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Fan Choice for Putting new AC in car
Posted: 26 Mar 2015 11:35
by Thomas
Am installing an aftermarket, new AC unit in my TR7 2 Litre. Will be putting in an electric fan. Use pusher or sucker? Which one would be best?
Tom
Posted: 26 Mar 2015 12:23
by tr8
Posted: 26 Mar 2015 20:39
by Hasbeen
Thomas, air conditioning will involve a condenser [air con radiator] which will have to be installed in front of your existing radiator. This will require it's own thermo fan, which must be mounted in front of the condenser, so must be a pusher.
You can continue to use your normal engine fan, or a thermo fan for engine cooling.
On mine, which used a stock under dash unit, but is otherwise all modern after market gear, I have the thermo fan on the condenser & a new, but stock cooling fan for the engine.
With this set up, even in our climate, the thing never gets over about 85C, which is about 1/4 on the gauge, in the 3 years it's been fitted.
Hasbeen
Posted: 30 Mar 2015 17:58
by Thomas
Pusher it is. That's what I thought but wasn't sure. What a good resource this Forum is!
Tom
Posted: 31 Mar 2015 10:08
by DutchTriumph
Air going trough the condensor also goes through the radiator. If I activate the AC fan on engine temperature do I need the separate fan on the engine?
Cheers,
Peter
1977 TR7 FHC, 1976 Spitfire 1500
Posted: 31 Mar 2015 13:40
by FI Spyder
Not sure about after market stuff but the engine fan constantly cools the coolant as it goes through the radiator, if coolant cools too much the temp is regulated by the opening/closing of the thermostat. The A/C pusher fans are constantly on when A/C is being used. A/C is shut off under full acceleration. When A/C is off and the temperature rises too high (has never happened in my car) the pusher A/C fans turn on (temp sensor in side of radiator) to help cool the coolant (three fans working in tandem). All in all works pretty well if everything is working (rad clear/no air bubbles/water pump working). Replacing three fans with one, not sure on an older system designed for three even with new components that will be more efficient.
- - -TR7 Spider - - - 1978 Spitfire- - - - 1976 Spitfire - - 1988 Tercel 4X4 - Kali on Integra - 1991 Integra - Yellow TCT

Posted: 31 Mar 2015 15:47
by HDRider
Actually the AC fans shut off when the system is cool enough. That usually won't happen around town but does happen with freeway driving even on fairly hot days.
Edward Hamer
Posted: 31 Mar 2015 15:49
by Hasbeen
Not all that much of the air going through the condenser goes through the radiator, unless you have an engine fan pulling it through, when you are traveling slowly or are stopped. They are some distance off the radiator, & allow the air flow out between.
My Mercury Capri is in getting a new engine cooling fan at the moment. The thing was still fine on the country road cruising at around 60 MPH, on 100F temperature & the air conditioning on full, but started getting warm driving through town. However it near boiled when I went through a drive through to get a cup of coffee. Just 5 minutes idling was enough with the radiator fan not working.
Hasbeen
Hasbeen
Posted: 01 Apr 2015 13:49
by DutchTriumph
<blockquote id="quote"><font size="1" face="Century Gothic, Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by Hasbeen</i>
Not all that much of the air going through the condenser goes through the radiator, unless you have an engine fan pulling it through, when you are traveling slowly or are stopped. They are some distance off the radiator, & allow the air flow out between.
Hasbeen
<hr height="1" noshade id="quote"></font id="quote"></blockquote id="quote">
When I took the AC parts out of a scrap car, I thougt the radiator and the condensor were very close against each other and there was some foam in between at the sides to force the air from the condensor through the radiator.
Maybe it was not original.
I was thinking to replase these old fans, once filled with water
With some modern more efficient and easy to find fans, something like this.
Cheers,
Peter
1977 TR7 FHC, 1976 Spitfire 1500
Posted: 01 Apr 2015 16:23
by Odd
You guys should look into how it was originally done to the TR8 with AC:
Two sucking fans <u>behind</u> the radiator - so connected that the cooling needs of the engine operate them either off - or in low speed mode - or (if low speed isn't enough) in high speed mode. (I have never seen mine go into highspeed mode unless I trigger it manually [so I know it works as intended]. Low speed seems effective enough for my 3.9 efi in 30+C weather... And! My radiator have the engine oil cooler <u>inside</u> the cool radiator tank = extra heat load...)
Overriding this logic was the function of the AC system: AC selected ON = High speed mode...
The condenser were fitted tightly upstream (in front) of the radiator - and it seems to be well-enough for dry-state America... [8D]
Nowadays:
those pesky old four-straight-bladed Magnetti Marelli fans can easily be changed out for the nine-scimitar-bladed Bosch fans for the Porsche Boxster - much more efficient and also less noicy while still being an easy fit mechanicly - since the PCD of the three bolts are the same, and the outer diameter of the fan blades are similar enough...
Marelli fans:
Bosch fans:

<font color="red"><b>My two 1980 Wedges...</b></font id="red">

Posted: 01 Apr 2015 16:53
by DutchTriumph
Exactly why I'm asking. I would like to build a good working system. All ideas are welcome.
I have a complete AC set from a scrapped 1979 car. I would like to use some more efficient parts, such as fans and a modern pump.
I'm not sure about the TR8 system, isn't the radiator leaning forward?
With the TR7 the radiator is upright, how about the space for fitting sucking fans?
Like those Porsche Boxter fans, specific model year?
Cheers,
Peter
1977 TR7 FHC, 1976 Spitfire 1500
Posted: 02 Apr 2015 00:02
by Hasbeen
Hi Peter, I had air conditioning fitted to my non air-con 7 over 3 years ago. I did some, & my local auto electrician/air-con shop did a lot.
I bought the complete system from a US import which was bound for the track, but found very little of it actually useful.
We overhauled the under dash unit, but did not do the water radiator. In my climate I do not want to introduce hot water into the cabin, so the heater element is bypassed.
We used the compressor mounting bracket, having machined the front down to mount a modern compressor in fan belt line, & that was about it.
The old condenser was too doubtful to use, as was the fan. Having had nothing but trouble with after market thermo fans, I did not want one of them. My shop knew a condenser/fan combination off some modern hatch was a suitable size, & bought one, the hoses, dryer & other bits were all new.
In the end the unit I bought probably saved a fair bit of time & effort in mounting an under dash unit, but not much else.
It was an expensive project, but worth twice the cost, now it's working.
Hasbeen
Posted: 02 Apr 2015 05:59
by Odd
<blockquote id="quote"><font size="1" face="Century Gothic, Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by DutchTriumph</i>
I'm not sure about the TR8 system, isn't the radiator leaning forward?
With the TR7 the radiator is upright, how about the space for fitting sucking fans? <hr height="1" noshade id="quote"></font id="quote"></blockquote id="quote"> Yes, it's leaning forward - and you'll have to get a complete set out of a TR8 hulk in the US. But it will easily fit into the TR7 since both versions use the same void under the WKC4077 headlamp panel. And all the holes are there already...
<blockquote id="quote"><font size="1" face="Century Gothic, Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">Like those Porsche Boxster fans, specific model year?
<hr height="1" noshade id="quote"></font id="quote"></blockquote id="quote"> Peter,
from the info I have the fans are for the Porsche Boxster 986 '97-'04 (?)
and the cooling fan OEM Part No is 996.624.135.00

<font color="red"><b>My two 1980 Wedges...</b></font id="red">
