Adjustable cooling fans
Discussion
My first post...!
I'm trying to get hold of some variable temp fans from Dave Beers at Mod-Wise, I rang number but the poor girl I spoke to said they only deal with Clarion stereos - she had no idea what on earth I was rambling on about.
I'm away with my Chimaera next week and I would like to set a two speed/two temp set up just to be comfy with the potential of traffic etc.
Anyone have any contact details?
Thanks everyone
I'm trying to get hold of some variable temp fans from Dave Beers at Mod-Wise, I rang number but the poor girl I spoke to said they only deal with Clarion stereos - she had no idea what on earth I was rambling on about.
I'm away with my Chimaera next week and I would like to set a two speed/two temp set up just to be comfy with the potential of traffic etc.
Anyone have any contact details?
Thanks everyone
Edited by Simon-n7710 on Monday 16th August 12:43
Modwise 2 speed fan controller 
it has its uses running the fans at half speed before the under bonnet gets silly hot , if temp then still increases further (high ambient outside temps/engine temp) then full speed kicks in , its a more efficient way of managing engine/under-bonnet temps IMO its why mainstream brands do the same thing and have been since the 80's VAG/PSA etc nowadays they are constantly variable PMW controlled so they stuck with it for good reason
it has its uses running the fans at half speed before the under bonnet gets silly hot , if temp then still increases further (high ambient outside temps/engine temp) then full speed kicks in , its a more efficient way of managing engine/under-bonnet temps IMO its why mainstream brands do the same thing and have been since the 80's VAG/PSA etc nowadays they are constantly variable PMW controlled so they stuck with it for good reasonThe only draw back if indeed it is one are the fan motors will be working more continuously so running warm.
Yes in traffic the fans do kick in but usually they still go off and on. The instant your moving at any speed over 20 mph they tend to stay off pretty quickly if everything is working correctly and the engines not overly tuned.
If the fans kick in earlier they will just be pushing hot air backwards towards your cabin so I’m not sure that will reduce heat around you by very much.
Using ROVERGAUGE to check temps when in heavy traffic on a hot day you should see a constant water temp of 88-91 with fans occasionally coming on the bring it back down to 85 ish. 85d is about the best temp range for efficiency I always believed. The exhaust build up of heat is going to happen at 75 just as much as 90 over a few mins.
Ha, ironically both Aston Martins and Audi R8 I drove all day at an event had tremendous heat effect and mostly coming from under the car and surrounding you.
I did have the windows open so not a lot different from a TVR other than my left ft didn’t get hot.
My view is someone should make some aluminium heat shields that are suspended up and around gearbox and engine bulkhead allowing air to pass by them and the casings.
The cabin wouldn’t get anywhere near as hot.
But it would be nice to have variable so keep us informed if you do it.
We all like a good idea.
Funny first post.
Yes in traffic the fans do kick in but usually they still go off and on. The instant your moving at any speed over 20 mph they tend to stay off pretty quickly if everything is working correctly and the engines not overly tuned.
If the fans kick in earlier they will just be pushing hot air backwards towards your cabin so I’m not sure that will reduce heat around you by very much.
Using ROVERGAUGE to check temps when in heavy traffic on a hot day you should see a constant water temp of 88-91 with fans occasionally coming on the bring it back down to 85 ish. 85d is about the best temp range for efficiency I always believed. The exhaust build up of heat is going to happen at 75 just as much as 90 over a few mins.
Ha, ironically both Aston Martins and Audi R8 I drove all day at an event had tremendous heat effect and mostly coming from under the car and surrounding you.
I did have the windows open so not a lot different from a TVR other than my left ft didn’t get hot.
My view is someone should make some aluminium heat shields that are suspended up and around gearbox and engine bulkhead allowing air to pass by them and the casings.
The cabin wouldn’t get anywhere near as hot.
But it would be nice to have variable so keep us informed if you do it.
We all like a good idea.
Funny first post.
Some cars have both fans powered from one relay others have 2 relays.
Mine has 2 relays so I have simply re-wired so the relays are switched individually.
I have replaced the standard Otter Switch with a 2 stage switch which brings the 2 fans on at different temperatures.
Standard Otter 95° - 88°.
Intermotor switch 50102
Stage 1 93° - 88°
Stage 2 97° - 92°
Steve
Mine has 2 relays so I have simply re-wired so the relays are switched individually.
I have replaced the standard Otter Switch with a 2 stage switch which brings the 2 fans on at different temperatures.
Standard Otter 95° - 88°.
Intermotor switch 50102
Stage 1 93° - 88°
Stage 2 97° - 92°
Steve
Steve_D said:
Some cars have both fans powered from one relay others have 2 relays.
Mine has 2 relays so I have simply re-wired so the relays are switched individually.
I have replaced the standard Otter Switch with a 2 stage switch which brings the 2 fans on at different temperatures.
Standard Otter 95° - 88°.
Intermotor switch 50102
Stage 1 93° - 88°
Stage 2 97° - 92°
Steve
That’s the other option, of course.Mine has 2 relays so I have simply re-wired so the relays are switched individually.
I have replaced the standard Otter Switch with a 2 stage switch which brings the 2 fans on at different temperatures.
Standard Otter 95° - 88°.
Intermotor switch 50102
Stage 1 93° - 88°
Stage 2 97° - 92°
Steve
My fans do work fine but I’ve blown two fuses in two weeks so wanted a half speed to reduce the initial load.
Another solution is to wire the fans in series on the lower temperature, then give them the full 12v at high temp. It does require at least 3 relays and quite a bit of wiring to do this, but it does mean on the lower setting both fan motors spin at a lower speed, without needing a pulse width type controller.
Simon-n7710 said:
That’s the other option, of course.
My fans do work fine but I’ve blown two fuses in two weeks so wanted a half speed to reduce the initial load.
If you've blown two fuses in two weeks that's a sign of a problem with the car, not that you need to reduce the load!!! Take a look at wiring in the engine bay and connectors. Engine bay heat kills old wiring over time. Connectors corrode. Earths become loose. Fan bearings and motors aren't as effective with age and have more friction, inducing more load. The additional resistance of these put together can be enough to blow fuses. My fans do work fine but I’ve blown two fuses in two weeks so wanted a half speed to reduce the initial load.
Interested in half speed solutions though. I am about to stick a Megasquirt ECU in my car, are there any off-the-shelf controllers that can simplistically control the speed of the existing fans that I could say send PWM signals to? A kinder ramp up would be nicer than blowing hot air in my face at full pelt in traffic at intervals. Worst case scenario, the double relay idea is not bad and quite cheap.
Edited by geordiepingu on Tuesday 17th August 12:03
geordiepingu said:
If you've blown two fuses in two weeks that's a sign of a problem with the car, not that you need to reduce the load!!! Take a look at wiring in the engine bay and connectors. Engine bay heat kills old wiring over time. Connectors corrode. Earths become loose. Fan bearings and motors aren't as effective with age and have more friction, inducing more load. The additional resistance of these put together can be enough to blow fuses.
Interested in half speed solutions though. I am about to stick a Megasquirt ECU in my car, are there any off-the-shelf controllers that can simplistically control the speed of the existing fans that I could say send PWM signals to? A kinder ramp up would be nicer than blowing hot air in my face at full pelt in traffic at intervals. Worst case scenario, the double relay idea is not bad and quite cheap.
Agree 100% and will sort the load issue. Fans are nice and quiet so I reckon wiring. But I do like the idea of a variable fan speed etc Interested in half speed solutions though. I am about to stick a Megasquirt ECU in my car, are there any off-the-shelf controllers that can simplistically control the speed of the existing fans that I could say send PWM signals to? A kinder ramp up would be nicer than blowing hot air in my face at full pelt in traffic at intervals. Worst case scenario, the double relay idea is not bad and quite cheap.
Edited by geordiepingu on Tuesday 17th August 12:03
Classic Chim said:
Penny was on one in that thread ..... unless he was post building.Nobody tried an electric water pump instead? Except the fact this is adding another point of failure of the car, I'm curious to know if the variable speed based on the actual temperature could help. When we are stuck in the traffic, having the fan running is good, but meanwhile the water is not circulating much. And when driving at high speed, it can reduce the flow to keep the engine warmer.
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