POLL: Double W124 fan, or large W126 fan - PeachParts Mercedes-Benz Forum

ROLLGUY · #1 04-24-2018, 11:42 AM

I have two fan options for my Sanden and Parallel Flow Condenser upgrade on my TD: http://www.peachparts.com/shopforum/diesel-discussion/390911-long-awaited-project-1982-300td-restoration.html

Which fan should I use? I have both, and either one will fit perfectly. I like the double for it's larger surface area coverage. I also like the W126 fan, because I can use the factory mounting (tweaked a little). What do you guys think?

Maxbumpo · #2 04-24-2018, 03:42 PM

Your double fans are missing the shrouding? I would imagine that if you kept that 124 shrouding that went with them, it would be a hassle to mount them, if they would even fit. Fabricating a new mounting set up doesn't sound like a lot of fun.

Diseasel300 · #3 04-24-2018, 05:12 PM

Gen II W126 fan works fine with the stock condenser on a Gen II 126 with the small tubes, even running 134a. With the parallel flow condenser, it should be more than adequate.

Be aware that running high speed will likely require an alternator upgrade for anyone with less than 90A. The stock 70A is barely able to keep up with the blower on high, probably why they ran low speed for the A/C condenser.

ROLLGUY · #4 04-24-2018, 05:48 PM

Quote:

Originally Posted by Maxbumpo

Your double fans are missing the shrouding? I would imagine that if you kept that 124 shrouding that went with them, it would be a hassle to mount them, if they would even fit. Fabricating a new mounting set up doesn't sound like a lot of fun.

It could have had, but I don't remember the double fan having a shroud, it was a long time ago that I got it. Either way, neither one is going to get a shroud in this application.

engatwork · #5 04-24-2018, 07:41 PM

I'd run the single, large fan.

vstech · #6 04-24-2018, 08:50 PM

Single is higher airflow, but dual may give better distribution...

ROLLGUY · #7 04-24-2018, 11:18 PM

Quote:

Originally Posted by vstech

Single is higher airflow, but dual may give better distribution...

Really? I would have thought that the two smaller fans would flow more CFM than the larger single fan. Yes I do like the coverage, and that is why I am torn between the two.

Mxfrank · #8 04-25-2018, 12:07 AM

I'm pretty sure that either setup will work fine. You can get a crude comparison of the fan's flow by measuring current draw, since the blades and motors are all similar "corporate" designs. A pair of small fans may give you a slight edge over one big fan of similar design, but it will only be maybe 10-20%. I think you should use the one that's easiest to fit.

If they're configured in the stock position as pushers, neither setup should have a shroud. The best you can do in a pusher setup is the built-in "ring" on the fan finger guard.

I you're going to use them as pullers, then use one big fan in the stock shroud. But I doubt you can reverse these blades.

ROLLGUY · #9 04-25-2018, 12:09 AM

Quote:

Originally Posted by Mxfrank

I'm pretty sure that either setup will work fine. You can get a crude comparison of the fan's flow by measuring current draw, since the blades and motors are all similar "corporate" designs. A pair of small fans may give you a slight edge over one big fan of similar design, but it will only be maybe 10-20%. I think you should use the one that's easiest to fit.

If they're configured in the stock position as pushers, neither setup should have a shroud. The best you can do in a pusher setup is the built-in "ring" on the fan finger guard.

I you're going to use them as pullers, then use one big fan in the stock shroud. But I doubt you can reverse these blades.

They'll be pushers for sure.

vwnate1 · #10 04-25-2018, 12:26 AM

The stock W123 alternator isn't 70A., it's 55 .

? Is using the 129 SAAB alternator part of this AC upgrade ? .

dieselbenz1 · #11 04-25-2018, 07:19 AM

I had lost one fan on my 124 years ago the temp went up maybe 8 degrees so I suppose redundancy of running 2 fans maybe worth something?

t walgamuth · #12 04-25-2018, 07:24 AM

Quote:

Originally Posted by dieselbenz1

I had lost one fan on my 124 years ago the temp went up maybe 8 degrees so I suppose redundancy of running 2 fans maybe worth something?

You have backup if one goes out but it makes that bit more complexity. Tough choice.

ROLLGUY · #13 05-04-2018, 12:40 AM

I decided on the W126 fan for a couple reasons. I was able to use the factory mounting bars (with a little modifying), and I thought it would be less taxing on the electrical system with the one single fan. I may use the double W124 fan on another car. Another thing I thought of, is that the hood latch might hit the fan. On the W126 fan, the latch gets close to the left rim of the fan, but would not retract all the way with the double fan. The secondary latch pull would stick out all the time, and I can't have that. If I was to mount the double fan lower, it would not be as effective as it would be if it was mounted higher.

Squiggle Dog · #14 05-04-2018, 12:51 AM

I went with the second generation W126 fan as well, in my W116. The fan shroud even has a 116 part number, so it looks original to the car. I've got one of your Sanden brackets with a new compressor and am currently working on converting the ACCII system to manual.

I upgraded to an 80 amp alternator and heavier alternator wire harness. I heard that the wire harness to the fan also needs to be upgraded and a different relay installed so the harness doesn't melt. I haven't researched that much yet.

vwnate1 · #15 05-04-2018, 07:24 AM

FWIW, removing the fan's grille will make it quieter and increase the air flow quite a bit too ~ it only operates when the hood is closed so fingers getting chopped off shouldn't be an issue .

I too would use the larger single fan .

View Poll Results: Which fan?
Double W124 fan	5	55.56%
W126 fan	4	44.44%
Voters: 9. You may not vote on this poll