Shifting with A/C

[attrapereves]

I've started using the A/C recently and notice that when shifting, primarily from 1st to 2nd, shifting seems clunky. I am shifting around 2500rpm. I release the clutch slowly, but the car seems to really "clunk" or jerk as the clutch is released. Has anyone else had this feeling?

 

[sx sonic]

With the A/C on there is extra load on the engine. Not only does it reduce power to the wheels but also slows the engine down faster; this is real noticeable when the clutch is depressed.

With the engine RPMs dropping quicker inbetween shifts your clutch release and throttle timing are no longer matching input and output shaft speeds. In other words not as smooth a shift.

Try shifting faster, it's what works for me.

 

[attrapereves]

Good to know. Thanks! I was worried that something was going on with my car.

 

[cornbreesha]

New to the sonic, but that happened all the time with my cruze

 

[CyberGreyTURBOZ]

Using the AC makes the car act completely different. Normally the rpm's will hang up there or float for a minute, but with the AC on the drop like a rock. It definitely takes some getting use to. You cant granny shift when usi g the AC. Depress the clutch fairly quick and match with quicker gear change. Just watch the tach close the first few times to not release the clutch to quick and rock the car bad.

 

[Natesriv]

yeah shifting at 2500 RPM is pretty low with that load. Try going to 3500 to 4000 RPM, see how that's going

 

[ChrisJ]

It takes practice but I can easily granny shift with A/C on often at 1500-2K.

If you want to take off fast you need to get your RPMs up before letting the clutch up, and even ride it a little, something I hate doing but sometimes it's necessary.

When shifting normal you need to give it more throttle and let the clutch up slower but you can shift smoothly with some practice.


What's really fun is when your fan is on slow and its cool out so the compressor cycles constantly. It's like a lottery, will I shift when the compressor is on or off?

And that is why I hate the fact GM put a fixed displacement compressor in the Sonic rather than a variable.

 

[attrapereves]

Using the AC makes the car act completely different. Normally the rpm's will hang up there or float for a minute, but with the AC on the drop like a rock. It definitely takes some getting use to. You cant granny shift when usi g the AC. Depress the clutch fairly quick and match with quicker gear change. Just watch the tach close the first few times to not release the clutch to quick and rock the car bad.

The car does act completely different. My wife's automatic Sonic really struggles with the AC on. I can almost floor it and get very little acceleration. These little 4cyls really struggle with AC and other power hungry stuff.

 

[ChrisJ]

The car does act completely different. My wife's automatic Sonic really struggles with the AC on. I can almost floor it and get very little acceleration. These little 4cyls really struggle with AC and other power hungry stuff.

Should've bought the 1.4T.

 

[CyberGreyTURBOZ]

It takes practice but I can easily granny shift with A/C on often at 1500-2K.

If you want to take off fast you need to get your RPMs up before letting the clutch up, and even ride it a little, something I hate doing but sometimes it's necessary.

When shifting normal you need to give it more throttle and let the clutch up slower but you can shift smoothly with some practice.


What's really fun is when your fan is on slow and its cool out so the compressor cycles constantly. It's like a lottery, will I shift when the compressor is on or off?

And that is why I hate the fact GM put a fixed displacement compressor in the Sonic rather than a variable.

The only time I stall mine is when the AC is on and I try to get going to quick and Boom dead. To really get any power with it running you really need to wind it out, but as for entering freeway and such I still turn it off real quick.

I have never noticed my compressor cycle on mine. That sounds like a fun game to play! I know enough about auto hvac that they usually do, but from certain scenarios. I did have a loose line fitting from the factory that caused obvious problems. My only other issue I have is the first time I use the ac everyday it makes a nice bang when I turn it on. I have never heard that before on any other car. Might be the nature of this little beast though.

 

[ChrisJ]

The only time I stall mine is when the AC is on and I try to get going to quick and Boom dead. To really get any power with it running you really need to wind it out, but as for entering freeway and such I still turn it off real quick.

I have never noticed my compressor cycle on mine. That sounds like a fun game to play! I know enough about auto hvac that they usually do, but from certain scenarios. I did have a loose line fitting from the factory that caused obvious problems. My only other issue I have is the first time I use the ac everyday it makes a nice bang when I turn it on. I have never heard that before on any other car. Might be the nature of this little beast though.

Yeah, taking off especially on a hill with the A/C on took some practice. It goes from "where's my power?!?!" to "oh, there's some".

I still have mixed feelings about whether or not my system is low on gas. I asked the dealer to check it, but it was in the 60s out so that probably didn't even happen. They claim it was working fine, but when I removed the highside cap right after they looked at it I got a "psssst!" which suggests the valve could be seeping. I did notice some oil with fluorescent dye in the valve as well though not outside anywhere.

I've never put gauges on it, never felt I should have to.

I'll probably wait for a good hot day and see if they will look at it again.


Part of what adds to the confusion is I run recirculate 99% of the time so with that plus the fan on #1 or #2 for all I know it should cycle some when its in the high 70s low 80s out. It does seem to cool decently.

 

[Stew]

...My only other issue I have is the first time I use the ac everyday it makes a nice bang when I turn it on. I have never heard that before on any other car. Might be the nature of this little beast though.

Yeah, mine does that too. Maybe instead of a dual mass flywheel for the engine GM should use one for the AC clutch, sheesh!