5 ms·

It's about predictable torque curve and throttle response. And this is where the current generation of hypercars come inL the Farrari LaFerrari, the Porsche 918

by rkangel 12y ago

It's about predictable torque curve and throttle response. And this is where the current generation of hypercars come inL the Farrari LaFerrari, the Porsche 918, the McLaren P1 and at a slightly different level the BMW i8. The electric motors can be used to 'fill in the gaps' in the torque curve, by providing extra power in the right places. You can use a turbo for good power to weight ratio, but the electric motor makes up for all the deficiences. And the efficiencies you get with the hybrid system means that you don't even have to bother with the turbo necessarily (Porsche and Ferrari don't have one) Every review, but particularly for the Ferrari, talk about the massive and instant power delivery you get when you floor it so clearly it works. You can also perform an additional trick that they use in F1 - use the electric power to spin up the turbo (and harvest energy that way too). That isn't in use in road cars yet that I'm aware, but it will be I expect. Basically my point is that it isn't about the turbo, it's about the electric motor. It might be on its own like the Tesla Model S, or it might be in a Hybrid system like the cars above, but the torque you get from an electric motor is just too good to avoid.

jongala 12y ago
Yeah, exactly — once you have an electric motor/generator and an energy store, the whole game changes because you can approach the power sync problem of lag in new ways. Also, the issue of turbo size and over/under producing boost and the need for wastegates can be better managed if there is a way to capture and store exhaust energy without routing it directly to the compressor. Some of the more sophisticated work here is also being done by Porsche in their LeMans program, which has (as I understand it) a uniquely complex turbo/hybrid setup. I think it's really exciting. Considering this type of usage — mostly transient stuff — it's tempting to think of a system for sports cars with a supercap energy store that's lighter weight than a battery store. Toyota use supercap stores in their LeMans car, I'll be interested to see if that trickles down anywhere.
- seanp2k2 12y ago
  Idk, is there something wrong with liking the simplicity and predictability of something with less computers and a big NA motor, like a Viper or a motorcycle? Enjoying driving is about much more than just speed and power-to-weight ratios, and the article makes a good point about their effective impact on air quality already being negligible. I'd rather see a bigger shift in industry standards such that e.g. power generation becomes more efficient vs the current trend of giving everyone who buys a Porsche 918[1], Tesla, or Prius a tax break for saving the planet. 1. http://www.fueleconomy.gov/feg/taxphevb.shtml http://www.fueleconomy.gov/feg/taxphevb.shtml because someone buying a $845,000 car which gets 20mpg city / 24 highway and carries 2 people definitely deserves a $3,667 tax break for reducing emissions
  - jongala 12y ago
    So two very different thoughts here, and I basically agree with both: yes, there is still a place for simple, mostly analog, NA powered sports cars, and yes, it is a distortion of the system for a 918 to get some kind of green subsidy. I was just speaking towards new paths in getting the most out of ICE-centered power systems, that an alternative power store and MGU can uncover better turbocharging options vs. a purely mechanically coupled turbine/compressor. These technologies are being developed at the less price-sensitive high end of the market, just as Tesla is doing with an all-electric drivetrain. They started at 100K+ roadsters, developed to an 80K luxury sedan, and are developing down market from there. I think it's totally appropriate to encourage a shift in industry standards, as you say, with incentives in this segment of the market (let alone where the Prius sits). It's a bit of an absurdity with the Porsche, but take heart that there are only 918 being made… As far as what kind of sports cars we should be encouraging, even mid-market cars are so fast now you really can't enjoy them on the road. That's why cars that emphasize a fun driving experience at still-sane speeds are the most interesting to me now, like the FR-S, the Miata, the Elise, etc. But that's a separate conversation.
- dubya 12y ago
  Supercaps are in Mazda 3's, so the parts are available. The system is call i-eloop. I think they're just used for powering accessories so far.
flyinglizard 12y ago
There's one significant problem with these hybrid powertrains, and that is weight. Porsche admitted the electric addition to the 918 V8 engine weighs about 300kg, all considered. The 918 is a very heavy car for what it is, at 1700kg, compared to 1380kg for the Carrera GT (it's ancestor, in a way). The Tesla Model S is also a very heavy car, at 2100kg. However that weight is somewhat offset by its placement, right near the road using a flat floorplan housing all drivetrain components. While the weight can be cancelled out in a straight line because these hybrid drivetrains can provide monumental straight line performance, the weight is still there for turning and braking. Turbos go around the weight issue - in fact, they can make for much lighter powertrains with a smaller displacement for a superior performance. The main problem with turbos, in Ferrari's perspective, mostly relates to the altered emotional connection with the car. No more 9k RPM revving motors with a godly sound, but something tamer (like the McLaren MP4-12C). If you ever got to drive a current generation Ferrari motor, you'd understand instantly why they are so adamant on preserving its character.
mrigor 12y ago
Volvo is working on an electric turbo apparently http://www.autonews.com/article/20141007/OEM04/141009809/volvo-tests-triple-turbo-4-cylinder-that-cranks-out-450-hp http://www.autonews.com/article/20141007/OEM04/141009809/vol...
philjackson 12y ago
You can also fill in the gaps with clever twin turbos these days. BMW are particularly good at it. Small one to spool up quickly and fill in the low range, larger one to take you through the mid.
- getsat 12y ago
  Nissan is pretty good at it, too. The twin turbo GTR destroys all of Ferrari's best offerings and costs 2.5-10x less while doing so. It's interesting that the author implies that only naturally aspirated engines give you the precise control you need in cornering when a 3.8L V6 with two enormous turbos strapped to it handily beats almost every other road-legal, non-gokart, NA-engine'd car except the Aventador... for only $100,000 brand new. http://en.wikipedia.org/wiki/List_of_Top_Gear_test_track_Power_Lap_Times http://en.wikipedia.org/wiki/List_of_Top_Gear_test_track_Pow... A tuned GTR easily beats the Aventador, though, for a fraction of the price. https://nurburgringlaptimes.com/lap-times-top-100/ https://nurburgringlaptimes.com/lap-times-top-100/
- jdc0589 12y ago
  Similar things have been done for decades. The Porsche 959 (1986-1989), Toyota Supra MKIV (1993.5-1998 USA), and FD RX-7 all had a sequential turbo setup, but they were all using two turbos of the same size. All The exhaust gas is diverted through a single turbo at low RPM to spool it quickly, then after a certain RPM is reached gas begins being diverted through both turbos equally. The problem is the control systems and extra plumbing get pretty complicated. The setup in the Supra is lovingly referred to as "the rat's nest"

by rkangel 12y ago

jongala 12y ago

Yeah, exactly — once you have an electric motor/generator and an energy store, the whole game changes because you can approach the power sync problem of lag in new ways. Also, the issue of turbo size and over/under producing boost and the need for wastegates can be better managed if there is a way to capture and store exhaust energy without routing it directly to the compressor. Some of the more sophisticated work here is also being done by Porsche in their LeMans program, which has (as I understand it) a uniquely complex turbo/hybrid setup. I think it's really exciting. Considering this type of usage — mostly transient stuff — it's tempting to think of a system for sports cars with a supercap energy store that's lighter weight than a battery store. Toyota use supercap stores in their LeMans car, I'll be interested to see if that trickles down anywhere.

seanp2k2 12y ago
Idk, is there something wrong with liking the simplicity and predictability of something with less computers and a big NA motor, like a Viper or a motorcycle? Enjoying driving is about much more than just speed and power-to-weight ratios, and the article makes a good point about their effective impact on air quality already being negligible. I'd rather see a bigger shift in industry standards such that e.g. power generation becomes more efficient vs the current trend of giving everyone who buys a Porsche 918[1], Tesla, or Prius a tax break for saving the planet. 1. http://www.fueleconomy.gov/feg/taxphevb.shtml http://www.fueleconomy.gov/feg/taxphevb.shtml because someone buying a $845,000 car which gets 20mpg city / 24 highway and carries 2 people definitely deserves a $3,667 tax break for reducing emissions
- jongala 12y ago
  So two very different thoughts here, and I basically agree with both: yes, there is still a place for simple, mostly analog, NA powered sports cars, and yes, it is a distortion of the system for a 918 to get some kind of green subsidy. I was just speaking towards new paths in getting the most out of ICE-centered power systems, that an alternative power store and MGU can uncover better turbocharging options vs. a purely mechanically coupled turbine/compressor. These technologies are being developed at the less price-sensitive high end of the market, just as Tesla is doing with an all-electric drivetrain. They started at 100K+ roadsters, developed to an 80K luxury sedan, and are developing down market from there. I think it's totally appropriate to encourage a shift in industry standards, as you say, with incentives in this segment of the market (let alone where the Prius sits). It's a bit of an absurdity with the Porsche, but take heart that there are only 918 being made… As far as what kind of sports cars we should be encouraging, even mid-market cars are so fast now you really can't enjoy them on the road. That's why cars that emphasize a fun driving experience at still-sane speeds are the most interesting to me now, like the FR-S, the Miata, the Elise, etc. But that's a separate conversation.
dubya 12y ago
Supercaps are in Mazda 3's, so the parts are available. The system is call i-eloop. I think they're just used for powering accessories so far.

flyinglizard 12y ago

There's one significant problem with these hybrid powertrains, and that is weight. Porsche admitted the electric addition to the 918 V8 engine weighs about 300kg, all considered. The 918 is a very heavy car for what it is, at 1700kg, compared to 1380kg for the Carrera GT (it's ancestor, in a way). The Tesla Model S is also a very heavy car, at 2100kg. However that weight is somewhat offset by its placement, right near the road using a flat floorplan housing all drivetrain components. While the weight can be cancelled out in a straight line because these hybrid drivetrains can provide monumental straight line performance, the weight is still there for turning and braking. Turbos go around the weight issue - in fact, they can make for much lighter powertrains with a smaller displacement for a superior performance. The main problem with turbos, in Ferrari's perspective, mostly relates to the altered emotional connection with the car. No more 9k RPM revving motors with a godly sound, but something tamer (like the McLaren MP4-12C). If you ever got to drive a current generation Ferrari motor, you'd understand instantly why they are so adamant on preserving its character.

mrigor 12y ago

Volvo is working on an electric turbo apparently http://www.autonews.com/article/20141007/OEM04/141009809/volvo-tests-triple-turbo-4-cylinder-that-cranks-out-450-hp http://www.autonews.com/article/20141007/OEM04/141009809/vol...

philjackson 12y ago

You can also fill in the gaps with clever twin turbos these days. BMW are particularly good at it. Small one to spool up quickly and fill in the low range, larger one to take you through the mid.

getsat 12y ago
Nissan is pretty good at it, too. The twin turbo GTR destroys all of Ferrari's best offerings and costs 2.5-10x less while doing so. It's interesting that the author implies that only naturally aspirated engines give you the precise control you need in cornering when a 3.8L V6 with two enormous turbos strapped to it handily beats almost every other road-legal, non-gokart, NA-engine'd car except the Aventador... for only $100,000 brand new. http://en.wikipedia.org/wiki/List_of_Top_Gear_test_track_Power_Lap_Times http://en.wikipedia.org/wiki/List_of_Top_Gear_test_track_Pow... A tuned GTR easily beats the Aventador, though, for a fraction of the price. https://nurburgringlaptimes.com/lap-times-top-100/ https://nurburgringlaptimes.com/lap-times-top-100/
jdc0589 12y ago
Similar things have been done for decades. The Porsche 959 (1986-1989), Toyota Supra MKIV (1993.5-1998 USA), and FD RX-7 all had a sequential turbo setup, but they were all using two turbos of the same size. All The exhaust gas is diverted through a single turbo at low RPM to spool it quickly, then after a certain RPM is reached gas begins being diverted through both turbos equally. The problem is the control systems and extra plumbing get pretty complicated. The setup in the Supra is lovingly referred to as "the rat's nest"