Couple Questions:

1. Just got my cobalt, got about 100km on it. How do you suggest I break it in and stuff before I can go speeds that will show it off a bit?

2. I bought a LS Coupe with 15 inch wheels and the dealer put some after market 17 inch Katana's on there. I heard talk earlier about the computer thinking a persons wheels were still 15's. If my car is still set to think its on 15's how would it affect my car and should I change it cause in winter I will be putting my 15's back on? And also how would I change it if the dealer said he couldn't?

3. What's the best method for tinting those dots on the back windows so I can tell the place I am going to get to tint them?

4. What CD's does the stock MP3 player read best? (CD-RW or CD-R or Stamped CD's)

5. Does having the A/C on high affect performance?

6. My Fuel Economy Sensor when I first drove my car out of the dealership was at 24.5L/100km now its at 14.5L/100km how does it calculate this number and why is it all over the place?

Any answers or suggestions would be greatly appreciated so please feel free to post here.

 

1. Not sure if you can go fast enojugh in a Cobalt 2.2L to show it off ----for speed anyhow If I were you--I would not exceed 4500 rpm or floor the car for the first 1000kms. Just my recomendation on that. Take it easy and let the engine break in a bit.

2. Go to this site and punch in your stock tire size and your 17" tires size. You'll see how close (or far off ) they are. Worst case the speedo will be off a little bit. Your computer has no clue what size your tires are.

Stock size is 195/60/15--I compared your 17's to that and they are very close. 0.2% speedometre difference. Switch back and fourth as needed. The only thing you'll notice is the ride/handling difference.



5. Having the a/c on period will affect performance and fuel econimy. High would probably be worse.

 

hmm
2. you might want to put stockers back on for winter usually performance tires arent very good in the winter, also your speedo might be a bit off, nothing to worry about though
5. yes a/c will rob your engine of some power, if you are gonna race, dont have the a/c on
6. mine goes all over the place too its really annoying im not sure if thats supposed to be like that or not

 

1) Break in is detailed in the manual, you are supposed to vary engine speed (rpms) for the first 500 miles.

2) The computer has a setting for the outter diameter of the wheels, if you change that then they need to be recalibrated. Changing the rim size doesn't necessarily mean you have changed the outter diameter of the wheel/tire.

3) My place wouldn't even try to tint the dots

4) I have only used CD-R's so far.

5) The A/C compressor has a clutch on it that disengages under wide open throttle.

6) The DIC gives a rolling average of the fuel economy since it's last reset. So after you first reset it it goes all over the place for a bit. I think it just calculates the inject duty cycle and figures out how much gas it's injecting over time. The longer it's been running without being reset the more stable the number gets.

 

Wow quick answers. Thanks alot guys, only thing really left is the tint thing. As for the CD question my main reason for asking it is I had a CD-RW that was a bit beat up and for some songs instead of playing it, it would play the notes really low. It was very wierd, sounded like devil music or something.

Sounds like I shouldnt worry to much about the tires or the econ thing so I am relieved.

 

I have heard various things about tinting. Some shops do it with no problem, some attempt but have poor results, some guys just put black vinyl over them. I suggest shopping around before committing to a shop.

 

what will happen if we floor the car within the break in period anyways..........(not from rest) just curious coz some said vary engine speed and some said no full throttle

 

probably nothing will happen, just dont do it often.

 

Where did you get that disengaged clutch under WOT information? That's a pretty nifty feature.

Whatever the fuel economy calculator does, it is correct. I have checked it on several tanks now. I reset it after a fill and check the calculations on the next fill. All my manual calculations have matched the computer down to the tenth of a gallon!

If you really think about it, it makes sense why the fuel economy goes all over. You just fill up the tank, the computer starts taking numbers. There is a HUGE difference in fuel econmy from no throttle to the various throttle positions. If you drove constant at 3/4 throttle, your gas mileage would be WAY low. No throttle is WAY high. So it's all over the place initially. Then as time goes on.. it's more of a weighted average and starts to smooth out. Your numbers are going to start gravitating toward a certain point. By the end of the tank, there are so many data points in the average, it's hard to change it anymore.

I did a poor job at explaining what was in my head, so I hope it make some sense.