[WEC] Porsche Prototype Discussion

[MyNameIsNigel]

Originally Posted by gwyllion

@MyNameIsNigel: You need to catch up the earlier posts in this thread

The direct link to these videos was already provided by deggis in the same post. And so was the 250 hp number for the front MGU.

Oups

I was too busy attending the Geneva Motor Show yesterday and missed that. Sorry for the double posts

[deggis]

Geneva stage pics: http://www.endurance-info.com/fr/pho...lon-de-geneve/

Just to see the livery on the real car; otherwise this is obviously obsolete to the Sebring car.

[Lanky Turtle]

Porsche 919 along with Audi R18 and others testing at Sebring today.
https://www.youtube.com/watch?v=xyM79Nq9cUA

[deggis]

How good video that is in terms of sound, is it that silent even compared to the Audi? :/

Wind probably blows some of the sound away (camera mic).

[Spyderman]

Originally Posted by Lanky Turtle

Porsche 919 along with Audi R18 and others testing at Sebring today.
https://www.youtube.com/watch?v=xyM79Nq9cUA

Very nice! Thank you.

[TF110]

The car seems quiet in other videos as well. A little bit louder than Audi.

[Lanky Turtle]

The mic kind of balances the sound levels but the Porsche is quite a bit louder than the whisper quiet Audi, at least under acceleration. But all the other cars there, the 911, BMW's, P2 Nissans are way louder than the 919.

[hcl123]

Very strange that turbine generator "on top" of the engine ...ummm

Yes it seems a single one Turbine Generator or TIGERS (unique).. . yet it can yet a Motor/generator apparatus ( >95% of time used like generator).

Hard to tell for sure, but from images seems the engine ancillaries are electric motived.

[GT6]

Originally Posted by Lanky Turtle

Porsche 919 along with Audi R18 and others testing at Sebring today.
https://www.youtube.com/watch?v=xyM79Nq9cUA

Yes thanks for posting the link

[mikuni]

Originally Posted by deggis

How good video that is in terms of sound, is it that silent even compared to the Audi? :/

Wind probably blows some of the sound away (camera mic).

It does seem very quiet, but it has a nice raspy note to it.

That's the biggest problem with these super efficient energy recovery vehicles - nose escaping is essentially energy lost, so they are attempting to keep that to a bare minimum.

[PascaLM]

Originally Posted by mikuni

It does seem very quiet, but it has a nice raspy note to it.

That's the biggest problem with these super efficient energy recovery vehicles - nose escaping is essentially energy lost, so they are attempting to keep that to a bare minimum.

Noise energy is nothing compared to heat and pressure in the exhausts ; but the noise is reduced by regulation (110 or 115 dB at 15 metres) and the labyrinthine system of turbo and generator.
The microphone and its amplifier sensibility can modify what should be the real perception of the sound. I have a digital recorder that can automatically raise a lower noises and reduce higher ones.

I like the sound too, like the Toyota of mid eighties or the WR.

[gwyllion]

Originally Posted by hcl123

Very strange that turbine generator "on top" of the engine ...ummm

Porsche wants to keep the engine as short and compact as possible. This is beneficial for weight distribution (engine weight close to center of the car) and the aerodynamics (lower rear deck).

Originally Posted by hcl123

Yes it seems a single one Turbine Generator or TIGERS (unique).. . yet it can yet a Motor/generator apparatus ( >95% of time used like generator).

I don't think that the exhaust ERS can/will be used as electric motor, especially because it is mounted in parallel with the turbo (and not in series).

[Gingers4Justice]

It's really difficult to tell with these videos, as it's hard to get a sense of perspective with the sound.

It does seem to be quite quiet, but then again, right at the end of the video, you can hear the Porsche very clearly when it overtakes the OAK. The Nissan engine certainly isn't quiet, especially at the pit-straight at Le Mans.

Sounds like a completely different engine to what you hear in the first video which surfaced.

http://www.youtube.com/watch?v=0Cir4T3DHQY

[bjohnsonsmith]

Originally Posted by Gingers4Justice

It's really difficult to tell with these videos, as it's hard to get a sense of perspective with the sound.

It does seem to be quite quiet, but then again, right at the end of the video, you can hear the Porsche very clearly when it overtakes the OAK. The Nissan engine certainly isn't quiet, especially at the pit-straight at Le Mans.

Sounds like a completely different engine to what you hear in the first video which surfaced.

http://www.youtube.com/watch?v=0Cir4T3DHQY

The problem with YouTube clips is the sound is compressed.

[hcl123]

Originally Posted by gwyllion

Porsche wants to keep the engine as short and compact as possible. This is beneficial for weight distribution (engine weight close to center of the car) and the aerodynamics (lower rear deck).

ummm... i suspect the peculiar position of that turbine generator has to do with heating... somehow try take advantage of the top ram-air intake to cool it down (with 4 cylinders and low displacement(2 L) a petrol don't need big intakes).

That is the problem with this devices placed near the engine (heat), perhaps the reason Audi ditched the ERS-H for now.. first time they can have a large top ram-air intake for the engine they are not going to restrict it in any way ( diesel wants to breath above anything else).

Originally Posted by gwyllion

I don't think that the exhaust ERS can/will be used as electric motor, especially because it is mounted in parallel with the turbo (and not in series).

It can and has advantages, after all a turbine is a separated device in any apparatus (connected trough an axle to a motor/generator or an alternator), and only the turbine enters in contact with the exhaust flow.

Yet true.. it can be only an alternator, that is, a generator only, but a motor/generator can perhaps even generate more electricity in the synchronous fashion (which an alternator can't) be it permanent magnet induction or switched reluctance ( only controls are more sophisticated and heavier ).

A tradeoff between flexibility and advantages for simplicity and durability ( hard to risk losing because of failure of one of this contraptions... for now!..)... be it parallel or series ( with a wastegate/bypass or possibly without it-> like F1 ).

[hcl123]

Originally Posted by bjohnsonsmith

The problem with YouTube clips is the sound is compressed.

lol ... no!... get used to it... Porsche sound is very little higher than the Audi's diesel (and its a smaller engine).

golden rule... the higher the "efficiency" the lower and more choked or hushed the sound is( no fuel burning in the exhaust pipe)... and no matter if its a petrol, and in the future the distinction will be nill/zero/nada! lol..

[Bandicoot17]

Jani's at the circuit

[PascaLM]

Originally Posted by hcl123

lol ... no!... get used to it... Porsche sound is very little higher than the Audi's diesel (and its a smaller engine).

golden rule... the higher the "efficiency" the lower and more choked or hushed the sound is( no fuel burning in the exhaust pipe)... and no matter if its a petrol, and in the future the distinction will be nill/zero/nada! lol..

Explosions in the engines give waves shocks and sound, not burning petrol in the exhausts pipe. Or I don't understand what you mean.

[hcl123]

lol... "explosions" is one thing that particularly you don't want in a petrol engine, its called "knock" and can destroy your engine.

Its "combustion" alright... and it follows a "flame-front" propagation from the top of cylinder adjacent to the spark plug to the bottom, and for max "efficiency" you don't want any fuel droplets to much or too much time adhering to the cylinder walls, because they will go unburned, and is this unburned part that goes to exhaust pipe and are hot/very hot and pressured , and when in a section of exhaust pipe they encounter oxygen again (entering from the exit) they will burn!...

That is why "once" in sporty high rev engines, if you suddenly cut the throttle -> suddenly dropping pressure of exhaust flow permiting oxygen to enter inside exhaust pipe from the exit, where is hot and pressure enough... you would see flames coming out of the exhaust pipe. This happened because racing type of petrol engines runs (used) all the time with a fuel rich mixture-> some fuel went unburned all the time.

You don't see that now in street cars because they don't run "fuel rich" anymore -> only stoichiometric 14,7:1 ... but the effect still happens to some degree now in motorsport in spite of no flames out of the pipe, its still fuel rich engines...

But all that will be past... direct injection permits much much better control even with kind of fuel rich engines, and there are ways to prevent droplets to adhere to the cylinder walls (swirl effects)... with that efficiency goes up, power available goes up, but the characteristic sound will be gone.

[ besides... believe it or not, diesel combustion "inside" the cylinder produce much more of that pressure waves and more energetic combustion ( not explosion) than petrol... that is why the much more torque... yet they are kind of silent -> so most of sound don't come from "inside" cylinders ]

[Lanky Turtle]

Originally Posted by Gingers4Justice

It's really difficult to tell with these videos, as it's hard to get a sense of perspective with the sound.

It does seem to be quite quiet, but then again, right at the end of the video, you can hear the Porsche very clearly when it overtakes the OAK. The Nissan engine certainly isn't quiet, especially at the pit-straight at Le Mans.

Sounds like a completely different engine to what you hear in the first video which surfaced.

http://www.youtube.com/watch?v=0Cir4T3DHQY

Even though they're all Nissan powered, all 3 of the P2 cars sounded different to me. The Oak car was a lot quieter than the Millennium car, and the Greaves car sounded like shotgun blasts everytime they shifted up through the gears.

[deggis]

Originally Posted by bjohnsonsmith

The problem with YouTube clips is the sound is compressed.

You think that exactly same original audio track of the video transformed into DTS/Dolby/whatever format would make the Porsche sound any louder? Recompressing and as a result lowering the audio quality doesn't magically remove perceived decibels from the exhaust note.

[hcl123]

Exhaust flow in any of this engines petrol or diesel... still has some considerable pressure. So you can engineer the sound to be louder or etc... if that doesn't go against efficiency by creating to much back-pressure conditions, that is ... and if you are crazy enough to bother lol

The best will be tiny loud speakers that are now possible real tiny (sort off)... "and flat"... powerful enough wasting little electricity... and in a material that is even "water proved"...

You can have a an all electric (BEV) with the sound of a sport V12 of the 80's LOL... the "sound processor" to do this now will also be tiny and very low power... and it can even simulate different rev speeds and gear changes LOL ( if there will be a market they will do it -> want it to sound a Ferrari... a Lamborghini ... a Bugatti ?? ... you got it ! )

[ every different type of exhaust from the manifold to the tail end, produces different sounds even if the engine is exactly the same...matter of fact you can eliminate most of the sound(to a degree) even in different type of engines... in production street cars is exactly that what they are doing... its muffled... all car constructors engineer their sound... including Porsche ]

[hcl123]

In motorsports nobody "really" engineer the sound... not a concern, not to bother with already too many details to bother... perhaps until now...

FIA and or FIA/ACO now demands less aggressive sound i think ... perhaps with the concern we can see some artists lol

[Gingers4Justice]

The sound issue will sort itself out. If a lack of sound turns people away, then the organising bodies and manufacturers will bring the sound back. So we'll just have to see.

[mikuni]

Originally Posted by Gingers4Justice

The sound issue will sort itself out. If a lack of sound turns people away, then the organising bodies and manufacturers will bring the sound back. So we'll just have to see.

I think F1 is leading the way for muted sound this year, particularly compared to how it has been in recent years. At least WEC/LMP1/2 has been slowly heading in this direction over time. I think providing the sound is still unique, and still provides an "atmosphere" the fans will still be happy without it needing to be in the hundreds of decibels. Time will tell.