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23 Apr 2014, 22:08 (Ref:3397470) | #526 | ||
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Last edited by gwyllion; 23 Apr 2014 at 22:15. |
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23 Apr 2014, 22:29 (Ref:3397485) | #527 | |
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Quite possibly... its heavy, but they are doing much more than simply change a capacitor pack, that car has the nose off, there isn't any capacitor in the nose section i think.
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23 Apr 2014, 22:45 (Ref:3397492) | #528 | ||
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Efficiency is not only about consuming less fuel in the sense of restricting the fuel entering engine (blind downsizing). Combustion in ICE has 2 real separated events, how much fuel you put inside a cylinder each time( and how efficient complete combustion it is with the pressures resulting of it taken advantage of to the max), and how many times per a unit of time you can repeat the same process(RPM). So you can put the same or more fuel each time deriving a much more efficient combustion which usually *must* mean higher torque ( otherwise there is something very friction or drag about your engine), and you can do that less times per minute, yet derive more power (rogue power = torque x rpm) and consume less fuel in the process. So for torque is specially not truth... reason why Toyota also went for a "torque" approach with more displacement ( meaning less revs). [ higher displacement also has an interesting property, specially if playing also with larger bores and redesigned engine heads, specially if your engine is "direct injection" (which is nor the case of Toyota) ... keep the fuel droplets out of the cylinder walls as much as possible, because they tend to go unburned, which is hard to avoid in a narrower engine, even if the injected fuel quantity is much less... so balancing under limits, higher displacement can have advantages for efficiency ] Last edited by hcl123; 23 Apr 2014 at 23:04. |
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24 Apr 2014, 02:20 (Ref:3397534) | #529 | |
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Unfortunately it turns out the TS040 shot is of the less interesting "LM" (closed) front end. That appears little different from last year's LM closed nose version, relatively speaking. Really more interested in the open nose version as the opening slot is very, very narrow. Much less inlet area than either Audi or Porsche.
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24 Apr 2014, 03:40 (Ref:3397549) | #530 | ||
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24 Apr 2014, 06:46 (Ref:3397578) | #531 | |
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hcl, fuel flow restriction determines your max power (and torque @ rpm) that was my main point. Take a look at some BSFC maps:
https://www.google.si/search?q=bsfc+...w=1309&bih=895 They look all similar, no mater if diesel or petrol and probably every competitor would like to optimize their engine so that it achieves their max power at max fuel flow in that sweet spot of efficiency. The end product is obviously a compromise of size/weight and efficiency. I try to get all the boost preasure, wastegate, exhaust preassure, and the only logic that I can get is if you design engine in a way that there is practically no exhaust pressure left (eg. atkinson cycle) then you are getting good efficiency. The fact that downsized turbo petrol must use waste gate that actually means that there is energy thrown out the exhaust (captured by MGU-H). I think there is a path in the middle, meaning that you can design a bigger engine with smaller turbo that wouldn't need much (or any) wastegate and I think Audi is on that path. If not they would definitely be running the MGU-H unit. Direct injection can give you lean burn under lighter engine load, but this is still to light load to get peak efficiency, DI is also good to maximize the engine power but this means running on rich fuel ratio and your efficiency goes down the drain. Toyota has D4-S system in some of their road cars (GT86, IS 300h), the system combines direct and port injection, why do you think they kept the port injection? |
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24 Apr 2014, 07:56 (Ref:3397595) | #532 | |
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I know in the future toyota will employ two types of fuel injection. I wonder if the rules will ever allow this? Maybe wrc will in the upcoming regs and Toyota are looking towards that. I know hybrid is a big talking point there, and if GT regulations allow hybrid powertrains, Id bet they take a look there with one also.
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24 Apr 2014, 10:09 (Ref:3397642) | #533 | |
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24 Apr 2014, 11:13 (Ref:3397662) | #534 | |
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A road going Audi 4.2 V8 TDI makes 850 NM and 385 hp... I'm willing to bet that the R18's 4.0 V6 TDI makes at least 1000 NM, if not significantly more.
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24 Apr 2014, 12:44 (Ref:3397689) | #535 | |
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You can have 383 kw (513 HP) at many different engine torque figures:
1220 Nm@ 3,000 rpm 915 Nm @ 4,000 rpm 610 Nm @ 6,000 rpm 407 Nm @ 9,000 rpm 305 Nm @ 12,000 rpm The general rule is that NA no DI 3.7 L engine will max out around <400 Nm, so it needs to rev to 9,000 rpm. TS050 needs 4.8 engine from Lexus LFA |
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24 Apr 2014, 12:57 (Ref:3397695) | #536 | ||
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IMHO, they would be better off with a big DFI V8 a'la AMG's M156 6.2 litre or Toyota's own 5 liter... |
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24 Apr 2014, 13:05 (Ref:3397700) | #537 | ||
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The figure of the audi motor is this: 915 Nm @ 4,000 rpm over 900Nm at 4000rpm where the final power is reached and over 1000Nm of torque peak somewhere between 2000 and 3000rpm. This only from the diesel engine. The combined torque peak surely is over 1500Nm. The new toyota engine should rev less than the old 3.4L. If we suppose that the 3.4 was revving to 9000rpm and the new 3.7 revs at 8500rpm, are required around 450Nm to develope around 540hp @8500rpm. Being an highrev NA engine the torque peak should be after 7000rpm, more than 450Nm of course but maybe less than 500Nm in my opinion. The combined torque of the TS040 surely is over 1000Nm too. |
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24 Apr 2014, 18:04 (Ref:3397831) | #538 | |
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https://www.youtube.com/watch?v=UUFH60cqn40
Endurance test! |
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24 Apr 2014, 19:21 (Ref:3397858) | #539 | ||
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And don't worry, not even with atkinson cycle (eh! not even with diesel cycle) you run out of exhaust pressure. NEVER there is practically no exhaust pressure left with thermal efficiencies that are below the 50%... and if ever would be possible this 50%, with crap reciprocating architectures that are the only ones allowed, it will take yet quite some time and a bag full of tricks. So there will be always some wastegate of sorts for a while, the problem of MGU-H is that it can generate quite additional back- pressures specially at high engine loads, that is, exactly when upon replacing the function of a wastegate is needed the most (a no-no), you need to have a very good designed exhaust system. Also Audi doesn't have a MGU-H because their VGT ( variable geometry turbine) is quite advanced... and with higher displacement, the turbo lag issue is well mitigated. I can bet Audi engine is the same block of the 3.7L, with a higher stroker crankshaft http://en.wikipedia.org/wiki/Stroker_Kit ... the same for Toyota... augments displacement, benefits power by the torque side, and can even reduce the weight of all rotating masses. ( higher displacement, more power, less weight) Direct injection gives you much better control than a throttled system.period A trottled system like Toyotas can give you more "mixturing time", that is , if fuel and air are mixed before the intake valve opens, and better pre-mixed fuel loads can have more efficiency. OTOH a throttled system has intake pumping loses because it is running against the quite higher vacuum it creates on the admission manifold ( a good part of the NA engines sound). |
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24 Apr 2014, 20:00 (Ref:3397864) | #540 | ||
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http://www.convertunits.com/from/ft+lb/to/N+m ( convert Nm to Lb-ft) That 4.2L V8 you mention is only doing 3225 RPM (quite low RPM, quite economic for such a big engine... or "hp" numbers are sandbagged(a lie) or even electronically cut(or artificially crippled), to not scare away costumers for the cheaper to make more lucrative petrol alternatives $$$... at 4200 RPM very easy for a well balanced V8 diesel (bah! i rided a VW polo GT diesel 3 cylinder - 80hp pushed 4k RPM) would be 501 hp on your saloon... even any knowledgeable street corner tuner could do that, to that 4.2L V8 diesel ) http://www.youtube.com/watch?v=eD7qNujbr8E I bet the 4L V6 TDI could yet do above 4K RPM on the 2014 fuel rules, in video of 2013 is easy to see above 4500 RPM, even with peaks close to 4900 So 4300 RPM with 950Nm gives 578 hp ... 4500 RPM with 1000Nm gives 631 hp ... 4900 RPM with 1000Nm gives 688 hp... If a diesel engine would have the typical road sporty petrol red line at 7000 RPM , and the same typical torque of a big racing diesel(1000Nm)... it would have 983 hp lol So ranting a big diesel engine is too big and is not fair... equal ranting applies for 10K RPM is too much and is not fair... why not trade, in fair limits ? (because the diesel would win LOL -> and its scary for many because there have been testes of push to break on V12 diesels engines already close to 8000 RPM... imagine that LOL) Last edited by hcl123; 24 Apr 2014 at 20:22. |
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24 Apr 2014, 21:03 (Ref:3397895) | #541 | |
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Sure there is and always be exhaust pressure left, but the question is how much? Minimizing it will get you an efficient engine by default, if there is too much left we are seeing that you can capture it with MGU-H, but this gives you higher MJ class (fuel penalty) when you use the energy to drive the wheels.
Throttle loses are only a small issue, because in a race the engine is running at WOT most of the time, if you have a slippery surface then for lower power you simply use lower rpm, but still WOT. And very nice video of Audi telemetry, where you can clearly see that most of the time the engine is run between 4.000 and 4.500 rpm, over that line power is probably slowly dropping, this fenomenom can be seen in every diesel car, and there is not much you can do about it. I doubt torque is increasing over 4.000 rpm in that diesel engine. I wonder if this year they will be running lower rpm, is there any telemetry from this year? There is no ranting that bigger is not fair, or higher rpm is not fair whatever gives them greater efficinecy and we will see what comes out |
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25 Apr 2014, 00:24 (Ref:3397934) | #542 | ||||
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A V8 could be much better... a V12 the best ( complete balanced, usually don't need weights on crankshaft). Quote:
Sure the Toyota engine revs lower but could have more overall power, specially at lower regimes. The problem of power with augmenting RPM but then diminishing torque, is that each and any combustion event needs time to complete, the higher the RPM the less time it has, highly rotative engines with very low torque figures are a very wasteful illusion on the hp figures, the lower torque figures means less propensity to push by higher loads, that is, the more the load the engine has to push the less the capacity to reach higher RPM, reason why a F1 engine only has 600 to 700 hp, but on a moto 4, put it on a real 1 ton car and it would struggle badly. I suspect Toyota decided for a torque approach (stroking -> augment the crank rocker arms distances a little further away from crankshaft center, larger circumference the rotating cranck does)... and decided very well, i think it could be below the 8500 RPM, but OTOH over 500 Nm is not far fetched. |
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25 Apr 2014, 01:39 (Ref:3397951) | #543 | ||
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25 Apr 2014, 01:42 (Ref:3397952) | #544 | ||
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25 Apr 2014, 02:12 (Ref:3397957) | #545 | ||
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25 Apr 2014, 04:07 (Ref:3397973) | #546 | ||
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25 Apr 2014, 06:21 (Ref:3398002) | #547 | ||
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Torque curve in NA petrol is a lot more even (level) in that 3.7 L you are looking at 300-400 Nm through the whole rpm range, but this means a very steep power curve, diesel engine has a lot more level power curve. |
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25 Apr 2014, 08:53 (Ref:3398045) | #548 | |
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Good thing they have those electric motors to help them with that grunt in low rpms. Porsche as well.
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25 Apr 2014, 09:23 (Ref:3398053) | #549 | ||
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The toyota 3.7 V8 surely works as standard small-medium NA displacement race engine. Torque curve constantly rises, reaching a peak close to the revlimiter (in my speculation 7000rpm torque peak, 8500rpm revlimiter) and the final power is a direct consequnce about how much critical is the torque drop after reaching the peak. Look at the street 458 italia and 458 speciale: 458 italia TP is 540Nm@7000rpm -> torque drops -> FP is 570hp@9000rpm 458 speciale TP is 540Nm@7000rpm -> the engine is more optimized so the torque drops less -> FP is >600hp@9000rpm To me figures are: audi 4.0 V6 TDI - TP 1000-1100Nm@2000-3000rpm -> FP >550hp@4000rpm TMG 3.7 V8 - TP close to 500Nm@7000rpm -> FP >550hp@8500rpm Of course, just speculation. Porsche engine specs are harder to speculate. |
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25 Apr 2014, 09:45 (Ref:3398062) | #550 | |
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I doubt Toyota is achieving 500 Nm and the rated power is also less at 520 PS (383 kW) and probably around 9 to 10,000 rpm
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