: Engine/Powertrain Observations



Huey Driver
11-03-11, 09:17 AM
I guess I was trying to be careful with my title selection. I dont want to start any flame wars, but I have some observations (or more accurately, questions) about what I am experiencing. I admit, up front, that in all likelihood, my expectations are incorrect rather than a problem with the car (2012 Lux, <1k mi).

At a stop and low speeds, it seems to have some rolling resistance. The first time I drove it, I was suprised that if I took my foot off the brake, it didnt start to roll... Something I would expect from a nice torquey V6. At lower speeds (less than 15mph) it almost seems like the parking brake is dragging. I know its not, because fuel economy is right in the top of the expected range. I did catch that the dealer left the tires inflated at 30psi (the first thing I checked when rolling resistance was felt). I was pretty sure they would do that (to get a 'smoother' ride during demos) but interestingly, I dont really notice any difference in ride at 30 vs 35psi. Anyway, perhaps all this is the transmission. I am used to my Trailblazer with the 4L60-E which was really a great ride. I'd kind of expect the 6T70 to be close to it, but its all probably in the programming. On the plus side, the transmission feels very free at highway speeds. At lower speeds, there sure is a lot of engine braking tho, again, feeling a lot like it does when accelerating. More, I think tho, I am just not used to the various 'pedal positions' it takes with this new system.

Another thing I have noted, though, is a noticable 'surging' under light to moderate acceleration around 40mph (like you would experience during rush hour traffic), it can be felt as well as heard. I'm not one to really beat the crap out of my motor, and have been initially cruising around in economy mode, so I suspect that, again, it is programming.

As I said, I dont really have any 'problem' with these observations, and I dont want to start a flamewar. I am interested in the technology and what its features are. I also know that this probably isnt limited to the SRX, but wasnt really sure so I figure if it needs to be cross-posted somewhere, someone will point me in that direction. Love the car, and so far, completely satisfied!

paid4c4
11-03-11, 12:24 PM
Huey, I picked our 2012 SRX this past Saturday and so far your observations and my observations are about the same. I haven't noticed the surging at 40 mph, I'll pay attention today to see if I feel it. I got the peddles adjusted so they're comfortable and have acceptable travel. Overall this is a great ride, it eats hills without any problems and it is already giving me better gas mileage than my 09 FX35 which I traded in. We're going on a 1000 mile trip in a couple of months which will give me a lot better experience with the SRX. I'll update my post after my trip.
Bill

Tigereye
11-03-11, 02:40 PM
Congrats on your new SRX. I've had mine almost two months and can offer my two-cents. The vehicle has a "hill-hold" feature in the braking. In other words, for a fraction of a section it will not roll when you release the brakes. I easily notice that when on any slight incline; although, not as much when on the flat. The first time I noticed the "surging" I was in Economy mode. However, having only a few hundred miles on it I switched the "Eco" off and that feeling went away. Now, with almost 2,000 miles on it I don't feel that anymore at all. (BTW - I actually prefer breaking-in a vehicle right! Very surprised at the power of the engine, especially on the highways.)

I've previously owned two CTS's. So far, am really enjoying the SRX. The more you drive it the more "neat" features you'll discover. So far, not one warranty issue!

Huey Driver
11-03-11, 04:26 PM
Yes, I agree. I might ask the dealer about it but at this point dont think its anything wrong. Its almost not noticable; only about a 50 rpm change on the tach (but you CAN see it on the tach) and just a little shove in the back that lets you know its there. It cycles at an almost perfect 1/sec rate. This is what makes me think its in the programming. If I can nail down how to make it repeatable, I'll try it without economy mode.

I meant to say in my original post that I dont use the parking brake, so I knew it wasnt that. Feeling how the transmission works, I just realize I dont know how its 'supposed' to work. My Trailblazer had a neat 'feature' on the transmission. It coasted really well when you let off the gas, almost no engine braking at all. One day I was on the highway running about 65 and let off the gas as my exit was coming up. About 45mph, what I kinda figured was the torque converter lock unlocked. It almost felt like it sped up because the rate of deceleration changed so much. It wasnt a flaw, but something that would get your attention if you werent thinking about it...

The SRX almost seems to be the opposite, in that it freewheels real nice at highway speeds, but as I slow down, and get down to 15 or 20, that braking really seems to kick in.

I also know its my driving style to plan ahead and not have to use the brakes a lot. My TB had 98k miles on it when I traded it in, and was on original brakes. It wasnt going to pass inspection again, but even at 90k, when the last one was done, they said it passed. I said there was no way it could and they said they pulled two tires and all was within limits.

TheCaptain
11-04-11, 02:41 PM
Don't forget peeps! The SRX transmission has an 'adaptive learning' program that continually attempts to learn your driving pattern. All SRX's drive like a boat from the dealer, and the more you drive it, the more it learns your style.
Unless you keep changing your driving style (racy, then fuel conservative) it'll eventually feel mostly normal soon enough!

Huey Driver
11-04-11, 02:50 PM
well, its going to go insane trying to figure me out! :cookoo: