Turbo VS Supercharger
04-Feb-2009, 03:29 PM
#1
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Location: Parry Sound
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Turbo VS Supercharger
Which would you prefer? Pro and Cons? Cost difference?
From what i understand, Turbo's have lag and SC are a little quicker. Though, with a Turbo, much more power can be achieved.
From what i understand, Turbo's have lag and SC are a little quicker. Though, with a Turbo, much more power can be achieved.
04-Feb-2009, 04:17 PM
#2
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Join Date: Jan 2008
Location: mississauga
Posts: 68
i prefer turbo. sc has all the power at all times and turbo has to spool, but i mean how long does it take to get to 3500rpm anyways ? im running a gt28rs dual ball bearing turbo...full spooled (7psi) at 3500rpm.
depends on which motor i guess.... but ill probally go turbo anyway.
04-Feb-2009, 04:35 PM
#4
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Join Date: Jul 2006
Location: Burlington
Posts: 15,101
SC use a few hp to make the power, and turbo's are free power. My old turbo make 9 psi at 3500 rpm's. The SC we are putting onto my boss 08 Z06 make's 170 WHP on only 6 psi, it's going from 453 WHP to 633 WHP. So SC can make just as much power as a turbo. Plus SC make that nice wine to them as you build the boost.
04-Feb-2009, 04:46 PM
#5
there are a lot of misconceptions about Turbo VS supercharger. I could write a book on that topic.....so i'll try to keep this short.
First there is the "lag" of a turbo vs instant response of a supercharger. The thing about this is the word "lag" is mis-used like you wouldn't believe. Most people think b/c there GT35R doesn't spool until 4000rpms its lagging, right? Well how I would define "lag" would be the time taken for a turbo to spool once the engine is within the boost threshold. The boost threshold is the RPM at which the turbo is capable of being spun hard enough to make positive boost.
So an example of this would be the GT35R on a B16 engine. I'd say that a GT35R would require 4000rpms on a B16 engine to get it spinning enough to see boost. Most people would say that if they punched it at 2500rpms that it lagged for 1500rpms (until 4000rpms) before it started to spool. But really its just outside of the boost threshold at this point.
With a supercharger there isn't a minimum RPM that it needs to start making boost. This is b/c a supercharger is belt-driven whereas a turbo is driven by the exhaust gases of the engine. So when you punch the gas on a supercharged car it starts to build boost immediately.
With a turbo you can use a smaller exhaust housing or wheel size on the turbo to lower the boost threshold on a specific engine or upgrade the exhaust size post turbine or use a better turbo manifold with equal length runners. All of these will help the turbo spool quicker.
Most people don't know what a turbo's compressor map is, nevermind know how to read one and plot the apropriate information to really make use of the available compressor maps. If you do know how to read a compressor map it'll really help you select the apropriate turbo for your desired goals, but it won't tell you at what RPM it'll start spooling or the lag characteristics of the turbo.
If you want more top end power with a turbo, you can pick a turbo that will acheive this, typically the larger the turbo the more top end power it will provide. Big turbos are good for drag racing or high powered street cars. This is b/c a drag car will launch at 6000+rpms and stay from 7000-9000rpms (or whatever) during the whole race, never dropping out of boost in that range. A big turbo is good for a high powered street car also b/c it'll take until 5000rpms or so to really start making lots of power, which will help with traction on a street setup.
Now if your car is setup well and will have the traction, i'd personally run a smaller turbo for a street car to get the quicker response time of a smaller turbo but use a nice ram-horn style manifold and 3" exhaust to help top end power. You can also use an electronic boost controller to basically help create an artificial torque curve if your turbo isn't so much of a top end turbo. Basically what you'd do is increase the boost a few PSI to help keep the torque curve from falling off quickly up top. If your turbo has a small A/R and isn't designed for high rpm power, there will only be so much you can do b/c the turbo will be out of its efficiency range at higher rpms, but these things i've mentioned will help.
Now to talk about superchargers a little bit. I think they're great for a fun street car. The problem with supercharged cars are the IAT's (intake air temperature) and how high they get without the use of an intercooler/aftercooler or water/methanol injection. They get really high, let me tell you. Hot air isn't so good for making power b/c it is less dense and typically will detonate quicker than colder more dense air. You can literally watch the IAT's increase with the RPM on a supercharged car, but with a turbo car thats makes use of an intercooler, you can watch the IAT's drop as the RPMs increase...which is good.
Superchargers are also nice b/c you don't have to run an oil feed or return line like you do with a turbocharger. Not having to worry about couplers leaking or exhaust leaks effecting a turbocharged engines performance is also a nice thing about superchargers.
Superchargers are however more difficult to upgrade than turbochargers. With a turbo'd car you can install a boost controller (very very easy to do if its a manual boost controller) and turn up the boost/power with the turn of a ****. On a supercharged car you have to remove pulley's to change the boost level.
People say that superchargers are easier to install, which i'd agree with, to an extent. I've installed turbo kits and its pretty easy, the worst part about it is removing the oil pan and welding in an oil return line fitting, i've also helped install superchargers and its easier, but its not what I would call easy. There are plenty of things to have to worry about that can be a pain in the neck.
First there is the "lag" of a turbo vs instant response of a supercharger. The thing about this is the word "lag" is mis-used like you wouldn't believe. Most people think b/c there GT35R doesn't spool until 4000rpms its lagging, right? Well how I would define "lag" would be the time taken for a turbo to spool once the engine is within the boost threshold. The boost threshold is the RPM at which the turbo is capable of being spun hard enough to make positive boost.
So an example of this would be the GT35R on a B16 engine. I'd say that a GT35R would require 4000rpms on a B16 engine to get it spinning enough to see boost. Most people would say that if they punched it at 2500rpms that it lagged for 1500rpms (until 4000rpms) before it started to spool. But really its just outside of the boost threshold at this point.
With a supercharger there isn't a minimum RPM that it needs to start making boost. This is b/c a supercharger is belt-driven whereas a turbo is driven by the exhaust gases of the engine. So when you punch the gas on a supercharged car it starts to build boost immediately.
With a turbo you can use a smaller exhaust housing or wheel size on the turbo to lower the boost threshold on a specific engine or upgrade the exhaust size post turbine or use a better turbo manifold with equal length runners. All of these will help the turbo spool quicker.
Most people don't know what a turbo's compressor map is, nevermind know how to read one and plot the apropriate information to really make use of the available compressor maps. If you do know how to read a compressor map it'll really help you select the apropriate turbo for your desired goals, but it won't tell you at what RPM it'll start spooling or the lag characteristics of the turbo.
If you want more top end power with a turbo, you can pick a turbo that will acheive this, typically the larger the turbo the more top end power it will provide. Big turbos are good for drag racing or high powered street cars. This is b/c a drag car will launch at 6000+rpms and stay from 7000-9000rpms (or whatever) during the whole race, never dropping out of boost in that range. A big turbo is good for a high powered street car also b/c it'll take until 5000rpms or so to really start making lots of power, which will help with traction on a street setup.
Now if your car is setup well and will have the traction, i'd personally run a smaller turbo for a street car to get the quicker response time of a smaller turbo but use a nice ram-horn style manifold and 3" exhaust to help top end power. You can also use an electronic boost controller to basically help create an artificial torque curve if your turbo isn't so much of a top end turbo. Basically what you'd do is increase the boost a few PSI to help keep the torque curve from falling off quickly up top. If your turbo has a small A/R and isn't designed for high rpm power, there will only be so much you can do b/c the turbo will be out of its efficiency range at higher rpms, but these things i've mentioned will help.
Now to talk about superchargers a little bit. I think they're great for a fun street car. The problem with supercharged cars are the IAT's (intake air temperature) and how high they get without the use of an intercooler/aftercooler or water/methanol injection. They get really high, let me tell you. Hot air isn't so good for making power b/c it is less dense and typically will detonate quicker than colder more dense air. You can literally watch the IAT's increase with the RPM on a supercharged car, but with a turbo car thats makes use of an intercooler, you can watch the IAT's drop as the RPMs increase...which is good.
Superchargers are also nice b/c you don't have to run an oil feed or return line like you do with a turbocharger. Not having to worry about couplers leaking or exhaust leaks effecting a turbocharged engines performance is also a nice thing about superchargers.
Superchargers are however more difficult to upgrade than turbochargers. With a turbo'd car you can install a boost controller (very very easy to do if its a manual boost controller) and turn up the boost/power with the turn of a ****. On a supercharged car you have to remove pulley's to change the boost level.
People say that superchargers are easier to install, which i'd agree with, to an extent. I've installed turbo kits and its pretty easy, the worst part about it is removing the oil pan and welding in an oil return line fitting, i've also helped install superchargers and its easier, but its not what I would call easy. There are plenty of things to have to worry about that can be a pain in the neck.
07-Feb-2009, 12:13 AM
#6
Member
Join Date: Oct 2007
Posts: 53
Well, there are many ways to answer this question. Aside from my other post I'll try to keep the sarcasm down about this topic.
First I will try and explain what these two units actually are.
->Supercharger, blower, screws, that silver thing..etc etc etc
Well, first of all, there are different types of superchargers. Today the common link that makes them superchargers is that are mechanically driven off of the motor via belt/chain/shaft (usually belt). This means that the output of the unit is predetermined and fixed. When the motor is at x rpm, the supercharger is at y rpm, the flow can be picked right off the chart. Pressure levels in your IM will me determined by your motors VE's. The higher the pressure levels, the less efficient your motor is compared to the volume of air that you are trying to move. By increasing your motors total volumetric efficency, the pressure levels will drop, but the flow will remain the same from the supercharger. At this point power will increase based on efficiency differences, since flow has stayed the same. The only way to alter the air volume is by changing the gearing between the motor and supercharger.
The first type I will touch on is the most common Roots/Eaton (JRSC style) blower. It has two screw like shafts of opposing threads (one RH thread the other LH thread obvi). They spin in a manner that creates positive displacement of fluid (aka air). The have a self containd lubrication system (most ppl never change the oil) in the snout. Invented literally the same time the ICE.
Pros
-Very simple to adapt to motors (easy to figure out)
-good performance output
-linear delivery
-whine is cool
-good throttle response
-low operating speed (less than 15k)
Cons
-Poor efficiency
-whine gets old fast
-difficult to adjust output
-limited to low pressure levels
-gay belts and ilder pulleys can frustrate the hell out of you on custom mods
-always moving air (unless its clutched like new mercedes units)
-difficult to intercool and almost pointless since the compressor is nearly maxed out at this point. It will just help you with det or octane rating required.
The second type of supercharger is becoming more and more popular. It looks like half a turbo. This is because it is. A centrifulgal blower with a gearbox attached to it is what vortex and rotrex and pretty much any other company that ends in ex is selling now. Although not a supercharger by the old skool engineers since is not a "positive displacement" blower but a mechanically driven dynamic compressor. But to the modern day crowd like us, if it runs off the motors crank its a supercharger. So blow me (haha - yeah bad joke). If you want a better explanation of this just read the turbo section below.
Pros
-Turbo LIKE compressor efficiency
-smaller than Roots type units
-easy to cool the charge
-can use a blowoff valve (if you like the quiff, I do, just not the smell...ewww)
-plus other supercharger benefits listed above
Cons
-Oil lines are now required
-more expensive than a roots unit
-on all the time (at idle your BOV will be expelling air)
The next is not well know but is a scroll compressor. It is a true old skool supercharger since it it a positive displacement air pump. There are many different types of scroll compressors, the most common is the G-lader. Used and invented by VW on their Corrado, the G60. It is a great idea since most people own a scroll compressor anyway. Their air conditioner in their auto and most household A/C's are scroll compressors. Well, beyond my digression VW sucked at this design (don't ask me why I have never bothered to rip one apart) and canned the G60 motor and just went 1.8T instead.
Pros
-Better Efficiency than Roots
-Extremely small
-Super smooth continous air flow
-Self contained oil (usually synthetic)
-Cheaper than centrifugal
Cons
-no real R&D so no product to buy
Now there are other types of superchargers that, well have little public knowledge. Since I'm not writing a history report I'll briefly mention them. There are piston type, rotary, and a sliding vane style. All are used in refrigeration systems but not automotive. Go figure?
Last but not least is the electric supercharger. Well, they are real (not the 40 dollar thingys on ebay) and extremely expensive. The amount of current required is rediculous. Battery banks and capacitors and voltage regulars. It's overwhelming. ex M62 needs 27HP to make 250 crank HP which is over 20KW = over 1400 amps at 14V DC. Rediculous and expensive.
If anyone want I can elbourate on anyone of these items later.
I'll edit this and add turbo's later. I'm tired and have my soccer league championships match tommorrow.
First I will try and explain what these two units actually are.
->Supercharger, blower, screws, that silver thing..etc etc etc
Well, first of all, there are different types of superchargers. Today the common link that makes them superchargers is that are mechanically driven off of the motor via belt/chain/shaft (usually belt). This means that the output of the unit is predetermined and fixed. When the motor is at x rpm, the supercharger is at y rpm, the flow can be picked right off the chart. Pressure levels in your IM will me determined by your motors VE's. The higher the pressure levels, the less efficient your motor is compared to the volume of air that you are trying to move. By increasing your motors total volumetric efficency, the pressure levels will drop, but the flow will remain the same from the supercharger. At this point power will increase based on efficiency differences, since flow has stayed the same. The only way to alter the air volume is by changing the gearing between the motor and supercharger.
The first type I will touch on is the most common Roots/Eaton (JRSC style) blower. It has two screw like shafts of opposing threads (one RH thread the other LH thread obvi). They spin in a manner that creates positive displacement of fluid (aka air). The have a self containd lubrication system (most ppl never change the oil) in the snout. Invented literally the same time the ICE.
Pros
-Very simple to adapt to motors (easy to figure out)
-good performance output
-linear delivery
-whine is cool
-good throttle response
-low operating speed (less than 15k)
Cons
-Poor efficiency
-whine gets old fast
-difficult to adjust output
-limited to low pressure levels
-gay belts and ilder pulleys can frustrate the hell out of you on custom mods
-always moving air (unless its clutched like new mercedes units)
-difficult to intercool and almost pointless since the compressor is nearly maxed out at this point. It will just help you with det or octane rating required.
The second type of supercharger is becoming more and more popular. It looks like half a turbo. This is because it is. A centrifulgal blower with a gearbox attached to it is what vortex and rotrex and pretty much any other company that ends in ex is selling now. Although not a supercharger by the old skool engineers since is not a "positive displacement" blower but a mechanically driven dynamic compressor. But to the modern day crowd like us, if it runs off the motors crank its a supercharger. So blow me (haha - yeah bad joke). If you want a better explanation of this just read the turbo section below.
Pros
-Turbo LIKE compressor efficiency
-smaller than Roots type units
-easy to cool the charge
-can use a blowoff valve (if you like the quiff, I do, just not the smell...ewww)
-plus other supercharger benefits listed above
Cons
-Oil lines are now required
-more expensive than a roots unit
-on all the time (at idle your BOV will be expelling air)
The next is not well know but is a scroll compressor. It is a true old skool supercharger since it it a positive displacement air pump. There are many different types of scroll compressors, the most common is the G-lader. Used and invented by VW on their Corrado, the G60. It is a great idea since most people own a scroll compressor anyway. Their air conditioner in their auto and most household A/C's are scroll compressors. Well, beyond my digression VW sucked at this design (don't ask me why I have never bothered to rip one apart) and canned the G60 motor and just went 1.8T instead.
Pros
-Better Efficiency than Roots
-Extremely small
-Super smooth continous air flow
-Self contained oil (usually synthetic)
-Cheaper than centrifugal
Cons
-no real R&D so no product to buy
Now there are other types of superchargers that, well have little public knowledge. Since I'm not writing a history report I'll briefly mention them. There are piston type, rotary, and a sliding vane style. All are used in refrigeration systems but not automotive. Go figure?
Last but not least is the electric supercharger. Well, they are real (not the 40 dollar thingys on ebay) and extremely expensive. The amount of current required is rediculous. Battery banks and capacitors and voltage regulars. It's overwhelming. ex M62 needs 27HP to make 250 crank HP which is over 20KW = over 1400 amps at 14V DC. Rediculous and expensive.
If anyone want I can elbourate on anyone of these items later.
I'll edit this and add turbo's later. I'm tired and have my soccer league championships match tommorrow.
12-Feb-2009, 04:11 AM
#7
Junior Member
Join Date: Oct 2007
Posts: 10
I've learned a lot of new information in this thread. Great information's delivered by zeeman and BigJ5. I'm actually on the verge of purchasing a JRSC to be put into a jdm b16a in a 93 civic, and I was wondering what kind of pricing would it take to have it installed? Just the labour. On a side note, BigJ5, could you elaborate further with the JRSC and the new vortex/rotrex.. besides the cooling which one is best tailored in terms of cost, setup, efficiency and durability?
Thanks,
Ken
Thanks,
Ken
12-Feb-2009, 02:07 PM
#9
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Thread Starter
Join Date: Dec 2007
Location: Parry Sound
Posts: 1,986
03-Mar-2009, 07:39 PM
#10
Member
Join Date: Oct 2007
Posts: 53
I'm actually on the verge of purchasing a JRSC to be put into a jdm b16a in a 93 civic, and I was wondering what kind of pricing would it take to have it installed? Just the labour. On a side note, BigJ5, could you elaborate further with the JRSC and the new vortex/rotrex.. besides the cooling which one is best tailored in terms of cost, setup, efficiency and durability?
Thanks,
Ken
Thanks,
Ken
To install a JRSC kit according to the Moss instructions it would take 6-12 hours depending on who is doing it. So, for cost analysis - shop rates are $45 to $125 an hour. Min cost is $270, max is $1500 + the governments unfair share of 5% G.S.T. (just so you know there should be no PST on service). But the reality can get ugly. A buddy of mine had a shop charge him almost 5 grand JUST to INSTALL a vortex kit. If he gave me 5 grand to install I would have at least included a couple hours with an "escort".
Regarding a roots style blower vs. a centrifugal vortex unit
Cost - roots is cheaper than vortex
- why? less machining, less real work.
Durability - roots units are known to be indestructable, as long as you change the oil and use it within its parameters. Vortex units also seem to be bullitproof so far.
- why? good manufactures put out good units. Bottom line
Efficiency - vortex units win hands down
- why? Simple, better design. Less heat is output by the unit while removing the latent temp increase from compression.
The real question is, what are your goals and budget? The best of the best isn't always necessary. Alfter all, I assume this is a hobby car, not an F1 racecar. Plus cooling IS an option for your B-series powerplant with either kit.
btw, I liked my JRSC on my D16 powered EL. Faster than a TSX, closer to a TL in performance. Ultimately, I went turbo because I'm an idiot who loves speed...and hate slow drivers
btw How the hell do you edit posts? I want to finish my previous one.
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