need help... [Archive] - Honda Ridgeline Owners Club Forums

hiPSI

10-23-2006, 12:01 PM

I wrote this a while ago and it should help you understand a little more.
Here is an explanation I wrote several months ago to another guy who had problems going up a hill.

His original post:
Below is a poor image of the driveway up to our mountain cabin. This represents only a porion (maybe 25%) of the driveway. The slope is fairly steep at the top, but certainly as you can see, not radical. Bottom line - the Ridgeline struggled to get to the top. At the top speed was down to 2-3 mph while rpm was as high as 3000 to maybe 3500. Traction was ok, no wheel slippage. I did the drive up with every combination of VSA and differential lock but the performance was always the same. Miserable. I fear that this is an example of limited torque or some computer function gone awry. The truck had a hard time on this hill without a load (2 adults). How bad will it be with a full load of whatever? This level of performance is unacceptable for me and unless there is some mechanical or electronic fault, will force me to trade at a substantial loss. Does anyone have any insight or advice?

My reply:
After reading this thread, I think the below explanation could help you understand how the ridgeline works and how it applies to your driveway. I wrote this several months ago in response to another question but it applies to your situation also. Hope this helps ease your mind on your decision to purchase this truck. In the explanation, slick also means covered with gravels.

The Ridgeline boasts VSA (Vehicle Stability Assist) and VTM-4 (Variable Torque Management).
Both work very well under most ordinary circumstances, but the VSA has some "quirks" that take getting used to.
First, a short explanation on VSA and how it works:
VSA (vehicle stability assist) is automatically turned on whenever the truck is started. There is a switch located on the dash in front of your left knee that can be pushed whenever you want to deactivate the VSA. Why would you ever want to deactivate a great safety feature such as VSA? Read on.
The VSA in simple terms works by "measuring" each wheel RPM and applying braking to the wheel that is determined to be slipping at the time. It will also reduce throttle if the VSA determines this is the best way to bring your truck under control.
Example: You are driving down the interstate at 65 mph in the rain and you go through a puddle and you hydroplane. The VSA will "sense" the rotation of the wheels are different and apply braking necessary to get all four wheels back spinning together, allowing you to continue to steer. I am simplifying this a lot, but the VSA works in conjunction with the anti lock brakes and the engine management system to determine all of this in a split second. It works very well in these conditions and will undoubtably save a lot of damage and lives.
The same goes for snowy or muddy roads.
Now, knowing how the VSA somewhat works, imagine going up a steep or really muddy dirt road or a slick snowy hill. You have to creep because it is so steep or slick. What will happen? The same thing that has happened to me several times. The VSA will sense the wheel slip and apply braking force to the spinning wheel and eventually (really just a split second but this is logic working) back off the throttle thinking it has done it's job. Remember though, you are trying to get up a slick or steep hill! What happens when you are going up a slick hill and the brakes are applied and the throttle gets deactivated? You stop or slow down when you want to go! If you know how the truck works, you have turned off the VSA before starting this journey to the top. If you don't know, you stay stuck or creep along. If you remember, you push the VSA button, spin a little and go on to the top. I now turn off VSA when I drive on slick hilly roads. I leave it on when driving on snow covered interstates. The VSA will also come on (even though you turned it off) if one of the TPMS (tire pressure monitor system) determines you have a low tire. This is good, unless you have aired down on purpose to drive in the sand! You must then pull the VSA fuse.
So, it has it's good and bad points. Now that I understand it, I love it. I turn it off when needed and most of the time I just let it do it's thing. For someone who does not understand it's operation, it could be not so good.

The VTM-4 works very well. In normal mode, the all wheel drive works just like it should...transferring torque merrily back and forth. When the VTM-4 button is pushed, you can "pseudo-lock" all four wheels into pulling up to a speed of 18 mph. It can actually transmit up to 70% of the output torque to the rear wheels, which is handy when pulling a boat out of the water on a slime covered boat ramp.[/

His reply before going out and trying to do it correctly:
Thanks, hiPSI. I'm hoping you are right and I am going to find out this weekend but... a couple of things - I tried going up with VSA turned off after initially having difficulty with it on. Both times, though, I was in 2nd gear with VTM-4 engaged. Each time the behavior of the truck was identical! It would gradually slow down from 10-12 mph to 2-3 mph while the engine rpm would continue unchanged (or actually climb), Meanwhile the accelerator pedal was floored and the truck seemed mired in mud. At no time was there any slippage and the engine never chocked down like an underpowered vehicle, unable to do the climb would. It just seemed to be working against itself! And his was with VSA switched OFF. Very puzzling.

His final reply after actually testing it using the correct method:
And the verdict is...
I just got in from the cabin and I have the results from the great hillclimb trial. As it turns out the one thing you DO NOT want to do is try to climb a hill in second gear/VTM4 lock/VSA off. It is apparent last weekend that perhaps I "outsmarted" myself and the truck.
The results:
- the RL in D, no VTM lock, VSA on - climbed the hill, no problem
- first gear, VTM-4 lock (or not), VSA on or off - no problem
- second gear, VTM lock or not, VSA on or off - great difficulty

Also a couple of other observations - when starting on the steepest part of the hill and in "D" or "1" with VTM locked or unlocked, the RL grabbed the hill and pulled on up with little difficulty or slippage. If I let off the accelerator, the truck would begin to roll backwards but application of throttle sent the truck back up the hill with minimal slip in the gravel (but some with VSA on or off). If I had the RL in gear 2 and stopped on the hill and let off the throttle, it would sit there and not roll back at all. If I then gave it the gas, the engine would rev up to 2500 rpm and the truck would barely move up the hill. Locked in 2, the truck is completely robbed of torque.
The results indicate that in almost any situation but locked in second gear, the RL was clearly "up to the task". The next test will be towing up the hill. I have a question for those technically savvy - why did the truck not rollback on the hill when in second but not any other gear?
Bottom line - the Ridgeline gets a reprieve and gets to serve another day. Thanks for all the insight and response. Keep on truckin'.