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31 May 2017, 04:51 (Ref:3737549) | #2626 | |||
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There's a reason GM didn't do roadcar-derived aero for the Caddy DPi. |
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31 May 2017, 06:30 (Ref:3737559) | #2627 | |
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The rumor is...a new Honda S2000 will debut this October at the Tokyo Motor Show.So that or a CTR bodywork for the Dpi.
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31 May 2017, 11:00 (Ref:3737646) | #2628 | |
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If HPD wanted to base their DPi car on the NSX, then go for it! Just hoping that it'll stay competitive after some adjustments from IMSA.
On the other hand, any news of ACO allowing DPi in Le Mans, racing in LMP1-P? |
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31 May 2017, 12:21 (Ref:3737671) | #2629 | ||
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the NSX Super-GT racer in Japan uses the 2.0L I4 engine used in Japanese SuperFormula dallara single seaters, yes its 600bhp, but it will not be capable of producing the torque that Cadillarc and Nissan are with far bigger engines, it will just be another Mazda style of fragile 2.0L turbo engine which BBQ's itself regularly.......they will need to either get a V6 with about 3.0-3.5 Litres capacity, such as the previous LMP2 engine would be ideal, I believe currently used by Shank in 3.5L guise......or they will need to increase the 2.0L I4 out to something like 2.5L and this might help bridge the gap......its a tough call, as the V6 is probably too heavy, but the I4 is too low on capacity, but would allow ideal weight distribution, either way Honda have 2 reasonable engine DPi starting points........I think its only a matter of time before a manufacturer realizes a big capacity I4 or I5 Turbo gasoline motor with 2.5 to 3.0 litres of capacity is the ideal tool for both the IMSA DPi job and LMP1 in WEC
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31 May 2017, 14:23 (Ref:3737708) | #2630 | |||||
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Quote:
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Also, to defend Honda's old P2 engine, re-homologating it as the beefier 3.5L is what turned it on here in North America. It never really got a chance in Europe to shine. Quote:
Chris |
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31 May 2017, 15:14 (Ref:3737721) | #2631 | ||
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erm, everyone keeps talking about just power figures in bhp, sorry but Cadillacs advantage is in the colossal amount of low down torque it makes, hence the air restrictors hardly made any change to its on-track performance .......power and torque characteristics are just as important as each other in a heavy car such as a GT or prototype.......you cant just talk about power in isolation
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31 May 2017, 16:01 (Ref:3737743) | #2632 | ||
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As far I know, in GT500 cars fuel flows triggers at 7000rpm or 7500rpm, where max output is released. Redline in those engine is at about 8000rpm. To reach 600hp @8000rpm are required 535Nm!!! so those engines run not less than 600Nm for almost the whole rpm range. Basically GT500 engine torque figure is comparable to the one of road mp4-12c, despite being 1/2 large. High power - high rev - DI - high torque release = state of art. If only could be found a way to make it the last 24 hour, it would be the ultimate sportscars engine. |
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31 May 2017, 17:53 (Ref:3737773) | #2633 | |||
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The problem with the 2.0 four bangers, though, is can they handle the boost to get the power and torque needed. Toyota managed it in the IMSA GTP days, but they destroyed a lot of engines and at least one or two engine dynos to do it. So far, Mazda hasn't. I do think that a four cylinder is a poor choice for endurance racing, but not for power or torque reasons if forced induction. I think that most four cylinders have rigidity issues that hamper their durability in high boost applications. A V block is much more torsionally strong. That's why Porsche's four banger in the 919 is a V4. That's why Audi went with a V6 in the R18 series, as well as a V8 in the R8, a V12 in the R10, and a V10 in the R15. All Toyota LMP engines have been V engines, be it V8s or the current V6 family. Not to mention that V engines can be easily designed to be stress mounted to the cars tub. Not of huge importance in DPI (where stock block engines are the common rule), but even in a semi-stressed mount, I feel that a V engine still has some advantages. Only VAG designed a successful stress mounted inline four for their F3 cars, and that was designed by Audi engine man Ulrich Baretzky. And no one's figured out how they did it. |
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31 May 2017, 19:13 (Ref:3737796) | #2634 | |
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I think the Mazda (actually an AER) engine is a bad example of the competitiveness of a small turbo. I don't think Honda or Acura will use that type in a dpi though. Most likely something already used in lmp or the NSX GT3 engine (which works as a mid-engine already unlike the ESM Nissan).
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31 May 2017, 20:38 (Ref:3737818) | #2635 | ||
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Sorry, missed the quote..but to chris a ways up...VAG is at lemans this year in p1 with porsche...you mean audi?
Sent from my SAMSUNG-SGH-I337 using Tapatalk |
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31 May 2017, 21:20 (Ref:3737829) | #2636 | |||
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31 May 2017, 21:29 (Ref:3737833) | #2637 | ||
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You seem to be forgetting that the Toyota engine initially wasn't that reliable, and, above all else, Toyota were dumping $25 million dollars a year into their IMSA GTP program by the time the Eagle Mk III came out. Even allowing for inflation, Mazda are spending a small fraction of that, and AER's engines have never been known to be rock solid.
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31 May 2017, 21:29 (Ref:3737834) | #2638 | |||
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Quote:
Chris |
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31 May 2017, 21:47 (Ref:3737841) | #2639 | |||
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31 May 2017, 22:24 (Ref:3737847) | #2640 | ||
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Agree 2.0 L4 WRC engines were beasts, just 300hp but costantly pushing over 500Nm. Guess only porsche and toyota lmp1 engines are better than GT500 engines, for the simple reason that are in the same performances range but consuming less fuel. |
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1 Jun 2017, 00:39 (Ref:3737852) | #2641 | |
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If Mazda had one of those Super GT engines, they'd be whooping some butt! Well, maybe not. The car (chassis, downforce) doesn't seem like it's fully up to snuff with the likes of the Dallara Caddy.
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1 Jun 2017, 09:09 (Ref:3737894) | #2642 | |||
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All we can do is wait and see. The withdrawal of Audi has clearly made the ACO realize that something needs to change NOW. DPi in LMP1 may or may not be answer, but the current status quo is approaching endgame, so plan for it or face a real problem. |
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1 Jun 2017, 10:06 (Ref:3737902) | #2643 | |||
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1 Jun 2017, 11:55 (Ref:3737914) | #2644 | ||
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The better question is why would anyone want to enter a slightly beefed up LMP2 car against bespoke LMP1 prototypes? |
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1 Jun 2017, 13:31 (Ref:3737925) | #2645 | |||
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1 Jun 2017, 13:50 (Ref:3737929) | #2646 | |
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It handily beat the LMP2s at Spa. Perhaps the LMP1 regulations would allow for example ESM to turn up the boost a bit but I still would be curious if that would be enough to keep up with the CLM.
And for next year there will be quite a few more cars in the class it seems. |
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1 Jun 2017, 19:09 (Ref:3737994) | #2647 | |
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1 Jun 2017, 21:39 (Ref:3738018) | #2648 | ||
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The problem with Mazda is that Toyota made a turbocharged 4 cylinder work. But Toyota had a huge budget for IMSA GTP back then, and they also used a steel engine block. I think that a lightweight aluminum block (at least how Mazda/AER designed it) just isn't up to snuff to handle huge boost pressures/compression ratios. Increasing turbo boost will increase power, but for how long until the engine turns more into roman candle than race engine?
I'd think that maybe Mazda would be well served, if they want to keep with the four banger route, to use a production derived block and head if it's beefier. Yeah, weight will undoubtedly go up a bit, but the Toyota GTP engine used a cast iron/steel engine block slightly modified from production (the Mazda Skyactiv gasoline and diesel engines use aluminum blocks for the record). Even VAG still use steel blocks on most of their three, four or five cylinder inline engines, even gasoline engines, for durability. And I doubt that they're much heavier than most aluminum block engines of similar size. A Ford Windsor small block in steel/cast iron is only marginally heavier than GM's all aluminum LS/LT engine, for example, when both are fully assembled. And even most aluminum V engines, be it road or race, are probably heavily reinforced to give them the strength and durability desired, mostly through bracing/strengthening webs. |
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2 Jun 2017, 01:42 (Ref:3738040) | #2649 | |
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It's not like Dyson was grenading the previous version of the engine every weekend.
Worth noting there is the possibility of more LMP1-P cars than DPi next year. |
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2 Jun 2017, 01:55 (Ref:3738041) | #2650 | |
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That's true, but the question is how long these privateers would last? One season or beyond that?
But let's go back to DPi regulations. Since they can't run in Le Mans in their current guise, would it be better if they bend the rules a bit like allowing a fifth chassis manufacturer or something? |
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