Superchargers and Turbos in GT5

[SVT Cobra GT]

In the previous GT games, mainly the PS2 GT games, there have been many Turbo gauges on the HUD.

do you think GT5 should have one for supercharged cars?

 

[flubbachany]

Don't the supercharged cars get a boost meter as well?

 

[Polo609GT]

Also, i think all vehicles should have to option to go turbo. But yeah, turbo guage, something nice..

 

[CyborgGT]

What I've always wanted is the choice of turbo or supercharging for ALL cars, plus the choice of different sized turbos (for boost at high or low rpm, as you desire), and single turbo or twin turbo.

 

[Shadow Wulf 2k]

They should definatly differentiate between centrifugal S/C's and positive displacement S/C's. Not allowing the P.D. S/C's on certain cars in GT4 made sense, as not all cars have the adaptor for that kind of S/C available, but a centri-S/C just bolts up to the accessory belt, and is more flexible in that respect.

I also wish there were ways to combine N/A tuning stages with the Turbo/Supercharger parts. In the GT4 descriptions of N/A tuning stages, some of the parts are things that can be used with forced induction.

 

[Spec M]

Yes I agree. One should be able to have cams, port polish, balance etc. as well as a turbine or super-charger.

 

[nd 4 holden spd]

Also, i think all vehicles should have to option to go turbo. But yeah, turbo guage, something nice..

What I've always wanted is the choice of turbo or supercharging for ALL cars, plus the choice of different sized turbos (for boost at high or low rpm, as you desire), and single turbo or twin turbo.

That would kind of defeat the purpose of some cars though, like being able to turbo a 3000GT SR which is lighter would render the VR4 and MR models useless. It's not if you can do it, it's if you should, that they make some cars in accessible to turbos. Plus they don't want turbocharged, 1500hp V8s stomping around GT tracks.

 

[Suzuki]

GT4(i know 3 had it) i think had a 16xx hp escudo pikes peak car... turboed with major turbo lag until it bearly spools up and then gets pegged on the limiter because it doesn't have any traction.

 

[nd 4 holden spd]

But that's a small V6, V8s wouldn't need such a big turbo and wouldn't have that kind of lag. Wheelspin on the other hand. All I hope for regarding forced induction in GT5 is a stage 2 an 3 supercharger, because I know the superchargers in GT4 were pretty weak ones.

 

[Jay]

V8s wouldn't need such a big turbo

The V8's turbo/s would be just as big.

 

[nd 4 holden spd]

Bigger displacement= bigger power. A V8 will not need as big a turbo to make the same power as a small car. Sometimes they don't need a turbo at all

 

[Jay]

Bigger displacement= bigger power. A V8 will not need as big a turbo to make the same power as a small car.

Engines need air (oxygen) to make combustion..... the Turbo has to flow the air (on turbocharged engines obviously), turbo's are rated on how much air they flow, if you have a turbocharged 1500hp supra, and a turbocharged 1500hp Corvette, they will need similar flowing turbochargers regardless of displacement.


This is why many rate turbochargers in HP, e.g I have a 550hp turbo..

adding a 550hp turbo to a stock 300hp V8 wont make it 850hp.

 

[nd 4 holden spd]

So you think that running a turbo at 9psi on a V8 and a 4cyl, they will make the same power? Don't make me laugh. That 4cyl would barely make the power the V8 made before being turbocharged. The V8 won't need as much boost to make more power.

 

[Jay]

So you think that running a turbo at 9psi on a V8 and a 4cyl, they will make the same power? Don't make me laugh. That 4cyl would barely make the power the V8 made before being turbocharged. The V8 won't need as much boost to make more power.

No, I have not even mentioned boost pressure.

Boost does not = flow

Much more air is being flowed to a 7 litre V8 than a 3 litre I6 at 9PSI.

Think of it this way, It takes more pressure to get the same quanity in a smaller space.

The V8 won't need as much boost to make more power.

True, but when the turbocharger runs out of flow (check the paticular turbo flow chart) both engines (small and big) will be limited to that.

Don't make me laugh.

You shouldn't be laughing.

 

[nd 4 holden spd]

Aye, so generally if you don't need as much boost pressure you will have a better power curve right?

I'm not sure I understand this whole flow part. You meant that each turbo gets the same amount of air through it at any given time between the 2 engines? One size turbo=max amount of air processable.

 

[Jay]

Aye, so generally if you don't need as much boost pressure you will have a better power curve right?

Power curve depends on how the engine spools the turbocharger, a large displacement engine will generally have a larger quantity of exhaust gases straight off idle, so would spool the turbocharger (and supply boost) earlier, this is why many manufacturers try make ways of spooling turbochargers early as possible especially on smaller engines, and are being quite successful at it these days.

I'm not sure I understand this whole flow part. You meant that each turbo gets the same amount of air through it at any given time between the 2 engines? One size turbo=max amount of air processable.

Think of the turbo as a pump, like a your garden hose, a large hose (large engine) will flow lots of water with lower pressure, but the pump that pumps the water can only supply a fixed amount.

A small hose (small engine) will also flow lots of water but with higher pressure, the pump is still offering the same amount of water in the end.

You want more water....... put on a bigger pump or two pumps.

Fuel air mixture will only burn at a rate of roughly 14.7 parts air to 1 part fuel (any more air it it will be lean, any more fuel it will be rich), you want more power, you need more air provided by the forced induction (then suupply more fuel accordingly), all these engines with forced induction are not pulling air in, they are getting it supplied by a pump (turbochagrer, supercharger, nitrous oxide Hence the name forced induction).

 

[nd 4 holden spd]

So the same turbo can pump so much air. Are you saying that a small engine can get more boost from that turbo? I think that's wrong, the turbo can compresss that air to a certain pressure and give that compressed air to the engine. A large engine will take more compressed air at once and make even more power.

 

[Jay]

Turbo boost is only limited to either the the strength of the Turbocharger (why many Japanese tuner cars go for high quality turbos like make from HKS) and until the turbine can't keep up with the flow with the air and stops providing extra boost.

A turbocharger may run out of flow on a 3.0L I6 at 40psi, while the same turbo can't keep up with flow on a 7.0 V8 and can only push 25psi into it, (end result is the same air).

Remember PSI doesnt = flow (the speed of air the turbo is pushing, not force on the air)

Your thinking a if a turbo can make upto 50psi on a 3.0L I6 it can also provide 50psi on a 8.0 litre V10, not true, iw would be lucky to make 25psi on the 8.0. Want more, get a higher flowing turbo.

 

[nd 4 holden spd]

What do you mean? If there is more gas coming from the 8.0L is just uses what gas it needs and passes the rest through, it might no get enough flow from the 3.0L to produce that much pressure. I really don't see how what you're saying could make sense.

BTW- 40psi is a LOT of boost

 

[Jay]

What do you mean? If there is more gas coming from the 8.0L is just uses what gas it needs and passes the rest through, it might no get enough flow from the 3.0L to produce that much pressure. I really don't see how what you're saying could make sense.

The big engine will supply more exhaust gas right away, soo spooling will happen earlier, a smaller engine has to start with less..... but if it flows 50lb's/min in, it will flow that out, just like the big engine.

So if a 8.0 is flowing 60lb's/min (thats air flow not boost) in it will a similar volume will come out to spool the turbo more (untill the wastegate needs to be used), if the 3.0L flows 60lb's/min in, it'll do that same as the big engine on the way out, and the output will be similar to the 8.0Litre at that point.

keep in mind the 8.0 may be flowing 60lb's (flow not boost) in at 2500rpm while the 3.0 maybe doing 60lb'/mins at 5000rpm but then the 8.0 is likely to redline at 5500-6000rpm while the 3.0L likely going to 7500-8000rpm.

BTW- 40psi is a LOT of boost

Yes it is alot, but how do you think these tuned smaller engines produce 1000hp+, the intake is smaller so more boost and revs is needed to make the same power. Thats why the engine blocks and general design are made to higher tolerances (but thats a different topic I have covered before).

 

[nd 4 holden spd]

Which inherently results in a lack of torque meaning the 8.0L will make as much power thanks to large displacement but have more torque to accelerate with.

 

[Jay]

Which inherently results in a lack of torque meaning the 8.0L will make as much power thanks to large displacement but have more torque to accelerate with.

Not lack of torque, thats what the air is providing... Torque, the horse power number comes from the formula

HP = rpm x T(torque) / 5252

Dyno's measure torque and calculate the HP real time and display it. Remeber look at the formula, HP is just a speed function of Torque.

The large displacement engine will not provide higher peak torque overall (using same forced induction) but in a straight bolt on for will provide a lower and likely wider torque band (depending on how the torque holds up at higher RPM's due to valve train)

Wide and torque bands are something many manufactures are also trying to provide without having to provide very large capacity's

 

[nd 4 holden spd]

No the 8.0L will make more torque, rearrange that equation and you find that more RPM inherently=less torque.
T= (HP x 5252)/rpm

A larger denominator = a smaller number. Guess what? The RPM is the denominator here. RPM makes power, but means less torque- forced induction or not.

 

[gman07]

I find it helpful to think in terms of mass flow rather than volume and pressure. A certain mass of air needs to be mixed with a certain mass of fuel to create a certain hp number. Because the larger engine inhales a larger volume of air, the air can be at a lower pressure and you still end up with the same mass flow. The smaller engine needs much higher pressure to achieve the mass flow needed to support the same hp level. Thus, the smaller engine's turbo needs to be efficient at higher boost levels, while the larger engine's turbo needs to be capable of high volume flow rates at low boost pressures.

I would really like to see boost gauges with some real numbers on them, as well as more realistic sounds.

 

[gman07]

No the 8.0L will make more torque, rearrange that equation and you find that more RPM inherently=less torque.
T= (HP x 5252)/rpm

A larger denominator = a smaller number. Guess what? The RPM is the denominator here. RPM makes power, but means less torque- forced induction or not.

Torque is the independent variable. Torque doesn't rely on hp, hp relies on torque; an engine produces a certain torque at a certain speed. From these two, hp can be calculated.

However, you are correct in that if you have an engine producing 400hp at 8,000 RPM and an engine producing 400hp at 3,000 RPM, the 3,000 RPM engine will be producing more torque at that point. However, this only tells you the torque being produced at peak hp, not the peak torque.

I'm kinda tired, so I hope this makes sense.

 

[nd 4 holden spd]

It does, but peak torque is probably higher for the lower revving one anyway.

 

[Jay]

To get down to business, the same flow of the turbocharger will provide roughly the same amount of end result energy. I as you pointed out mistakenly related it directly to torque and wrongly some turbo salemen related it to HP, probably because it has more appeal to tuners. I personally just check flow maps.

It all depends on how the engine is setup and tuned and how that energy is used, if the turbocharger supplies 70lb's/min of flow, it depends on where on the rev range it is supplied, at lower RPM's it will suppliment Torque and at higher RPM's it suppliments HP but the amount of energy consumed (converted) end result is the same. Which is why cars are geared differently, to take advantage of where the energy is.

So yes, a 8.0L may provide more torque peak but it will have a lower HP peak than the 3.0L using the same overall air flow supplied by the turbo, it equals out as the energy is the same.

 

[Eric.]

That would kind of defeat the purpose of some cars though, like being able to turbo a 3000GT SR which is lighter would render the VR4 and MR models useless. It's not if you can do it, it's if you should, that they make some cars in accessible to turbos. Plus they don't want turbocharged, 1500hp V8s stomping around GT tracks.

Who cares what they think!?

 

[nd 4 holden spd]

Watching that video reminded me of a few more things, if they had 2000hp turbo V8s in GT5 they'd have to model the wheelies and wheelspin they do.

 

[Jay]

in GT5 they'd have to model the wheelies

Thats what I have been hoping for, for a long time. I want drag tyres in GT that can hook up good enough to lift the front's, even with the power and weight reductions available in GT4 many cars could lift fronts easily.