nore03

Why wouldn't they make it as an option to turn on and off? I mean sometimes it's great to have like when the weather is bad or when your driving aggressively and wanna get the most out of the car but what about when your just on the highway at 65 with cruise control on or if you arent doing any driving that really needs all 4 wheels every time. It would save soooo much on gas and would probably make it a little quicker if all the power is going to 2 wheels instead of 4. With all the tech stuff in this car wouldnt it be simple to just put a button in the car that just turns off the shawd if you didn't need it? A couple times when i have been driving the sh-awd has malfuntioned and i was only using the front 2 wheels and you could feel the difference and see the gain in mpg. Am I missing something as to why not just give us the option?

danmm7

iTrader: (1)

The SH-AWD system is way too complex and sophisticated to be turned on and off with a switch or a lever. This is not an old Jeep with a simplistic 4x4 drive train where pulling a lever cuts the power to the rear wheels.
The RL has dozens of sensors that communicate with the sh-awd computer. It is not a simple mechanical system, quite the opposite actually - this is why it is so seamless, transparent and effective. Yes, it 'eats' more gas but in my opinion it's well worth it. If i wanted to save on gas, i would buy a FWD 4-cyl Honda Accord (or TSX), not a 4000lb+ luxury sedan with 290hp under the hood.

It's important to recognize that the sh-awd is useful not only in bad weather or aggressive driving. It helps and enhances the handling and SAFETY of the car 95% of the time - city, freeway, snow, rain, dry.

For example:
... sh-awd can help a LOT during on-ramps when you're turning and accelerating - wet or dry. You turn it off, and all of a sudden the heavy RL will become a lot less planted on the road. Do you want to turn the sh-awd on and off on every ramp and decide on your own when you need it?

... sh-awd can help a lot when you're driving on the freeway with 65mph and all of a sudden you have to quickly turn to avoid an object on the road or another slow moving car. You will NOT have time to turn-on the sh-awd on such short notice if it's disabled, trust me. A front wheel drive car will be a lot less safe in such situation - i tried it.

... what happens if you turn off the sh-awd, the weather gets nasty, you 'forget' to enable sh-awd (or you keep it off intentionally to "save on gas"), you loose control and you crash. Some people do stupid things to save two bucks in gas. This is liability for Acura.
Their entire message around the sh-awd is that you have a safer and very well handling car.

In other words, Acura did not want to allow the average driver out there to decide if they need the sh-awd or not. I don't blame them. All other performance sedans that offer AWD do not give you this option either.

chopstix

Very well explained.

rtr

there is a button on the dash that turns the SH off into normal AWD function! The car feels funny and im sure you will get worse gas mileage...

037

what button would that be? the only button that you can hit is the VSA

GoHawks

There is no such button.

Aman

IIRC standard split in day to day driving is something like 90/10. So 90% is going to two wheels during normal conditions anyways.

The car knows...

dwboston

The car can be converted to FWD by removing the carbon fiber driveshaft. That's one of the procedures the techs use (at least they did with my car) to test whether the driveshaft bearing had gone bad. The car is driveable with the driveshaft removed, and it probably doesn't have any torque steer.

friesm2000

iTrader: (4)

LMFAO, not likely to be a real carbon fiber driveshaft on a production car, unless it is a performance car, like a z51 corvette or something along those lines
more then likely it was a steel driveshaft, with an aluminum one being possible also

as far as FWD, you are still spinning the rear diff, when you are going down the road, so not really much advantage to it really

sleepinxlionhart

Um..No.

Officially from Honda.

"Lightweight carbon fiber dual driveshafts carry power to the rear differential unit."

09's: http://www.honda.com/newsandviews/article.aspx?id=4412

Seems like it's a step above from the 05's that had
"A lightweight carbon fiber reinforced composite propeller shaft carries power to the rear drive unit."
05's: http://www.honda.com/newsandviews/article.aspx?id=2091

friesm2000

iTrader: (4)

dual driveshafts?, do they mean the two-piece shaft? cause right there is some marketing-hype


and the reinforced composite driveshaft is much more believable, at least to me

wackjum

Here's a pic of the 2005 RL driveshaft.





I took the picture from this post: https://acurazine.com/forums/showpos...22&postcount=2

dwboston

You may not believe it but it's true. It was a big topic back in 2004 when the car was introduced. They used CF because the car is extremely heavy and a steel driveshaft would have made it much heavier.

sleepinxlionhart

Hm, now I'm wondering how much lighter the 09-11's are compared to the 05-08's.

Aman

Cool, didn't know the RL had a CF driveshaft.

But please explain to me how converting a 300 horsepower car to FWD will not have any torque steer.

Chas2

In answer to your question, not much according to official releases, which seem to be suspect in some years...2005 was the lightest, surprisingly the 6 spd does not add that much weight, if you can believe the figures they publish.

Curb Weights (lbs)
2005 = 3984

2006 Base = 4012
2006 Tech (CMBS+PAX) = 4074

2007 Base (2006 Base, less features) = 4012, could be an error
2007 Tech (Close to same as 2006 Base) = 4074, likely an error, probably 4012 or 4014
2007 Tech+CMBS/PAX = Not stated, probably around 4076

2008 Base = 4014
2008 Tech = not stated
2008 Tech+CMBS/PAX = 4076

MMC
2009 Base = 4083
2009 Tech = not stated
2009 Tech+CMBS = 4110

2010 Base = 4083
2010 Tech = 4085
2010 Tech+CMBS = 4110

MMC+6 Spd
2011 Base = 4099
2011 Tech = 4112
2011 Tech+CMBS = 4112

justnspace

iTrader: (1)

I guess no one got the Super Handling joke.

sleepinxlionhart

That's interesting how it got heavier, especially from the 05s to the 06s. But specifically, I was wondering about the driveshafts themselves, since they seem to be a bit different comparing the pre and post MMC models. But thanks for the info nevertheless.

max parker

don’t know if this is still relevant, but yes it is very simple. There is a fuse on drivers side on mine labeled fuse number 2, and when pulled it deactivated AWD, VSA, and hill start assist. I’ve tested it on multiple trips and roll races and concluded that it does in fact save gas, as well as acceleration in 3rd-6th gear. Also because the AWD system was made from the FWD, it will not damage driving components. The only issue I ran into was 1st and 2nd gear loss of traction, and torque steer so it is not good for daily driving. But in conclusion rolling acceleration is faster, and MPG does better on freeway despite what everyone is saying. Multiple tests and data collection via Ktuner, and just reading display of mpg at certain speeds/gears and recording and comparisons have proven the difference. Braking is not affected much by the change, but safety and handling are, therefore I wouldn’t recommend doing it.

Blues Legend

Exactly, Max!

Get a dumb-ass prehistoric FWD or RWD car if you really cannot appreciate the benefit, or are too penny-pinching to pay for the fuel.

PS - the car is quite delightful in 'Snow' mode - like a big Subaru!