Revisiting electric fans

[vkberlina]

I have never had sucess with electric fans cooling my cars properly mainly in summer
I have tried pretty much anything, 3 & 4 core radiators, extra water storage, single 18" fan, 2x16" mounted on an alloy shroud to direct as much air through the radiator as I can, tinkeredwith thremostats and restricter plates, eventually the best I have gotten is only over heating on hot days in traffic, but its not reliable enough. The only thing that has ever worked is the original massive clutch fan.

Last night I spotted these on ebay, so whats everyones thoughts as good as they say? The fit looks good Commodore VB-VC-VH-VK-VL V8 Turbo | eBay

cheers
Scott

[VBRED]

Well the shroud all fits up nicely and looks purpose made for the application. It would be the best ellectric fan option for an early girl. Definitely worth trying. Reasonably priced to.

[DerekP]

I feel your pain. I have spent a lot of money trying to keep the bastard cool and it is a constant struggle. The best I have come up with so far is a 3 line radiator, the original clutch fan and a massive 18 inch electric auxillly fan combo. Still tends to get right up there on the temp gauge on particulary hot days in traffic, especially with the A/C on. As for the ebay ones, haven't tried them so couldn't really comment. Just that they all claim to be the best thing since sliced bread and usually fail to deliver.

[Darren_L]

why do you want a thermo fan so bad ?

There is little if any benefit apart from maybe space issues with a clutch fan. Contrary to popular belief, they don't save you fuel, in fact it could be argued that they use MORE fuel as electric motors combined with an alternator required to maintain the power required is far less efficient than a direct drive fan, which is virtually 100% efficient apart from some slippage in the clutch. And the only time you'll gain hp with electric fans is after they have switched off and the charging system is back to full voltage. And by that time a clutch fan has all but disengaged anyway, so it's barely using any power from your engine.

You'll never get a thermo fan/s that can fit in your engine bay that can hope to match the flow of a large directly driven engine fan. Just compare the size and pitch of those clutch fan blades to the piddly little blades on a thermo fan and then consider what's powering it. We are talking kilowatts powering an engine fan, not watts.

The question I guess then could be asked, why do thermos work fine on LS engines ?
1. an alloy engine is usually far more efficient than cast iron in transferring heat
2. the surface area on a VT onward radiator is considerably larger than the earlier Commodores. More surface area means the radiator itself is capable of radiating more heat and it also means there is far more area to fit larger diameter thermo fans. That's why VT thermo fans don't fit the early radiators without butchering them of course. And even then a significant portion of the fans sit in front of the radiator tank which reduces their efficiency.

I've also tried various thermo fans on my previous 308 VH and never had the carefree cool running that I had with the factory clutch fan. Not to mention most of the time you need to upgrade the alternator to cope with the huge additional current draw (a pair of decent thermos will draw around 30 amps!!) I swapped back to the clutch fan, and my engine temps don't get past 1/3 on the gauge, even on the hottest days in peak hour traffic.

[DerekP]

Quick question DarrenL - do you run A/C on either your current or previous VH's? For me this is usually the only time mine overheats.

[vkberlina]

My main motivation is damaging water pumps picking big RPM on a track motor im planning on building, previously I used to do water pumps on street engines pulling 7000rpm also the engine picks up rpm quicker without the fan.

As for powering a 120amp alternator should do the trick

I have tried to find the old school fan blades that flatten out with higher RPM but havent found a supplier.

I have never had problems with the factory setup except for the sound of the fan running sounding like I have a prop plane trapped under the bonnet.

scott

[Darren_L]

Quick question DarrenL - do you run A/C on either your current or previous VH's? For me this is usually the only time mine overheats.

both cars had/have A/C - my previous VH only had the A/C working after fit the clutch fan back on and no overheating problems.
The SS has A/C too, no overheating problems. Both cars had a condensor fan fitted as well, not sure if you have one fitted to yours ?

[Darren_L]

My main motivation is damaging water pumps picking big RPM on a track motor im planning on building, previously I used to do water pumps on street engines pulling 7000rpm also the engine picks up rpm quicker without the fan.

As for powering a 120amp alternator should do the trick

I have tried to find the old school fan blades that flatten out with higher RPM but havent found a supplier.

I have never had problems with the factory setup except for the sound of the fan running sounding like I have a prop plane trapped under the bonnet.

scott

ah fair enough, a track engine probably would be better suited with thermos as it's rarely going to need a fan anyway.

Although if you are hearing the clutch fan making a big noise, then chances are the clutch on the fan is stuffed. I have heard some noisy clutch fans around and it can only come down to a faulty clutch. The clutch should really only be engaging when at slow speeds or stationary. Sometimes they can be a bit noisey on a cold start until the fluid thins a bit, but having said that, I never hear the fan in my SS, even on the video footage I've watched of it at the race track at full noise. And the engine isn't overly loud so if the fan was noisy I'd definitely hear it, Most times the fan only seems to be running at half speed and when I bring the revs up, it doesn't seem to pick up a lot more speed, in fact any noise it makes seems to be overcome by the increased engine noise.

[DerekP]

both cars had/have A/C - my previous VH only had the A/C working after fit the clutch fan back on and no overheating problems.
The SS has A/C too, no overheating problems. Both cars had a condensor fan fitted as well, not sure if you have one fitted to yours ?

Yes it has a condensor fan fitted, in fact it is the massive 18" electric fan I referred to in my earlier post - it has been wired in to be on all the time the A/C is running, and still on hot days she overheats. I don't get it mate, any suggestions?

[LazDang]

Ive got the fans in shroud mentioned in the first post over an alloy radiator. they're alll on individual relays with a manual overide. i can sit in stopped traffic in summer now with the temp gauge sitting on cold. i found i had to put a 12" on the front to push air through however.

[vkberlina]

Ive got the fans in shroud mentioned in the first post over an alloy radiator. they're alll on individual relays with a manual overide. i can sit in stopped traffic in summer now with the temp gauge sitting on cold. i found i had to put a 12" on the front to push air through however.

what sort of ambient temps are you talking in NZ?
I have always had cooling probs in summer 38+deg days with electrics in traffic

scott