A W

Are there any differences between the SH-AWD systems in the RDX compared to the MDX?

mrgold35

The sh-awd on the RDX and MDX have pretty much the same parts. The MDX has a different programming with 30% front and 70% rear distribution under normal driving conditions. The RDX is opposite with about 70%-90% front. The RDX and MDX perform about the same at the limits with the exception of the RDX is more front driven.

Carbon2008RDX

They are exactly the same from what I can tell from Acura's website as well as brochures I have. 90:10 to 30:70 torque with 100:0 to 0:100 at the rears overdriven 1.7%. I belive the ZDX is the same as well. The RL on the other hand is different as it has "an accelerator clutch pack" that allows the RL to spin the rears about 5.7% faster vs. the RDX/MDX which is limited to 1.7%. The RL also has a slightly different torque distribution of 80:20 to 30:70 torque with 100:0 to 0:100 at the rears.

mrgold35

I found more info about sh-awd on Wikipedia:

http://en.wikipedia.org/wiki/SH-AWD

It gives more details on front/rear and side/side TQ distribution for RL, TL, RDX, ZDX and MDX. It also gives more details like:

- The MDX can transfer 90% of the power to the front wheels for straight line efficient cruising
- +2009 RL has sh-awd in all 5 gears (I’m assuming all other vehicles only have sh-awd in gears 2-5 or 6 only)
- RL can transfer 70% of power to the rear in hard cornering compared to the MDX 50%
- For the MDX, up to 70-percent of available torque can be directed to the rear wheels during hill climb acceleration for maximum traction

Other than the RL, sh-awd seems to be the same for the rest of Acura line-up.

I always thought it was kinda wierd that you have to break the law to take advantage of the sh in sh-awd? If you drive the speed limits, you only need the awd at most depending on road conditions. I have to hit a turn at 10 to 20 mph over the speed limit to feel the sh-awd on the RDX. Just thinking out loud.

Mr Marco

^Wow, good information. I had know idea they were that different.

A W

That last part is kind of disturbing if it's true. But I guess it kind of makes sense technically. It's odd that you have to make it a "hard turn" and not just a regular turn to feel the SH-AWD.

JCRDX11

Same here; I thought it would have come a little close to the Subaru but it is not.

Subaru goes where ever you turn and steer; the RDX in the other hand.
I would have to go on a sharp turn and than turn hard and press on the gas to feel/see the sh-awd working.

Scary at first but indeed it is there and working.
This is just my experience and opinion; it won't be my responsible if you try it incorrectly.

It just tells you that not all awd is the same.
My top choices for AWD are subaru, audi and acura IMO.
Engine wise that would last longer would be Acura, Subaru..Audi is out of the question.

djbonsu

iTrader: (3)

^^to each its own but i KNOW that the sh-awd in the acura is defintely better than audi's quattro system! not sure about the comparison to subaru tho...i would still think its superior being that u can transfer torque front to back AND left to right. just my $.02

Mr Marco

You can bet Audi will be adding software and a clutch to deal with the bad press from that video. See the new system in the A-7.

A W

Subaru's AWD system can do the same things the Acura's SH-AWD can in terms of right to left (and vice versa) and front to rear torque transfer with the Subaru VTD and VDC systems. They just can't increase the wheel speed like Acura's SH-AWD can.

VietNinjaJ30A1

The new "Torque Vectoring" AWD system that Nissan put in their Juke is similar to SH-AWD, but it says that it can put up to 50% of the rear torque in either L or R wheel. Which sounds like to me that it won't actually INCREASE the wheel speed, but rather use the differential to lower the wheel speed of the opposite side?

pickler

Actually the RDX also gets 70% torque to the rear during cornering compared to MDX's 50% to the rear. The only time the MDX gets 70% of the torque sent to rear wheels is during hill climbs or descents. Also during cruising RDX has ability to send 90% of the torque to the front wheels while mdx can do 50/50.

MMike1981

hey guys, if you are really interested in the ruling technical aspects about any system for the RDX...should really be reading www.acuranews.com rather than reviews or posts etc. You will get every (mostly) thing you would want to know about the inner-workings, including this topic, in comparison to every other SHAWD installation in the brand. Acura News is fantastic and detailed. Check it out. The RDX system operation is unique to the RDX.