Why Aren't We All Swapping To Superchargers?

[No Crust Racing]

I've been trying out some podcasts on my phone and I downloaded some of the automative related ones from howstuffworks.com (don't waste your time).

The one thing that did strike me as interesting was the podcast on Turbo's vs Supercharging.

In Yank land the Supercharger is apparently king of all and you only ever have a turbo if you got one on the car when you bought it 0_o

I've never owned a supercharged car but my understanding of the drawbacks was that it's a constant parasitic load even when you don't want the extra power (where as we can all drive "off boost" to an extent). There's far less room for adjustment boost wise, more boost = new pulley (or am I misinformed here?) and generally the cost of a supercharger kit is a fair stab above what we could do turbo wise - again that's my understanding not gopsel and really that understanding just comes from general reading.

They do make some good points though, more linear power delivery, far less complexity in the system (when talking typical oil/water cooled turbo vs your basic sidemount supercharger). In hearing that it got me thinking, why aren't we all switching to superchargers for motorsport, supposedly easier tuning, less complexity, in some cases less heat and smoother power delivery has got to be a good thing for clutches, boxes, engine and box mounts, traction etc.

I've intentionally left out the differences in lag as I'm talking more about motorsport where once you get going lag isn't really "too" much of an issue for a turbo car on the track.

I'm just throwing it out there for general discussion not asking if I should do it

[Duncan]

motorsport? the only race cars that run superchargers are drag cars. In everything else the higher efficiency of the turbo wins hands down.

And lag should not be an issue in any modern race car....just pick a turbo that is on boost for the required rev range

[GTR-N1]

Turbo'd Beemers are renowned for using less fuel than supercharged Mercs.

A supercharger requires a bit of energy to be bled from the engine to drive it. The engine has to burn extra fuel to provide power to turn the supercharger. Admittedly, increased charge density increases the engine's specific power & power to wt., but it also increases the engine's specific fuel consumption.

A turbocharger is driven by exhaust gasses. Intake air is compressed by the power generated by the heat from exhaust gas. This system is more "efficient" as Duncan says.

The R35 GT-R that won Tokyo Auto Salon last year has 2x Rotrex superchargers as well as the 2x turbos for greater linear power delivery, but man, the fuel consumption has gone thru' the roof!

[Nee-san]

motorsport? the only race cars that run superchargers are drag cars. In everything else the higher efficiency of the turbo wins hands down.

And lag should not be an issue in any modern race car....just pick a turbo that is on boost for the required rev range

+ 1

I have seen a back to back comparison of MX5 race cars same 1.6L engine but one supercharged and one turbocharged ( with very similar flow capabilities)

the turbocharged MX5 made more power in all but the lower extremities of the rev range and proceeded to make ~185 hp against the supercharged's ~150 yes, same dyno but different day.

[FineLine]

Having followed 33racer's exploits in fitting a super charger to his skyline I think I'll stay snail driven for a long time to come.

[No Crust Racing]

motorsport? the only race cars that run superchargers are drag cars. In everything else the higher efficiency of the turbo wins hands down.

And lag should not be an issue in any modern race car....just pick a turbo that is on boost for the required rev range

Higher efficiency in regards to fuel usage? Would there really be that much of a difference on the track under WOT applications? Interesting...

Turbo'd Beemers are renowned for using less fuel than supercharged Mercs.

A supercharger requires a bit of energy to be bled from the engine to drive it. The engine has to burn extra fuel to provide power to turn the supercharger. Admittedly, increased charge density increases the engine's specific power & power to wt., but it also increases the engine's specific fuel consumption.

A turbocharger is driven by exhaust gasses. Intake air is compressed by the power generated by the heat from exhaust gas. This system is more "efficient" as Duncan says.

The R35 GT-R that won Tokyo Auto Salon last year has 2x Rotrex superchargers as well as the 2x turbos for greater linear power delivery, but man, the fuel consumption has gone thru' the roof!

twin charge would be nice but I think the cost is somewhat prohibitive. I understand the fundamental differences in how they work but I'm wondering why if the only "con" is fuel economy, why it isn't done more often on race cars where fuel economy is not the highest priority in many cases.

+ 1

I have seen a back to back comparison of MX5 race cars same 1.6L engine but one supercharged and one turbocharged ( with very similar flow capabilities)

the turbocharged MX5 made more power in all but the lower extremities of the rev range and proceeded to make ~185 hp against the supercharged's ~150 yes, same dyno but different day.

Interesrting stuff, same boost?

Having followed 33racer's exploits in fitting a super charger to his skyline I think I'll stay snail driven for a long time to come.

Some more interesting stuff, what was found?

[ohno1]

i used to have a commodore with a decent sized centrifugal blower hanging off it.. was fun but a roots style blower would've probably been better if it was available at the time

- made decent power, but in reality more 'laggy' (lack of a better word.. maybe 'peaky' is better description) than my gtr (which in my opinion is quite peaky in it's power delivery, although i'm used to V8s)

- sounded fkn HEAPS better at idle + at redline than my gtr does.. a blower whizzing away at idle at the lights is probably the most awesome thing going..

- the motor it was on was very torquey so really the blower only helped past 3k -- definitely not suitable for a RB26, would be painful to drive it like that

- it was actually really good for traffic light battles.. would often seem to beat cars with supposedly more power?.. although it was backed by a histalled/shift kitted auto, and 27% lower diff ratio may have something to do with it's consistency..

- getting it up on the stall and planting it would create smoke and spray rubber all over the place haha

- im not sure if you really want a blower to be doing 8500rpm + 20psi? would have to be a fairly big one, and while the power band would be a larger than a big single turbo or big twins, i'm sure you'd make less overall.. skids would be a bit easier though haha

having said that.. im very happy with my twin turbos

[FineLine]

Some more interesting stuff, what was found?

Nothing really untoward Dan, Just the herculian effort to get it to fit and work and the noise factor. Its the loudest damn thing i ever heard.

If they were more freely used I am sure there would be commercial kits to fit them to rb engines but even if there were its a far bigger job than fitting a turbo.

[Birds]

Superchargers are widely used in America because the cars are typically of larger displacement, therefore usually have more torque, making the supercharger a worthwhile addition - think of how an air conditioning compressor affects performance in a 2 litre versus a 5.7 litre. Unless you have a very small supercharger (in which case gains aren't going to be fantastic), you don't want to supercharge a small displacement engine and chase alot of power. They are more driver friendly throughout the course of daily driving due to the more linear power delivery. Also, many vehicles in America have a V engine configuration which is more difficult to turbocharge (the simplest form is a twin turbo setup; one for each bank of cylinders).

So whilst superchargers are to a degree linear things, turbochargers are obviously not...they are shithouse down low and excellent up high...but given motorsport is spent within the upper and mid rev ranges, the disadvantages down low don't come into it and your engine may as well be naturally aspirated with almost twice the hypothetical displacement. Where superchargers are good throughout the whole rev range, they don't have a specific "advantage" up top and actually begin to drop off in efficiency when it comes to the upper rev range. They are more a low down and midrange thing.

[R31Nismoid]

Supercharger is king in the US?

Why then are massive workshops like Underground making TT street setups for Ferrari & Lambo's?

If blowers were "the way", then such high end workshops would be using them.

Each has its own advantages either way.

One of my mates here @ work has a blown 540ci in his Camaro, makes a lazy 1000hp lol.

[No Crust Racing]

i used to have a commodore with a decent sized centrifugal blower hanging off it.. was fun but a roots style blower would've probably been better if it was available at the time

- made decent power, but in reality more 'laggy' (lack of a better word.. maybe 'peaky' is better description) than my gtr (which in my opinion is quite peaky in it's power delivery, although i'm used to V8s)

- sounded fkn HEAPS better at idle + at redline than my gtr does.. a blower whizzing away at idle at the lights is probably the most awesome thing going..

- the motor it was on was very torquey so really the blower only helped past 3k -- definitely not suitable for a RB26, would be painful to drive it like that

- it was actually really good for traffic light battles.. would often seem to beat cars with supposedly more power?.. although it was backed by a histalled/shift kitted auto, and 27% lower diff ratio may have something to do with it's consistency..

- getting it up on the stall and planting it would create smoke and spray rubber all over the place haha

- im not sure if you really want a blower to be doing 8500rpm + 20psi? would have to be a fairly big one, and while the power band would be a larger than a big single turbo or big twins, i'm sure you'd make less overall.. skids would be a bit easier though haha

having said that.. im very happy with my twin turbos

Interesting to hear from someone who's done both.

Nothing really untoward Dan, Just the herculian effort to get it to fit and work and the noise factor. Its the loudest damn thing i ever heard.

If they were more freely used I am sure there would be commercial kits to fit them to rb engines but even if there were its a far bigger job than fitting a turbo.

Interesting to hear, I'd of thought fitment would have been on par with a turbo install but that would depend on the type of supercharger.

Superchargers are widely used in America because the cars are typically of larger displacement, therefore usually have more torque, making the supercharger a worthwhile addition - think of how an air conditioning compressor affects performance in a 2 litre versus a 5.7 litre. Unless you have a very small supercharger (in which case gains aren't going to be fantastic), you don't want to supercharge a small displacement engine and chase alot of power. They are more driver friendly throughout the course of daily driving due to the more linear power delivery. Also, many vehicles in America have a V engine configuration which is more difficult to turbocharge (the simplest form is a twin turbo setup; one for each bank of cylinders).

So whilst superchargers are to a degree linear things, turbochargers are obviously not...they are shithouse down low and excellent up high...but given motorsport is spent within the upper and mid rev ranges, the disadvantages down low don't come into it and your engine may as well be naturally aspirated with almost twice the hypothetical displacement. Where superchargers are good throughout the whole rev range, they don't have a specific "advantage" up top and actually begin to drop off in efficiency when it comes to the upper rev range. They are more a low down and midrange thing.

It seems my understanding of it all rings pretty true amongst others as well then. I stand by my comment to avoid that particular pod cast.

Supercharger is king in the US?

Why then are massive workshops like Underground making TT street setups for Ferrari & Lambo's?

If blowers were "the way", then such high end workshops would be using them.

Each has its own advantages either way.

One of my mates here @ work has a blown 540ci in his Camaro, makes a lazy 1000hp lol.

"In Yank land the Supercharger is apparently king of all "

Sorry I should have specifically pointed out that I was referring to the overtone of the podcast I was listening too. This is not my opinion and im not here advocating for the supercharger, just throwing it up for general discussion. Hence why this topic is not in the forced induction or motorsport section as a "How can I/Should I go about this for my car".

Looks like what I thought to be the case seems to be the shared understanding. Glad I'm not going crazy.

[R31Nismoid]

meh to the podcast - there is always for, there is always against. pro/con

makes the world go round

[NOS4R2]

Horses for courses really.

I have an S/C14 on my datsun A15 in a 1200 sedan. the extra torque is really enjoyable, and very useable. Its like driving the car if it had a much bigger engine, but without the weight.

For an appliaction like drag racing, or driving hard around tight winding hills it's great. When I need more go, I just squeeze the pedal that bit harder. It doesn't have the same top end push that a turbo does, but by the time it begins to lose that kick in the back, I'm already going fast enough to get in a heap of trouble if mr plod was to catch me.

Someone once said, "horsepower sells cars, torque wins races". I do love the fat bottom end torque just itching to be released.

I love it so much I'm going to fit a screw supercharger to the CA18det in my datsun 510 too.

[No Crust Racing]

Always good to hear the opposing view.

Do you think it's really worth the effort of removing the turbo on the CA or are you talking twin charged?

Standard CA turbos are so small that there's almost no lag as it is.

[lachlanw]

because youll make more horespower on the same boost with a turbo

because superchargers have disgusting adiabetic efficency .although the twin screws are getting better they are still not as efficient . and dont mention a centrufigal , you might aswell have a turbo .

top fuel cars only run "blowers" because of politics

did you know it takes about 1000 hp to drive a blower on a top fuel car ? could recover over 80% of this running a turbo

[lachlanw]

if you really want an argument stop calling it lag and start talking about boost threshold

[Peter89]

Higher efficiency in regards to fuel usage? Would there really be that much of a difference on the track under WOT applications? Interesting...

this is taking about the efficiency of creating the increased pressure. turbos are powered from exhaust gases, so are kinda "free" power so to speak. while superchargers are using the engine to create the power but at the same time, drawing some of it for themselves. so it doesn't matter how the car is driven, the engine is less efficient or slightly restricted by the supercharger because of the increase inertial forces required to turn the engine.

as said before this leads to a less responsive engine and less gains from peak revs.

if you're driving hard, lag should be no issue and if it is, your revs are far too low

also, if you're running 1bar on a supercharger, it's still going to take some revs to produce that much pressure. down low is better but it's not perfect.

Edited September 2, 2010 by Peter89

[Nee-san]

if you really want an argument stop calling it lag and start talking about boost threshold

the first is just a description of the latter.

[ohno1]

At the end of the day you really need to judge it on application basis

It's all fine and dandy to talk about either going turbo or blower on a RB/CA/SR/1-2JZ or something similar; where there are cheap, ready turbo manifolds and entire setups are availalble (OEM no less!), but consider an efi motor which didn't come out turbo from the factory.. what a massive headfark and much larger expense to get turbos on it..

The other thing is legalities, or perception of legalities. Pop the bonnet of a 5L Commodore with a dirty big single turbo setup.. a cop doesn't know what he's looking at, but knows that all this pipe work and this thing that you've have to 'massage' the strut tower to fit is certainly not legal. I drove around for at least 2 years with an unpermitted blower, was pulled over a heap of times.. even had a cop shine his torch around my engine bay and literally failed to notice a blower roughly the size of his head hanging off the throttle body. Having said that no one ever said anything when i was driving through RBT stops and this thing was whizzing it's head off at idle..

Maybe I've gone too far in one direction here.. that's mainly for N/A to forced air setups..

There's no way I'd remove a factory turbo setup to go a blower, that's a reverse headfark that's unnecessary as well.. it would be a crazy thing to buy a XR6T and remove the GT35/40 only to replace it with a Whipple, and that's a 4L motor..

I think in a video game world where effort for work was nil and everything was instant and easy, then you'd go turbos every time.. otherwise there's definitely grey areas

[sh@un]

Turbo'd Beemers are renowned for using less fuel than supercharged Mercs.

and the new gen V8 hi-po Mercs will now use decreased capacity (from the NA 6.2L down to 5.5) with twin-tahbins for better economy/emissions while still having huge power