Air Conditioner is WEAK

Blue_Hen_TDI

Top Post Dawg
Joined
Oct 23, 2005
Location
Slower, DE
TDI
owned: 96 B4V, 06 Golf, 12 NMS, 15 GSW
IMO, long highway runs won't really change MPG results with hot country setting, its the stop and go that will hit the MPGs. I'd do it if I were you.

I think VW stock profile of compressor usage is dependent on RPM speed, at say 2K rpm at 70MPH, it takes an additional 5% of fuel to run the compressor, but at idle running that compressor running full tilt prob takes 50% more fuel, so VW tried to dial back the duty cycle of the compressor when the rpms are under a certain value to gain an MPG or so.
Sounds like good logic.
 

adjat84th

Veteran Member
Joined
Dec 13, 2008
Location
Virginia Beach, VA
TDI
'01 Jetta TDI/'15 Golf TDI
Does the hot country change simply keep the compressor locked in the high output setting? When I first turn on my AC it will idle at 1k RPM, but after the cabin is cool (climatronic) it settles to normal idle. It's usually just me in the car, so vents are pointed in my direction and never any issues with being warm. I typically have it set to 80-82°.

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VeeDubTDI

Wanderluster, Traveler, TDIClub Enthusiast
Joined
Jul 2, 2000
Location
Springfield, VA
TDI
‘18 Tesla Model 3D+, ‘14 Cadillac ELR, ‘13 Fiat 500e
Does the hot country change simply keep the compressor locked in the high output setting? When I first turn on my AC it will idle at 1k RPM, but after the cabin is cool (climatronic) it settles to normal idle. It's usually just me in the car, so vents are pointed in my direction and never any issues with being warm. I typically have it set to 80-82°.

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It modifies the supply air temperature set point. In general, it will blow about 10-15F colder air than in the normal country mode (depending on set temperature and actual cabin temperature). The upside is obviously more powerful cooling. The downside is worse fuel economy because the system has to work harder to achieve a higher delta T across the evaporator and overcome a higher differential pressure between evaporator and condenser. It may also modify the recirculation strategy. I'd have to watch VCDS to determine to what extent various parameters have changed.

A person could also switch back and forth between hot country and normal mode at will depending on weather. For example, you might want to run normal mode during spring and fall, and switch to hot country during the dog days of summer. This would preserve fuel economy when you don't need maximum cooling.
 

lawnarjax

Well-known member
Joined
Oct 5, 2009
Location
Jacksonville Fl
TDI
2015 GSW TDI SEL, 2006 Jeep Liberty CRD, 1994 Safari Trek (Isuzu 4BD2TC)
Mine was already in the HC mode when I bought. I am beginning to think the previous owner was a vcds user as there were features turned on that I don't think were activated from the factory, like the high beams with fogs, already on when I got it. I find that the cooling is not as good as my 2010 JSW overall. Especially at startup, the florida heat really is a torture test, and I was pretty impressed with my 2010's ability to cool off quickly even with a black interior. The new girl just does ok, not bad, but i am not turning the vents off me like I was in the old girl. I can't say what it does to gas mileage a it is not humanly possible to drive the car in the daylight without the ac or windows open, and that would ruin the test. Next time I drive on at night on a long trip I will check it and post thoughts.
 

Growler

Got Soot Vendor
Joined
Nov 24, 2003
Location
Millersport, Ohio
TDI
Schmutz, 2015 Golf Sportwagen DSG & Schnurren, 2001 Golf GL 2 door 5M
I think I have to take back my earlier MPG reduction for using the hot country setting.

Earlier I said that I was seeing a 2MPG hit with the hot country setting, but really the car was so new to me when I changed it over to hot country the reduction I was seeing was likely due to having more than one driver and the differences in their driving styles.

I do believe that the HC setting does reduce mileage, but I dont see 2mpg hit any longer. Perhaps I can account for as much as 1mpg. basically having HC enabled when possible, is worth the small MPG loss. if you click on the Fuelly link in my signature next to SCHMUTZ, you will see that my MPG is hovering around 43-44MPG per tankful if nothing else it has increased as the car has added miles.. I am at 8k miles on the car now.

is anyone else tracking every tankful on Fuelly? I would love to see what others are getting in their GSW S DSGs...
 

JettaRon91vw

Member
Joined
Sep 18, 2015
Location
Fort Stewart GA
TDI
2015 GSW SE DSG
I track every tank with fuelly. Currently at 38.6 average doing mostly city driving with the AC on most of the time. Car has 4500 miles. Not exactly what the TDI was intended for but just about every other weekend the family and I take a road trip somewhere and then I'll get much higher mpgs only to do city driving during the week and ruin my average. Best I've gotten was 41.4 on a tank.
 

IndigoBlueWagon

TDIClub Enthusiast, Principal IDParts, Vendor , w/
Joined
Aug 16, 2004
Location
South of Boston
TDI
'97 Passat, '99.5 Golf, '02 Jetta Wagon, '15 GSW
Changed to the Hot Climate setting today. Driving home from the airport yesterday with the outside temp in the mid-80s I had the fan on 3 to keep the car comfortable. And the air was noticeably less cool when traffic stopped. Today I drove my '02 Wagon to work and the A/C in that car is significantly colder.

Short road trip tomorrow, it's supposed to be close to 90 out. We'll see how it does.

And I filled it up tonight, 42.3 in mixed driving. 1,800 miles on the car.
 

jason_

Veteran Member
Joined
Jun 2, 2014
Location
grand rapids michigan
TDI
2015 s wagon dsg
So changing it made no difference? Possible vw paid a programmer something to do to keep their desk job?

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740GLE

Top Post Dawg
Joined
Aug 19, 2009
Location
NH
TDI
2015 Passat SEL, 2017 Alltrack SE; BB 2010 Sedan Man; 2012 Passat,
Changed to the Hot Climate setting today. Driving home from the airport yesterday with the outside temp in the mid-80s I had the fan on 3 to keep the car comfortable. And the air was noticeably less cool when traffic stopped. Today I drove my '02 Wagon to work and the A/C in that car is significantly colder.

Short road trip tomorrow, it's supposed to be close to 90 out. We'll see how it does.

And I filled it up tonight, 42.3 in mixed driving. 1,800 miles on the car.
All I can say it try your coding again, we drove back from Maine this past weekend 80+ temps had the fans on 3 but dialed back the temp adjustment from coldest the vent temps were around 50F or so, but again this was on a long highway run where I think hot climate isn't that much of a factor.

PS the wife still thinks I'm crazy for driving around with a meat thermometer stuck in my vents.
 

IndigoBlueWagon

TDIClub Enthusiast, Principal IDParts, Vendor , w/
Joined
Aug 16, 2004
Location
South of Boston
TDI
'97 Passat, '99.5 Golf, '02 Jetta Wagon, '15 GSW
Funguy is right. Tried it today. It wasn't as hot out as I expected: this morning temps were in the mid-80s but overcast. With 4 people in the car I never had to bring the fan higher than 1 to keep the car cool. Air from the vents felt much more like my MKIV. And the MFI is showing 45 MPG for the 1st 350 miles, a lot of it at 75-80 MPH. So I doubt there's much, if any, FE penalty.
 

Funguy

Veteran Member
Joined
Jan 18, 2005
Location
Front Range of Colorado
TDI
2015 Golf Sportwagen dsg and 2015 Passat 6 M/T
That sounds pretty good. I am starting to believe that this "hot country" modification is a good solution to the anemic A/C's in these cars
 

740GLE

Top Post Dawg
Joined
Aug 19, 2009
Location
NH
TDI
2015 Passat SEL, 2017 Alltrack SE; BB 2010 Sedan Man; 2012 Passat,
Changed to the Hot Climate setting this morning, after yesterdays drive home from the airport with the outside temp in the mid-80s I had the fan on 3 to keep the car comfortable. And the air was noticeably less cool when traffic stopped. Today I drove my '02 Wagon to work and the A/C in that car is significantly colder.

Short road trip tomorrow, it's supposed to be close to 90 out. We'll see how it does.

And I filled it up tonight, 42.3 in mixed driving. 1,800 miles on the car.

Fixed for yeah! Stop and go and at idle is where the HC setting shines
 

sjones

Member
Joined
Jun 12, 2007
Location
Brandon, FL
TDI
2012 Jetta Sportwagen TDI; 2009 Jetta Sportwagen TDI (totalled by flood)
2012 JSW TDI does not have this feature evidently.

Thanks for sharing. I made the change to HOT COUNTRIES on my 15' TDI S and the difference is very well noticeable in Houston summer.
My 2012 JSW TDI apparently does not have this feature as nothing is listed under BYTE 12. It has had the diesel "fix" done to it so I wonder if the reprogrmmed ecu deleted this feature?
 
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