RDX10

As some of you on here know, I have voiced my displeasure with Acura's tuning of the SH-AWD in the RDX vs their tuning on the MDX. So I experimented with a couple things.

First I tried using sport mode to see if that may change the computer algorithms to get it to overdrive the wheels more often. I can't say that I noticed anything at all with this.

I then tried something else, I turned off the VSA and I was very very surprised, the SH-AWD activated on a relatively mild long curve, just like it does on the MDX. I thought I was on to something and then tried taking a couple other mild curved turns with the VSA off, but it didn't activate those times. So I then Tried some more aggressive turns with the VSA off and to my surprise, it activates nearly 80% of the time; With the VSA on it only activates maybe 5-10% of the time, even with very aggressive turns.

So I feel that I may be on to something, it seems that having the VSA on somehow limits or nearly stops the SH-AWD from activating at all.

On a sidenote: I took a 2007 MDX tech for the test drive today and was both happy to see the SHAWD activating (I mean fully activated like 100% to one rear wheel) on a relatively mild right hand turn with maybe 1/3 throttle and pissed because I would have to drive batshit crazy to get that affect in my RDX. Granted, the RDX has good body control, but there are times where I like to drive hard and the SHAWD responds and I have this level of control that shocks me. I don't know why it sometimes activates and sometimes doesn't. I sometimes take a turn and then it gets this almost bogged down feeling and the SHAWD doesn't activate at all while other times it activates at the perfect time and I get this amazing streamlined curve to the turn.

kingkong222

so you're complaining about an AWD system that you know nothing about in terms of engineering and operation? Why can't you just drive the car like the rest of us and quit being so freaking critical of something you know nothing about?

RDX10

LOOOOOL wow this is a fresh load of bullshit. Please feel free to hop off my thread and go troll somewhere else. My complaints are valid and you don't know me, so don't try and tell me what I do and do not know. Oh and thanks for playing!

mrgold35

The RDX fwd bias sh-awd can hinder handling to the point you are at the very edge of the safely envelope or going +20 mph over the posted speed limit on a curve to get the system to work to my liking. We don't get much weather in the southwest to see sh-awd work in that way. I got sh-awd to drive like a bat out of hell during dry conditions.

The RDX sh-awd is working; but, not to the same degree as my MDX on the same curve. The RDX can still out maneuver the MDX because of its smaller size, tons of low end TQ, less mass, and upgraded suspension. When I drive my TSX around the same curves, it feels like the TSX rear is being dragged behind it. The RDX and MDX feel it is being pushed in the rear and you can feel the rotation.

Maybe because of the top heavy design, extra mass, or towing duties is the reason for the more aggressive sh-awd in the MDX? The MDX drives like a smaller vehicle because of the more aggressive sh-awd; except when I need to fill her up at 17-18 mpg (19-20 mpg with RDX driving the same way). I wish there was a sh-awd "reflash" to put the MDX programming in my RDX.

RDX10

Thank you for not wasting my time and contributing something very useful and productive.

I agree, there are many times where I took a turn a little harder than I thought and then the SHAWD never activated at all. This is my fault because obviously I am driving a top heavy SUV. But what is frustrating is that the system seems to work randomly. I can take the same turn and one day it activated while the other time it does not. To add insult to injury, there are times where it activates exactly like what I was hoping and the rdx just glides through the curve like a small hot hatch. I agree with you, I also got it to drive like a bat out of hell, just that it only delivers 5-10% of the time.

I don't understand why the RDX is tuned so much less than the mdx. Why state that it has shawd if it is only going to activate less than 5% of the time and almost never when I expect or need it. The MDX I drove activated exactly how I expected the RDX to work. That was like throwing salt in the wound. The RDX and MDX are mechanically identical, I can't understand why they tuned it differently. Maybe being lighter, they were worried that if they tuned it as aggressively as the MDX, it would be far too prone to oversteer.

The MDX I drove felt much smaller when it was in motion, but from a stop, it felt like a boat. Certainly made me rethink selling my RDX and buying an MDX. I am going to test drive one more, if the same result, I am keeping the rdx.

mrgold35

I find the RDX very useful as an in-town commuter/errand vehicle for 1-3 folks. The MDX is best as my out of town, comfort, +4 passenger, and/or hauling a lot of stuff vehicle. For me, the RDX is still the most enjoyable overall as long as I can drive it hard (no passengers). The MDX can run out of steam at higher speeds and altitudes with the 3.7L engine while the turbo is not as much. My RDX performed like a champ on I-70 in Colorado at Eisenhower pass at +11,000 ft. So you gain in one area and down in another.

It would be nice if the RDX did have a more aggressive sh-awd mapping. I also think the RDX could really benefit from the 6AT or 9AT. There might be hope down the road for the return of the turbo making its way back into the Honda/Acura line-up for the next models after 2019-2020 make over.

I haven't checked out the ZDX; which, is basically a MDX with less room (I think a little less than our RDX overall). I don't know if the ZDX has the more aggressive MDX sh-awd mapping or the 07-12 RDX front bias sh-awd mapping? I would go for a ZDX before even considering a +13 RDX.

RDX10

I also find the RDX very good for around town driving. Parking is a breeze, and I like that it is both short and narrow, I can park in much narrower and tighter spaces without worrying about door dings. 90% of the time, it is just me in the RDX, but having come from many luxury vehicles, I tend to expect a little more and the MDX seemed like a logical step for me. However that 3.7 just couldn't motivate it enough for me and the absence of a sport mode and paddles really wasn't working for me. It wasn't that it didn't have enough power, more that the throttle lag and transmission downshift delay was horrendous. literally no joke took 3-5 seconds between mashing the gas pedal and the engine waking up and the transmission downshifting. I do have some delay in my RDX, but it is relatively minor and while moving, it is almost not there at all.

If the RDX had the new 6 speed auto in the 2010 refresh, I would be all over that. I bet it could reduce 0-60 times by at least half a second while producing better fuel economy. I feel that Acura is going to wake up with the next generation of its' cars and give us the turbo and SHAWD back. I can even see the MDX getting some form of forced induction, I think they would be wise to take out the 3.5 and put in a 3.0 turbo like volvo, and BMW have done.

I haven't looked at the ZDX either, but I strangely really like it and think it would be a good single person, or couples vehicle, so perfect for me. I can bet it has the MDX tuning, the ZDX is a BIG car, and I can bet the TL has the RDX tuning. Maybe Acura did some testing and found that the too aggressive tuning was dangerous. I say this because I took a very sharp left hand turn a month ago and the SHAWD sent 100% to the right rear wheel and the rear end kicked out in the turn. That was impressive and scary lol. I really like the ZDX though, I am considering one after the RDX goes (maybe now or in the future). I too would easily consider it over the 2013+ RDX.

RDX10

AGREED 1000%. I think I sometimes focus so much on the SHAWD activating or not that I forget how amazing this thing handles.

In the rare times where I do drive the 09 santa fe, good lord I miss my RDX within 2 minutes. Everything from seating position, to seats, to speed, to body control, to ride, to steering feel. I suddenly notice how good the RDX really is when I drive other vehicles. My RDX is going in for service next week, I wonder if I will get a new RDX loaner as well.

I believe you, trust me. The new RDX is a mom mobile 150%, it wallows in turns like fluffy marshmallow. But I do give them the fact that it feels much more luxurious and looks more upscale than our RDX. But I will take good handling over fluffy pillowness any day of the week.

For me it isn't that our RDX doesn't handle well, It is that the potential for amazing small car rivaling handling is there, they only had to tune the SHAWD system like they do on the MDX. I tried searching online for an oem SHAWD controller to see if I could replace the MDX one with the RDX one..no luck so far.

rdxron

If you want SHAWD to send more power to the rear you need to be deep in the throttle 3/4 or more and the steering wheel turned. It does nothing if you're not buried in the go peddle. It's not designed too. The RDX system is a cheaper version of the MDX system. This means smaller weaker drive shafts. Same with the rear differential and rear drive shafts.

Here's a video that will help you understand. https://youtu.be/sZvwdmlTOL0

RDX10

Nice find! I really appreciate that video

I really hate how difficult it is to get the shawd to activate, in reality, it should not be throttle regulated, but should be steering angle modulated like it is in the MDX. There are a few touches in the RDX (soft touch on whole upper doors, carpeted rear trunk area..etc) why would they cheap out on what they originally used to make the brand known.

Looking at that Video, it would appear that you are correct, they used cheaper parts in the rear and therefore if it is used less, they won't break as often. I don't know, I think people would have gladly paid a few hundred more to get the full functionality.

rdxron

Acura gives us what they think we want not what we actually want.

RDX10

That has been their motto forever sadly....

TheWrench116

iTrader: (1)

i wish it would step up a bit more in straight line. if i don't rotate tires every 1500-3000 miles they are toast... some more in the corners wouldn't hurt either. on another note you might want to look into the RSB upgrade. it makes it stick like glue and feels like it should have come that way from the factory.

RDX10

I really think it should have sent 70% to the rear during hard acceleration. I get WAY too much torque steer when mashing the throttle. It sometimes gets uncomfortably jerky. I would have liked it to activate just a little more, though now that I have gotten the hang of it, I can get it to function a lot more like how I expected, there seems to be a sweet spot in steering wheel angle and throttle to get it to send power 95% of the time.

Thanks for the note on tires, I have to install my new set soon and I am glad you mentioned the need for a good rotations schedule.

I absolutely will be buying the rear sway bar. The cdn to american exchange is horrible right now. It costs you guys $260 and costs me like $340. Had it been the start of summer, I would have done it. But being at the start of winter, I know I won't take any turns hard so I can sort of bide my time till the dollar goes up.

Though I am worried that they would sell out before I could buy one. I think combining the RSB + fatter wheels that line up more with the fender would make for a sweet setup. I also seen the post on the prothane kit being available soon!!! It may be a little of a stretch, but this is my poor man's cayenne!


Edit: did you change your signature? I was sure it said 330tq yesterday lol. WOW!!!

TheWrench116

iTrader: (1)

yes it did but this is what ill be running at the track so I'm going to leave it in my signature along with my drag strip times. once i have them.

TheWrench116

iTrader: (1)

wonder how much of a PITA it would be to get the MDX drive line into an RDX??? custom transmission addapter flex plate rear drive shaft axles rear cradle motor mounts think i missed anything? does the mdx come with a 6 speed auto?

RDX10

Nice! Can't wait to see the numbers, this is going to be a sweet run

You may also have to get the MDX TCU as well, I don't know if it would play nice with the RDX canbus system though. The 2010-2013 mdx is a 6 speed auto, the 2007-2009 is a 5 speed auto. Don't know specifics, but imagine they would have beefed up the MDX tranny quite a bit compared to the RDX to handle the 5K towing duties.

I think first gear in the 6 AT is a little lower than first gear in the 5 AT, and the gears are spaced slightly closer together. Should yield a considerable bump in acceleration.

Something I have been trying to research online is taking the SH-AWD control module out of the MDX and putting it in the RDX. In VW world where I used to play, you could control the AWD systems by replacing the haldex control unit. They even made models with remote controls where you could pick eco, normal, and sport. I can't find anything anywhere which leads me to believe it is the same control unit and the dealer flashes it to the specific model. If this is the case, we could have SH-AWD functioning like it does on the MDX relatively easily. Imagine the handling possibilities!

I read threads about people's SH-AWD light coming on and the dealer replacing their control unit, so there is one for sure.

kingkong222

Ok Mr. Acura engineer. So tell me what special project have you done for Acura lately? I don't know much about you but I sure hell know that you don't work for Honda/Acura just like everyone on this forum. So what makes you more special than I am? Oh wait, owning an Acura doesn't count. I've seen your other threads. All you do is complain about why Acura doesn't do this or that. If Acura is that bad you can always buy a Hyundai.

RDX10

I won't feed the troll. Thank you for your opinion. Have a nice day!

TheWrench116

iTrader: (1)

i think they go about it in a different manner on different chassis. different mechanical would lead to different electronic control. but i could be wrong.

RDX10

But the mechanicals are the same between the tl,mdx, and rdx. It is strictly a software thing. But they could have had other reasons foe that. The profit margins are much much larger on the mdx vs the rdx and tl.

rdxron

The mechanicals are not the same. The RDX has smaller drive shafts and rear differential than all other SHAWD vehicles. And it's because the system is designed to be cheaper and less aggressive than the others.

RDX10

No I mean the general layout is the same. Like the RL is the only vehicle with shawd that has an extra physical part (the acceleration device). All other shawd equipped vehicles have the same general mechanical layout, not the same exact parts.

On a side note, your assumption for Acura using smaller parts is to save money and put an inferior awd system in. Did you consider that they purposely put lighter parts because this is the only 4 cylinder shawd vehicle so they didn't need stronger parts/to save weight for fuel economy?

My personal theory is that the turbo didn't provide the fuel economy they thought it would and therefore they had to detune the awd system to send less power back in order to save some more on fuel economy. True full time awd (50/50 split) does a good number on fuel economy.

mrgold35

Acura is kinda strange by sinking so much $$ into the RL and RLX when the sales numbers are so low for the last +10 yrs? They don't seem to want to push ALL of the super-duper coolest tech features on RLX down to the best selling models like sport hybrids system, 7DCT, surround view camera, Krell sound system, cool HUD, power fold side mirrors, etc...

Acura has the habit of keeping the HP range in-line with prices/models. Acura could of very easily add more hp/TQ to the 07-12 RDX; but, it would have met/exceeded the MDX engine output specs. Some folks wouldn't want to purchase a $54,000 MDX when the $36,000 RDX had more standard power. Pretty much every manufacture that has a lesser model that makes more HP than the next model up has to put a price premium on that lower model (S, AMG, M, Caddy V-series, Camaro ZL1, Hellcat, etc...).

We have a little more flexibility with the 2.3L turbo to add more power; but, the sh-awd, 5AT and wide AT gearing just takes so much of it back.

My guess is the turbo wasn't designed to run 100% of the time and sh-awd takes some HP to work. I think Acura made the RDX sh-awd with so much front bias because you might be at no/low boost when the sh-awd starts to kicks in and the "sh" system may rob too much engine power away from acceleration before being really effective. I have so much more HP in my MDX at 1200-1500 rpms and my sh-awd kicks in compared to my RDX with just awd at most at the same rpms. I think the MDX sh-awd programming might make the RDX feel slower/sluggish/underpowered at lower speed/boost unless you did Hondata, ETS intercooler, exhaust, and 1st cat delete to make up for it.

The 2.3L turbo engine and sh-awd really belongs in the TSX or in a type-s ILX since they are almost 1000lbs lighter and the 2.3L + 8/9AT will have enough power before boost kicks in.

TheWrench116

iTrader: (1)

i think we would have been better off as a community if they had put this K23 into more vehicles.

KenB350z

With this DSS shaft more power is delivered to the rear for sure. It's a little more noisy, but worth it.

RDX10

I find it odd that honda would go through all that work and testing and design of the turbo engine, only to put it in one of the poorest selling models vs putting it in something it belongs in like the tsx or tlx with the dual clutch. I imagine if Acura put in a 5 speed dual clutch in the RDX, it would have been amazing. Though in their defense, the paddles work not too bad in the rdx.


Reply above in bold.

RDX10

Can you imagine they used the 2.3t like VW uses their 2.0t....good god. We'd have multiple companies providing plug and play tunes, more engine parts...etc. But that damn top mount IC.

You are saying that because of less weight it has less rotational drag and therefore more power sent to the back of the available power going back there. But not that you actually have more power getting sent there.

TheWrench116

iTrader: (1)

check sensor count and part numbers of those sensors. if they all match then look at the controllers(traction control SHawd) and how they all work. if they are all can-bus like our little gem then maybe we can make something happen.

RDX10

If I could find a detailed schematic of the internal wiring...etc, I would do this, but finding info on this unicorn is very difficult.

justnspace

iTrader: (1)

p.s. VSA on cuts power and limits throttle.

RDX10

Yeah it does, I guess it is so slight in its application that it is limiting power from getting sent to the back during hard cornering.

RDX10

Took the rdx out in the snow today (having a blizzard at the moment) and my tires are really really shitty. Have it booked in for winters this tuesday.

Well anyways, I do this test with all my AWD vehicles when it snows heavy like this, basically I put the front wheels on the driveway but stop just when the rear wheels touch the edge of the medium high curb at the end of my driveway. I then did a test with traction control on, good lord did it cut power and not allow anything at all to happen (btw drove the whole time around town for over an hour with it off and felt better vs it on). I then turned it off and tried again and to my surprise the shawd activated and sent 70% of the power to the rear for the whole 10 seconds that I tried to get up the crub with my foot at all different throttle positions. It was really cool to see the rear wheels getting all the power which never happens in a straight line while moving.

My tires are shit so I couldn't get up even with the shawd trying its' best. But makes me really wonder, my RDX went into practically RWD mode, doesn't that sort of defeat the purpose of an awd vehicle? I completely expected it to be a 50/50 split max or even to send some power to the rear in little bursts, but instead it just sent the power to the rear and stayed there.

Something else I noticed is that it didn't do any lsd type work, it didn't try at all to send power left or right in the rear. It initially looked like it was trying to send power in one direction or the other in the rear but defaulted to 70% rear after.

Can't wait to give it the new snows on tuesday! Should be a tank!

mrgold35

We had a light snow fall of about 4 inches last week. My MDX did the same thing on a steep snow covered driveway when visiting a buddy. I didn't need to park in the driveway, just wanted to see what the sh-awd would do. A lot of wheel spin with about 70% power to the rear and 30% to the front with Conti DWS tires. The MDX kept moving forward and never felt like it wasn't going to make it.

I think the sh-awd will only apply tq to one wheel if the g-meter is activated on a tight curve or if wheel on the opposite axle is losing/lost traction. Since both front tires had the same limited to no traction, rear tires had the same traction level and the g-meter was activated; TQ was sent equally to each rear tire. I'm with you in thinking some TQ should of been sent to the front tires? It state on Wikipedia for the RDX:https://en.wikipedia.org/wiki/SH-AWD

SH-AWD operating parameters include:
- Up to 90 percent of available driveline torque can be transferred to the front wheels during high-speed driving

- During straight line full-throttle acceleration, up to 45 percent of available torque can be transferred to the rear wheels

- In hard cornering during acceleration, up to 70 percent of available torque can be directed to the rear wheels for enhanced vehicle dynamics

- Up to 100 percent of the torque sent to the rear axle can be applied to either rear wheel as the conditions dictate

Just sounds like a firmware thing with the RDX compared to the MDX?

Kaputnik

^^Hey guys can I slightly hijack the thread here? Not much going on here in the forum and you're talking snow....

If you have a separate set of winter tires & wheels with the TPMS sensor installed, such as a set available from TireRack, does the TPMS system automatically get recognized when you switch out your summer/winter wheels?

I'm in Northern CA where winter tires are not necessary, but I will make some ski trips up to the Sierras. First time with the RDX (sold my Toyota 4x4).

You never know about the Tahoe area. Can be bone dry or snow like hell. They don't salt roads out here either. Hate the thought of carrying cables for the front tires, as I am all on all-seasons. Blizzaks might be nice for winter - I only put ~2500 miles on the car in the winter anyway (If I did it, guarantees yet another summery winter of course).

mrgold35

I had the same issue in NM and CO with sunny and dry in the city and blizzard conditions near the ski resorts up the mountains 10-15 miles later. That is why I did the Conti DWS and snow chains. I've been lucky to not have to put the chains on after 4 years (very shorten ski season +5 yrs because of low snow pack also helped). I figured there are plenty of guys wanting to make a quick buck to put them on for you at the designated chain-up areas.

RDX10

I don't blame the RDX for not making it up, my wheels are literal shit, I should not be driving on them, but we had a literal dump of a foot in one day. I did that sort of spinning roller experiment except I had ice under all 4 wheels. Something I should of tried/would have tried if it wasn't so late is to scrape the snow under one of the rear wheels and then scrape the snow out from under one of the front wheels and see what happens. I wonder if it would have sent some power to the right or left in the rear or front. The traction control was INCREDIBLY aggressive, was so aggressive that it wouldn't send any power to the rear at all when activated......another counterproductive design, should have sent some rear when it sensed that much wheel spin.

I still don't get why it didn't try and send any power forward when it realized that the rear wasn't getting any traction. I have always only had RWD based center diff type AWD systems. This is my first ever transverse FWD based AWD car. In all the other vehicles, you could see and feel power moving back and forth as evidenced by the rocking motion. Sending 70% to the rear constantly isn't productive or helpful at all.

I also believe it is firmware.

No worries, this side of the thread needs a serious dose of life support. Trying to inject some lol. TPMS is supposed to automatically reset after a certain amount of kms, provided it is one that can interact with the computer. Someone here tried 2013 tech rims on their rdx and they didn't work.

I would take the chains both ways because you never know, I am not familiar with the lake tahoe area, however I have seen pictures with the snow higher than houses on either side of the road. Better to be safe than sorry.

Kaputnik

^^The CA highway folks have a level 3 alert that only allows cars through with AWD/4WD, snow tires AND chains. That's when you see the snow and ice as high as houses. Level 2 is AWD plus snow tires. Probably pick up a set of cables for the front tires just to be safe.

Snowing up there right now!

RDX10

Yeah I would do it just to be safe, it isn't like the cables take up a lot of space either right

Tomtwtwtw

As long as you have OEM or compatible sensors installed on the new wheels, it should work. I believe the TPMS system in the RDX uses a small sensor near each wheel to automatically pick up the TMPS data. This prevents you from having to manually reassign the sensors to the wheels when you rotate tires (I had to do this on my old car). This same logic should apply to swapping out one set of wheels for another.