I don't think PD understands how a supercharger works

[JTSnooks]

I've seen a few people in here claiming that a supercharger's boost level is entirely dependent on engine RPM while a turbo's isn't because of the wastegate. Did anyone ever stop to think that maybe a supercharger has a wastegate as well? Only it's obviously not on the exhaust, but rather usually internally "wastegated". The excess boost is usually vented back into the intake tract. In other words, the supercharger is almost always capable of producing more boost than the engine needs, and the excess is "blown off" internally. This is why you'll see a flat boost curve (as was shown in the graph earlier) all the way from 1500rpm to 6500rpm depending on the application.

 

[Killer_Kustums]

In the description to add a supercharger, it says that it gives the most boost in the low to mid RPM range. That's completely untrue, as the higher an engine revs the MORE power a supercharger will give. This is because the crank turns the blower, and the faster the crank is spinning the harder the blower is working.

Pretty stupid oversight.

No actually it's true. Superchargers are better in the low to mid range RPM's and turbos are better for the mid to upper ranges of the RPM's

 

[Rotary Junkie]

No actually it's true. Superchargers are better in the low to mid range RPM's and turbos are better for the mid to upper ranges of the RPM's

Roots or twin-screw superchargers, yes.

Centrifugal superchargers? Nnnnnope.

 

[turboash78]

What I don't get is... why in GT3 and 4 we could get 1000 hp+ Skylines and Supras, but not for some reason we can't!? I guess automotive technology has regressed since then...

Also, if GT5 implemented REAL supercharger whine sounds... I'd never leave the house!

 

[Poppins]

In the description to add a supercharger, it says that it gives the most boost in the low to mid RPM range. That's completely untrue, as the higher an engine revs the MORE power a supercharger will give. This is because the crank turns the blower, and the faster the crank is spinning the harder the blower is working.

Pretty stupid oversight.

I dont think you realize that you are incorrect. Because superchargers work very well and efficiently at low rpms and the higher they go the harder it is to spin the supercharger making it take alot of power from the engine. This completely negates the centrifugal chargers like procharger, as they are basically a modified turbocharger with very good ball bearings and are able to perform very well and not take much engine power away.

The top fuel superchargers take over 500 HP from the crank JUST to spin the supercharger.

 

[dLo GSR]

where is the OP? hiding under his rock?

 

[Poppins]

Think about it like this. If you hooked up your 350 small block to a 6-71 supercharger (that is meant to feed 6 cylinders each 71 cubic inches, this is from a detroit diesel two stroke engine) It isnt going to be able to turn the supercharger very easily.

 

[gary31]

where is the OP? hiding under his rock?

Yeah he still wants to be right so he stopped reading this thread...i think it says something like that on page 2 or 3.

Because you wrote that before you wrote what I qouted...but whatever man I'm not even going to continue posting so you can be right and I can be right and we'll both be happy.

 

[Enzo309]

Ok I can prove you wrong. Take a took at the video for a few seconds. All of those cars are running a roots blower. They rev at around 10,000 rpm. Just to give you an idea of how much boost they are getting, they weigh 2800 lbs and run a 500 cubic inch v8 on methanol.

Take the supercharger off and you would have a pass around 190-195 mph, around 7 seconds problably a little under. The supercharger is giving them enough power to go 50 mph faster and an entire second faster in only a quarter mile. All of it is at high rpms.

Hell there is a guy running a turbo with a 526 hemi at 2850 lbs that does 0-255 in 5.8 seconds.

I mean the SLR McLaren vs the Porsche Carrera GT

the SLR was pulling on higher speeds but the SLR obviously is 400 kg heavier and a v8 thats limited to 7000 rpm partly to make it a reliable engine I guess

at the start though I think the supercharged v8 of the SLR was already better in torque and power than the naturaly aspirated v10 of the carrera GT


it was a rolling start but anyway both had same horsepower but the SLR was 400 kilograms heavier

 

[Zenmervolt]

I've seen a few people in here claiming that a supercharger's boost level is entirely dependent on engine RPM while a turbo's isn't because of the wastegate. Did anyone ever stop to think that maybe a supercharger has a wastegate as well? Only it's obviously not on the exhaust, but rather usually internally "wastegated". The excess boost is usually vented back into the intake tract. In other words, the supercharger is almost always capable of producing more boost than the engine needs, and the excess is "blown off" internally. This is why you'll see a flat boost curve (as was shown in the graph earlier) all the way from 1500rpm to 6500rpm depending on the application.

1) Wastegate != Blow-off Valve. A blow-off valve (or diverter valve) vents excess compressor pressure to atmosphere (or back into the intake tract for a diverter valve). A wastegate bleeds off exhaust gas from the turbine ("hot side"). A wastegate prevents the turbine from over-speeding at high RPM and limits overall manifold pressure by siphoning off the turbine's power source. A blow-off or diverter valve prevents compressor surge/stall by venting transient high pressure events that occur when the throttle is rapidly closed.

2) If excess boost from a supercharger were being bled off, you'd hear a continuous "whooshing" noise from the air escaping.

3) In most roots/twin screw superchargers, the only control on supercharger output is the pulley size. That's why you can simply slap a smaller diameter pulley on a Terminator Cobra and get a lot more power. The only thing limiting the boost is the speed at which the supercharger spins.

4) In a roots/twin screw supercharger, it displaces a fixed amount of air per revolution. The volume of air passed by this type of supercharger is effectively linear with RPM. That's why you get a flat boost curve; the supercharger's output scales at the same rate as the engine's breathing.

Now, if you're thinking of centrifugal superchargers, then those are different. But no-one in this thread was talking about those.

 

[CarreraGT]

That whine is just from the transmission. You don't hear a whine from any supercharged car in GT5, it's just silent. Even on a stock ford GT.

I remember you could hear the supercharger whine in the Ford Mustang in GT2, haven't tried it in GT5 though.

I remember because I spent hours one day with the tv turned up flat out just to hear it 👍

 

[desmosabie]

I havent been here ina few months, scrolled down the list, saw this thread, and laughed. I mentioned PD's problems with supercharging a week or so after the game came out here in the bugs an problems thread. Nobody seemed to care, and PD as always seemed to have the Turbo/S.Charger characteristics backwards. Superchargers dont lag. <-- i shouldv'e spelled out the last bit of punctuation. But PD's superchargers do, worse than the turbos too.. ha, whatever. Thats what you get when playing games I guess.

 

[The_Reformed]

O you mean the guys that have to rebuild the engine every race?

👍 LOL, finally someone with knowledge

 

[The_Reformed]

That whine is just from the transmission. You don't hear a whine from any supercharged car in GT5, it's just silent. Even on a stock ford GT.

Thats cause on a stock Ford GT, you don't really hear the whine in real life, seen videos, and rode in one at full blast. note i didnt say cant hear it at all

 

[GT5Pro]

Check out the new Rotrex supercharger, KraftWerks uses them in their kits. It's planetary drive so you get the great down low torque of the supercharger and the ungodly high impellar speeds that rival a turbos for that high rpm punch.

Check out this K20 in an EG

 

[The_Reformed]

I havent been here ina few months, scrolled down the list, saw this thread, and laughed. I mentioned PD's problems with supercharging a week or so after the game came out here in the bugs an problems thread. Nobody seemed to care, and PD as always seemed to have the Turbo/S.Charger characteristics backwards. Superchargers dont lag. <-- i shouldv'e spelled out the last bit of punctuation. But PD's superchargers do, worse than the turbos too.. ha, whatever. Thats what you get when playing games I guess.

They can lag, depends how big a supercharger you have on. They just have less lag

 

[bloodstriker]

Has everyone failed to realise that this whole thread war is over the DESCRIPTION of a supercharger... Sure if superchargers were working like turbochargers and vice versa i'd understand but c'mon guys..

 

[shigllgetcha]

Has everyone failed to realise that this whole thread war is over the DESCRIPTION of a supercharger... Sure if superchargers were working like turbochargers and vice versa i'd understand but c'mon guys..

People here would argue over the colour of the sky....

 

[GrimSinn]

Superchargers boost is limited to the size of the pulley, usually maxing out around 12psi. However as the speed of the engine increases the efficiency of the SC goes down, making it's gains fade out in the high rpm's. If you want more boost, you need to go Turbo where you can increase the size of the turbo to insure you move enough air efficiently.

 

[Zenmervolt]

Check out the new Rotrex supercharger; KraftWerks uses them in their kits. It's planetary drive so you get the great down low torque of the supercharger and the ungodly high impeller speeds that rival a turbo's for that high rpm punch.

Check out this K20 in an EG

That's a centrifugal supercharger. We've been talking about positive displacement superchargers.

Also, even a Rotrex will still run into the issues that you see with a turbo (a maximum impeller RPM, maximum compressor side flow rate, etc). While the Rotrex is definitely an improvement over the standard centrifugal supercharger (which traditionally has very little low-end boost), it simply represents another choice with its own set of trade-offs. It's not a magic bullet.

 

[Zenmervolt]

Superchargers boost is limited to the size of the pulley

Well, limited by the size of the pulley anyway.

usually maxing out around 12psi.

No. Where the boost will max out depends on the size of the supercharger and the size of the engine. If I slap an Eaton M45 (designed for 2.0-3.0 litre engines) onto a 5.0 litre V8, I'm not going to get very much boost even if I use a ridiculously small pulley. Conversely, if I slap an Eaton M112 (designed for engines over 5.0 litres) onto my 2.3 litre Volvo, I'm going to get a hell of a lot more than just 12 PSI of boost.

It all depends on how the setup is matched.

However as the speed of the engine increases the efficiency of the SC goes down, making it's gains fade out in the high rpm's.

This is true of turbos as well. You can't simply spin the impeller infinitely fast to flow more air. There's a point after which efficiency goes down for turbos as well. In fact, many cars with stock turbos also suffer from boost fade-out at higher RPM for exactly this reason.

If you want more boost, you need to go Turbo where you can increase the size of the turbo to insure you move enough air efficiently.

There's nothing stopping a person from going to a physically-larger supercharger either, so this argument is a non-starter.

 

[Parnelli Bone]

I remember you could hear the supercharger whine in the Ford Mustang in GT2, haven't tried it in GT5 though.

I remember because I spent hours one day with the tv turned up flat out just to hear it 👍

No. In GT2 we could not equip superchargers at all. The Mustangs in that game (either the GT or the SVT) also could not accept turbos. You must be thinking of GT4.

 

[deftonesmx17]

And.....this is why I play Forza. I'm a tuning guy and out of all it's "two whole issues", at least they nailed tuning.

 

[Enzo309]

Thats cause on a stock Ford GT, you don't really hear the whine in real life, seen videos, and rode in one at full blast. note i didnt say cant hear it at all

someone in my building has a ford GT and it doesn't sound as loud as the ferrari 599 which is also in our parking

yeah its not like a McLaren SLR's supercharger

you dont hear it very much

 

[CarreraGT]

No. In GT2 we could not equip superchargers at all. The Mustangs in that game (either the GT or the SVT) also could not accept turbos. You must be thinking of GT4.

No it was definitely GT2, but from memory it was a stock Mustang. I'm not too good on my Mustang specs, but thinking back I don't think they even offered a supercharged model back then...

Now you've got me thinking. Maybe it was just some weird made up PD engine sound and not a supercharger at all...

 

[GAFFiO]

I'm pretty sure the spooling speed of the Supercharger is a direct result of the 3rd gear ratio in the gearbox so your all wrong...








💡

 

[Crispy]

Having had a Supercharger in an MX-5 before, I can tell you that PD got it pretty accurate.