ipribadi
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| Beyond the frictional reductions, the K24 benefits from an increased compression ratio (now 11.0:1), new valve timing, and improvements in both intake and exhaust flow. The result is peak horsepower identical to last year's K24 (201hp @ 7000rpm), but an 8lb-ft increase in torque (now 170lb-ft @ 4300rpm). |
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80honda
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In this Honda News release, they mention 172 ft-lb for the manual, but I didn't see the auto.
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80honda
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ipribadi wrote:
| Beyond the frictional reductions, the K24 benefits from an increased compression ratio (now 11.0:1), new valve timing, and improvements in both intake and exhaust flow. The result is peak horsepower identical to last year's K24 (201hp @ 7000rpm), but an 8lb-ft increase in torque (now 170lb-ft @ 4300rpm). |
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YEP, here it is.
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JeffX
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80honda wrote:
ipribadi wrote:
| Beyond the frictional reductions, the K24 benefits from an increased compression ratio (now 11.0:1), new valve timing, and improvements in both intake and exhaust flow. The result is peak horsepower identical to last year's K24 (201hp @ 7000rpm), but an 8lb-ft increase in torque (now 170lb-ft @ 4300rpm). |
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YEP, here it is.
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You know, when I saw those numbers for the torque and CR in the back of my mind I was thinking they seemed to be the same and I was going to double check them. Of course, I got distracted and forgot to go back and do that. But you are correct, it appears that the 11.0:1 CR and the 170lb-ft torque rating are unchanged for 2011, at least according to the specs. I don't know why the technical documents state otherwise but I will followup with Acura and report back.
this is the exact passage from the technical document:
For 2011, the 2.4-liter DOHC i-VTEC® inline four-cylinder engine remains as the standard engine. The engine offers good acceleration while generating excellent fuel efficiency. The all-aluminum I-4 engine produces 201 hp and 172 pound-feet of torque (6MT), and incorporates Acura’s i-VTEC® "intelligent" valve control
system that features Variable Valve Timing and Lift Electronic Control (VTEC®) combined with Variable Timing ControlTM (VTCTM). Though peak horsepower is virtually unchanged versus the previous generation 2.4L engine, peak torque output has risen by 8 lb-ft. In addition, the engine’s torque curve has fattened considerably. Horsepower, for example, is up five percent at 4,400 rpm. The result is stronger throttle response and better acceleration just about everywhere in the engine’s operating range. To achieve these power gains, the engine has a higher compression ratio, new valve timing, and intake and exhaust flow improvements. An aluminum and resin composite intake manifold reduces weight over the previous I-4’s aluminum design, while better insulating the engine’s incoming airflow from under-hood heat. |
and now that I'm reading it again I'm beginning to think that this was a cut and paste error. I bet this is the exact passage that existed in the 2009 TSX technical document, only they've changed it to say "2011". So the "previous generation" was referring to the '08 model's K24A. But I will wait for Acura to clarify.
Last edited by JeffX on 12-23-2010 11:34
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JeffX
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if the official specs are truly unchanged, I would be very surprised if the '11 version doesn't perform noticeably better on a dyno, but this wouldn't be the first time this has happened.
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JeffX
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I heard back from Acura - they confirmed that it was a cut and paste error in the technical document, so the specs are in fact identical to last year's version of the engine, even though there has been significant friction reduction.
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SoichirosHeroes
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Jeff wrote:
I heard back from Acura - they confirmed that it was a cut and paste error in the technical document, so the specs are in fact identical to last year's version of the engine, even though there has been significant friction reduction.
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That's why I love TOV! Who else would have caught that?
Thanks for the follow up confirmation.
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owequitit
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Jeff wrote:
I heard back from Acura - they confirmed that it was a cut and paste error in the technical document, so the specs are in fact identical to last year's version of the engine, even though there has been significant friction reduction.
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Friction reduction translates directly to power production, so even barring any other changes, it could and should still make noticably more power than last year. Perhaps they are just not claiming the increases, because if friction really is that drastically reduced (and they did make some pretty heady changes), then power should have gone up measurably.
Also, just for the record, for those that don't know better, forged steel crankshafts, micropolished crank journals, and dot matrix molybedenum piston coatings are things you find in full on blueprinted and "massaged" racing engines. To put it in perspective, in order to get a forged crankshaft in a Corvette, you have to step up to the Z06, as the "regular" models get cast cranks. The upside is greater strength per unit of material and manufacturing consistency, which translates directly into more durable, efficient, long lasting and smooth engine production.
I have decided to start clarifying this stuff since most people around here don't seem to actually know much about the details of engine manufacture that Honda still excels at, and it may help reverse some of the wholly incorrect beliefs that Honda has lost the edge in engine technology.
Essentially, one area where Honda is encountering criticism is in engine construction. The problem is that they are largely the only ones that are providing what amounts to a blueprinted, street legal race engine in most categories that they compete in, and have been since the early 90's, or earlier, as EVERY Honda engine has had forged cranks for as far back into the 80's as I can remember.
The importance of these manufacturing technologies is that it is what allows Honda's engines to simultaneously the best sounding, highest winding, smoothest and most fuel efficient engines on the market. It is technology typically reserved for high end, expensive racing engines, and it is a standard feature on every Honda road car sold. Honda also builds the engines to VERY exact tolerances, meaning that the machining is very tight, and there is very little variation from engine to engine. NASCAR did not reach Honda's production tolerances until just a few years ago (I believe it was in the 200-2003 time frame). Again, racing technology in road engines.
Also, it is likely that these changes may very well have resulted in FE gains that are par with DI, despite providing none of the drawbacks, and even though it isn't in line with the latest must have technology catch words of the day.
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