Frigiking A/C

[Philphlash]

After spending several thousand $$$$ to bring my '71 280SL A/C up to specs I only get air flow out of the right vent.  Even covering over the vent with a book doesn't seem to change much.  The mechanic says this is "normal". Please advise as to what is "normal".  Also, what should the air temp at the unit read? I know it is not a 2005 car, but can I expect reasonable comfort? Any replies will be greatly appreciated!

[TR]

Phil -- You've both described, and summed up, my feelings well.

What you are describing is exactly the situation with my '71 280SL 4-spd, with A/C.

I have spent years and way too much dough on this, as well as getting the engine to hold temperature during prolonged periods of idle, with the A/C running in 100+ degree weather.

Feel free to e-mail me if you want the story of how I am (hopefully) getting this done.

BTW, I have an '04 CLK500 cabriolet ... and I will not be satisfied until the '71 280SL has much of the same level of comfort.  I think it's possible...just time consuming and expensive.

Tom in Boise
'71 280SL 4-spd, signal red w/lt. tan interior, restored/enhanced

[willsam]

I have heard much the same thing as you guys.  

I offer a little background info/history for what it is worth.  About 8 years ago a retired friend of mine wanted me to drive him a distance to offer tech help on a Model A engine.  He said I would enjoy meeting the Model A owner.  After introductions were made I found out the A owner had retired from Frigiking in the Dallas/Ft.Worth area.  (The other maker of AC units for Mercedes was John E. Mitchell Co which made Kuhlmeister in downtown Dallas.  I was able to visit their firm before they were bought and dismantled by the competition and took advantage of their service dept)

The Model A guy was the actual person who designed, engineered and developed the AC for the W113.  He had a room that was off limits to everyone but his team.  The Mercedes factory would crate a W113 or other Mercedes and ship it to Frigiking where they would remove the car inside their room, execute the AC design, recrate the car, and ship it and the AC unit back to Germany prior to the official launch of the car.  

I wish at that time I had asked him why they did not baffle the inside of the underdash unit to equally distribute the air.  As you know all the air goes to the passenger and none to the driver.

When it was time to get AC in the girlfriend's 230SL we went to a local guy Jerry West 972-771-3791, www.europeancoolerair.com who has been in the AC fabrication business for years.  He had his own design for the underdash unit which ducts air directly at the driver.  This is not an original unit, but it is one that genuinely cools the occupants.  Remember, this had to satisfy my girlfriend whose standards were the 230SL should cool as well as her daily driver.  The 4 bladed fan was replaced by one large electric fan which at first was operated thermostatically but I eventually wired it to run constantly.

I talked to Jerry about reworking the original underdash units with internal baffles.  He said he can do it, but the unreinforced fiberglass they made the units out of is very likely to fracture or break when screws are removed.  He has an alternative where he will duplicate the original case in ABS plastic.  If anyone wants technical details, call him.
Hope this helps, Will Samples

[TR]

Will Samples -- Hello to you sir.  You would have no reason to remember me, but years ago I visited you at your shop in Dallas.  I think it was your "old" location.  I appreciated and enjoyed our visit very much.  Also, you kindly sold me two full sets of decals for the W113, of which I still have one; along with several other things.  Then later I bought a soft top from you.  A few years ago (maybe 4 or 5) I was in Newport Beach for the Fashion Island show, and was not certain but thought I saw you there judging cars.  I did not want to intrude, so did not say anything...but then perhaps it wasn't you.

What you have posted here is very interesting.  Over the past several months we have been putting lots of effort into redirecting the air within the Frigiking unit of my '71 280SL.  This includes adding a much higher volume fan...although its outer physical dimensions are the same.  Plus, with a series of difficult-to-design baffles and extremely fine screens (of the type used in food processing or chemical applications), we have managed to significantly improve the Frigiking's air flow & distribution.  In addition, we are now running the A/C out the round chrome vents on each side of the dash.

My wife and I plan to drive the car to St. Louis for the 4th of July.  It will be hot, humid, and likely the sun will be beating down hard.  We did this last year in a new '04 CLK500 cabriolet and did most of that 4,500 mile round-trip with the top down.  We intend to do it this year in the old '71 280SL.  My wife will not tolerate a hot car, under any conditions.  Last year we drove in 100 degree weather, with the top down and the A/C running full blast.  This, coupled with M-B's wind deflector, makes 500 miles per day at freeway speeds in a convertible a pleasant experience.  We'll see how it works this year in an old 280SL with a modified Frigiking A/C & engine cooling system.

Tom in Boise
'71 280SL 4-spd, signal red w/lt. tan interior, restored/enhanced

[willsam]

Hello Tom,
Good to hear from you and thanks for the fun memories, it has been awhile.  I have attended Fashion Island only once as a spectator, so you may have seen me, but not as a judge.  Never hesitate to say hello, I am never too busy to stop and talk shop.  Sounds like you have the AC problem in hand and have done all the R&D work that the Frigiking people did not.  Enjoy your trip to St.Louis and tell us how it went.  Will Samples

[George Des]

Tom,

Gernold did a similar mod on someone else's A/C unit (FK or KM) where he replaced the stock fan motor with a higher volume unit. What unit did you use and where did you find it? Did it use the stock blades? I have to get back inside my unit to re-anchor the motor and would consider just replacing it with the higher volume unit if the price and effort is worth it.

Thanks--george Des

[TR]

George -- Yes, my mechanic provided that A/C blower motor info to Gernold.  I believe the vendor was Spal.  Here's a link to their web site...you'll see a photo of the dual squirrel cage fan here: http://www.spal-usa.com/html/spalhome.htm


Tom in Boise
'71 280SL 4-spd, signal red w/lt. tan interior, restored/enhanced

[TR]

I went to visit the car today in the upholstery shop.  The Frigiking A/C was out, so I was able to look over the new Spal fan.

In case anyone is interested in this fan, which fits the Frigiking unit but has far superior performance than the orginal blower, here's the info I wrote down:

Spal (corporation  Italy)
Type 006-A40-22  12V
e1 02 2752


Tom in Boise
'71 280SL 4-spd, signal red w/lt. tan interior, restored/enhanced

[tdun824259]

Tom,

I'd love to hear exactly what has worked for you with regard to your overheating issues.  Tried to contact you with email and haven't been successful.  I have a 71 280sl Auto with the same issues and would love to know the most effective (time and money)way to solve the issue.
Thanks
Tim Dunagan
tdun824259

[George Des]

Tom--you're reading my mind--I looked up the website and could not figure our which number unit you might have used. What is the approximate cost of the blower unit and were there many mods that needed to be made to back of the metal box or the mounting braket for the unit on the footwell. I have an extra one on hand and took a good look at the back of the eavporator unit. The blower unit simply screws on to the back of the evaporator box with four screws with the original blower--is it the same with the SPAL unit and what is the difference in air flow.

Thanks--george

[TR]

Tim -- I'd of thought the e-mail link on my profile would have worked for you.  But nevertheless here's that address: tomrose@fiberpipe.net

I suspect we've gone way over the top in terms of getting this '71 280SL 4-spd with A/C to run cool under the most demanding of conditions.  However, we have not yet had the chance to test all of it out.  Should soon though.

BTW, we have put new-everything into the heater system too...all M-B parts, including new ducting.  My wife insist on her comfort(!).  A purist may not necessarily appreciate the modifications which are required to achieve new-car like creature comfort...including the addition of a seat ventilation system (internal fans), seat heaters, and back massagers.  In order to make these devices, which will all be internal to the seats, function properly we have no choice but to go with current-style perforated leather, shallow seams, etc.  The work on these significant seat modifications will begin next week.  We're going to stay as true as possible to the original concept of the seat upholstery, but some functional changes will be required.  Should see how all of this works within a couple of weeks.

One more thing.  There are lots of hidden bits & pieces of technology being built into the car.  Such as an in-line heater unit for the windshield washer fluid, a turn signal left-on reminder, auto-on headlights, auto-diming mirror with built-in entry gate & garage openers, outside temp. monitor, etc., etc.  Because of this we also had to significantly increase the amperage of the alternator.

Anyway Tim, shoot me an email, or we call talk via phone if you'd like and I'd be happy to tell you everything I can.

Tom in Boise
'71 280SL 4-spd, signal red w/lt. tan interior, restored/enhanced

[TR]

George -- My lead mechanic is the one who found this Spal blower.  As I recall it was around $300...something like that.  I blows 2-3 times the air volume of the orginal Frigiking fans.  The installation of the fan itself was, as I understand it, very simple...essentially a bolt-on.

My guys also put in a new, big compressor, as well as a new condensor...the type that comes on a new E class as I recall.  Lots or work has gone into redistribution of the Frigiking's air too (such as coming out the dash side vents).  The standards I'm judging against is the comfort of a new CLK500 cabriolet, and my friend's brand new 600+HP AMG SL600 (which I have the pleasure of borrowing on occassion).

Well, we shall see how these efforts all do within a few weeks I suppose.  However, it will all be for naught if the engine will not hold temperature during prolong periods of idle on the hottest of days.

Tom in Boise
'71 280SL 4-spd, signal red w/lt. tan interior, restored/enhanced

[George Des]

Tom,

I ordered and just received the blower unit you had installed on your a/c unit. I ordered from SPAL and it ran $127.00 less shipping. I have a spare Kuhlmeister evaporator box that I removed the stock blower unit from it to see how the new one will match up. It's a pretty close fit. I will need to relocate the condensation relief tube that's mounted on the back of the box since it interferes slightly with location of the blower unit. I'll probably throw the box into the bead blaster, cut off the tube and spot weld it to the bottom of the unit and repaint the whole thing before mounting the blower. Looks like I'll have to figure out a way to attach the bottom of the blower to the footwell bracket as well. My current unit blows cold on R134 using a parallel flow condensor, but my current blower has a slighlty loose motor mount that causes the fan blades to scrape the housing every time I turn a corner--not good! I like the fact that the SPAL unit has a plastic housing and set of blades--no rust or potential for short circuits! I expect this is going to run a little hot here in the D.C. area with our temp up in the mid-90's with 90 % humidity, especially in traffic but hope at highway speeds it will run cool enough to make it worthwhile. Thanks for the tip and let me know how your works out.

<To Tom Sargent--I know Gernold had put this same unit into yours--how is it working out in this tropical rut we seem to be stuck in in the D.C. area?>

George Des

[TR]

George -- I hope that higher-volume blower unit works for both you and Tom Sargent.  You will both probably have a chance to try yours out before I do.

Re the bottom of the unit, that black metal black box; I just talk via phone with my interior guy and learned he's covered it in black leather(!).  Also, he told me that the lower "lip", which runs all the way across the bottom face of the Frigiking (just below the vents) is now covered in black leather too.  I haven't seen any of this yet...but think I'll like it.

Have you tested the air volume output of the new blower against the old blower yet?  My mechanic hooked them both up across a 12 volt battery to demo the difference to me, and it seemed encouraging.

Tom in Boise
'71 280SL 4-spd, signal red w/lt. tan interior, restored/enhanced

[George Des]

Tom,

I hooked it up to a battery charger to get an idea of the difference in volume. It is much greater than the stock unit. Probably due in large part to the larger size of the fan blades themselves. Like you, though, I'd feel a lot better if I could get the engine temperature to stay within normal limits during prolonged idle. I may have mentioned that I have two different sized parallel flow condensors, but opted to use the larger on the theory that bigger is better. Now I'm wondering if the bigger sized condensor may actually effectively block off too much air flow across the radiator. Perhaps it may be better to use the smaller condensor. I'll have to experiment with this a bit--but it's just such a PITA to change out the condensor--off with the hood, evacuate the unit, drain the cooling system, out with the radiator, etc, etc, etc,. Oh well!

George Des

[Tom]

George,

Could not be happier with the A/C changes that Gernold made.  As you've detected, the SPAL blower really pumps out the cool air-I rarely take the blower speed off the low position.  The recent hot weather in DC was a real test-I would take the 113 anywhere on any hot day without concern for comfort.  Knock on wood-no engine overheating.

The other modification was to run a 2 inch pipe behind the unit to provide additional air to the driver.  Works great.  Don't know why the left side of the stock Frigiking unit does not blow air-seems to be purely decorative.

Best,

Tom

1971 280sl Tunis Beige Metallic (restored & enhanced)
1971 280sl Tobacco Brown (low mileage stock)
1970 280sl Deep Red (Project Car)

[George Des]

Tom,

Had Gernold made any mods to the radiator--is it a high efficiency one- or the condensor ? I thought I heard you say you are runing R134A as well. Is that correct ? I'm sure you've found as I have that the rotary compressor seems to hardly make any draw on the engine. My 230Sl is the 5 Speed ZF and I can hardly notice a drop in the idle rpm when the clutch kicks in. What does your temp normally run at in this weather we're having. I've got the Euro temp guage with the 79 degree thermostat. On the highway at running speed, I barely break the 80 mark. If I get caught at a red light and have to let it idle for a while--you know how long the red lights are around here--it'll start to climb up around the 90 mark. Goes right back down though once under way.

Will do some work on the A/C probably this weekend to get the new blower in place.

Best to you

George

[TR]

Tom -- I'm very glad to read your A/C mods worked.

I hope to have mine up and running within a couple of more weeks.  Should have the active ventilation (internal fans) for the seats going by then too.  The test, in my mind, will be if the car is comfortable in 100 degree weather, with the top down ... and engine temp. holds steady during periods of prolonged idle.

As mentioned, in addition to the Spal blower, we've made a lot of internal mods to better re-direct the air within the Frigiking unit, as well as to get the round chrome vents on both sides of the dash to function as A/C outlets.

Tom in Boise
'71 280SL 4-spd, signal red w/lt. tan interior, restored/enhanced

[TheEngineer]

About one year ago I did my air conditioning system: There was not much R-12 left and I pumped it into my truck. Then I evacuated to about 70 microns and let it sit overnight. It rose to 200 microns. Then I filled it with Duracool 12. I get about 42°F at the outlets when driving. Standing in traffic the temperature rises some. I have a three row radiator and no overheating problems. It cools the cab just fine, but I'm in Seattle where it doesn't get as hot.

[George Des]

Thought I'd be able to try out my A/C this weekend with the new SPAL blower, but as usual ran into a few snags. The condensation tube on the rear of the evaporator box runs horizontally out the back and is located where it interferes with placement of the new blower. As I've found out this is a short copper tube soldered to the box. Out with the propane torch and the tube came right out. The area where the tube came out needed to have a small patch mig-welded in and sealed and then the tube relocated directly under the original placement but now running vertical. What at first looks to be a fairly simple job get complicated real fast since the box had to be stripped of all paint, resealed around all the seams and then re-painted--that's where I am now. Fortunately, I had a spare evaporator box and this was all done w/o touching the unit that's sitting in the car right now. Otherwise, the car would have been inoperative through this whole ordeal. Hopefully, I'll be able to drop the unit in the car sometime this week and replace the current box and blower with the new blower and box unit.

<Both Toms--do you know if your blower units were connected through a relay. Noticed that the new SPAL blower draws 26 amps on full and not sure the orignal rheostat is rated that high. I have a relay under the hood that I had originaly intended to use when I installed the A/C unit but is curently not hooked up so it is no big deal to hook into that if I have to.>
George Des

[Tom]

George,

Not sure about the relay-will check and let you know.

Best,

Tom


1971 280sl Tunis Beige Metallic (restored & enhanced)
1971 280sl Tobacco Brown (low mileage stock)
1970 280sl Deep Red (Project Car)

[TR]

George -- I don't know either.  But my lead mechanic is working on the car over the weekend.  So I'll call him and ask about both things.  Hopefully will get back to you pretty soon.

Different, but perhaps related;  My car has so many (mostly hidden) electrical/electronic updates/enhanceents that we replaced the alternator with a new higher amperage unit.  Also the battery.  Lots of wiring changes/upgrades too.

Tom in Boise
'71 280SL 4-spd, signal red w/lt. tan interior, restored/enhanced

[TR]

George -- Just spoke with my mechanic.  Sounds like we may have a different arrangement on the condensate tube running out of the Frigiking evap. box.  He reported no problem with that and the relative fit of the new Spal blower.  But it sounds like you have your situation under control anyway.

Re the fan control switch.  We did put in a new switch to support the new Spal blower motor.  As I understand it, amperage and fusing was checked.  But the fan switch was changed...and it is a 4-position switch; off, low, medium, and high speeds.  All the new A/C components have now run in the shop for sometime (not yet on the road) and seem to be doing fine.  But just for fun the mechanic, later today, will insert an amp meter to measure how much current draw is really happening, and will also double-check fusing & wiring.  He reports that a rheostat is not being used for controlling the A/C fan blower motor.

Hope this helps.

Tom in Boise
'71 280SL 4-spd, signal red w/lt. tan interior, restored/enhanced

[TR]

George -- Oops.  I meant to say, "He reports that a RELAY is not being used for controlling the A/C blower motor".  Don't know why I typed in the word rheostat there instead of relay.  Sorry for the confusion.

Tom in Boise
'71 280SL 4-spd, signal red w/lt. tan interior, restored/enhanced

[TR]

George -- More info on the old/new Frigiking A/C unit, w/Spal blower; re your current draw question.  Just talked with my guy.  He ran a series of tests a few minutes ago and came up with this data:

1) At low blower spd:     8 amps w/compressor clutch not engaged.
..............................12 amps w/compressor clutch engaged.
2) At med. blower spd:  10 amps w/compressor clutch not engaged.
................................14 amps w/compressor clutch engaged.
3) At high blower spd:  12 amps w/compressor clutch not engaged.
...............................15 amps w/compressor clutch engaged.

I appreciate your intital question.  Thank you for raising that question/idea of running it thru a relay.  Because we built in several spare relays to support the numerous new electric/electronic enhancements currently being made to the car, we now have the easy ability to run the A/C controls thru one of those spare relays.  And so to unload this current draw off the ignition switch we're going to go ahead and use one of them to do this job.

Hey, why not?  We have plenty of spare relay and wiring capacity for this.  And for supporting the new 600W amp.  And for the 6-pack CD player, along with the new XM satellite radio receiver (all of which will run thru the old Becker Europa stereo).  And for the new security system, w/paging capability via Hirshmann antenna auto-up/down.  And for the remote door locks, and power windows.  And for the new seat heaters, seat fans, seat back massagers.  And for the new auto-dimming rear view mirror w/built in additional interior lighting, exterior temperature and compass readouts, gate & garage door openers.  And for the auto on/off headlight system.  And for the new in-line windshield washer fluid heating system. And for the new built-in 750/1500W power inverter for AC power if & when needed. And for the 3 new electric cooling fans for the engine.  And for the new engine helper coolant pump. And, and, and...  No wonder we needed a bigger alternator, Ultima battery (w/built-in charger), along with a lot of new & bigger electrical wires, eh?

Did you actually in-line measure the 26 amp draw from the new Spal fan, or was that in their literature/specs?  Based on the series of installed & actual operating tests my mechanic just did, your 26 amps sounds high.


Tom in Boise
'71 280SL 4-spd, signal red w/lt. tan interior, restored/enhanced