Curious...AWD converted to RWD.

[BlaydeX15]

One of you guys needs to ship me your AWD fuse, and I'll ship you my RWD fuse.

...That's how cars work, right?

 

[Callum]

I have read through every single DTC code, document, AWD diag sheet that KMA has to offer. Not a single one mention anything about the fuse, or decoupling the system. I did read a little bit into the DTC codes and it looks like the system just powers down and does not throw a code on the dash but a DTC Code that resets once you cycle the ignition and the fuse has been replaced. The clutch packs, AWD ECM/ECU, and HECU just goes to sleep and the system reverts into a traditional 2WD vehicle.

Honestly, probably stepping on some toes here. Looking at how the system communicates and is wired into the canbus system...looks like an afterthought to me after they designed the RWD version they thought "aw shit we need AWD too" and slapped in it

 

[MerlintheMad]

Admittedly, woke up on the wrong side of the bed this morning...sorry.

Lol. I was feeling it; random bitterness.

KIA is developing D-AWD which pretty much makes the Stinger (and G70 FWIW) RWD, well 98% RWD.

That's a good point. If Kia is ready to provide RWD by essentially turning AWD off, who am I to say that it's a stupid idea? Go ahead, burn your rears up, it's your money and your car.

 

[Callum]

I guess I can update here...since I have been in "RWD" mode for 2 months. I'm throwing the fuse back in and going back to AWD. It's a blast, but this car struggles with an open diff.

No error codes, no drivability issues. 100% functional. Until I find an LSD to install, she will be AWD!

 

[MerlintheMad]

I guess I can update here...since I have been in "RWD" mode for 2 months. I'm throwing the fuse back in and going back to AWD. It's a blast, but this car struggles with an open diff.

No error codes, no drivability issues. 100% functional. Until I find an LSD (Limited Slip Differential) to install, she will be AWD!

Well, yeah, that is the first thing I would have thought. No LSD means rough turns. Off the line with tires smoking, no problem, swing this way and that, have fun (if that's your thing). Everything else, worse. I'm surprised you left it RWD that long. I'm surprised you left it RWD as soon as you were done fooling around.

 

[SKStinger]

I guess I can update here...since I have been in "RWD" mode for 2 months. I'm throwing the fuse back in and going back to AWD. It's a blast, but this car struggles with an open diff.

No error codes, no drivability issues. 100% functional. Until I find an LSD (Limited Slip Differential) to install, she will be AWD!

I agree. I did the same and for the same reasons.

I did find though that I would get an error code in my UVO app. (Electronic Stability Control) as we discussed above. It immediately went away when i replaced the fuse. The error had no impact on the way the car performed.

 

[Revvdmedia]

I guess I can update here...since I have been in "RWD" mode for 2 months. I'm throwing the fuse back in and going back to AWD. It's a blast, but this car struggles with an open diff.

No error codes, no drivability issues. 100% functional. Until I find an LSD (Limited Slip Differential) to install, she will be AWD!

I'd be curious to know if that works well. My assumption is that the factory tuning (brake based torque vectoring) is tuned for the open diff, I wonder if a LSD would conflict with this AWD dynamics tuning?

If not, yes, throw on a LSD and maybe wire up a switch to the AWD fuse to break the connection so you have a RWD "switch" in the cabin haha.

 

[WildBill]

Most of the time a LSD will be performing as an open dif, especially when cornering which is when the vector based braking is applied.
I can't see that there would be any major issues.

 

[Callum]

I'd be curious to know if that works well. My assumption is that the factory tuning (brake based torque vectoring) is tuned for the open diff, I wonder if a LSD (Limited Slip Differential) would conflict with this AWD dynamics tuning?

If not, yes, throw on a LSD (Limited Slip Differential) and maybe wire up a switch to the AWD fuse to break the connection so you have a RWD "switch" in the cabin haha.

That is my plan, to trace the ground wire to the fuse back into the cab, or closest to the switch panel and wire in a kill switch. The LSD would prevent any sensors from activating the torque vectoring since that is based on wheel speed differences. If the LSD locks, the rear wheels are spinning at the same speed.

Based off my "fun times", turning off trac/stab also disables torque vectoring in AWD. Hence some rather smokey all wheel drifts on the track.

LSD would only enhance the AWD feature, and great enhance the RWD fun!

 

[Revvdmedia]

It might never happen, but for those looking for a "factory" solution, I hope Kia follows up the limited production GTS with a "kit" that includes a LSD and the tuning to match, including RWD mode...if not prohibitively expensive.

 

[Shrikecorp]

That is my plan, to trace the ground wire to the fuse back into the cab, or closest to the switch panel and wire in a kill switch. The LSD (Limited Slip Differential) would prevent any sensors from activating the torque vectoring since that is based on wheel speed differences. If the LSD (Limited Slip Differential) locks, the rear wheels are spinning at the same speed.

Based off my "fun times", turning off trac/stab also disables torque vectoring in AWD. Hence some rather smokey all wheel drifts on the track.

LSD (Limited Slip Differential) would only enhance the AWD feature, and great enhance the RWD fun!

I'm planning to do something very like this, from my post in How to launch on boost

...when I get around to it.

 

[Hydrajin]

This a good drift machine mode lol.. The nature of how this AWD works suggests there is no adverse side effects to disabling it for a bit of sideways fun but I wouldn't fix the front wheels and run the back like on a RWD dyno.
The system is RWD until it slips in the back. It will send power as needed to front with slip detection, removing the fuse should be just interrupting that signal going to the front diff; if the front diff never receives a signal, it just won't engage at all.
The towing info in the manual, it's similar to RWD dyno; the fixed front and spinning rear may have an impact on the AWD system but if it's just for going sideways, the front will still be rotating so it wouldn't stress the system... It just wouldn't hook the front and pull the car through a corner to correct the drift.

All this said, it's probably best to have traction and stability off in sport mode so it doesn't try to signal the front to correct anything. As with any mod of this nature, try at own risk but I do it in the winter for tire saving sideways fun and haven't noticed any issues with it. Aside from a bit of fun in fresh snow, mine is always in comfort mode sending up to 50% front as needed, cornering with push pull and daily driving is far better with that AWD system active.

 

[WildBill]

I don't believe your comments are correct. This is an AWD vehicle you are referring to. It is not RWD until slip detection. The different modes apply different percentages of torque to the rear vs front but it is always sending some power to the front.

When you pull the fuse you completely disengage the center diff which will then, no longer send any power to the front wheels. The front dif is open and will always be okay going straight, diagonal, or sideways.

I agree that anyone does this at their own risk but with the electrically variable viscus center differential, with no electrical power, there is no transfer of motor power.

To really test it we need someone to put all 4 corners of their car up on blocks, pull the fuse and see if the fronts drive at all.

 

[Hydrajin]

I don't believe your comments are correct. This is an AWD vehicle you are referring to. It is not RWD until slip detection. The different modes apply different percentages of torque to the rear vs front but it is always sending some power to the front.

When you pull the fuse you completely disengage the center diff which will then, no longer send any power to the front wheels. The front dif is open and will always be okay going straight, diagonal, or sideways.

I agree that anyone does this at their own risk but with the electrically variable viscus center differential, with no electrical power, there is no transfer of motor power.

To really test it we need someone to put all 4 corners of their car up on blocks, pull the fuse and see if the fronts drive at all.

Interesting! I've read that it's rear driven until it needs to send power to the front somewhere when I originally looked into this. I'll see if I can get all 4 corners up in the air and run it without the fuse to see what happens. Would that really be an indicator though? On previous part time 4wd Pathfinder, the front would still turn if rolling freely in the air even if it was disengaged, it would turn the fronts because there was still some motion being sent but it wouldn't actually be putting down power to ground because it would only be rears delivering the full power.

 

[WildBill]

Interesting! I've read that it's rear driven until it needs to send power to the front somewhere when I originally looked into this. I'll see if I can get all 4 corners up in the air and run it without the fuse to see what happens. Would that really be an indicator though? On previous part time 4wd Pathfinder, the front would still turn if rolling freely in the air even if it was disengaged, it would turn the fronts because there was still some motion being sent but it wouldn't actually be putting down power to ground because it would only be rears delivering the full power.

I half expect that the fronts would find some very light power being sent to them due to there being "some" friction in the differential but I'd expect that a light amount of pressure would stop them from spinning.
Here is an old video about how the Dynamax system works. So what we'd be doing by removing the fuse is cutting power from the little hydraulic pump and eliminating the the pressure on the clutch pack.

If you find something on the system being on-demand be sure to post it up. Info about Kia's AWD systems as they relate to specific models is very scarce.

 

[WildBill]

The original link referenced on the forum is dead but this was originally posted about the Sportage in 2011. In the stinger the ends are reversed, IE it is RWD by default and applies varying torque to the front wheels. I honestly don't know about the on-demand nature in the end. I'd assume for a sports car it would always be applying power but if it can react in 150 ms then maybe it just "feels" like it is always there.

The DynaMax AWD coupling is basically like some others in that an electric motor operates an oil pump to pressurize a housing with a multidisc clutch. The hydraulic pressure applies the clutch so required torque is transferred from the front-drive-based system to the rear differential—the greater the pressure, the more torque is shifted to the rear.

However, there are numerous differences vs. other systems, both within the coupling and with the high level of active control that speeds response, to improve overall performance.

First, the CAN bus (Controller Area Network) monitors signals, principally throttle position, steering angle, vehicle speed, and road texture (an algorithm that includes wheel speed sensor signals). The signals go to the AWD computer, which calculates the ideal front-rear torque split that it anticipates.

The computer then operates the motor at up to 10 rpm to run the pump, to build up the required hydraulic pressure (maximum of 320 psi/2.0 MPa) for the clutch. This is accomplished with the aid of a feedback signal from a pressure sensor on the clutch housing. The motor stops when the correct clutch-apply pressure is reached.

At start-up the system presets the front-rear torque distribution so there is no slip on the front axle. As the vehicle moves down the road, the DynaMax computer continuously monitors sensor readings, to anticipate changes in upcoming driving conditions.

The computer recalculates impending torque split requirements from the CAN bus data and, if necessary, makes instantaneous adjustments in motor-pump-to-clutch-housing system oil pressure with the help of the housing pressure sensor.

Because Magna engineers designed the DynaMax system to react quickly in changing traction conditions, such as encountering an icy road patch, it never starts from an "off" position.

If the pressure must be increased (for more torque transfer to the rear), the motor turns forward to operate the pump. If the front-end traction is good, the computer simply backs off the motor-pump assembly to reduce clutch-apply pressure. Then more torque (and if it's appropriate, all the torque) is delivered to the front wheels. There are no pump valves to open and close.

The pump is a gerotor type. Engineers note that its tight internal tolerances enable it to maintain commanded pressure for a short duration, as effectively as a plunger- or valve-type pump. If the time period for steady state becomes extended, so that leakage starts to reduce the apply pressure, the pump runs to reload the hydraulic circuit as required.

As a result, the DynaMax computer's typical response time to "tune" for an impending change in torque-split requirement is 50-100 ms. If a torque increase is needed from the engine, it takes up to 300 ms to build up, observed Walter Sackl, Magna Powertrain's global product manager, so in some cases the engine may determine the actual time period.

In any event, the response of the DynaMax itself should occur well within 150 ms, Sackl said.

The computer algorithm for the clutch looks for consistently good front-end traction and when possible will maintain 100% to the front wheels for fuel economy. The algorithm, however, is adaptive; in "sporty driving" it will apportion torque as needed between front and rear, Sackl said, and it will transfer 100% to the rear if appropriate.

The up-to-100% front-or-rear torque split, in conjunction with the AWD computer's active control approach, also minimizes oversteer and understeer in normal driving situations, he added. In addition, the system has a manual-select position for a 50-50 torque split.

The DynaMax coupling was sized for light weight and engineered for minimum energy use. Its 727 lb·ft (1000 N·m) peak torque design capacity is more than adequate, even with a generous safety margin, because the new Sportage's 2.4 L engine's rated peak torque is 168 lb·ft (228 N·m). However, Kia intends to use this coupling in forthcoming vehicles.

The Sportage has a tow capacity of 2000 lb (907 kg); Kia's testing showed that even with maximum loads, including hill climbing, the coupling's internal temperature never reached a thermal shutoff level. A contributing factor is the cooling provided by the large oil capacity of the DynaMax housing, Sackl said.

The fluid fill, unlike competitive designs, is life of vehicle, he added.

Kia has an exclusive arrangement with Magna Powertrain that with required competitive development times should last for two model years. The DynaMax coupling is being built in Korea in a plant that is a joint venture between Magna Powertrain and Hyundai WIA, a parts manufacturing affiliate.

 

[Hydrajin]

I half expect that the fronts would find some very light power being sent to them due to there being "some" friction in the differential but I'd expect that a light amount of pressure would stop them from spinning.
Here is an old video about how the Dynamax system works. So what we'd be doing by removing the fuse is cutting power from the little hydraulic pump and eliminating the the pressure on the clutch pack.

If you find something on the system being on-demand be sure to post it up. Info about Kia's AWD systems as they relate to specific models is very scarce.

So one thing I do remember is htrac is not Kia AWD, it seems to be Magna Steyr technology licensed to Hyundai for use.. which is probably why not all AWD offered is htrac AWD (costs of license). The Magna Steyr system is RWD until needed to be AWD for maximum efficiency. I'll try to find that article that explained what htrac was.
Update link:
News Release - Magna AWD System Helps Hyundai Genesis Achieve New Levels of Driving Performance

For those who don't know Magna.. it the company OEMs reach out to when they simply can't make a good enough part or system. Magna builds the Benz g wagon because Benz doesn't have the ability to build it as well as Magna does.. lack ability not knowledge.. magna has a huge root system in automotive manufacturing where highest quality at lowest possible cost is needed for parts, manufacturing methods, and full vehicle assembly. Magna AWD is the refined version of the best AWD tech (Quattro) if I recall correctly. I work in R&D so I have to know all this and constantly assess market through market research -__-... Market research potentially the most boring job ever 70% of the time, 100% of the time if ur not nerdy like me lol.

 

[JDM_Man]

AWD Canadian Stinger GT Limited, traction control doesn't work with this fuse out or the system doesn't work well enough to control the power.

 

[Frenchy_418]

I have done nearly 1000km in RWD and its no problems at all. The car is fun when you want but you just cannot to be as dirty on it as if it was AWD. If anything you get to learn more about the car and probably drive it better after. With more respect.

 

[Callum]

I wonder if you plugged in the GTS TCU, if that would work? The LSD parts are not expensive through the dealership and getting a performance shop to swap the gear set isn't crazy. It's just labor in the garage if you can get the pumpkin out