upgrading radiator fans?

[MHunter]

My Ultima is overheating in traffic on hot days. I'm wondering if upgrading the stock radiator fans would help, or if there's a better solution? What CFM are the stock fans pulling?

[Graham-P]

Can't remember the model number but a lot of us have fitted 11" Pacet fans, they shift about 1100 cfm each, twice as much as the standard ones. You might be able to fit 12" fans, be a squeeze I think.

[BogBeast]

I fitted 10" Pacet Profans to my Sport.

Made big difference, well worth it IMHO

Demon Tweeks were the cheapest (believe it or not..) http://www.demon-tweeks.co.uk/Search.do?method=del...

I believe that 11" will fit the later cars - pacet have some pretty good diagrams http://www.pacet.co.uk/11inchpacets.php so it should be pretty easy to figure out.

[MarkWebb]

I also fitted Pacet fans for double the airflow. I also fitted a electric water pump with speed control to control temperature and removed the thermostat. I now have not the slightest hint of overheat. In my view the electric water pump was well worth it allowing water to be circulated fast even when engine is idling.

[MHunter]

Thanks, I'll look into this. The bigger fans use a lot more amps though, I've found 12" fans with 2150 cfm, but they draw 23 amps. two of those might be too much for the battery.

[C Lee Farquar]

I have a couple of 12" HD Spal fans that draw a similar amount. Obviously I don't know your battery/alternator set up but I haven't found them unduly draining. I get the impression there's a surge when starting but that they don't draw as much when up and running.

[MarkWebb]

Not sure what size fans I fitted but they came close to blowing the fuse on the fan relay! No battery problems as long as you haven't got one of those Jet Ski batteries that Ultima used to use. I have EFI and an electric water pump with no problem. It is not the battery that would cause a problem anyway it is the Alternator which needs to be man enough to cover all the loads when car is running. I have 75amp with no problems at all. Some people may install a 120 amp one.

[356Speedster]

I've fitted a pair of 11" Pacet CF1111P fans (the P at the end being the important bit!). I bought them direct from Pacet in the UK, thus avoiding Demon Thieves' mark-up. They will need a 30a fuse on your fan relay tho', as they pull over 10a of current each.

With my LS3 idling in the garage, they control the temps without issue, no hint of overheating.

Hope that helps.

[MHunter]

I do have one of those small batteries. Odyssey PC625. what's the recommended replacement for them?

I forgot about the relay fuse, I'll have to upgrade that too. And check the alternator output. Thanks for reminding me.

[Steve_D]

I also used the 11" Pacet CF1111P fans and also bought them direct from Pacet.

I then fitted one of the old fans to the oil cooler.

Steve

[MarkWebb]

Fuse is in place to protect the wiring. Nothing else! Uprating the fuse without checking that the wiring can handle it it is a recipe for a bonfire of large proportions! My pacets run on the std 30amp fuse. However my oil cooler fan was also connected to this circuit and the total load did blow the fuse. Oil cooler now wired seperately.

[MHunter]

I'm going to order a pair of those http://www.jegs.com/i/Proform/778/141-642/10002/-1... low amp usage, 1200 cfm, 2.5" height should fit under the grill.

[Steve_D]

MHunter said:

I'm going to order a pair of those http://www.jegs.com/i/Proform/778/141-642/10002/-1... low amp usage, 1200 cfm, 2.5" height should fit under the grill.

Don't know what rad you have but there is no way you could fit 12" fans on my rad.

Steve

[MarkWebb]

I actually had to remove my top fan grill to fit my fans however I think it would just about have fitted with some mods. The factory grill although just what you need for IVA is flow restricting in itself.

[MHunter]

I ended up going with the 11" Pacet fans, and they seem to be doing the job just fine. I might need a lower temp thermostat to get them going a bit earlier. Thanks all for the recommendations!

[V8Dom]

MHunter said:

I ended up going with the 11" Pacet fans, and they seem to be doing the job just fine. I might need a lower temp thermostat to get them going a bit earlier. Thanks all for the recommendations!

The thermostat wont kick the fans in earlier, its a temp controlled switch that does that.
Dom

[MHunter]

Derp! That's what I meant.