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Sidwin

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Discussion starter · #1 ·
I went down pikes peak yesterday and even though I was in first the car wanted to up shift to second when I hit 30. I had to ride the brakes and keep it in first to stay under 28mph. In my wife Subaru they have a button when going down steep hills. How do we do that in the xc90?

Thanks - Sid
 
I went down pikes peak yesterday and even though I was in first the car wanted to up shift to second when I hit 30. I had to ride the brakes and keep it in first to stay under 28mph. In my wife Subaru they have a button when going down steep hills. How do we do that in the xc90?

Thanks - Sid
I imagine the off road driving mode is capable of doing it, but I think it limits you to like 10-15 mph. I have yet to use it for downhills like that. Otherwise, use the manual shifting mode with your gear shifter to stay in the gear you want to.

Sent from my SM-G975U using Tapatalk
 
This is a large screen shot, but it looks like the off road mode is the only hill descent mode.
Image


Sent from my SM-G975U using Tapatalk
 
Discussion starter · #4 ·
The car at 30mph even in manual mode will try to upshift. The rom goes over 5k rpm and hangs out at 6k when u hit over 28mph. I thought for sure it would stay in first.
 
:thumbup:
This is a large screen shot, but it looks like the off road mode is the only hill descent mode.

Sent from my SM-G975U using Tapatalk
It's great for proper off-road hill descents. I use it quite a bit for sketchy and steep descents over loose dirt, gravel, mud, and even snow. It's great at managing speeds - easy to set your desired speed - I typically use it within 3-8mph depending on conditions.

On-road, definitely downshift. The downside of the 2L 4cyl is it's not enough compression/engine braking and as the engine RPMs increase it will upshift. You don't want it to get stuck in 1st while gravity accelerates your T6 past redline. It sounds like Subaru's hill descent control is not as fine tuned for off-road where you want to keep speeds in the 3-8mph range.

The upside is with a T8 there's additional "engine" braking with B gear (for ERAD braking) and it's totally fine to lightly ride the brakes to increase ERAD braking for greater battery regen. I just wish I could dial up B's regen - it would be great if the mode selector would double as a way to dial it up or down.
 
Discussion starter · #6 ·
This is a large screen shot, but it looks like the off road mode is the only hill descent mode.
Image


Sent from my SM-G975U using

Tapatalk
I saw that as well. Just wondering if anyone has any experience with it. I hope on my next 4500 miles ahead I don't have any more slopes that requires this much engine braking. I've never had a car that had to engine brake that hard for that long. I honestly thought the climb was going to be more work but to be honest going down felt like more strain on the engine.
 
Discussion starter · #8 ·
If I recall correctly, off-road mode maximum speed is 25 mph. The speedometer actually will show you the maximum allowable speed. And the car will not allow you to exceed it.
Interesting. Part of me doesn't want to have to find out lol. I watched Volvo videos on the older models doing it. It said it is using brakes plus engine. That's pretty much what i was doing. But I had to do it for 18 miles. I'm trying to figure out is Volvo doing anything special. Doesn't sound like it.
 
Discussion starter · #9 ·
Image
This is a large screen shot, but it looks like the off road mode is the only hill descent mode.

Sent from my SM-G975U using Tapatalk
It's great for proper off-road hill descents. I use it quite a bit for sketchy and steep descents over loose dirt, gravel, mud, and even snow. It's great at managing speeds - easy to set your desired speed - I typically use it within 3-8mph depending on conditions.

On-road, definitely downshift. The downside of the 2L 4cyl is it's not enough compression/engine braking and as the engine RPMs increase it will upshift. You don't want it to get stuck in 1st while gravity accelerates your T6 past redline. It sounds like Subaru's hill descent control is not as fine tuned for off-road where you want to keep speeds in the 3-8mph range.

The upside is with a T8 there's additional "engine" braking with B gear (for ERAD braking) and it's totally fine to lightly ride the brakes to increase ERAD braking for greater battery regen. I just wish I could dial up B's regen - it would be great if the mode selector would double as a way to dial it up or down.
Good point about small engine not having enough compression for engine braking. Definitely in first the car wants to get away from u if u don't help with the brakes.
 
If I recall correctly, off-road mode maximum speed is 25 mph. The speedometer actually will show you the maximum allowable speed. And the car will not allow you to exceed it.
It'll let you exceed 25mph and it'll automatically switch to AWD mode to let you keep accelerating in the faster speed mode. If you've got air suspension it'll also drop to AWD ride height.
 
Would it make a difference if you set the drive mode to dynamic? The gearing map may be willing to stay at a lower gear at a given vehicle speed.
Yes it'll hold perhaps a little longer (closer to redline) but you're also forgetting, if the transmission is shifting up already it's because the engine speed as accelerated and it's being pushed (by gravity pulling the car down faster) to the next gear. it has to upshift based on high engine speed from the speed the car was accelerated to by the downhill. Just because you're not giving it throttle doesn't mean that gravity isn't accelerating it and pushing engine RPMs up if the incline is steep enough or gearing ratio not high enough to improve engine braking. Even in a stick gravity can drag the engine past redline it overcomes engine braking/compression. If you don't apply brakes or shift up in a manual it would be just as bad.

What he's experiencing are downhills that exceed engine braking power for the gear he's in. He may be able to slow down and downshift one more gear to get more engine braking power but it's also possible the incline may be too much for available gears and engine compression. Sometimes you just have to apply brakes and still keep it in a lower gear to augment the brakes. In our V40 it's 1.9L 4cyl it was plenty. It could also be gearing as newer transmissions have lower gear ratios for fuel economy and it works given how much more torque and power newer engines have to offset lower gear ratios. All part of mountain driving. What I have found is for the size the 2L 4cyl doesn't provide enough engine braking force for the size of the car - it's about compression and not about HP in that case.
 
Good point about small engine not having enough compression for engine braking. Definitely in first the car wants to get away from u if u don't help with the brakes.
And don't forget, the way HDC works is by selectively applying brakes on wheels and keeping it 1st gear. At speed the only time you want selective wheel braking is for traction/stability control like to prevent roll overs or keep you pointed in the direction you have your steering wheel aimed.
 
Discussion starter · #14 ·
I tried off road at mt Rushmore. It was bad. Once it upshifts it automatically turns it off. I was hoping to use it like the directions and let it go down the mountain in 3rd or 2nd but every time it went to 3rd it turned off.
 
I tried off road at mt Rushmore. It was bad. Once it upshifts it automatically turns it off. I was hoping to use it like the directions and let it go down the mountain in 3rd or 2nd but every time it went to 3rd it turned off.
Odd - what happened? Were you using it to keep you going slowly downhill or just driving? If you lift off the accelerator it crawls and holds a set speed on a downhill. To do what you say you must have given it more and more gas until it switches back to Constant AWD (I think that'd be Comfort on your T6).
 
Discussion starter · #16 ·
I tried off road at mt Rushmore. It was bad. Once it upshifts it automatically turns it off. I was hoping to use it like the directions and let it go down the mountain in 3rd or 2nd but every time it went to 3rd it turned off.
Odd - happened? Were you using it to keep you going slowly downhill or just driving? If you lift off the accelerator it crawls and holds a set speed on a downhill. To do what you say you must have given it more and more gas until it switches back to Constant AWD (I think that'd Comfort on your T6).
I tried 3 times. Two times with the car in auto and once in manual. The direction said manual in 3rd should have worked but sure enough I got to 3rd and the icon for hill descent disappears.

Correct I gave it gas then it shifted to third and turned off off road mode. I was hoping to be able to go down mt Rushmore in 3rd gear with engine braking. But so far all off road mode on a descent feels like engine braking with regular braking.
 
I tried 3 times. Two times with the car in auto and once in manual. The direction said manual in 3rd should have worked but sure enough I got to 3rd and the icon for hill descent disappears.

Correct I gave it gas then it shifted to third and turned off off road mode. I was hoping to be able to go down mt Rushmore in 3rd gear with engine braking. But so far all off road mode on a descent feels like engine braking with regular braking.
Yes, that's what hill descent control is, it automatically uses engine braking with selective wheel braking when going downhill to control speed. It's great at crawling and excellent on steep and low traction surfaces - loose dirt and rocks, mud, snow, etc. I use it often off-road. It really shines when towing off-road, too. I used to keep my R-Pod at a farm down a steep gravel road. I'd let it crawl on it's own with the R-Pod wanting to push us downhill. Super steady. If you want to go faster/set a higher speed add gas and let it hold at that speed. There's no other magic power yet besides the computer managing your speed using engine and brakes. With a T8 you also get the ERAD to help for slow it down and regenerate the battery while it does.

Off-road is as good going down a rutted out trail controlling speed as it is making it up hill cross axle.
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Climbed over crusty snow and >15% grade and with HDC it was a slow crawl back down.

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Enjoying social distancing well above the snow packs we had to go over.
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With our 2010 I have to shift into 1st and manage my speed manually with the brakes. Off-road and HDC do a great job at simulating 4WL.

Excellent where ever we want to go. Air suspension is a good choice to improve the approach, breakover, and departure angles along with Off-road and HDC to keep it safe and controlled.
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