Biggest a/c condenser angled behind the hood supports?

[ray_]

12 hours ago, xavier296 said:

I'll be that guy. Why do you need bigger than 10X18? I realize Rob is always on the noble quest for more 2002 knowledge, but it just seems like we are leading less experienced people down a path where they read this thread and believe they NEED a condenser bigger than 10X18 in order to have adequate AC temps.

 

My car has 10X18, modern compressor, 12" spal fan, stock Behr evap with R134 expansion valve, and a couple cans of R134a. It blows 29-32 degree air at my face within 1 minute of getting on the road. And I live in Florida. and I hate being hot. 

 

Bottom line: For all you faithful searchers, 10X18 condenser will get it done!!

Xavier, what blower and evap are you running?

 

Cheers,

[Conserv]

Bravo, Barney!

 

Your installation is clearly distinguishable in its need for greater condenser area: your evaporator has twice the capacity of a common ‘02 evaporator. That’s amazing. You’ve got real A/C in an ‘02!

 

Best regards,

 

Steve

 

[BarrettN]

I've wondered - for example, 10"x18" - by what thickness? Are all condensers the same thickness, or can a person sneak a little extra thermal capacity into the equation going with one that's thicker? 

Edited May 28, 2021 by BarrettN

[thehackmechanic]

@BarneyT: That is truly a work of art. It looks just beautiful, and surprisingly in keeping with the feel of the rest of the vintage interior.

 

@Conserv: Steve, yeah, this is seat-of-the-pants "bigger is better." I'm not doing any calculation.

 

@jimk: I can't argue with anything you say, but my experience with rejuvenated or retrofitted a/c in vintage BMWs is that it's not difficult to get it blowing cold when it's in the high 80s or low 90s here in Massachusetts, but when I drive down to The Vintage or other road trip destination, and hit patches of near-100-degree temperatures and high humidity, the cooling—to completely misuse a metaphor—runs out of steam. So when you say "So if the condenser is big enough to fully condense the freon, that's it," my gut (and that's all it is; I have no sub-cooling measurements to back it up) is that the condenser isn't big enough under high temperature and humidity conditions. Of course, I could be doing something else wrong (mis-sized expansion valve, less-than-optimal amount of refrigerant), but I just don't see the downside of getting the condenser and fan as big as you can.

[jimk]

1 hour ago, thehackmechanic said:

I can't argue with anything you say, but my experience with rejuvenated or retrofitted a/c in vintage BMWs is that it's not difficult to get it blowing cold when it's in the high 80s or low 90s here in Massachusetts, but when I drive down to The Vintage or other road trip destination, and hit patches of near-100-degree temperatures and high humidity, the cooling—to completely misuse a metaphor—runs out of steam. So when you say "So if the condenser is big enough to fully condense the freon, that's it," my gut (and that's all it is; I have no sub-cooling measurements to back it up) is that the condenser isn't big enough under high temperature and humidity conditions. Of course, I could be doing something else wrong (mis-sized expansion valve, less-than-optimal amount of refrigerant), but I just don't see the downside of getting the condenser and fan as big as you can.

You are right.  I addressed ONLY the question of condenser.  Changing only one component in an A/C system to a bigger size only takes advantage of the sizing margin available in the other components.  As you said, condenser size, expansion valve, evaporator, fan and compressor each need examination.

To knock out moisture is a big factor on the evaporator.  Dry air doesn't take nearly as much "steam" as humid air.

@BarneyT's "Blizzard" system will keep you comfy.

[M3M3]

2 hours ago, thehackmechanic said:

but I just don't see the downside of getting the condenser and fan as big as you can.

fan capability is KEY.  to some extent, nearly any size condenser will do the trick IF THERE IS ENOUGH AIRFLOW THRU IT.

 

most systems have no issues cooling while the car is going down the highway on a dry day.  plenty of airflow.  but once the car slows down, especially if hot and humid, the ac system struggles.  enter the FAN.  more is better.   there is a reason why when you turn on an ac system the electric fan comes on.  in the E30 community is is common to jumper the stock fan to always run on HIGH if the ac is on.

 

if i was doing ac in a 2002, i would be going with a 16in, or at least a 14in, high CFM elec fan.  yes, they will fit.

 

 

[ray_]

If you happen to live where it's HOT (and HUMID) -- the biggest limiting factor in the easily fit systems is the evaporator (and  blower) IMO.

[0257]

As summer approaches, I’ll get to test how effectively ICE Air’s “upgraded Clardy” kit really works when it counts.  Though it’s a black box when you receive it, owner Bob Poggi says the evaporator has an extra row of coil.  The passenger side of the unit does seem to extend a little further out than the old Clardy.  The blower is clearly (if a little deafeningly) more powerful than the original, and the 10x18 evaporator doesn’t seem to hold the system back.  I was clocking 30ish degree temps at the grilles right after installation about a year ago (right before I decided to tear Zouave half apart to do other jobs).  Driving up to Tampa and back tomorrow,so maybe we’ll see....

Edited May 28, 2021 by 0257

[0257]

2 hours ago, jimk said:

You are right.  I addressed ONLY the question of condenser.  Changing only one component in an A/C system to a bigger size only takes advantage of the sizing margin available in the other components.  As you said, condenser size, expansion valve, evaporator, fan and compressor each need examination.

To knock out moisture is a big factor on the evaporator.  Dry air doesn't take nearly as much "steam" as humid air.

@BarneyT's "Blizzard" system will keep you comfy.

I’m trying to imagine what the front of Barney’s car sounds like with the A/C on.  Will be in Austin in July for a demonstration, if he’s willing!

[thehackmechanic]

THE ANSWER TO THE QUESTION (I think)

Okay, I decided to have some fun this morning.

 

First, remember that, as I've photographed here and in my a/c book, condenser width is quoted as the distance between the outside edges of the big tubes that run along the sides. The quoted width does NOT include either the brackets or the threaded fittings that the hoses screw onto. Together, those typically add about an inch and a half. So, if you're going to mock something up to see if it fits, you need to add on that extra width. And keep in mind that there's an additional minimum of about an inch-and-a-half taken up by the fittings on the hoses. 

 

To recap:

 

--The width of the hole in the nose in front of the radiator is 15.5", but you can fit a wider condenser through it by turning it and feeding it through. However, at some point you run into clearance issues.

 

--The generally-quoted maximum safe condenser size for not cutting the horn brackets and mounting the condenser vertically in front of the radiator is 10x18". On my roundie tii, I measure the inner distance between the horn brackets at 19 3/8". If I recall correctly, I think it's a little narrower on the square tail light cars.

--On a previous '72, I'd cut the horn brackets and was trying to find the biggest condenser that would fit. An 11x24" condenser was too big to make the turn as I tried to put it through the nose. The binding-up point is that the lower left corner of the condenser hits the lower inside edge of the left hood support. To get it to clear, you need to tilt the right side of the condenser down to tip the left side up, and 24 inches (which is really about 25.5 inches) is too wide; you run out of room to be able to tilt the right side down before hitting the extension of the right frame rail, as you can see in the image from 2012 below.

 

--On that same '72, I successfully fit an 11x20" condenser (misquoted in my book as 11x21), but again, on that car, I'd cut the horn brackets.

 

--The new goal here is to see what you can fit by a) not cutting the horn brackets and b) fitting the condenser at an angle in front of the horn brackets but behind the hood supports. My idea was that, by threading the needle and sliding the condenser in front of the horn brackets, I could fit something bigger (wider) than if I was limited by the width between the brackets. In addition, the tilted-behind-the-hood-supports location gets the heat of the condenser away from the radiator, which is good for both of them.

 

You'd think you can mock something up with cardboard or foam, but to realistically simulate the tight clearances, you really need something as rigid as the condenser itself, and as close to the same thickness as possible. I found a 3/4"-thick piece of particle board, about the same thickness as a modern parallel-flow condenser.

 

I first cut it to 11x23". At that size, like the 24"-wide condenser nine years ago, I couldn't even fit it behind the left hood support and begin to slide it through.

 

I then cut it to 11x21.5", which is the effective size of an 11x20" condenser. It DOES begin to make the turn, but the condenser's height is now an issue, as the combination of the width and the 11-inch height makes it too tall to get the top of the left edge in front of the horn bracket.

 

I cut an inch off the top. At 10x21.5" (the effective size of a 10x20" condenser), it clears the horn bracket, slides behind the hood support, and the right side can then be slid into place. Yay. So that appears to be the answer. It's not much bigger than 10x18, but just because the answer isn't what you expect doesn't mean that it's not the answer.

 

 

Unfortunately, a quick web search shows that 10x20 is not an available size. Neither is 10x19. There's an 11x19x7/8 condenser available from Nostalgic ac ($89 plus shipping), and a 10.75x19x1 unit available from Restomod Air ($139 plus shipping), but I'd need to mock up these sizes to be certain they'll fit, and these are more expensive than the $35 I paid for the 10x18 I put into Bertha two years ago.

 

And now, the second surprise: I usually buy condensers on Amazon, as I can easily return them if they don't fit. Unfortunately, the dirt-cheap $35 Climaparts CNPF1018 is no longer available. In general, the supply of cheap 10x18 units on both Amazon and eBay isn't what it was a few years ago. They're certainly available any number of other places online, though.

 

In conclusion, the idea that mounting the condenser at an angle in front of the hood supports rather than vertically between the horn brackets buys you more clearance for a substantially wider condenser doesn't appear to be true. You could probably fit a 10x20", two inches wider than a 10x18, but, unfortunately, that size doesn't appear to be available.

 

Time to let go of this odd little obsession, buy a 10x18 condenser, and install it.

 

--Rob