| wmquan |
Okay, that's just the scare headline. They won't have less actual power.
According to Temple of VTEC, they will follow a new specification for stating horsepower and torque::
quote:
For the 2006 model year, all Acura horsepower and torque specifications have been updated to reflect revised Society of Automotive Engineers (SAE) J1349 (Rev 8/04) net calculations that went into effect in January of 2005. These new calculations reflect a number of significant changes in the way horsepower and torque are measured and may cause SAE net horsepower and torque totals published in 2006 media materials to differ from the figures published in previous years. To avoid confusion, all 2006 Acura press materials will specify “SAE net (Rev 8/04”) after all horsepower and torque figures to denote adherence to the new standards.
http://www.vtec.net/news/news-item?news_item_id=384913
The MDX "drops" to "253 horsepower SAE net (Rev 8/04) @ 5800 rpm, 250 lbs-ft. of torque SAE net (Rev 8/04) at 3500 rpm." It had been 265 hp @ 5800 rpm and 253 lbs-ft between 3500 and 5000 rpm.
The TL "drops" to "258 horsepower SAE net (Rev 8/04) at 6200 rpm, 233 lbs-ft. of torque SAE net (Rev 8/04) at 5000 rpm." It had been 270 hp @ 6200 rpm and 238 lbs-ft @ 5000 rpm.
The RL "drops" to "290 horsepower SAE net (Rev 8/04) at 6200 rpm, 256 lbs-ft torque SAE net (Rev 8/04) at 5000 rpm". It had been 300 hp @ 6200 rpm and 260 lb-ft @ 5000 rpm.
Obviously there is no actual power drop in the vehicle, just a different way of measuring the same power.
So I'd presume that the whole industry is moving to this new SAE J1349 standard, so everyone's horsepower and torque numbers for 2006 will go down? Or have some manufacturers already been using the more conservative measurement? Will some manufacturers suffer a bigger drop because their previous measurement was too far from J1349?
I'm not familiar with these measurements, but I figured we have a lot of engineering expertise here. |
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| SuperTech |
Some engines rating went up believe it or not. Not any Hondas I think. But I know of one from another make that got an extra 5 ponies from this new thing. This new system is supposed to ensure more "consistency" in power output of mass production engines. Whatever that means.
I wish they'd drop the rating at the crank altogether. You can't just bolt the wheels directly to the crank. There's losses through the transmission, axles, etc. They should just rate cars by what they put down to the ground. Period. No correction factors to come up with crank horsepower. A Charger with a 340hp V8 will put more power to the wheels than a extended cab 4wd Ram with a 340hp V8. It should be no wonder why some people will test drive the Charger, then the Ram, and wonder why the Ram just "doesn't feel like 340hp." |
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| wmquan |
quote:
Originally posted by SuperTech
I wish they'd drop the rating at the crank altogether. You can't just bolt the wheels directly to the crank. There's losses through the transmission, axles, etc. They should just rate cars by what they put down to the ground. Period. No correction factors to come up with crank horsepower.
I agree that measuring power at the wheels would be great. I guess that'd be a no-no for the marketing folks since people get excited about high numbers at the crank.
Would you know how Hondas/Acuras typically fare at driveline losses? Do they typically have less driveline losses (more power making it to the wheels) than other brands?
Thanks. |
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| SuperTech |
Rule of thumb...longer the powertrain, and more paths for powe...more loss. This is why a 154" wheelbase pickup will typically lose more than a 1/3 of it crank hp by the time it gets to the ground.
This is one of the many reasons why FWD is and has been so popular with automakers. It is the most efficient. More efficient means they don't need as big of a motor since they aren't losing as much power through the drivetrain as a RWD layout, and a smaller motor means more conomy. Multi faceted benfits. From a performance/enthusiast's view...FWD sucks though.
Anyways. I would suspect that the losses are all comparable to other FWD designs. Obviously the automatic transmissions rob a little power. And in the MDX, the VTM-4 setup steals a bunch of power too. Anytime something is slipping, flexing, or coupled somewhere...not all the power is being transfered between the two parts and it's being lost in friction.
I've seen speculations of what driveline losses are in some other RWD sports cars and so on. But it's all internet secondhand knowledge. Until I hear a Porsche, Dodge, GM, whatever engineer flat out say percentages for their particular car...I'm not believing much. My internet secondhand speculation. I don't know what are cars put to the wheels, and I've never seen dyno sheets from people who take their cars to a shop to measure it at the wheels. but if I had to guess...I'd say somehwhere around 15% for the typical Honda. More like 20-30% for the MDX/Pilot/Ridgeline.
Heard any dyno numbers? Am I close? Not many people can find a 4wd dyno. Let alone would they test a stock, ho hum, SUV on one. |
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| Sinecure |
I've never seen a 4wd dyno. They must exist, no? I'm looking forward to putting my Yamaha R6 on the Dyno once I get it rebuilt (oops, I blew the motor shifting the wrong way at 120 and 13K RPM like a moron). You have to love M-cycle HP numbers. 5-600lbs rider + bike weight and 105 Rear Wheel HP. Big bikes are making 150+hp. Yowsa! I wonder how my lap times in the MDX would compare to the R6? HeeHee. S2000 would be a different story since you can power slide through turns a lot better in a car than on a bike.
Sorry to jack this thread. |
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| Dick at Incline |
Here's a link to a dyno test on a 2000 Boxster S. Stock HP at the rear wheels shows about 215HP, advertised HP by Porsche is 250HP, so that's a 14% loss in the drive train. Manual transmission, 6-speed.
http://www.babblers.org/forums/show...&highlight=Dyno |
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| NBP_MDX |
| I have a feeling there will be an ECU upgrade on all Acura models in 2006 (not sure about MDX though), most likly from Hondadata. |
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