dumb question but is torque what its all about?

[r3ccOs]

Based on non-science observations and anecdotes and understanding the measurement of HP vs torques...

I think the modern turbo car with variable valve timing is not only effective, but with the very minute or almost non-existent lag, is most effective way to get vehicles moving due to the flat torque they make...

I find that the trend of the modern turbo car is to use smaller turbos,, willing to compromise the engine at top RPM, and feed the boost earlier down low and longer.

For instance, my observation on my ecoboost with the K03 sized turbo's per bank, give me 11.7 boost right up until say 5200 RPM where you see that they can no longer keep up... (thinking that even with a tune, you'd see that happening due to the physical limitation of the small turbos)

Turbo at the boost at whatever psi set by the waste gate, almost provides a consistent torque curve until it no longer can provide the engine with enough air...

I think this is very true even in big Diesel's using say a 57/61... where the torque isn't' necessarily strictly due to the nature of the fuel, but rather that diesels can move fuel and air through a ridiculous compression ratio, which in turn can spool a huge turbo, that when adding 30PSI almost is tripling the displacement (6.7l) of the said displacement through almost its entire RPM range, which I also notice tapers off fast once it gets past where the turbo can provide sufficient boost.

So, when people can't comprehend the physics as to why a GTI with 210 HP can do a sub 6 second 0-60 run, is it because its making max torque (due to full boost) as low as 1500 RPM...
So if the engine in turn maxes out in HP and Torque by 5000RPM, but you still have 100% of the torque immediately in to the next gear, the acceleration is going to be far more linear, when compared to say a peaky K24Z7.

sorry, this was wordy but are my observations correct?

[rage2]

Basically yea. Much wider torque curve than a NA car. Teslas are a great example of this phenomenon, where it makes full torque at 0rpm and has no gears which is why it's so fast off the line and at low speeds. No gas engine car can touch it. Past 100km/h it's about the same as a 500ish hp car, and runs out of steam past 200km/h.

[dirtsniffer]

I think this is sort of two topics. Boost vs NA. at altitude NA cars will have make significantly less power than advertised.

Horsepower vs torque is different. You want as much area under the power curve as possible. Previously that was done with displacement or high revs but now stock cars, through forced induction, make more power down low. Having the power down low for road vehicles is great because that is where you spend most of the time, in that 1500-3500 rpm range. More low end torque means more low end power.

For high performance cars that see high rpms it makes sense to have the a later peak torque and a higher power. As it will have more power under the curve for its typical operating range.

Edit: to answer your question it's all about power. Torque is a force and power is the rate at which that force is applied. Peak hp and torque help sell, but it's all about the shape of the power band.

Gearing is a whole different topic.

[Darell_n]

Your Ecoboost makes great torque and can hold on to 5200 rpm. If you can still hold that boost up to 7500 rpm, now you're making horsepower too. Very tough to accomplish low end boost without running out of steam quick. I think my WRX runs out of steam at like 4500. It pulls harder on the highway in 5th or 4th, than passing in 3rd.

[Sentry]

I hate small turbos that blow their load too early. Big torque spike that fools you into thinking it's fast and then it nosedives. I'd gladly take a bigger turbo with a little "lag" for something that pulls hard to redline.

I drove a tuned N55 135i today and it felt pretty unsatisfying compared to my M5 even though it made the same peak whp and MORE peak torque due to it's tiny early-spooling turbo. The reason being my car has more area under the curve. It may make less torque but it's available everywhere instead of at a sharp mountain peak where a turbo first hits full boost.

http://i.imgur.com/vdWpBjo.jpg

[nismodrifter]

ALH tdi's ftw

http://image.trucktrend.com/f/67896386+re0+ar0+st0/2002-volkswagen-jetta-tdi-dyno-chart.jpg

[r3ccOs]

Originally posted by Sentry
I hate small turbos that blow their load too early. Big torque spike that fools you into thinking it's fast and then it nosedives. I'd gladly take a bigger turbo with a little "lag" for something that pulls hard to redline.

I drove a tuned N55 135i today and it felt pretty unsatisfying compared to my M5 even though it made the same peak whp and MORE peak torque due to it's tiny early-spooling turbo. The reason being my car has more area under the curve. It may make less torque but it's available everywhere instead of at a sharp mountain peak where a turbo first hits full boost.

http://i.imgur.com/vdWpBjo.jpg

so this is where I think the variable vein technology was supposed to provide "value" but became too much of a complex and costly solution...

I think that the supercharged/turbo combo is going to be adopted more, as it essentially eliminates lag, lets the supercharger provide the immediate benefit while pre-spooling a larger turbo in a multistage fasion.

Then will over time the Hybrid-turbo solution I would reckon like in F1, where the hybrid provides the immediate almost 0 RPM torque and yet can also be used to pre-spool the turbo.

[rage2]

Originally posted by nismodrifter
ALH tdi's ftw
That's the opposite of what you want for straight line performance. It's the same torque curve as an electric motor, but without the 0rpm advantage. Just runs out of steam right after peak.


Originally posted by r3ccOs
Then will over time the Hybrid-turbo solution I would reckon like in F1, where the hybrid provides the immediate almost 0 RPM torque and yet can also be used to pre-spool the turbo.
This. The new hybrid supercars does this so well, excellent 0rpm performance, and in the case of the McLaren P1, "torque fills" the gaps left by turbo lag.

I don't think we'll see electric turbo prespooling like in F1. The whole MGU-H setup that prespools the turbos and harvests energy by acting as a wastegate works well in racing applications because you're at WOT all the time, on the street where you're barely WOT it would never harvest anything, and become dead weight. Much simpler to just fill the torque gap with motor to the wheels and not turbo.

[killramos]

Originally posted by Sentry

I drove a tuned N55 135i today and it felt pretty unsatisfying compared to my M5 even though it made the same peak whp and MORE peak torque due to it's tiny early-spooling turbo. The reason being my car has more area under the curve. It may make less torque but it's available everywhere instead of at a sharp mountain peak where a turbo first hits full boost.

http://i.imgur.com/vdWpBjo.jpg
http://www.fabspeed.com/content/hosted_images/forums/m235i_dyno.jpg

Weird thing is the that the graph on an N55 is exactly the same as your M5's
Grey line stock. Not the cleanest graph but i was trying to find one with a similar scale to the one you presented.

tl: dr the torque band is pretty much the same as your M5's so I'm not really sure what your point is about the sharp mountainous peak? Only difference is you get that torque starting earlier ( which dyno's have a tough time showing ).

Combine that with altitude effects and :dunno:

Credit where credit is due BMW has always done a great job with their torque bands, even in the transition to all turbo engines. The new B58 looks even more promising, holding its torque through to ~5300 rpm rather than starting its decline just south of 5000 in the N55. http://www.n54tech.com/forums/attachment.php?attachmentid=41653&stc=1&d=1448998247 On paper its no more peak power or torque, but in terms of performances its a huge difference.

[r3ccOs]

Originally posted by rage2

That's the opposite of what you want for straight line performance. It's the same torque curve as an electric motor, but without the 0rpm advantage. Just runs out of steam right after peak.


This. The new hybrid supercars does this so well, excellent 0rpm performance, and in the case of the McLaren P1, "torque fills" the gaps left by turbo lag.

I don't think we'll see electric turbo prespooling like in F1. The whole MGU-H setup that prespools the turbos and harvests energy by acting as a wastegate works well in racing applications because you're at WOT all the time, on the street where you're barely WOT it would never harvest anything, and become dead weight. Much simpler to just fill the torque gap with motor to the wheels and not turbo.

QFT... so the wastegate is basically a turbine, very cool but you're right if you're not generating boost, there is not real net benefit other thank elminating pre-spool lag, which can be had with a supercharger or just good enough with an electric motor coupled to the crank, as that will get enough air moving through the cylinders anyhow

[Darkane]

I'd love to see more hybrid/NA vehicles.

A 50hp/100tq motor on a FRS would be amazing.

[r3ccOs]

Originally posted by killramos

http://www.fabspeed.com/content/hosted_images/forums/m235i_dyno.jpg

Weird thing is the that the graph on an N55 is exactly the same as your M5's
Grey line stock. Not the cleanest graph but i was trying to find one with a similar scale to the one you presented.

tl: dr the torque band is pretty much the same as your M5's so I'm not really sure what your point is about the sharp mountainous peak? Only difference is you get that torque starting earlier ( which dyno's have a tough time showing ).

Combine that with altitude effects and :dunno:

Credit where credit is due BMW has always done a great job with their torque bands, even in the transition to all turbo engines. The new B58 looks even more promising, holding its torque through to ~5300 rpm rather than starting its decline just south of 5000 in the N55. http://www.n54tech.com/forums/attachment.php?attachmentid=41653&stc=1&d=1448998247 On paper its no more peak power or torque, but in terms of performances its a huge difference.

I think how to smooth the band out of a turbo is with the right cams leveraging variable valve timing... and now is the way to provide supplementary linear "power" delivery in performance applications.

that N55 motor has most of its torque beginning as early as 1300, the torque begins to taper at 5200 is still balanced and designed to generate peak horsepower at 6700 RPM

so even though the torque is lessened, the engine (and intake system) is still able to provide enough air (even with the turbo not being able to keep up) for the engine to make high RPM peak horsepower and based how horsepower is a unit of measure of rate of work done... makes up for the reduced torque

[rage2]

Originally posted by r3ccOs
so the wastegate is basically a turbine
No, that wouldn't be efficient. It's a motor/generator that's connected to the turbine/compressor shaft:

http://image.superstreetonline.com/f/66480747+w+h+q80+re0+cr1+ar0+st0/magneti-marelli-thermal-energy-recovery-system

To control compressor speed, the unit acts as a generator to harvest energy, putting resistance on the shaft and converting kinetic to electrical energy. It then acts as a motor from the transition to off throttle to throttle to speed up the shaft to eliminate turbo lag. There's still a mechanical wastegate in place in case that the MGU-H unit fails, so that the turbo doesn't overspeed, overboost, and blow shit up.

Pretty complex setup that has almost zero gains in street applications.

[dirtsniffer]

but fuck is it cool!

[Darell_n]

I prefer starting with a large enough engine to spin the tires before the boost builds at 4000 rpm. Provides street traction control and 2-step and/or laughing gas for spirited starts. Any manufacturers offer these options? :)

[r3ccOs]

Originally posted by Darell_n
I prefer starting with a large enough engine to spin the tires before the boost builds at 4000 rpm. Provides street traction control and 2-step and/or laughing gas for spirited starts. Any manufacturers offer these options? :)

but that's what we're saying... even big engines don't produce peak torque down low, they are linear but still peaky.

so... a big engine with a forced charge like the LS3 in the CTSV or Camero SS or Z06 is an example of where you have ridiculous power throughout the entire rev range.

[sr20s14zenki]

I think it was Carrol Shelby that said "horsepower sells cars, torque wins races"

I always liked this one tho. "Horsepower is how quickly you hit the wall, torque is how much of the wall you take with you"

:D

[rage2]

Originally posted by Darell_n
I prefer starting with a large enough engine to spin the tires before the boost builds at 4000 rpm. Provides street traction control and 2-step and/or laughing gas for spirited starts. Any manufacturers offer these options? :)
You can't beat electric motors off the line. With the ability to have full torque at 0rpm, you can manage torque to the drivetrain to provide maximum torque that the tires can manage without spinning and reach the absolute limits of traction that the tires can provide (assuming there's enough torque with the electric motors).

With a gas engine that always has a minimum engine speed (idle) and even if you have retarded torque at idle, you're relying on a clutch/tq converter to transmit optimal power to the drivetrain to get the best acceleration without wheelspin from 0, which is why you're never going to have the consistency or the performance that an electric motor can provide on street tires.

If you look at Tesla's acceleration curve, it destroys everything right off the line and gains a massive advantage in both distance and speed in the first 200ft. Every other car is just playing catchup at that point to the 1/4 mile even though at the same speed the Tesla isn't really putting that much power to the wheels anymore.

That's why a hybrid setup is the way to go. Get the first 200ft advantages with the assistance of an electric motor, and gas powered goodness at higher speeds. Coupled with AWD, it's the best of all worlds, and why the Porsche 918 does silly 9.8s@146mph 1/4 mile times all day long.

[heavyD]

As for current turbocharged gasoline engines for a daily driver I would take an engine with big midrange over one that has lag and makes power higher in the rev range. When I replaced my 2013 STI with my 2015 Focus ST the Focus felt immediately quicker in stop and go traffic because the ecoboost engine provides massive mid range power while the EJ257 has to be worked hard to hit peak power and it's just not practical to be going full throttle from light to light.

[sr20s14zenki]

^ The focus ST is hilarious. I have a dyno sheet from one i did somewhere here. It apparently spikes the boost in the low revs to give you more power right away. This one made like 260 ft lbs at 2500 rpm LOL. Ill see if i can dig it up. its got this massive hump at the beginning of the pull,a nd then normalizes

[sr20s14zenki]

Crappy pic, but here it is . I think hes got the Mountune goodies, charge cooler, downpipe, exhaust...tune. i forget



http://i163.photobucket.com/albums/t320/ca18det240sx/12825302_10207526005082159_1701565604_n_zpsb5cbuhvv.jpg

[dirtsniffer]

what happens at 2700 rpm?
end of overboost?

[sr20s14zenki]

Originally posted by dirtsniffer
what happens at 2700 rpm?
end of overboost?

Yeah pretty much. I would have to print out the whole trace to show map, etc. But it spikes to 20 psi and by the end of the run its 12 psi. It says in the owners manual that it does that temporary overboost on purpose. LOL. before i knew that, im looking at the sheet like "Wtf?". We werent tuning or anything, it was just a base line for curiosity.

[r3ccOs]

Originally posted by sr20s14zenki


Yeah pretty much. I would have to print out the whole trace to show map, etc. But it spikes to 20 psi and by the end of the run its 12 psi. It says in the owners manual that it does that temporary overboost on purpose. LOL. before i knew that, im looking at the sheet like "Wtf?". We werent tuning or anything, it was just a base line for curiosity.

Unless the wastegate itself reduces the boost by opening up to keep the turbo's from perpetually spinning to get up to 20psi up the rev range (if the turbo is big enough) I reckon that the turbo is small and is designed to provide the immediate torque and HP to get enough forced air/fuel until the engine itself can take over to use its RPM to get to max power (HP) while still providing some boost.

much more liveable that way to have a no lag and fat midrange.

I think in the past where turbo's were "on tap" as extra power when needed, the intent is to provide boost all the time, allowing for smaller displacement engines to give the livability of a larger displacement at the sacrifice of the top end of the engine.

that said, I wonder if that means more turbo engines are built imbalanced and emphasis on advanced cam positions on purpose, with the design to maximize the benefit of the boost to generate more torque.

[sr20s14zenki]

Originally posted by r3ccOs


Unless the wastegate itself reduces the boost by opening up to keep the turbo's from perpetually spinning to get up to 20psi up the rev range (if the turbo is big enough) I reckon that the turbo is small and is designed to provide the immediate torque and HP to get enough forced air/fuel until the engine itself can take over to use its RPM to get to max power (HP) while still providing some boost.

much more liveable that way to have a no lag and fat midrange.

I think in the past where turbo's were "on tap" as extra power when needed, the intent is to provide boost all the time, allowing for smaller displacement engines to give the livability of a larger displacement at the sacrifice of the top end of the engine.

that said, I wonder if that means more turbo engines are built imbalanced and emphasis on advanced cam positions on purpose, with the design to maximize the benefit of the boost to generate more torque.

Most likely. I drove the car, the thing was a little terror LOL. And im used to things in the upper 400-500 hp range.

[r3ccOs]

Originally posted by sr20s14zenki


Most likely. I drove the car, the thing was a little terror LOL. And im used to things in the upper 400-500 hp range.

with boost, and torque I think that you just don't have to rely on RPM to make "power"

I would imaging that the advances in turbo's from KKK, Borg Warner etc... in turbo diesel applications (whether truck or European small engines) have had a substantial influence on this.

Diesel fuel still has the advantage of being able to create ridiculous cylinder compression, allowing for even more boost, case in point a Cummins 6.7

but I mean why even bother looking at a TDI when fuel costs are similar, when a gas motor can produce just as much torque and far more HP using the same technique.

[danno]

Originally posted by heavyD
As for current turbocharged gasoline engines for a daily driver I would take an engine with big midrange over one that has lag and makes power higher in the rev range. When I replaced my 2013 STI with my 2015 Focus ST the Focus felt immediately quicker in stop and go traffic because the ecoboost engine provides massive mid range power while the EJ257 has to be worked hard to hit peak power and it's just not practical to be going full throttle from light to light.

How do you compare those to the golf r? I find it comes into boost much later than my 2007 gti did, but it pulls hard at 5k and up.

My v8 audi rs4 responded much better off the line but slowed as it built. I never got to do a drive Side by side of the rs4 and golf r but I think they were roughly the same speed.

[Darkane]

Originally posted by danno


How do you compare those to the golf r? I find it comes into boost much later than my 2007 gti did, but it pulls hard at 5k and up.

My v8 audi rs4 responded much better off the line but slowed as it built. I never got to do a drive Side by side of the rs4 and golf r but I think they were roughly the same speed.

Your high strung V8 was good off the line and lost steam as it revved? That's contradictory of that engine. Why do you feel this happened and how?

[danno]

It's probably more of a throttle response. I understand that it doesn't sound correct but it is how it felt.

Rs4 was quick to respond to the throttle, the golf r I can floor the pedal and it doesn't move till 3500-4000. I was swaping between cars daily and the difference was substantial. I know a tune will get me better throttle response in the golf r, just havnt done it yet.

[Sentry]

Originally posted by killramos

http://www.fabspeed.com/content/hosted_images/forums/m235i_dyno.jpg
The drop off is steeper on the N55's dyno.

Below 5000 the N55 has a 20-30ftlb advantage but you have to wait a half second, the S62 is instant and punchy.

Above 5000 the S62 has a 20-30ftlb advantage and feels more rev happy instead of as if it's wheezing.

I'm not saying N55/N54s aren't good. Just that they'd be a whole lot better with a bigger turbo(s) that carries torque to redline. :D

[heavyD]

Originally posted by danno


How do you compare those to the golf r? I find it comes into boost much later than my 2007 gti did, but it pulls hard at 5k and up.

My v8 audi rs4 responded much better off the line but slowed as it built. I never got to do a drive Side by side of the rs4 and golf r but I think they were roughly the same speed.

It doesn't hit hard as soon as the ST but it pulls much harder over 6k RPM where you already shifted at about 5800 RPM with the ST. It's has a little bit of turbo lag but overall it's a pretty flexible engine.

[sr20s14zenki]

Just to add to the discussion, i cannot WAIT to see how things progess when/if konigsegg makes this available to all auto makers.

http://koenigsegg.com/freevalve-technology-unveiled-at-beijing-motor-show-in-qoros-qamfree-concept-car/

Think of what kind of torque you can generate on small engines, with infinitely changeable cam profiles, both in lift and duration. The possiblities are HUGE imo. Instead of getting a new cam, you just change the program....:eek:

[Neb]

Originally posted by sr20s14zenki
I think it was Carrol Shelby that said "horsepower sells cars, torque wins races"

I always liked this one tho. "Horsepower is how quickly you hit the wall, torque is how much of the wall you take with you"

:D


So true!

Torque is definitely where it's at.