Nothing wise-*** at all... I'm a tinkerer and probably, well almost definitely, OCD and am always looking for better ways to do things or fix stupid stuff I screwed up (like putting the temperature sensor on the upper radiator hose).

I currently don't have any digital sensors or system, just the existing barrel gauges and such. I WANT to add a system that will allow me to send all readings to a tablet or phone, but haven't started that project yet. That gauge is a simple mechanical gauge with a little probe that sits down into the coolant on the coolant rail (the engine mounted hard line that supplies coolant to the engine) - nothing fancy there.

The thermostat switch I use to control the primary fan is mounted into an aluminum radiator hose adapter between the two coolant lines on the lower radiator. ( ) The switch itself is really two pieces - one piece is a NPT threaded mount into the radiator hose adapter and the other is the actual thermostat that screws into the NPT mount - this is actually nice as it allows you to easily swap out different ON/OFF switches really easily. (https://www.americanvolt.com/collections/thermostats/products/automotive-radiator-fan-thermostat-switch-3-8-inch-electric-temperature-sensor-probe)

 

Hi Greg, that's a great post.
I was wondering if you had any details of the fast idle solution you used with your electric fan - This is something I need to get round to on my own car as the current draw really pulls the engine speed down at idle.

 

On my car, and I think all pre HEs, there is a solenoid that pokes into the front end of the INSIDE face of the A bank (RHS) airbox; This joins one of the many tubes attached to the inlet system and when activated it let extra air into the inlet manifold. OEM this is wired to come on with the aircon compressor. This is in fact 100% unnecessary as the V12 has plenty of grunt to handle the aircon compressor at its 750 rpm recommended tickover.
What I did was to remove the OEM 12v feed from the compressor (the earth can stay), and wire up a 12v feed from the fan relay switching circuit to also switch on the solenoid. If you use the power circuit from the fan itself, put in a 5 amp fuse. This works well for me.
Attached a snap (I have removed most of the OEM inlet tubing and my solenoid is connected to the manifold as a T into my crankcase catch can circuit, which is why the tubing looks non-standard).

 

Beautiful and good to know. As an HE, 1990, I have this solenoid as well, and I actually got the thing to function... And it works well at giving a slight bump in RPMs when the AC is on. A different story of course - although I actually got my AC working, being a convertible, I rarely use it and at this point (even after scouring the earth for the idler pulley) I don't even have a belt on the AC appliance - which may change. Blah blah blah,,,

I'll go with this, Greg. Thank you! It should require just a little extra wiring when I do what I need to do.

I have a question about relay control and planning for the 2 speed fan. The threaded temp switch at the pump inlet that now controls and on off for the aux/AC fan. If a 2 way switch is used here, one at say 185 or 190 and the other day 200 or 205, would that be a good way to control the 2 high speed low speed relays? There are m22 1.5 thread (is that the right thread?) dual switches available.

 

I do not see why not, providing the smaller fan comes on early enough, ie at a;ow enough temperature.

p.s. please remove from your posts the un-needed portions of the post being quoted, as this makes them too long for convenient reading! For example the pics in your above post.

 

Understood! I do this stuff on my phone almost always and it can be tough texting and editing wise. But I get it completely.

So I got these big old high amp relays on the LIST and a dual temp fan control switch. M22 1.50? Can anyone confirm this thread size?

Also have a second shroud so I can stand around an scratch my head awhile and try and act like I'm smart. Getting it together.

I got the fan linked below and the controller on the way, but the controller I think I will return.

I'm wondering what folks think, YES about this combination of bits and components but also (importantly) the temperature ranges and anything else I should be thinking about.

https://a.co/d/egIic5L

https://a.co/d/5FEKE1K

https://a.co/d/aJ5kcxi

https://www.t7design.co.uk/m22-x-1-5...8-5bc-d95.html

 

I'm going to court some controversy I'm afraid - I've read a few times and ended up writing an entire technical diatribe ....

I will keep it brief - be careful with that fan - a fan that blows and sucks should ring alarm bells - that is not how good fan design works - you need a specific blade profile to pull that off and the images they show ain't it .... blade count, blade pitch and blade profile matter - a blade that sucks won't do so good at pushing and the converse is true - anything that does both will be a compromise solution - if you reverse a propeller driven aeroplanes engine do you think the propeller will still work but in reverse? - I looked for their fan performance details (as in the performance graph), I looked for the patent numbers too - nothing so they ain't that proud so beware snake oil I say - at least Spal publish their performance data as do Comex - Italians are very good at fans .... and running a fan fast can be counter productive - it is all about thermal transfer and boundary layers.

There is way more to moving air with a fan than simply making something that looks pretty or impressive - in fact fewer straight blades are often more efficient - I'll stop before it becomes a diatribe again ....

 

Lol. I don't expect that this thing is going to be very pretty, at all, haha... But shoot, we'll see...

My understanding (in this case) of whether the fan is pushing or pulling is simply a matter of where it is placed in reference to the radiator (puller being most efficient option in most cases)... I intended to go in the PULLER direction, and in that, will place the fan behind the radiator, under hood...

If the fan was used as a pusher, the same side of the fan that would facing the rad as a puller,,, would simply be placed away from the rad as a pusher, BUT on the other side of the rad...

For the propeller analogy - For the analogy,,, what is the physical divider that is/would be similar to the radiator in a car? More air?

 

The puller is more efficient so a good choice - and why most fans are there these days, it is also less of an impediment to air getting in at higher road speeds. In addition the pusher fan needs to overcome high pressure from air bouncing back off the fins and tubes and typically a different blade profile is used.

The dual stat is a neat idea - I hadn't seen those but based on your post I've bought 2 - so if it doesn't fit I'm blaming you ... I could have gone and checked of course but nah .... too lazy.

On the propeller front the blades in order to be efficient are actually shaped like a wing with the fatter part at the front and the curved underside facing predominantly in the direction of rotation, the pitch changes toward the outside edge to compensate for the additional speed it has vs the centre. If you simply reverse it without also reversing the pitch and profile it creates drag - even stalls the blade. If the blade has a curved underside that faces the direction of rotation so to move from pull to push I'd expect to reverse the fan pitch and the polarity.

Unless that fan on Amazon requires the blade to be turned over I wouldn't expect it to work well - the curved leading edge should face in the direction of rotation - Davies Craig fans from Australia are an example where they expect you to actually turn the blade over and switch polarity if you want to move downstream (push) vs upstream (pull).

This is the difference when you order a pull vs push from Spal - its bladed to suit - been looking for examples .... not found any .

 

JJJ
Yes it is M22 the thermostatic switch in the water pump inlet.
THis item:
Only use one if you ALSO have a cabin switch to turn on the fan using a separate circuit.

We have clearly advised, JJJ that you should ONLY buy a SPAL. Ben's post is correct. Just starve yourself for a few weeks and buy a SPAL, or you will live to regret it.
As you have no aircon, I would just wire the smaller fan to come on 100% of the time with the ignition. Complexity is the enemy of reliability. Then use the Grant Francis system for the large fan, with a suitable temp in and off range, such as the higher setting on the one yuo posted a link to.

My overall view is that your proposed system is too complicated. The temp range on your dual thermostatic switch will anyway mean the small fan will be on all the time, except for the first 10 minutes.

 

Hi Jay

I've just found a Video of my Twin Fan XJ40 Spall Fan Set Up in case it may be of interest, although I took it out and went back to a Mechanical Fan

 

Ok. To all. I am extremely grateful for y'all... I need to come up with a solution,,, so I'll rant a bit. If you're getting sick of me,,,, I'll just have to continue on and do the best I can with what info y'all have provided and what's already on the forum.

Ranting - 100$ difference in price matters. This month XKR - 4 new tires - purchased a possible solution for many in the 2003+ XKR world are struggling with - a possible an alternative for a hype expensive XKR fuel pump, then there is MORE.... Porsche - exhausting clutch work, 4 tires on the horizon next month and +++++ $ there... XJS speedo (finally), all this cooling stuff, new pads a few weeks ago, all new belts, ignition amp work and an extra amp just because - on the list - shocks, all 4 motor mounts - someday soon some soft parts suspension stuff.... Still, and more, I have a LONG list for each car. It's just the way it is... $$$$... Then, gas (don't get me started), rent (again, no fun)... Blah blah blah

I LOVE my XJS and have no intention on destroying it!

In this case "DERALE".... Are they as GOOD as Spal,,,? NOPE,,, probably not... But, I have read 1000 reviews and MOST are good. Some better than good. Derale is a regular and high selling brand being sold by many of the major SPEED shops in the USA. People are putting them on all SORTS of mode-ed big engine high rev-ing cars and trucks. Some work trucks. Racing vehicles... Many clearly say that they last, move a massive amounts of air - that they work as described and well for their needs. Solved their heating problems. etc

If it fails, I'll pull over, call a tow truck, and fit a Spal...

A couple days ago, with record NYC heat my car was running with the needle a HIGHER (towards H) than half way between N and H... It was that way for an hour and it could NOT recover. There was NOTHING I could do about it. When I turned the car off and came back several minutes later,,, the car was HOTTER than I left it... That doesn't happen on ANY other car I own, at all... It was bad... I need a solution.

I need and take y'alls advice - as best as I can. Sometimes I agonize over it and it keeps me up at night... All the second guessing.

My plan - MOSTLY from the experience y'all have shared...

And, I will have an AC again someday.

- Have a manual way to turn on/control fan in cabin. Easy.
- Mount the fan as close to the rad as possible and securely - most likely with a moded OE shroud - or make something up.
- Have the m22 switch threaded into the OE pump housing to control fan(s) on temps and speeds.
- control fans with 2 70-80 amp relays with B+ coming from the main on fire wall. Fused. Mounted on the OE rad plate.
- was thinking about a way to wire signal to instrument cluster so the TRAILER symbol on the instrument cluster lights alerting me when fans are running.
- Run (if it works) the small and large fan with the LOW temp on the m22 switch,,,, kicked to high with second relay (as stated in instructions) when needed as controlled by m22 switch... Might even save me some gas in start up!?
- Work out BUGGS as they show up, and they will...
- May just have the fan ALWAYS running on low.

- Well see

Unless the job tells me otherwise, I don't plan on using the controller. May return it. If I don't like the "FEEL" of the fan, maybe I'll return both, combine the cost of the controller and fan, and return for a SPAL? I mean, this ain't life and death. It's supposed to be fun.

 

Interesting OB, it is good to see those fans - way way way too small - you need circa 5000cfm passing through the radiator - not surprised they were noisy 25% of the fan isn't moving air it is just motor and frame, that fan type is quite efficient though because of the ring around the fan blade tips - can't find any numbers for the air they move but I believe the original install for these wasn't simple On/Off - doesn't the XJ40 have some kind of speed controller ?.

I wasn't saying incidentally that the fans are bad but don't fall for hype, 2800 cfm for a fan that size isn't a lot, buy them with a purpose in mind and retain a healthy distrust until proven otherwise - that a lot of people have purchased - all I can say is that snake oil always sells well but it is still snake oil - bit like the torches sold on amazon with 100,000 lumens - yeh right - from a single or even double COB LED not happening. Not criticising here - simply providing a caution - this is not brand snobbery at work - I don't use Spal either - mine are Comex.

On the indication front I don't know if I'd bother, at best it tells you the relays closed, it doesn't actually confirm the fans running, the only way you could be sure is the return temperature from the radiator. You could potentially slave a couple of LED's off the dual thermostat on for low and one for high - at least you would have an indication that the fans were being called for and at what speed. I don't know if I'd go as far as locating them in the cabin.

I would never let the fans shut off completely below a certain speed just to move air.

The turning the car off thing and getting hotter that is actually normal - and why the idea for a circ pump is a good one - this happens to all engines but fitting an aux pump or something is hiking the complexity and cost.

If you want to know crazy my system is 100% digital control and monitors bank A and B flow temperatures, return temperature and adjusts the fans accordingly for both sequence and speed, my fans do not have relays at all and use high current Mosfet H-Bridges, controller is actually behind the left hand headlight, I'll also be using your dual thermostat as an indicator to the system that my control algorithm needs work, once finished I'll have a USB port in the cabin to hook my laptop into for observation and programming. My control attempts to maintain a return temp of 80 Deg C or less - I'll be studying the radiator / fan combination performance to see how much heat I can remove with the minimum speed possible. I have an override toggle to put both fans to high speed, I am also considering an under the hood temperature sensor and building that into the fan sequencing - so you aren't even close to complicated yet

 

Hi Ben

Don't want to Hijack Jays Thread but they did keep the Engine just as cool as the Mechanical Fan, it was just the Noise I didn't like as well as the prospect of getting a Flat Battery

 

Ben
Those fans on OB's post are from a 6 litre Jaguar saloon. They provide hurricane levels of airflow. In their original installation they had (what i believe are called) pulse width control so their speed was regulated. OB could only have them at full speed or off.
I am no SPAL snob, it is just that my own experience has been that any other brand does not do the job. JJJ may be right about Derale, for all I know. Also never heard of Comex fans, which shows my profound ignorance, are the good?

 

Yeah,,, those fans are PWMODULATION fans getting a signal from the ECU (I'm pretty sure) in the xj40...duty cycle is regulated by a signal coming from the CTS on the 'newer' Jaguar cars. For about 8 seconds I thought about how to run PWM fans on an XJS using a fan set that has a PWM pack built-in - and controlled by the CTS... Yeah, for about 8 seconds.

What would be interesting to know IS - say from the xj40 - the ohms the range of the xj40 CTS,,,, and how the duty cycle of the fan correspondeds to ohm signals from the CTS... The fan units have a power supply piped right in,,, then the signal wire. Might it work to put one of those IN-Hose sensors in a car,,, use a xj40 coolant temp sensor to provide a signal, and run the fans that way? Simple as that? Using the OE built in fan controller would be better than any aftermarket gizmo...

I can't see any reason why Jaguar wouldnt use an almost pure ohm signal from the CTS to the the ECU, then back out to be the PWM fan module built into (or close by) the fan packs to interpret speed control... I have two PWM packs from 2000-ish XKs (well, they are in my cars). It would be an interesting experiment... I think it's 5v going to the CTS and then a measure of the resistance based on coolant temps? I don't know electricals well enough to figure out what it would take.

 

They have too little service to tell but they are Italian.

PWM is how my fans are managed, this is probably why the fans were noisy since in normal service the time they would spend at 100% would be extremely rare

 

So, dual fan set up. These are from an X-Type. Simple signal wire from ECU... I would bet my pinky toe that the signal is simply a direct resistance info stream from the stype CTS based on coolant temps

 

The CTS in cars - at least recent use a fairly standard resistance range - there are some small variations but the ideal would be simply find a way to use the XJ40 sensor. I do have a couple of resistance tables for Lucas type sensors stashed but there's no way for me to post them here.

I had a look at a wiring diagram for the X-Type and it looks like it could be a straight 0 to 5 volts - I'd need a module in hand to figure out for sure.

 

So, just goofing around I looked. Looks like on the 2003+ XKR for instance besides 2 B+ inputs there is just ONE other. A single white wire that goes into the coolant fan module... I'd bet (and will see some day soon) that the signal coming in from that wire corresponds to the signal coming off of the CTS at the thermostat on the car... We shall see. If that's the case,,, hmmm?