Oookay, looong post alert. It seems that there's an issue with the search results not returning posts from before the forum changeover, and I've raised the issue with Antoine. In the meantime, here are a few of my posts from earlier in the thread:
0-60 test run comparison - 1 second difference between a single 34F run and a single 16F run.
In my CX-9, I did a 0-60 run in mid-October, when temps were at 1c (34F), and got a time of 7.8. I just did another 0-60 run at -9c (16F) and got a time of 9.0.
It does appear that the engine loses some power at colder temps, based on my own crude testing. Keep in mind that I tried to keep parameters as consistent as I could, but other factors may also contribute to the difference in reported times. For example, tires are the same and testing track is the same. While pavement was dry during both tests, the most recent test had some blowing snow on the road, so there was likely some traction loss or a minimal amount of wheel spin.
CX-9 appears to be affected, but not to the same degree as the CX-5.
For the record, my CX-9 doesn't devolve into some anemic 2.0L engine that can't get out of it's own way. It just feels like the boost has been dialed back a bit when the engine is being wound out.
If this is by design (and it seems to be), I have no problem with it as long as I know why it was implemented. If I know that it was done to protect the engine in some way, I wouldn't care so much. To be honest, I really don't care at all since I never need to accelerate hard enough to notice the difference, especially in the winter, with ice/snow on the ground.
Suggesting a better (IMO) test scenario..
I had done my own testing earlier in this thread and realized afterwards that my testing was not ideal. I think the best test to determine if there is an actual power loss would be to test WOT acceleration while at a cruising speed in temps above 20F, then again in temps below 20F. Get the car to 25mph, then go WOT and see how long it takes to get to 50 or 60. Repeat in warmer/colder weather and compare. A test like this would mimic real-world operation (highway merge) while a 0-60 acceleration test would not.
IMO, a slightly slower 0-60 time is still something to take note of, but it is much less important than WOT acceleration from cruising speed. I can't think of any reason I'd want to go WOT from a complete stop when it's below freezing (ice/snow could be on the road, tires will have less traction, surrounding traffic would generally be slower).
Testing WOT acceleration from cruising speed at 36F.. I planned to do another test to compare, but roads have been too icy/snowy. Can't expect much when even 19F is well below freezing, and more than cold enough for ice to form on the roads.
2018 CX-9 AWD, outside temps at 2c (36F). TCS off, engine cold.
Here's a general idea of what the road looked like.
Not dry, but not really wet either.
Dougal's post is notable to me, because it seems that the colder air is benefiting the engine to some degree, in the form of better mileage.
So is this good or bad?
I was just in the New England area and although it never got colder than 23F, the car felt fine. However, I don't do 0-60 runs and I don't floor it for the heck of it. Driving on the highway and passing cars felt the exact same as always. What I did notice in my time up there was that my gas mileage was about the same as it is down south - which honestly surprised me. In the past, with my CX-5 NA, my mileage would always be worse in the cold and with winter gas.
My reply to Dougal's "is this good or bad?" I also threw out a theory regarding the heavier CX-9 vs. the lighter CX-5.
It doesn't mean anything until I perform the same test, in the same conditions, but at a colder temperature, which would be -7c (19.4F) or colder. Once I've filmed that test, I'll post it so everyone can see the results for themselves. So far everything else appears to either be anecdotal, or a fair comparison hasn't been documented and posted here.
Even with this testing, this would likely only apply to the CX-9 as there are likely differences in tuning between this car and the CX-5. For all we know, the CX-5 is tuned to pull power because the lighter car paired with the OEM tires would result in the TCS kicking in way too often. Here's a question - does the Reserve/Signature come with the same tires as the GT/Touring/Sport (in the same wheel size)?
The reason I asked is because its possible that Mazda used a different tire on the GT compared to the tire used on the GT Reserve and the Signature. I'm trying to find out whether or not they are using a specific tire with the turbo models to offset potential wheel spin/grip issues that may have arisen from using the GT tires. If they are in fact using the same tires across the board, that could be a potential reason for detuning the turbo in colder weather (because they're using tires that were paired with the N/A version of the CX-5). I believe the CX-9 came with either Bridgestone tires or Falken tires across all trims, including the FWD models - I'm not 100% sure though.
Cliffs: The CX-9, in my experience and with my limited testing, does experience the same issue in cold weather, but to a much lesser degree. It is not significant enough for me to notice, mainly because I don't accelerate at WOT when the temps are cold, regardless of how dry the road appears to be. Rubber also gets harder when it's cold, and traction is reduced as a result. I think this issue boils down to a combination of factors - overboosting and/or oil dilution prevention, traction control due to cold weather conditions, and too much torque for the lighter CX-5.
If this issue was significant enough for me to notice, I'd be doing the following. I don't think that I personally would be pushing for a fix, but I would want to know exactly why the issue was happening.
I'm kinda surprised you haven't raised a bigger stink - I sure would. Here's what I'd do:
1. Take car in again and get the corporate and dealer acknowledgements in writing. Spoken words mean nothing.
2. Post a good quality comparison video on YouTube
3. Post on Mazda's social media platforms
4. Reach out to corporate independent of dealer with history of your problem and the video evidence.
5. Reach out to as many auto reviewing people as possible to spread the story.
6. If that doesn't get traction, then dig up your state's lemon law and see what qualifies.
Seems like it's time for folks to file complaints with NHTSA and get this on their radar screen. That might eventually force a formal Mazda response...or a fix.
If some are correct that the turbo has been dialed-back to diminish oil dilution issues in cold weather, I gotta think that it's an acceptable trade-off, within reason. But at this point it's only conjecture.
Maybe a software update is in order.
