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Posted: **Tue Feb 18, 2025 10:53 am**

I have been watching this with some interest. I don't have an amp meter on Project2, but do have a voltage meter. Anything above 12 volts, and I reckon the 160 amp alternator is charging. With aircon on at idle (800rpm for me) I am getting a little over 13volts (14.5 while driving). I have my electric compressor set to the low speed, which is a 40 amp draw. This provides plenty enough cool air for ute cabin, but may not be enough for a sedan or wagon. My question is about idling. How much time do you intend to spend idling compared to driving? Is it the time spent waiting at traffic light with a charged battery, or is it going to be 20 minutes in the car park? If its the former, then there is no issue. If it's the latter, then might have to throttle back air con. Either way, not much to worry about IMO.

Posted: **Tue Feb 18, 2025 11:33 am**

I was hoping you would chime in on this mate, what alternator are you using on your beast ???

Posted: **Tue Feb 18, 2025 12:36 pm**

I'm running a knock off Bosch 160 amp. Pulley ratio is about 2:1 so alternator is theoretically producing 82amps at 1200rpm. Seems plenty for my needs. I have attached the output chart for info. Also running a 12inch Davies Craig fan set to come on with aircon. Shroud keeps everything cool.

Posted: **Tue Feb 18, 2025 1:30 pm**

Plenty of options, mine is rated 170A, test bench sticker reads 147 @ engine idle (1000rpm) and 174 max, does still have slight voltage drop as my engine idles @ 800. Depends how much people want to worry about flaring headlights, dimming gauges etc etc.

Posted: **Tue Feb 18, 2025 1:33 pm**

Forgot to mention, good result with the new rad/fan set up.

Posted: **Tue Feb 18, 2025 2:01 pm**

Brett027 wrote: Tue Feb 18, 2025 12:36 pm Also running a 12inch Davies Craig fan set to come on with aircon. Shroud keeps everything cool.

Interested in the shroud design for the Davies Craig fans - is your fan flush with the core face, or set back?

... asking for a friend who needs to put two into Number One Son's VL in the next week

briby wrote: Tue Feb 18, 2025 1:30 pm Depends how much people want to worry about flaring headlights, dimming gauges etc etc.

I'm trying to find anyone who actually uses the factory dash light dimmer. I suspect they were made by Lucas, with the standard "off, dim and flicker" settings.

Cheers,
Harv

Posted: **Tue Feb 18, 2025 3:17 pm**

Hi Harv, fan uses plastic tabs that go through core fins to mount and it sits flat on the condenser core and under the bonnet locking plate at front. It's a 'slim line' type. That plate limits the size of external fan. There is room for 2 side by side 12" fans, but one is enough for my set up it seems. Use the Davies Craig temperature controller.
There is a pic where you can just see it in Project 2 towards the end of the posts.

Posted: **Tue Feb 18, 2025 3:25 pm**

briby wrote: Tue Feb 18, 2025 1:30 pm. Depends how much people want to worry about flaring headlights, dimming gauges etc etc.

This is about poor voltage regulation, not amps produced is it not?

Posted: **Tue Feb 18, 2025 4:28 pm**

Brett027 wrote: Tue Feb 18, 2025 3:17 pm Hi Harv, fan uses plastic tabs that go through core fins to mount and it sits flat on the condenser core and under the bonnet locking plate at front. It's a 'slim line' type. That plate limits the size of external fan. There is room for 2 side by side 12" fans, but one is enough for my set up it seems. Use the Davies Craig temperature controller.
There is a pic where you can just see it in Project 2 towards the end of the posts.

Sounds familiar - I've got two of the Davies Craig 10" units on the wagon, similarly limited by that bonnet locking plate. Number One Son's VL has more sideways room, but sadly not enough motor depth to let me run a SPAL fan. So two Davies Craigs it will be.

From what I understand of shrouding, the issue is mainly one where the car is at low speed. Diagram A shows an open fan, no shroud. Some of the air gets pushed through the core, but some of the air realises it is an easier path to flow sideways, around the core (like the arrows with the green asterisks).

By putting a shroud on, all the fan air is forced through the core, like Diagram B.

Diagram C shows a Davies Craig fan. They are integrally shrouded, as they have a plastic "ring" around the fan blades that covers between the blades and the core. Because they are intergrally shrouded, as long as they are up against the core then all the fan air goes through the core (the black arrows) at low speed. When the car is at highway speed, almost all the core is uncovered, and lots of highway air can flow through (the green arrows).

I have seen some people shroud the Davies Craig fans like diagram D. The shroud is a piece of flat steel/ally plate, with a circular hole cat for the fan. At low speed, the core gets all the fan air (all good). But at highway speed, most of the core is blocked off, and cooling is reduced.

I reckon diagram C is the way to go when using Davies Craig fans, but open to other views.

: fan shrouding.jpg (1.01 MiB) Viewed 83 times

Cheers,
Harv

Posted: **Tue Feb 18, 2025 6:10 pm**

Run the factory splash plates under the front, with the rubber wind deflectors on the bonnet underside, and you should not need a shroud. My 179 still runs cool on 40 degree days.

FB ute fixer upper, EK van on rotisserie

Posted: **Tue Feb 18, 2025 6:31 pm**

Brett027 wrote: Tue Feb 18, 2025 3:25 pm
briby wrote: Tue Feb 18, 2025 1:30 pm. Depends how much people want to worry about flaring headlights, dimming gauges etc etc.
This is about poor voltage regulation, not amps produced is it not?

Yeah Brett, aren't we talking about low amps low volts at low engine revs, i'm not a sparky, don't know the ins & outs on the correlation of volts to amps, only going on my own experience on how i overcame my problem.

Posted: **Tue Feb 18, 2025 9:51 pm**

Brett027 wrote: Tue Feb 18, 2025 10:53 am I have been watching this with some interest. I don't have an amp meter on Project2, but do have a voltage meter. Anything above 12 volts, and I reckon the 160 amp alternator is charging. With aircon on at idle (800rpm for me) I am getting a little over 13volts (14.5 while driving). I have my electric compressor set to the low speed, which is a 40 amp draw. This provides plenty enough cool air for ute cabin, but may not be enough for a sedan or wagon. My question is about idling. How much time do you intend to spend idling compared to driving? Is it the time spent waiting at traffic light with a charged battery, or is it going to be 20 minutes in the car park? If its the former, then there is no issue. If it's the latter, then might have to throttle back air con. Either way, not much to worry about IMO.

years ago a mate had a T bucket with the alternator running off the tailshaft we used to go cruising through the city and the cross at night so lots if sitting and low speed driving with lights etc on never had any battery issues

Posted: **Wed Feb 19, 2025 7:59 am**

Errol62 wrote: Tue Feb 18, 2025 6:10 pm Run the factory splash plates under the front, with the rubber wind deflectors on the bonnet underside, and you should not need a shroud. My 179 still runs cool on 40 degree days.

Not much wind to deflect at idle Clay. That's when shrouds do their best work.

Posted: **Wed Feb 19, 2025 10:15 am**

True Brett. I run an engine fan. It will get to 80-90 idling depending on ambient. At speed it runs a bit cool, even on hot days. I’ve come to the conclusion there is such a thing as too much radiator. It is a HR three core snd I have an 82C thermostat.

FB ute fixer upper, EK van on rotisserie

Posted: **Wed Feb 19, 2025 12:17 pm**

With too much radiator and a working thermostat, the thermostat should squeeze slowly towards shut at freeway speed. The radiator should then stay at 82C. If it gets lower than 82C the thermostat is effectively shut, the block heats up very quickly, and the thermostat plug lifts off the seat again. Some things that might prevent that:
a) the thermostat has a bypass (does not fully close) or has been drilled.
b) the thermostat and coolant temperature sensor are in two different places, at two different temperatures.
c) the thermostat has significant hysteresis - it opens at 82C, but doesn't close again until 75C or so.

Cheers,
Harv

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