad (Nov 9, 2000)

*Re: Parasitic losses of supercharger vs. turbocharger... (dazed&confused)*

if you think about it a charger can eat up like 4-6 a/c units worth of drag, the motor wasn't balanced or designed for that, displacing all that drag has to take its toll on something.. Then again, car manufacturers really don't care if your rod bearings go after the warranty, they would love for that to happen, so your motor self destructs and you get a new motor







I'm sure some of the stock blown motors (ford svt) have been beefed up to slow this action, but other than us, nobody cares if a car lasts more than 5 years or whatever mileage. The whole auto industry would collapse if everyone drove their cars for 10 years. 
Every thing you do to your motor has a good/bad side affect. Most tuners haven't spent millions of dollars to research the long term benefits of their mods, nor do they care. Hell most kits aren't even CARB approved cause it costs so much money to get it done. 
No biggie, rod bearings aren't hard to replace (on an 8v).
If you look at the vr6 motors of 10 years ago , you'll see a ton of long term health issues , vw has probably worked to improve on them, but i'm sure as the older mk3's get into their age, the flaws will come up as well (head gaskets, water pumps, timing chains/guides). vw doesn't care as long as it doesn't kill their passengers


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## lugnuts (Jul 26, 2001)

*Re: Parasitic losses of supercharger vs. turbocharger... (mrkrad)*

a real world comparison....
9A motor, 10.8-1 c/r, Procharger, front mount intercooler, 20 psi, CAM2 fuel.
256 whp, 218 wtq
same motor, 9.2-1 c/r, TO4B/.63/stage 3, same IC, 20 psi, 93 octane pump fuel.
340 whp, 318 wtq
more hp and tq than the blower starting at 3400 rpm 
to be honest, mid range boost was the main reason the turbo killed the sc so bad, but the peaks dont lie.


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## 2DoorFury (Jun 23, 2002)

*Re: Parasitic losses of supercharger vs. turbocharger... (lugnuts)*

Centrifugals are massive torque-eaters too.

I hardly know anything about this. Could you explain what robs more torque and/or power, the centrifugals or eatons?


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## evoeone (Feb 27, 2002)

*Re: Parasitic losses of supercharger vs. turbocharger... (jasonyates)*

quote:[HR][/HR]Ok, so the crank pulley having to turn a supercharger takes away some power, and the exhaust having to turn a turbocharger also uses some power. I am inclined to think that more power is robbed by a supercharger, but I am just curious if anyone has done any comparisons or anything??[HR][/HR]​how does the turbo take power to use? dont understand what youre saying.... the way i see it is that the gas is going out of the car, turbo'ed or not so it just spins the fan thus not taking any power to use... how is that using power or requiring power? inn other words, how is that considered using power?


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## bogard (Nov 8, 2002)

*Re: Parasitic losses of supercharger vs. turbocharger... (evoeone)*

a turbo does not have parasitic losses like superchargers do because of the fact that they are run on exhaust gasses that would otherwise be useless.


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## evoeone (Feb 27, 2002)

*Re: Parasitic losses of supercharger vs. turbocharger... (bogard)*

quote:[HR][/HR]a turbo does not have parasitic losses like superchargers do because of the fact that they are run on exhaust gasses that would otherwise be useless.[HR][/HR]​thats what i thought


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## Dubweiser 2.0 (Sep 27, 2002)

*Re: Parasitic losses of supercharger vs. turbocharger... (bogard)*

No this is not true Turbos DO have parassitic loss. It is almost insignificant when compared to a Super charger especialy a roots based but think about it. What is one of the first mods for power u do?? Exhust right? this is because the easier the gas clears the engine the more power you get (to a point but Im not gonna talk about when u start losing TQ for very little hp) SO if you put a turbine in the path that slows it down (lag) so it "cramps" your engine until it spools. Read "Maximum Boost" good explenation in there and it will teach you soooo much about turbos.
-Jake


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## redfox435cat (Jan 14, 2003)

*Re: Parasitic losses of supercharger vs. turbocharger... (bogard)*

The parasitic lose comes from the backpressure created by pushing the turbine. Taking away power the same way a tuned exhaust adds to your power. The lose is not as great as a sc. The only real down side of the turbo is the lag while a sc creates boost right away.


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## RobBlev1 (Jan 22, 2003)

*Re: Parasitic losses of supercharger vs. turbocharger... (redfox435cat)*

quote:[HR][/HR]The parasitic lose comes from the backpressure created by pushing the turbine. Taking away power the same way a tuned exhaust adds to your power. The lose is not as great as a sc. The only real down side of the turbo is the lag while a sc creates boost right away.[HR][/HR]​I must very much disagree with you, centrifugal S/C,s (not roots type) DO NOT make boost right away, in fact turbo's when properly sized will spool much faster than a Paxton, Vortech, ZF, or Procharger type S/C. Look at the Dyno sheet of a VR6 w/S/C and you will see the peak hp at the very end (more crank speed, more S/C speed, thus more HP) and a very late and low torque curve. Turbo comes on much faster thus torque usually much higher.


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## leebro61 (Nov 7, 2001)

*Re: Parasitic losses of supercharger vs. turbocharger... (RobBlev1)*

We finally agree on something http://****************.com/smile/emthup.gif 
I was under the impression (but not completely sure) that the parasitic loss from a charger resulted in the relatively low tq numbers. It seems most turbo vr6s make the same if not more wtq while Sc'd vr6s make quite a bit more hp than torque.


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## RobBlev1 (Jan 22, 2003)

*Re: Parasitic losses of supercharger vs. turbocharger... (leebro61)*

The loss of HP and TQ is great with S/C vs. Turbo but it is the slow response of centrifugal S/C that ultimatly kills the gains of such a FI system vs. Turbo.


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## Marty (Jul 14, 2000)

*Re: Parasitic losses of supercharger vs. turbocharger... (RobBlev1)*

The SC system makes plenty of power. It just lacks the meaty torque down low. When racing you're only using the torque in the upper RPM range (decent horsepower is an indication of high RPM torque). This is why a 200 hp Honda with 110 ftlbs of torque will whoop on a stock VR6. The down-low torque is tons of fun though...


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## RobBlev1 (Jan 22, 2003)

*Re: Parasitic losses of supercharger vs. turbocharger... (Marty)*

quote:[HR][/HR]The SC system makes plenty of power. It just lacks the meaty torque down low. When racing you're only using the torque in the upper RPM range (decent horsepower is an indication of high RPM torque). This is why a 200 hp Honda with 110 ftlbs of torque will whoop on a stock VR6. The down-low torque is tons of fun though...[HR][/HR]​Sorry to be contrary but *200* or so whp for a $4k S/C kit vs. *350* or so whp for a $5k turbo kit? Do the math and I do not think that S/C makes plenty of anything other than noise!


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## leebro61 (Nov 7, 2001)

*Re: Parasitic losses of supercharger vs. turbocharger... (RobBlev1)*

Allright, now I think your an idiot again. Who said 200whp, try more like 270whp


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## RobBlev1 (Jan 22, 2003)

*Re: Parasitic losses of supercharger vs. turbocharger... (leebro61)*

quote:[HR][/HR]Allright, now I think your an idiot again. Who said 200whp, try more like 270whp







[HR][/HR]​How about dropping the name calling...
As for 270whp? I thought the off the shelf AMS kit is good for only 200-220 whp? What kit for $4k adds 120 more whp?


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## leebro61 (Nov 7, 2001)

*Re: Parasitic losses of supercharger vs. turbocharger... (RobBlev1)*

Sorry, I guess I just didnt like you telling me and many other texers that we wasted 4k plus dollars. 
I will come out and admit that at the same boost levels, turbos will always make more power/torque.
As for the AMS/Eurotech kits, they normally dyno around 240ish-250ish whp, and Ive saw a stock Eurotech kit that made 255whp on a 98 vr6.
The 270whp was achieved from a Eurotech kit, 310cc injectors and a custom ATP chip. This was on 91 octane at ATP. This is currently the same setup that I am running, and it pulls pretty hard.
And as for saying Marty doesnt know his stuff about blowers, not a good idea















http://mbmsoft.com/ed/dyno.jpg


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## 2DoorFury (Jun 23, 2002)

*Re: Parasitic losses of supercharger vs. turbocharger... (leebro61)*

Can someone please explain the science behind why a centrifugal charge doesn't make the torque down low like a lyshom charger.


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## RobBlev1 (Jan 22, 2003)

*Re: Parasitic losses of supercharger vs. turbocharger... (2DoorFury)*

Read my earlier post on this thread...
To sum up, Vortech type blower is like a belt driven turbo, using the same type of compressor design. However unlike turbo which can spool up regardless of rpm (since it relies on increased exhaust gas generated by the engine) S/C is RPM dependant thus requiring higher engine speed to increase boost. The slower you build boost, thus hp, the lower the torque.


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## 2.0LGtiPwr (Mar 23, 2002)

*Re: Parasitic losses of supercharger vs. turbocharger... (JettaRed)*

Along with getting a smaller pulley, would it be possible to skip over some of the stuff the belt runs over? Like the A/C etc.....?







I don't think that was too clear^. probably because I don't know how many things the belt runs over to drive a charger, like a cetrifugal. In other words, if a centrifugal charger needs RPM to build power and parasitic loss comes from the engine having to spin the belt of the charger to make that power then wouldn't the belt be more uninhibited to spin if it had less of a congested path. For example, if the belt could be spun strait from the cam gear ( direct path)?????

[Modified by 2.0LGtiPwr, 6:06 AM 2-27-2003]


[Modified by 2.0LGtiPwr, 6:08 AM 2-27-2003]


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## RobBlev1 (Jan 22, 2003)

*Re: Parasitic losses of supercharger vs. turbocharger... (2.0LGtiPwr)*

quote:[HR][/HR]Along with getting a smaller pulley, would it be possible to skip over some of the stuff the belt runs over? Like the A/C etc.....?







I don't think that was too clear^. probably because I don't know how many things the belt runs over to drive a charger, like a cetrifugal. In other words, if a centrifugal charger needs RPM to build power and parasitic loss comes from the engine having to spin the belt of the charger to make that power then wouldn't it be freer to spin if it had less of a congested path. For example, if the belt could be spun strait from the cam gear ( direct path)?????[HR][/HR]​Only changing the drive ratio would change the rate at which the S/C will respond. (smaller pulley, more S/C rpm vs. engine rpm) Reducing parasitic drag like a/c etc will not effect the ratio. Only two pulley's matter regarding ratio: Crank & S/C


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## 2DoorFury (Jun 23, 2002)

*Re: Parasitic losses of supercharger vs. turbocharger... (RobBlev1)*

the g60 robbed 18ft/lbs of torque
the lysholm like 38ft/lbs
and eaton nearly 60ft/lbs for the same amount of cfm/boost.
This is what I was talking about, how come the chargers rob different amounts of power? They are all belt driven and I would think since we are saying how much they rob it should be around the same amount of boost. Does it have to do with the weight of the rotors inside the charger?


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