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21 May 2011, 20:13 (Ref:2883631) | #1051 | |||
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Also 1980s F1-engines and the 2.1l (?) from the AAR Eagles come to mind. But that was of course with a petrol engine, and not being a tech-head, I have no idea if it is in any way applicable to Diesel engines... |
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21 May 2011, 20:31 (Ref:2883634) | #1052 | |
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With petrol that specific power output is easy.
The AER and AMR LMP1 turbo engine produce 550+ hp from 2 liter (275+ hp/liter). In F1 the current V8 engines produces 750 hp from 2.4 liter (312 hp/liter) and previous V10s reached almost 1000 hp with 3.0 liter (333 hp/liter). I highly doubt that those numbers can be achieved with race diesel engines. |
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21 May 2011, 22:13 (Ref:2883665) | #1053 | ||
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My point is just that the challenge is clearly not hard enough now. It's not Audi's fault. Still, the R18's program goal (to make me - and others - look at Audis like technologically cool cars because they overcame a difficult challenge in Le Mans-style racing) is not reached for me because of that.
I personally think they could still push the boundaries quite a bit more. I think they could survive the 50hp deficit that would come with a smaller inline four diesel by using KERS, still benefiting from truck-like torque and optimizing their superior chassis even more. With the opponents they are running against and the torqueless engines the rules force on them, I find it outrageous that the rules still give the diesels a power advantage on top of the vastly superior torque figure that pulls them up to top speed a lot faster than anyone else. The diesel on-track battle will have to be extremely good to make me forget about all this. That's just me; some other hardcore fans seem to be happy with the way things are, seemingly believing that the 2 factory outfits are way ahead solely because of their resources and that the rules are all right - that the different engine types have nothing to do with the huge gap. Now comparing road car engines is never perfect, however looking at the 3 engine types found in the 3-series BMW shows how well a diesel can do: -the M3 V8 is good for 420 horses from 4 liters. It's the fastest 3 series. -the 3 liter turbo engine is now good for 320 horses. It's not as hardcore as it could be but it's easy to imagine a 400-ish hp version of it if there wasn't a V8 in the M3 with more or less similar performances. -the 3 liter diesel make 280-some horses and much more torque than any other 3 series engine. The car gets performance figures (various accelerations) closer to an M3 - with a bigger atmospheric engine - than to those of the turbo petrol engine of the exact same size. Now if the diesel engine was "equalized" (given the displacement advantage it has over petrol engines) like under ACO rules, it would be 4.3L (1.08*atmo) or 5.5L (1.85*turbo). **Again, this doesn't mean much and these are just numbers, but I think it shows how a diesel engine can not to be bigger than a petrol engine and still give better performance. |
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21 May 2011, 23:00 (Ref:2883681) | #1054 | ||
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21 May 2011, 23:25 (Ref:2883684) | #1055 | ||
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The diesel rules are giving the majority of LMP1 entrant a great non-race since 2006. Every year there have been people on that middle ground believing things were almost equal... but after constant rule adjustments, we have yet to get to what could remotely look like a level playing field. To me the odds of seeing a good year of racing at the top between petrol and diesel cars are lower than those of seeing the category implode. (OK I've just been reading the Bear's last column...)
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21 May 2011, 23:29 (Ref:2883686) | #1056 | |||
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The 335d needs a displacement of 3.0 liter to produce 210 kW. If it has to produce 309 kW like the M3, it would need a displacement of 4.4 liter (= 3.0 * 309 / 210). That is 10% more displacement than the M3. With the Schnitzer numbers it would need 4.3 liter (= 3.0 * 331 / 230) or 8% more than the M3. In the ACO rules the difference in displacement between NA petrol (3.4 liter) and turbo diesel (3.7 liter) is 9%. Mmm, coincidence? |
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21 May 2011, 23:51 (Ref:2883696) | #1057 | ||
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The difference in laps between the first Audi/Bentley and the first non-Audi/non-Bentley in the pre-diesel years:
BTW I totally agree that the rules are not yet correct. I would like to see the ACO decrease the minimum weight for petrol cars from 900 to say 850 kg as compensation for the torque advantage of the diesel. Last edited by gwyllion; 22 May 2011 at 00:00. |
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21 May 2011, 23:58 (Ref:2883700) | #1058 | ||
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Are we really using numbers from a tuned street BMW to prove the ACO equalization formula is right??? Let's not even get into the hundreds of details that can skew that comparison...
The BMW diesel gives performance that is at times better than the other engines and at all times better than what you would expect from the numbers. But what really tops it off is that ACO rules suggest that it is MUCH too small because a diesel has to be 8% bigger than an equivalent atmo petrol engine or 85% bigger than a turbo petrol. Such an advantage would simply take it out of the 2 other engines' league. Last edited by Félix; 22 May 2011 at 00:03. |
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22 May 2011, 00:03 (Ref:2883704) | #1059 | |||
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22 May 2011, 00:37 (Ref:2883713) | #1060 | |
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Ok, who cares about LMP1 and GTE, I want to discuss LMP2. What is the justification for the Judd getting a restrictor reduction? I don't mind this being done if there was a slight error in the initial rules, but was this done simply because the Judd wasn't as fast as the Nissan? I don't approve of balancing done just for the sake of ensuring everyone has equal power. They might as well just run spec FLM engines in that case. I had hopes for LMP2 being a really good class, but between this, the cost capped confusion, and the difference between "real" stock engines and stock derived race engines indicates that LMP2 is a "true" ACO spec!
As for LMP1, I don't know if the diesel-petrol rules are balanced, but I don't watch this form of racing expecting to see 12 cars finish on the lead lap at the end of 24 hours. I don't expect to see that many cars on the lead lap at the end of 1 hour. I do, however, expect that the competition for the 24 hours occurs months before the actual race in engine rooms, dyno rooms, and test tracks across the globe. Please don't take that away from me. Those of you who want spec or pseudo-spec racing have plenty of other options, but the rest of us don't have many other options. |
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22 May 2011, 01:01 (Ref:2883718) | #1061 | |||
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I found the following number for the M3 E90 (420 hp, 400 Nm):
Those numbers confirm that official BMW 0-100 km/h times. The tuned 335d can keep up during initial acceleration because of its huge torque, but from 80 km/h on the M3 pulls with its extra 80 hp. Last edited by gwyllion; 22 May 2011 at 01:13. |
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22 May 2011, 01:10 (Ref:2883719) | #1062 | ||
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22 May 2011, 08:22 (Ref:2883784) | #1063 | ||
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The 335i (standard) does a good job keeping up with the slightly more powerfull 335d (tuned). This can be explained by the weight difference, which result in an almost identical weight-to-power ratio: 1610 kg or 5.3 kg/hpfor the 335i coupe vs 1766 kg or 5.2 kg/hp for the 335d touring. BTW the weight-to-power ratio shows why the M3 is so much faster in acceleration: 1610 kg for 420 hp gives 3.83 kg/hp. For what it is worth, the 335i has better handling than the heavy 335d.
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22 May 2011, 08:52 (Ref:2883795) | #1064 | ||
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The point is NOT the different road BMWs with different gearboxes (and 1000 other things) that make comparing performance numbers impossible.
The point, I repeat, is that under ACO rules the way to get "equivalence" between the 3 road engines (between their specs to be precise) would be with a diesel engine 1.85x bigger than the turbo petrol engine or 1.08x bigger than the atmo petrol engine. Now tell me that looks fair. You can even try to extrapolate from road car numbers if you like, but the point remains that giving diesels that big of an advantage is overkill. Additionally, if we want to keep talking about road cars, the ACO rules have little relevance because nobody makes diesel engines that big for the road. |
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22 May 2011, 08:56 (Ref:2883798) | #1065 | ||
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Er yeah they do actually, infact GM makes a 6.6l V8 turbo diesel....
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22 May 2011, 09:19 (Ref:2883813) | #1066 | |||
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BMW and Mercedes made a V8, VAG had the Touareg V10 and the 6-liter Audi V12. They don't make them anymore. Audi makes a 4.2 diesel V8, but I'm sure it sells much less than the smaller diesels available in the same cars. Big diesels are not used in road cars. Endurance racing is good for testing engine tech that applies to road cars. |
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22 May 2011, 10:50 (Ref:2883837) | #1067 | |||
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Land Rover sells the Range Rover TDV8, which has a 4.4 V8 diesel engine. That car is not designed to tow a house Quote:
Small V8 petrol engines revving at 11000 rpm are not that relevant for road cars either. I doubt that many Atom 500 V8s, Caparo T1s or Radical SR8s have been sold last year. |
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22 May 2011, 12:09 (Ref:2883855) | #1068 | |||
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Sorry Wikipedia said otherwise but I concur that they must still sell a few hundreds yearly - for the price of a small house. Mea culpa.
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As I've written months ago, the ACO should alternatively have left the option open for bigger petrol engines while giving them very small restrictors so they can't rev but still can achieve credible torque numbers if it wanted to keep on giving diesels big displacement. That's a far better solution for road car manufacturers who are used to building bigger V8s, V10s and V12s that don't rev over 8000rpm - and it's the solution they seem to favor on road cars with the development of direct injection to return decent fuel consumption and emission levels. (I'm thinking about the engines in the most recent Ferrari California, 458 and FF, both Lamborghinis and even all the 911s now have DFI - except GT3s) Pescarolo is even proving that's a better solution this year by getting better fuel consumption from his castrated Judd without DFI - whilst certainly not outrunning anyone on the straights. It's an equivalence issue; they could change the rules on either end to make it less ridiculous. Thinking the basic engine size equivalence could remain that wrong for another race, nevermind the next 2-3 years makes me very sad and not optimistic at all about the class' future. (I hope it's all clear enough now!) |
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22 May 2011, 15:06 (Ref:2883929) | #1069 | |||
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The ACO toke the most convenient solution by replacing the big LMP1 engines with the smaller LMP2 engines. BTW downsizing is also occuring in sportscars. The Nissan R-GT has a V6 turbo, the McLaren MP4-12C has a V8 turbo, the next BMW M5 will get a V8 turbo instead of a V10, the Ferrari Enzo successor will get a V8 turbo instead of a V12, Audi is said to go for smaller displacement (e.g., V8 turbo instead of V10 turbo) for their future RS cars, ... |
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22 May 2011, 15:13 (Ref:2883933) | #1070 | ||
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The R35 Nissan GT-R actually has a bigger turbo V6 than the straight 6 in the old R34 (3.6l vs 2.6l)....
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22 May 2011, 15:20 (Ref:2883936) | #1071 | |
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22 May 2011, 17:12 (Ref:2883989) | #1072 | ||
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22 May 2011, 21:54 (Ref:2884129) | #1073 | ||
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Trussers Blog |
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22 May 2011, 22:07 (Ref:2884136) | #1074 | |
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I think that Paul is exaggerating the impact of the restrictor break when he writes "the extra air entering the engine should provide enough horsepower to reduce lap-times by up to a couple of seconds." According to Henri Pescarolo it is only worth 1 second.
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22 May 2011, 22:56 (Ref:2884149) | #1075 | ||
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Yes, at around 2%, if taking the weight break, that's around 10-12hp. That will barely budge the lap time. Last edited by MulsanneMike; 22 May 2011 at 23:02. |
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