Dick W. I had more time to analyze your graphic. In the lower right part of the picture right under the words "Outside condenser unit" is a pipe that shows high temp, high pressure and is 100F. How does it go from 100F to 20F just by getting air passed over it from the blower? To tell you the truth I know this mod may not have drastic results but because of the low cost of the foam and about 10 minutes of work I didn't mind doing it. To me it makes some sense. Since I want the air to be cooler, the foam will help the pipe stay cooler by shielding it from engine heat while the car is not moving and from somewhat less engine heat while the car is in motion. I believe this newly insulated larger diameter pipe is the one having cooled freon going to the evaporator on the inside of the car and having this a little cooler will help lower temps a little. The evaporator must be right behind the firewall as right below the firewall on the very bottom of the car is the small hose that condensation drips as the evaporator has warm outside air passed over it and starts to warm up again and fan blowing cooler air over it. Like I said in the beginning I would rather not have this issue looked at by the dealer as they may be sloppy as they can be and cause a leak that will remain for the life of the vehicle. Today was low humidity and temp while driving was 92F and vent stayed at around 40F still 2 deg lower than previously. To finalize my results I am waiting for a hot and humid day like a few days ago to see if it will still be 40F.

 

Soon2015FitWillBeMine - Good info. Please keep us posted. If you get good result, I will do it to my car also. TIA!

 

The figure could just as well have put the blower on the other side of the pipe 'cause the blower has ZERO to do with the refrigerant cooling. See the "Expansion device"? It has everything to do with the cooling. It cools the refrigerant by allowing it to expand from a high pressure liquid to a low pressure gas. This is both a phase transition from liquid to gas and a pressure drop. If you doubt that gets cold, go buy a can of canned air and spray it all out on the palm of your hand. Then you'll see how this trick works. (Disclaimer: I will not be held liable for your frostbite.)

OK. If it works for you.

The cold refrigerant in the larger diameter pipe, the suction pipe, is returning to the compressor. But I'm OK with you not believing that. And I'm 100% OK with you believing your mod makes you get better results from the AC. At some level I'm less OK with this thread giving it any patina of fact. If you control test conditions, I'm confident you will find your mod made zero difference in physical performance. It might have a placebo effect.

Yup. It's in the HVAC fan box along with a coil for hot water (the "heater core") and a door for temp control to modulate how much air goes through the heater core and how much goes through the evaporator core and a door to control recirc vs. fresh air intake into the cabin. There's another three tubes going through the firewall there somewhere. High pressure refrigerant in, coolant in, coolant out.

Don't follow that. But the evaporator gets cold because the expanded refrigerant gas flowing through it is cold. As cabin (recirc) or outside (fresh) air goes over the evaporator coils and cools, its ability to carry water vapor declines, so the water vapor condenses to liquid water. Getting this water out of the cabin rather than into a puddle on your car front floor is what the drain line is for.

 

Two things. First your reading of 40 or 42 is the lowest that you want to and can go. That is not the absolute evaporator temperature which is a few degrees cooler than that. The evaporator is also the place where outside or recirculated air gets cooled and the moisture in the air condenses. Once the evaporator hits 32 degrees that moisture freezes and restricts the air flow and cabin cooling.

I modified my Colorado to get a few degrees cooler but I set the cut off thermistor to a 39 degree value at the vent. You are hitting the cutoff point and the AC system turns off the compressor briefly to maintain the 40 to 42 temperature that you are seeing. What you are seeing is normal operation

The return or suction line that line you are seeing or feeling getting cold is the line that contains the gas that just absorbed the cabin heat giving you cold air inside. That gas will be compressed and then cooled in the condenser to remove the accumulated heat before being sent to the evaporator for air cooling again. Any additional heat picked up by the line in the engine compartment will have to be removed by the compressor / condenser combination. So insulating it is a good idea though you may not see any addition results other than slightly reduced compressor cycle times. Again my Colorado and my Blazer both have factory installed insulation on that line. Do NOT insulate the smaller diameter, higher temperature line in the engine compartment.

 

From looking at the parts diagrams, it appears that there is a long, flexible section of insulated suction pipe that wraps around the engine to the compressor. It appears to mate with a much shorter assembly of two pipes at a junction I'd guess to be on the R inner fender. It appears that the shorter assembly carries both the liquid and suction lines between this inner fender junction and the firewall side connections to the expansion valve and evaporator.

As I've said several times, if the smart guys at Honda who design this stuff thought that insulating this short section mattered in any significant way, they would have done it.

 

I think n8cv is on to something here! Thermostat controlling how often the compressor turns on is starting to make sense to me. If I can reduce the compressor run time then that is good too even if I don't get the temp lower. I will save on wear of the compressor and increase mpg. So I guess this mod is worth doing but will not get the car cooled off any more.

 

Well this has been riveting.

Here, let me go anecdotal on you. It's been hot as snot here in the land of eternal sunshine known as LA. Heck we've even had humidity after tropical storms came through.

Not once have I thought the AC couldn't keep up with the demand. The Fit has always been pleasantly cold enough.

BT dubs those diagrams hurt my brain, at least what remains of it after a week of working on Reality TV shows.

Sic Semper Fitus!

 

I've lost track. A/C is simple. There is no such thing as hot and cold.. only heat and absence of heat...

The evaporator's job is to change freon from liquid to gas. This is exothermic. Takes heat from the cabin and translates to the freon. The condenser is endothermic.. changes the freon from a gas to a liquid... compressor's job is to provide the endothermic energy for the gas to go back to the liquid.. The condenser's job is to loose heat from the interior and compressor to change back to a liquid.

Pretty simple thermodynamics. If lines need to be insulated, they'd be so from the factory. Factory engineers have thought of this stuff. if needed, it'd be done.

 

I wrote a thread about my A/C when I first got my fit. Took it in to the dealership and of course nothing wrong was found but it never gets cool in my car unless it's under 80 degrees outside. We have had lots of 90 to 100 degree weather lately and it is just miserable in my car.

 

Since I created this thread I have noticed that with time the temperature gets cool enough for me to tolerate. The foam pipe insulation does not lower the vent temperature but in theory should allow the compressor to turn on less often as the coolant in the pipe stays cooler on the way inside the car where it reaches the evaporator and gets warmed up as warm air passes over it. If you or anyone find a solution to actually lowering the vent temps then post here. Thanks

 

You are still getting the way the system works backwards.

 

Backwards or not it will keep the R134a colder which either turns on the compressor less often or have lower temp.

 

LOL. If it works for you…

 

I have a 2010 Fit and I live in central Texas. Temps in the 90s and low 100s. My a/c is not very cold either. Even in full blast, the car never gets cool. I went to Walmart to buy one of those DIY a/c recharge kits and when I hooked the gauge up to the low pressure line, it said my r134a was full. This only started happening this year.

Any suggestions as to why the a/c is not blowing cold?

 

@nuwde - I want to say there is an A\C mod for your model but you would need to go search in the 2010 fit forums.

 

Time to lock this thread forever, IMHO.

 

Japanese AC is always cold to me hah