line size

[Tileinstaller1]

Im currently working on doing a motor swap in a foxbody mustang and doing the ac

My current issue and question is I bought a new set up condenser lines and drier and hoses etc my existing evaporator has a size 10 suction hose and size 8 return line Im assuming thats the correct term but the new system has a number 6 to the drier and condenser

10 from compressor to evap
8 from compressor to condenser
and it says 6 from condenser to drier from drier to evap

long winded but my question is can I go from the size 6 line on the one side of the drier and size up to the 8 that I currently have on my evap I found a fitting that reduces the number 8 to a 6 just didnt know if it was ok to do so

thanks for any help much appreciated

[JohnHere]

Unless I'm misunderstanding, I think you're mixing terminology a bit. Do you mean a #10 from the evaporator to the accumulator, and a #8 from the accumulator to to the compressor (on the LP side)?

Also, the #6 from the condenser to the R/D, and then from the R/D to the evaporator (on the HP side), seems okay to me.

But I"m somewhat confused: Are you running a TXV (R/D) or an OT (accumulator)?

[Tileinstaller1]

Im probably explaining it wrong Im doing a cobra swap into my fox body mustang and trying to leave the factory evaporator in the car and at the same time I want to lines etc hidden in the fender area and out of the way so using and making custom lines.
So I purchased a new condenser kit from classic auto air it came with lines fittings a drier etc and came with o ringed an fittings

So I may have confused myself also

So I need to go from compressor to accumulator to evap if Im understanding correctly thats the number 10 hose

Then the number 8 from comp to the high side of condenser I believe is right

Then the low side of condenser number 6 to the drier then the drier to evap

I left out the whole part of the accumulator which I missed based on the instructions from classic auto air they have it as this


#6 Liquid Hose: condenser to drier to evaporator

#8 Discharge Hose: compressor to condenser

#10 Suction Hose: compressor to evaporator

which is right but I guess Im supposed to be smart enough to remember accumulator

so back to my original question so from their drier which is a number 6 can it be bumped up to a number 8 which is on my stock evap

again thanks for any help

[Tim]

Classic Auto Air not supplying support on this? That would seem odd as I know them and they are always helpful.

PS: do you not have an expansion device on the evap? Normally they are #8 to the core and #6 off the valve.

[Tileinstaller1]

they dont seem to be much help the answer I got pertaining to the # 6 on the drier being bumped up to a number 8 at evap was that he didnt have that information if it would be ok to do so

that is really the only question I have if I can do that without any issues to the system the drier in the kit is number 6 line my factory evap is an 8 so it needs to be reduced to the 6 just wanted some clarification if its ok to do so the rest i have figured out at this time

thanks for any help

[Tim]

Are you accounting for the expansion device? All the units I've seen have an expansion device attached to the evap core, on those underdash units.

[JohnHere]

The smaller the hose ID, the greater the velocity and pressure. So it might or might not work if you go with a #8 hose instead of the called-for #6 hose. Worse comes to worst, you'll have to plumb it over if it doesn't work.

Another possibility that comes to mind is to use a #6 hose all the way from the R/D to the TXV (presuming this is a TXV system) using appropriate adapters.

[tbirdtbird]

I am late to the party here, but I think from your original post you are mixing up the direction of flow, and that is causing confusion in the replies.
The #8 line on your existing evap is not a return line, it is a supply line...this is the high pressure liquid input to the evap. The #10 is the vapor return line.
So, on the high pressure liquid supply side, IMO you can use an adapter fitting from #6 to #8 to no disadvantage. Use of the #6 high pressure hose has become the standard, but the high pressure line doesn't care. I believe the hoses in more modern times have been sized to the minimum diameter needed to get the job done, thus saving on materials.
The low pressure (vapor) return line is sized at #10 because vapor doesn't flow very well. In some cases in years back that line was actually a #12, but IMO it then became evident that a #10 was sufficient.

So the direct answer to your question,
"long winded but my question is can I go from the size 6 line on the one side of the drier and size up to the 8 that I currently have on my evap I found a fitting that reduces the number 8 to a 6 just didnt know if it was ok to do so"
is IMO yes. I myself would have no problem doing this.

In the original post, this wording
"10 from compressor to evap"
would be more correct if it read
"10 from evap to compressor" in terms of how the flow goes.

Refrigeration engineers always start with the low pressure side of a system and how that is plumbed to the compressor.

Also, I totally agree with John about this statement he made: (please know that John is MACS certified and very sharp)
"Another possibility that comes to mind is to use a #6 hose all the way from the R/D to the TXV (presuming this is a TXV system) using appropriate adapters."

[Tim]

If you glance at the Mustang kits on Classic's site. They "all" use a TXV/drier set-up. This means #8 valve to Evap core and #6 off the valve. Not sure why need for a step-up/down fitting is needed.

[Carguychris85]

In terms of liquid flow leaving the condenser I do not see the need for anything larger than a #6 myself in that application. GM used a #6 line even in dual evaporator systems without issue. The largest expansion valves and orifice tubes are much smaller in cross section at their metering area than a #6. I have owned numerous GM dual air systems in vans and SUVs. The metal liquid line off the condenser is the same size from the condenser to the point the lines split front and rear as a single evaporator system. R12 and R134a systems basically had the same size ID liquid lines as well. The R12 systems were #6 off the condenser and the R134a systems the metric equivalent. The #6 liquid line was even the normal on systems with the old A6 compressor and that unit is an absolute monster as far as displacement and refrigerant volume go.

The charge volume will change from hose length and hose ID changes, but that is fairly straight forward to work around. I have had to operate systems, recover refrigerant, drain compressors and adjust oil levels in custom systems multiple times to get the compressor the required oil volume. Just something that has to be done when you start messing with custom setups.