When I hear four-wheel-drive lock, I think of a 50/50 power split or at least a set distribution of power front to rear for off-roading purposes. Despite its name, this is not what the Mitsubishi Outlander's "4WD Lock" does.
According to Mitsubishi, "in lock mode, the system still apportions front and rear torque automatically, but sends more power to the rear wheels. In dry conditions, 4WD Lock places priority on performance. More torque is directed to the rear wheels than in 4WD Auto mode to provide better control when accelerating on snowy or loose surfaces, and enhanced stability at high speeds." Up to 60 percent of the power is sent to the rear wheels under full-throttle on dry pavement -- 4WD Auto sends a maximum 40 percent to the back.
So essentially, 4WD Auto is a front-biased auto four-wheel-drive system, while 4WD Lock is rear-biased. The previous-generation Acura MDX also had an automatic all-wheel-drive system that sent more power to the rear wheels when accelerating for better steering control.
I took the Outlander out on a driving loop to test what effect 4WD Lock had on handling. It certainly wasn't a night-and-day change between front-wheel-drive only and 4WD Lock, but I definitely could detect a difference. There's a little less understeer noticeable, and the steering felt better in tighter turns -- although it still tends to feel like it's attached to the rubber bands of a SoloFlex. Unlike the also-nimble CR-V, the Outlander's ability to be rear-biased certainly gives it a leg-up on the competition when handling is a priority.
I'm not sure what leaving the Outlander in 4WD Lock would do to fuel economy, but if the difference was negligible, this is the mode I would leave it in every day. Having said that, they probably shouldn't call it "Lock" when it does not in fact lock.
James Riswick, Associate Editor @ 18,902 miles
7driver says:
03:44 PM, 11/ 6/07
Sheesh, perhaps you should check if they apply the same loose definition to Anti-Lock Brakes. ext thing you know, those tags marked "Airbags" don't really have airbags in them.
daxtripper says:
04:08 PM, 11/ 6/07
Well, they don't actually have air in them, that's something.
bimmerjay says:
04:21 PM, 11/ 6/07
uhh, they do actually. :-)
Sounds like a case for the call-it-what-it-is police. 4WD Lock does imply that a transfer case or differential locks a 50/50 torque split... so why would Mitsu call it this when it's something very different?
billt9 says:
08:24 PM, 11/ 6/07
spelling police:
paragraph 4, sentence 1,
"effect" is the noun.
"affect" is the verb, unless you are a psychiatrist.
daytona_500 says:
10:16 PM, 11/ 6/07
Good call bill. I'm surprised at how many people screw up those two. Kind of like brakes and breaks.
dodo2 says:
09:54 AM, 11/ 7/07
I'm not sure why Mitsu calls this 4WD mode "Lock", but they are not alone. Toyota calls it the same in the RAV4 and it works in a similar way, although it disengages above 25 mph (Mitsu’s stays on regardless the speed).
Hard to believe, but maybe they couldn't find a better word?! What about "4WD Plus" or "4WD Enhanced" or something like that?
jriz says:
10:15 AM, 11/ 7/07
Oh yah billt9? Well, you didnt capitolise any words in your comment, and it's sentanse structure was non-existant!
The RAV4's is not quite a lock, however, it does provide a held ratio of 55/45. It should probably be called "4WD Hold." This system IS designed more for off-road use, specifically to get the vehicle unstuck. It does disengage at 25 mph or when the brake is pressed, to "enhance the effects of ABS and VSC control," according to Toyota. The RAV's hill start assist control and downhill assist control are the features that particularly make it the preferred vehicle for light off-roading. Not that anybody really does that in a RAV4, but should you need to...
qqt414 says:
10:18 AM, 11/ 7/07
Anyone have any experience with fuel economy in 4wd LOCK. i would love to leave my outlander in lock everyday but psychologically i would think im wasting gas for nothing on my morning commutes.
SubyTrojan says:
10:48 AM, 11/ 7/07
Hahaha!
James laughs in the face of grammar and spelling nazis! That'll show you guys (and gals)!
For what it's worth, dodo2 tried to enlighten all of us a long time ago about the Outlander's 4WD. Thanks for being gracious enough not to say, "I told you so," dodo2!
redliner says:
10:55 AM, 11/ 7/07
Do the Outlanders doors "Lock" too?
dodo2 says:
08:40 PM, 11/ 7/07
qqt414: IIRC the Owner's Manual recommends not to use the 4WD Lock mode under normal driving conditions. 4WD Auto is enough.
James: I cannot see how one could claim that the RAV4 is a better off-road vehicle than the Outlander based on the fact that it has hill start/descent assist buttons and a 4WD "Lock" that holds the 55/45 ratio up to 25 mph? What if under the same off-roading circumstances, the variable torque distribution in the Outlander, in the Lock position gives you the “perfect” 50:50 ratio? What about shift your gears manually (can’t do that in the RAV4) and break in order to modulate the acceleration/breaking as needed? Please correct me if I’m wrong, but I don’t remember seeing the Hill Start/Descent Assist on the Jeep Wrangler’s feature list. Does this mean that the Wrangler is less off-road capable than a RAV4?
I guess until you put them on the same off-road, measurable, tests it's just pure speculation based on paper specs. And since we are speculating, the Outlander has a full inch more ground clearance over the RAV4, plus you can disable the ASC versus not being able to do so with the VSC on the RAV. This, plus the fact that the “Lock” mode on the Outlander can be maintained regardless of the speed are advantages on the Outlander’s side IMO.
Regardless, none of them are designed for off-road duties anyway; they are just plain and simple “all-weather” 4WD systems.
jriz says:
10:20 AM, 11/ 8/07
We (including myself) did drive the RAV4 and Outlander on the same off-road course, quite literally back to back, and found the RAV to be more adept. Not a huge difference, but that was our observation.
dodo2 says:
12:05 PM, 11/ 8/07
James: I see and I wouldn't argue, but could you elaborate on that?
jmvcar says:
10:27 AM, 11/14/07
This has nothing to do with the 4WD Lock issue.....but, we're seriously considering buying one of these and have a concern I'm hoping you or any of the folks who have spent time behind the wheel can address: when we test drove it, we didn't notice any air vents for the second or third row. Did you ever drive the Outlander with passengers in the back and, if so, did you notice if there were problems getting cooled / heated air back there? Many thanks.