Is it OK to run a fan blade with electric fan??

Is it OK to run a fan blade with electric fan??

Author
Discussion

Moto

Original Poster:

1,237 posts

253 months

Monday 20th June 2016
quotequote all
I'm just toying with an idea to run both a standard fan blade together with an electric fan mounted in front of the radiator.

Presumably the standard fan 'sucks' and the electric fan 'blows', so they should help each other and increase air flow and therefore cooling?

I realise there will be a small drop in power but realistically I'm guessing it's not a lot.

Why I hear! Well the electric fan currently keeps the engine cool perfectly well on it's own. Although it is manually switched on/off inside the car. I like it manual so that I can turn it off when starting the engine so as not to stress the battery. Also I don't turn it on unless the water temperature gets above 90 - often it never does unless sitting stationary in traffic. Occaissionaly I forget to turn it on soon enough though and notice it at 120+, when the electric fan then struggles to get it back down in stationary traffic.

OK, it's probably a dumb idea but don't hold back telling me why....

Moto

GAjon

3,734 posts

213 months

Monday 20th June 2016
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You need to be careful, if you get them going wrong directions you might go up! wink

The engine fan needs the grp cowel to do any good, and even that's not great, electric fan at the back sucking air through is preferable, that said on my M it's at the front blowing.

Andrew Gray

4,969 posts

149 months

Monday 20th June 2016
quotequote all
Hi I had the same decision to make on the Taimar
However we did have the Radiator uprated and fitted the Cowl as well which meant the Radiator had to be adjusted position wise with the thicker rad.
All worked well until I was in heavy traffic on a hot day I even opened the bonnet to allow heat out as we where crawling along to get over the Betty Bridge for over an Hour.
On my return I ordered two small fans and did exactly what you said and wired them to a switch and relay rather than thermostat so they could be turned on before the heat rises at times like this.
They don't get used that often but good to know they are there in case.
I certainly would fit the engine fan in this case
Andrew

phillpot

17,116 posts

183 months

Monday 20th June 2016
quotequote all

Ditch the engine driven fan and fit a thermostat to control the electric fan. Sorted wink

plasticpig72

1,647 posts

149 months

Monday 20th June 2016
quotequote all
I like the idea of both, belt and braces. If your engine ever boils ONCE is TOO MANY.
Alan

Andrew Gray

4,969 posts

149 months

Monday 20th June 2016
quotequote all
phillpot said:
Ditch the engine driven fan and fit a thermostat to control the electric fan. Sorted wink
I understand your Thinking Mike but there is something to be said for being in control as well an override switch is great I have them on both the Tuscan and the Vixen regardless of having a thermostat I have yet to need it but useful all the same.
The 3000s now does not have any issues although in fairness the peace of mind of the Evans allows you less worry to go 10 or even 15 degrees over without worry as its more the pressure than the heat that's the worry when overheating and the Evans has no significant pressure until it boils at 180 degrees so hitting 110 115 occasionally does not have the same fear as with a water based coolant.
Andrew

phillpot

17,116 posts

183 months

Monday 20th June 2016
quotequote all
Andrew Gray said:
I understand your Thinking Mike but there is something to be said for being in control
In certain situations, yes wink


Ok, I'll let you have a manual over-ride switch if it satisfies your need for control.

RCK974X

2,521 posts

149 months

Monday 20th June 2016
quotequote all
I would use a thermostat with a manual override ... and a warning light somewhere visible... belt and braces.

Moto

Original Poster:

1,237 posts

253 months

Monday 20th June 2016
quotequote all
OK - so I hadn't considered the need for a shroud. I also think a thermostat is a sensible solution but whilst keeping a manual over ride. But if an electrical gremlin (in a TVR, surely not) enters the electric fan wiring it would be nice to still get home OK.

Has anyone got a photo of such a shroud?

Moto

tomtrout

595 posts

163 months

Monday 20th June 2016
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Nothing to stop you having two control circuits, one thermostat driven and one with a manual switch. I'm not really sure why you need a manual switch if you have a properly set up thermostatic switch. If the engine over-heats when the fan is on and the car stationary then perhaps you need to have a closer look at the whole cooling system.

Dollyman1850

6,318 posts

250 months

Tuesday 21st June 2016
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Fit 3 Fans !!!!!

Sorry.. Ditch the engine fan…Fit the largest electric fan at the rear of the rad pulling through the core…Fit it in conjunction with an otter switch in the water circuit and if you really want to fit an override switch.
In reality running a fan makes no material difference to a car if you are running faster than 25mph..It is purely for stop start traffic where airflow is reduced and as such allows you to get rid of the heatsoak the engine produces
9 times out of 10 fitting 2 fans unless perfectly in harmony re flow rates will only cause turbulence and a restriction in the airflow path and will reduce the flow through the core

As for Evans..Well the science speaks for itself…It prevents a car boiling but is no good for many reasons…Principally it just runs hotter, raises an engine core temp by a significant margin, saps an engine of power and is mega expensive but if it works for you then fair enough.. I will stick with the free stuff that falls from the sky.




Edited by Dollyman1850 on Tuesday 21st June 06:44

plasticpig72

1,647 posts

149 months

Tuesday 21st June 2016
quotequote all
Moto,
does your car have the very low wide rad under the sparewheel in the nose. Or is it a central rad
Alan

Moto

Original Poster:

1,237 posts

253 months

Tuesday 21st June 2016
quotequote all
I had presumed it's all original, however as there's no shroud, maybe not.



Moto

plasticpig72

1,647 posts

149 months

Tuesday 21st June 2016
quotequote all
Moto,
i just looked at your profile so you have a Vixen with a 1600 Kent engine. Central rad
Alan

Edited by plasticpig72 on Tuesday 21st June 12:23

Andrew Gray

4,969 posts

149 months

Tuesday 21st June 2016
quotequote all
Dollyman1850 said:
Fit 3 Fans !!!!!

Sorry.. Ditch the engine fan…Fit the largest electric fan at the rear of the rad pulling through the core…Fit it in conjunction with an otter switch in the water circuit and if you really want to fit an override switch.
In reality running a fan makes no material difference to a car if you are running faster than 25mph..It is purely for stop start traffic where airflow is reduced and as such allows you to get rid of the heatsoak the engine produces
9 times out of 10 fitting 2 fans unless perfectly in harmony re flow rates will only cause turbulence and a restriction in the airflow path and will reduce the flow through the core

As for Evans..Well the science speaks for itself…It prevents a car boiling but is no good for many reasons…Principally it just runs hotter, raises an engine core temp by a significant margin, saps an engine of power and is mega expensive but if it works for you then fair enough.. I will stick with the free stuff that falls from the sky.




Edited by Dollyman1850 on Tuesday 21st June 06:44
Good old fashioned water you cant beat it especially when you want to get the old steam up in the pit lane great Video just a shame they don't allow anything but water on the track.
With Evans it would have been sorted and straight back out there.
Andrew

Moto

Original Poster:

1,237 posts

253 months

Tuesday 21st June 2016
quotequote all
Thanks all - decision made. Scrap the standard fan blade idea and fit an automatic water temp switch.

Moto

anonymous-user

54 months

Tuesday 21st June 2016
quotequote all
GAjon said:
You need to be careful, if you get them going wrong directions you might go up! wink

The engine fan needs the grp cowel to do any good, and even that's not great, electric fan at the back sucking air through is preferable, that said on my M it's at the front blowing.
Why a rear pull fan. Is there a reason why that's better than a front push?

GPW41

150 posts

143 months

Tuesday 21st June 2016
quotequote all
Yes, the discharge air from a fan is turbulent so when this hits the heat exchanger fins there is an increased pressure drop as the air flow is straightened to pass through. Higher resistance to work against equals lower air flow rate.

plasticpig72

1,647 posts

149 months

Wednesday 22nd June 2016
quotequote all
On a 1600M i had 2 fans side by side infront of the wide low rad under the spare wheel.
imho there are advantages with fans infront. You can get in safetly with a strobe light to see timing marks and they are out of the way. For the last 40 years my Lotus Elans have had the fans always infront of rad and no overheating problems which the Elans are well known for.
I have only been owning TVR's for the last 6 years so maybe i have things to learn.
Alan

anonymous-user

54 months

Wednesday 22nd June 2016
quotequote all
My Vixen fan is OE in front, in a shroud and blind rivetted to the rad sides. However back in the day they probably weren't too bothered about the details of wind turbulence it was more just a case of 'get a fan in'