Test Drive...?

[J_82]

I am a retired automotive engineer
Just to set the record straight. Because turbo's use absolute pressure sensors to control boost pressures they will produce the same hp & torque in the Eisenhower tunnel as they will at sea level. That is a proven fact.
N/A & supercharged engines will lose power at higher altitudes.
That is also a proven fact.
Some folks like the sound of a big v8 but facts are facts when it comes to high altitude go & torque.

Absolute pressure is just a better way of measuring boost pressure, Psig can also be used. I think what you meant to say was that turbos are more efficient therefore are less affected by the lack of oxygen at higher altitudes.

 

[J_82]

Too bad the 6.2 only comes in a Denali or Escalade, they are expensive $$$$$$

 

[shane_th_ee]

Absolute pressure is just a better way of measuring boost pressure, Psig can also be used. I think what you meant to say was that turbos are more efficient therefore are less affected by the lack of oxygen at higher altitudes.

Not quite... If I understand what he's saying correctly, an engine with a turbo will respond to a drop in mass air flow (due to altitude) by increasing the turbo boost to maintain the correct ratio of combustion gasses. A naturally aspirated engine responds to a drop in mass air flow (due to altitude) by reducing the amount of fuel injected into the combustion chamber (to achieve the correct ratio between the gasses to support combustion). What type of pressure transducer one uses (absolute or gauge) is really immaterial to how the engine achieves the correct ratio of combustion gasses...

 

[J_82]

Not quite... If I understand what he's saying correctly, an engine with a turbo will respond to a drop in mass air flow (due to altitude) by increasing the turbo boost to maintain the correct ratio of combustion gasses. A naturally aspirated engine responds to a drop in mass air flow (due to altitude) by reducing the amount of fuel injected into the combustion chamber (to achieve the correct ratio between the gasses to support combustion). What type of pressure transducer one uses (absolute or gauge) is really immaterial to how the engine achieves the correct ratio of combustion gasses...

I know that I was saying turbo compared to supercharger.

 

[JExpedition07]

Fan of the ford 6.2 as well but they don’t currently offer it in the light duty segment.... i mean it’s a beast. Ecoboost is a good powertrain but for V8 motorheads one would be nice.

 

[gtnator]

The GM 6,2 Yukon XL Denali tops out around $82k with all available options, which is still cheaper (lol if I can even use that word when talking about an $80k plus vehicle) than the fully loaded Expy Max Platinum, by about 2k. Pretty comparable.

The Denali looks better, in my opinion. The Expy has better features, ride quality, safety, and most importantly for me, quality. Now we’ll see what the actual quality numbers are with the Expy redesign, but GM is still having huge quality problems with its full size SUVs: Tahoe, Yukon, Suburban and variants. That’s how I and a lot of others ended up becoming interested in the Expedition.


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[JExpedition07]

I will say i have noticed GM has some quality issues. I have a family member who owns a Denali and it’s seen it’s share of issues in 60k. No buffering or vibrations though, which is a majority of the complaints. It seems GM fixed those issues as of recent but not all units were effected anyway. Part of Fords quality is the fact they’ve ran Expedition simililary since 03’ and with time comes better quality and less bugs. They found something good and ran along with it which is why I and many others bought them. New models always bring new issues unfortunately. But i agree ford has a leg up on overall quality and don’t get me wrong so far i think i like the new one.

 

[rumline]

Getting back to the test drive aspect for a moment, [emoji16] I finally got to drive an Expedition today. It was a base 4x4 XLT Max 201 with 20" wheels added and the sunroof. I barely got to drive it because the couple that was buying it let me take it for a quick spin while they drew up the paperwork. It had just been delivered last night and the couple had just finished their test drive and decided to buy it when I got there at 1pm.

I have never driven an Expedition of any vintage before so I'm not sure that my perspective will be meaningful to you all but here goes.

From the reviews I was expecting a lot of body roll and to feel like I was driving a gun boat, since they always couch their praise like "oh yeah it drives good, for a huge SUV" or something like that. It definitely didn't feel like I was driving a Mini Cooper, but coming from a Grand Cherokee it didn't feel much bigger. Body roll was well-controlled and didn't feel any more than my Jeep does. The suspension was super smooth, soaking up bumps in the road with aplomb. It almost felt a little too disconnected. Or maybe I'm just used to more bumps in my Jeep. I wonder how the CCD will change the road feel, especially when you switch it to sport mode. IIRC the XLT only has fixed shocks, right?

The engine had plenty of power. Turbo lag was about normal. My Grand Cherokee has the V6 ecodiesel so I'm used to driving a heav(ier) turbo SUV. Hitting the gas from a stop you had to wait a second for the turbo to spool, but if you were already driving and then applied more throttle it responded instantly. The transmission might need some break-in time, because it hunted a little for gears after coasting for a while and then applying throttle again.

Dayum that B pillar is huge! I remember one or two reviews that mentioned it but brushed it off. It's farther forward than I'm used to in other cars, like I can just see it in my peripheral vision when facing straight forward. I might have been able to move the pedals further forward and thus move the seat up as well but I doubt it had much room left in it. Anyway, I underestimated how much that little loss of visibility would throw me off. It almost forces you to use your blind spot monitors more, although I'm sure it's just something you can get used to after owning it a while.

In "Normal" terrain mode the truck is in RWD. I wanted to get it in 4Auto since that's how my Jeep is all the time, so I fiddled with the selector dial until I got into sand mode. I couldn't really tell a handling difference on dry asphalt, in the maybe 2000 yards I had it activated. Even though it said 4A on the instrument display, I forgot that sand mode is for loose terrain only as I got binding on a sharp turn into a parking spot. Switched back to 2wd before the salesman knew what was going on lol. I'm sure once you get used to the different modes you'll learn what is what, but if a mode locks the differential, I'd prefer a different visual indicator than just plain "4A".

Parking was a snap. The turn radius is pretty nice, even with the extended wheelbase. It's easy to tell where the edges of the vehicle are. I did have to back up to adjust but that was because the spot at the dealership was pretty narrow.

Overall I was very impressed with how it drove, especially for being pretty much the base configuration.

 

[JExpedition07]

4Auto locks the vacuum Hubs so the wheels are locked to the CV shafts up front. No power is sent forward to the differential until rear wheel slip is detected, at least that’s what my manual states for my truck. So there generally isn’t a handling difference because it’s just arming the system to send power forward if needed. Did the one you drive have a two speed transfer case?

 

[rumline]

No it didn't, because you need the HD tow package to get that.

How you described yours is how I thought the system would work. I wouldn't expect binding in that case though. But when I looked at the 4WD screen (I forget what it was called) in the center display it showed power flowing forward to the front wheels. (?) I definitely need to read the manual to try to understand how the 4WD system works.