Meryla State Forest

Rally

Rally

Forum Member
Joined
Jul 11, 2008
Messages
3,928
Location
Sydney
Car Year
1999
Car Model
WRX
Transmission
6 Speed
Meryla State Forest 10-12th August 2018

We had another enjoyable weekend away in the NSW southern highlands. Somehow we always seem to find somewhere new to go to. This time it was a different campsite, which apart from having to deal with some yobbos from Bogan City and their utes, guns and willingness to cut down trees, was fantastic. And, Alex joined us on the Saturday morning in his newly acquired SH XT auto, complete with brand new coilovers and KO2's.

We actually didn't do that much off roading. The 2 Daves brought their Landcruiser and Pajero. This was the first time out for the Pajero, and it got a thorough going over!

I nearly got stuck for the first time ever with the diff locker, this time in deep mud and water. I had already gone through this mud hole on the way through, but there was a big drop off and when I came back the other way, it was the body of the car or the bullbar hitting rock. I had fallen into an oversized bathtub, with sheer drops at each end. However, after a few attempts I managed to climb up the side of this bathtub. In doing so I really did a diagonal climb, which showed the true worth of the locker diff. When I get the video I will post it up.

We then went and re-did the first climb we did to test the locker. I made it up first go, easily, Here is the video of this climb from a few months ago. I am showing this in order to compare the difference between my SG on RE002's with centre and rear lockers, and when Alex attempted the same climb in his SH on KO002's.
[ame="https://www.youtube.com/watch?v=-vk09und-9o"]Meryla S/F Easter 2018 - YouTube[/ame]
 
The SH XT on the same climb. It was interesting how the auto just sat there, and the traction control I understand the SH has cannot cope with the terrain. It's a fascinating comparison between auto and manual, traction control vs diff lock, road tyre vs off road tyre. The difference in ground clearance between the 2 cars is about 10mm, measured at the rear. Alex does eventually get up, and this is shown on the video in the next post.



https://youtu.be/tmU6_Jf_76g
 
With more speed and determination, Alex prevails! Have to admire the determination. And great driving, even more so not to damage his sump- no sump guard. https://youtu.be/u3QHLRhTlWM
 
Apologies to everyone who has seen this video before, but I said to Alex I would post this video up. Alex discovered first hand just how slippery the surface was. Thankfully he was only a bit sore- his CB radio came off far worse! [ame="https://www.youtube.com/watch?v=xPAGu15SW20"]Meryla S/F Easter 2018 #4 - YouTube[/ame]
 
Interesting comparison between the modified SG and the stock SH. Traction control is not the problem as it should have been, and looks like it was, switched off on the SH. VDC is the system that distributes torque to the wheels with traction and it operates with or without traction control.


The comparison certainly indicates that momentum plays a big role as the SG had more of it in comparison with the first attempt by the SH. I would be interested in comments by the driver of the SH to see whether he followed the recommended procedure in such conditions of keeping the right foot down, resisting the natural urge to back off when the front wheels lose traction and wait for the VDC to work the way it is intended.
 
When I did the run yesterday, I went slower than on the video. In fact, I nearly stalled it because I wanted to go as slowly as possible and went so slow I had to engage the clutch briefly to blip the throttle. It’s much steeper than the video makes out.
 
Nice comparison videos but why is the image so small/narrow ?

By the looks, his new coilovers don't have much travel as he lifts wheels all the time, sure that doesn't help for traction.
 
Rally, what bumper is on the front of your Forester?
 
I don’t know why the image is as it is. Maybe there is more to using an iPhone 7 than I am aware of. I would have thought vdc would have overcome unweighted wheels.
 
jf1sf5 said:
Nice comparison videos but why is the image so small/narrow ?

By the looks, his new coilovers don't have much travel as he lifts wheels all the time, sure that doesn't help for traction.
Click to expand...

Does anyone know whether SH Forester XT has thicker away bars than the X. If they do this might explain the wheel lifting.
 
Rally said:
I don’t know why the image is as it is. Maybe there is more to using an iPhone 7 than I am aware of. I would have thought vdc would have overcome unweighted wheels.
Click to expand...

VDC will apply the brake on the lifted wheel so power goes to the wheel with traction but there is still only half the amount of tyre tread on the ground which means traction on the grounded wheel is more likely to be overcome by the power than if both wheels were in contact with some power going to each. That's why the right front can be seen spinning when the left front lifts.

Even a locker won't make that much difference because traction always depends on the size of the contact patch. The lifted wheel wont spin because both wheels are locked together but there will still be only the same amount of traction available.
 
Not sure I understand your point of view. The cars weight stays the same even with 2 wheels off the ground meaning you have approximately twice the weight on each wheel still on the ground.

I think that traction has more to do with torque distribution than thread on the tires. Another aspect for better traction on this type of terrain is soft rated suspension and maximum droop, thats what helps most keeping the wheels on the ground.

I have already tested my Forester 1" higher with the same suspension setup (HotBits coilovers), the only gain is ground clearance and maybe the look, everything else is worse....
 
The only wheels spinning are the wheels in the air, the other wheels are providing no drive. If all the wheels were spinning then you would be right by saying that the lifted wheels were limiting traction. The vdc system just can’t cope.

I was certainly surprised at the limitations of the electronics. You can see them working initially to re-distribute drive but then it quickly reached it’s limits. Yes, it’s better than having open diffs as it eventually got up. However, it’s clearly nowhere near as good as having diff locks.

The auto box was also part of the problem. You could hear the engine revving a couple of times but nothing was happening. This was indeed a surprise. It wasn’t throttle lag as has been another issue, as you can clearly hear the engine revving. In which case it would seem a mechanical solution would fix this (torque converter).
 
I guess I did not see that VDC climb, I only see Rally's car, but here is how it goes from my experience:


--AT cannot be a problem, unless it is a CVT issue;

--KO2s on a Subaru in challenging terrain must be at no more than 20 psi or contact patch is minimal;

--on a Subaru, traction control (some call it VDC button) must be off. Otherwise, good luck. If "on," it kills the engine so you go nowhere, especially in slippery conditions. On a 4x4, on road traction control should be off automatically "off" when in low range;

--on a VDC Subaru, you must keep the foot on the gas for VDC to get the job done. Can get upwards of 10 seconds in some cases!

--VDC will get you through. Never been stopped, but did struggle a great deal on three occasions. However, VDC is passive and without x-mode, rather slow for rocky conditions.

--Specialized offroad traction control, as on Toyotas, is much more aggressive than VDC and works better: prevents wheel spin much better.

--Even so, the rear locker makes a difference on ledges and on loose, rocky climbs where the rocks are medium-sized or bigger.

In sum, yes, in rock, traditional locker is not matched by even the best offroad electronics. That said, the latter should get a reasonably built (not overweight and "overheight") vehicle through any non-extreme terrain. Now, with the right amount of rain, etc...things can get tricky.

Tidbit: if you watch 4WD Action, you will see Graham's Isuzu spinning but mostly getting through. That's exactly how VDC worked on my Outback. On the 4Runner, offroad traction control does not allow spin in rock at all. It is funny how Graham raves about the Isuzu but I guess he is sponsored by the brand. To me, its traction capabilities look no better than a Subaru's.
 
Rally said:
I don’t know why the image is as it is. Maybe there is more to using an iPhone 7 than I am aware of.
Click to expand...

An easy fix is to turn the phone sideways.
Much better for our horizontal eyes.
 
Thanks Ben, will give it a go
 
Rally said:
The only wheels spinning are the wheels in the air, the other wheels are providing no drive. If all the wheels were spinning then you would be right by saying that the lifted wheels were limiting traction. The vdc system just can’t cope.

I was certainly surprised at the limitations of the electronics. You can see them working initially to re-distribute drive but then it quickly reached it’s limits. Yes, it’s better than having open diffs as it eventually got up. However, it’s clearly nowhere near as good as having diff locks.

The auto box was also part of the problem. You could hear the engine revving a couple of times but nothing was happening. This was indeed a surprise. It wasn’t throttle lag as has been another issue, as you can clearly hear the engine revving. In which case it would seem a mechanical solution would fix this (torque converter).
Click to expand...

We must have been looking at different parts of the video. There is a point where the left front wheel leaves the ground, stops spinning and the right front spins in the gravel, throwing up dirt and rocks. This is where the VDC is working but there is not enough traction to move the car forwards as one rear wheel seems to be spinning too.


Your assumption that the VDC is not coping is not objective as there are too many variables such as tyre pressure, the line the driver took, which mode the transmission was in and the way the driver operated the accelerator.

VDC works in a cycle. The computer detects wheelspin, applies the brake to that wheel and torque is redirected to the wheels the are not spinning. Provided the driver keeps constant or increasing pressure on the throttle, the computer will maintain control of traction. If, however, the driver eases off on the throttle, even slightly, the VDC goes back to start the cycle over again

I agree that the VDC takes too long to decide what to do, allowing wheelspin to occur in the first place. Porsche, for example, on the Macan, (which my son owns) has a very similar system but the delay is imperceptible. I am glad, however, that my SH Forester cost me less than half of a Macan! :)


I also agree that the auto transmission on the SH is garbage. It hunts around for gears at times on the road in Drive, but when locked in 1st gear there shouldn't be a problem. I have certainly not experienced any hesitation such as you heard on Alex's car. Whether there is a difference between the way the auto operates on NA vs turbo, I wouldn't know.

What this little demonstration has convinced me of, if I take your assessment as it stands is that if I want to do any serious off-roading, I need to get rid of my SH Forester, buy an SG and put lockers in it. This would cost so much time and money I really should just buy a Toyota and be done with it. :rotfl:
 
Anything can be a problem, an auto is no exception and you need to see the video to see why it’s a problem.
 
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