Electric PAS Pump swap

[AndyC]

Peter.
thanks.
I hadn't thought about the heating from the point of view that when you generate more heat (engine going faster) you have a lot more air flow anyway, so fully appreciate that now, and I'd assumed the mechanical pumps could kick the water round as fast as an electric one, didn't realise how low the flow was. I may have to consider that option for one of mine. I take it you've removed the whole pump housing and adapted the whole system as a result. Is it covered in a topic here already?


With the alternator, I agree bigger pulley means lower torque for the driving pulley, but you still need to generate the same amount of electrical energy over the whole run, so it will have to turn the alternator at a heavy load for longer if it's turning less often, so fine for racing and track laps etc, but in the dark and cold when you're drawing a bigger electrical load it will just mean it takes longer to re-charge the battery, not something racers worry about.

If you have any pics of the water pump change that would be great. Oil cooling, tell me about it! I've had to fit a second cooler on the Esprit.

I do like the idea of the PAS being activated when needed, that's a big saving.

Andy

[AndyC]

Peter, I just found your post showing how you did it, so can see you left the housing there to use the thermostat bypass etc.

I noticed on the Davies Craig site they specify if the unit is used as the only pump it must be run continuously, I assume you've had no issues with hot spots forming in the engine. http://www.daviescraig.com.au/Controlle ... ntent.aspx Q8.
It makes me wonder if a small pump as a permanent running one to prevent hot spots and a bigger Davies Craig type to move the coolant when needed might do the job that I'm considering it for.

Andy

[Ozzy_UK]

Oz, Do you know how accurate your temp gauge is? I'm assuming that this is an original gauge on the car which is now over 20 years old.
Dan

true i dont know how accurate the gauge is, but when it says 90 and a bit, the first fan kicks in (set on the new kenlow controller for 92C) and when it says 100C on the gauge the 2nd fan kicks in, and this is set 100C on the kenlow unit too...

its the ally rad and silicon hoses causes the cooling system to be working a little too well...

i guess what i really need is a variable electric water pump, to pump slower when warming up to 90C ish, and then faster when over that to bring back down...

oil temp sensor/gauge might also be worth looking at...

Oz.

[Lotus-e-Clan]

Andy

Ive had both my Imp engines apart and there are definitely NO hot spot issues.

Is this the bit you mean taken from the Davies Craig site?


The EWP may be used with a Davies, Craig Thermal Switch (Part Nos. 0401 and 0402) as an auxiliary pump. If the EWP is the only pump in the engine it should not be run with an on/off thermal switch like a radiator fan. Your engine needs some flow all the time or hot spots will form outside the cylinders.


If so they are telling you not to use a FAN switch (like a Kenlowe!) to control the EWP. Both Davies Craig controllers (analog and digital) vary the flow by pulsing and they are safe. ie the EWP has some sort of flow all the time.

On oil temperatures:

If anyone fits an oil temperature gauge be aware that you only see part of the picture if you fit the sensor in the sump!

When ragging it at high revs the SUMP oil temperature will go sky high and you can't do a lot about that. This is because the "splash" oil is super-heated by the pistons and cylinder surfaces and then falls into the sump raising the temperature....it will be even WORSE with a turbo for obvious reasons.

I know this sounds a bit "anal" but I have TWO matched oil temp sensors in the Clan ..one in the sump and one in the oil return from the cooler. I can switch between the sump and cooler sensors from within the cabin.

When ragging it with WOT, the sump temperature quickly rises 10 degrees higher than the oil cooler return which stays fairly constant @ water temperature,

BTW I use a WATER to OIL cooler which cools the oil return temperature to water temp. So my cooled oil is 80 -85C nearly all the time. The sump temp will be 95C when ragging it @ WOT but when you calm down the sump temp quickly cools to 80-85C....so the I can see the oil coiling is OK.

If I just had sump temperatures only I'd be thinking things are getting out of control and would back off unnecessarily. .

[AndyC]

Thanks Peter.
Yes that was the question. I wasn't sure if they meant the flow for 10 seconds then stop for 30 seconds was insufficient (or can water flow past the pump in the forward direction?), or whether it was their way of saying, yo need an DC controller if you want this as your main pump. By your answer I now know it's the latter.



I'm thinking about this for my Turbo Esprit rather than Excel, the Excel isn't set for outright max power, but if I can get the Esprit to behave itself in traffic that would be great (summer time is hell, winter time is not great) and that's with a good rad, but that's because it has an engine with increased power output.

[Ozzy_UK]

i thought oil needed to be in the 100 - 120C range to be in the "good" useable range (if using v. thin oil?) - im on 10w50 VR1 Valvoline racing stuff...

[Ozzy_UK]

Thanks Peter.
Yes that was the question. I wasn't sure if they meant the flow for 10 seconds then stop for 30 seconds was insufficient (or can water flow past the pump in the forward direction?), or whether it was their way of saying, yo need an DC controller if you want this as your main pump. By your answer I now know it's the latter.



I'm thinking about this for my Turbo Esprit rather than Excel, the Excel isn't set for outright max power, but if I can get the Esprit to behave itself in traffic that would be great (summer time is hell, winter time is not great) and that's with a good rad, but that's because it has an engine with increased power output.

do you have an ali rad and silicon hoses? that combination dropped my water temp 20C!!! hence im now struggling with water getting UP to temp...
Guildford radiators made my rad totaly bespoke and cost £300, they also make the elise rad for lotus

[Lotus-e-Clan]

i thought oil needed to be in the 100 - 120C range to be in the "good" useable range (if using v. thin oil?) - im on 10w50 VR1 Valvoline racing stuff...

Thats the MAX for some oils.

You won't get anywhere near that if you are changing up early. You need to take it to 6.5 - 7 k or keep it over 5k all of the time to see 100C...unless your oil cooling is inadequate of course.

Friends with circuit racers lapping with 9 krpm panic if the oil reaches 110 C (cooled oil NOT SUMP oil ..that would be even higher) 'cos it's curtains for the bearings sooner rather than later.

If your cooled oil is 20c above your water temperature you will have problems....it's the cooled oil that goes to the bearings.

[Ozzy_UK]

i thought oil needed to be in the 100 - 120C range to be in the "good" useable range (if using v. thin oil?) - im on 10w50 VR1 Valvoline racing stuff...

Thats the MAX for some oils.

You won't get anywhere near that if you are changing up early. You need to take it to 6.5 - 7 k or keep it over 5k all of the time to see 100C...unless your oil cooling is inadequate of course.

Friends with circuit racers lapping with 9 krpm panic if the oil reaches 110 C (cooled oil NOT SUMP oil ..that would be even higher) 'cos it's curtains for the bearings sooner rather than later.

If your cooled oil is 20c above your water temperature you will have problems....it's the cooled oil that goes to the bearings.

yeah that said im talking sump temps... but thought 150C-160C was about the limit in the sump, not 110C...
Oz.

[Lotus-e-Clan]

I did say cooled oil at 110C is too high NOT sump. And 150 -160C sump temps would need some careful management cooling wise! I wouldn't be happy with that all....but that's just my view.

Take a look at this as an example of oil temp range.

Porsche engine life and oil temperatures

Get yourself a oil temp gauge soon if only to rule out overcooling. If youre normal running oil temp turns out to be always below 70C then you'll get more engine wear over the long term...that is of much more concern than the 78C water temperature you are experiencing.

And if it's running less than 78C water temp then you can easily fix that with a change of thermostat as it would mean yours is faulty....and not to do with a more efficient rad because the stat holds up water in the engine and away from the rad until the preset temperature is reached.

Lotus knew what they were doing targeting 82C as the water temp and ideally the oil temp will be the same and that's consistent with the data in the Porsche url link above.

BTW I don't know why you want 90C and above water temperatures in a 912 engine. Moderns might run at higher temperatures than a 912, but they have engine management to optimise combustion at those temperatures and "live on safe side of detonation". A 912 wouldn't be happy with 90+C all the time.

[Ozzy_UK]

I did say cooled oil at 110C is too high NOT sump. And 150 -160C sump temps would need some careful management cooling wise! I wouldn't be happy with that all....but that's just my view.

Take a look at this as an example of oil temp range.

Porsche engine life and oil temperatures

Get yourself a oil temp gauge soon if only to rule out overcooling. If youre normal running oil temp turns out to be always below 70C then you'll get more engine wear over the long term...that is of much more concern than the 78C water temperature you are experiencing.

And if it's running less than 78C water temp then you can easily fix that with a change of thermostat as it would mean yours is faulty....and not to do with a more efficient rad because the stat holds up water in the engine and away from the rad until the preset temperature is reached.

Lotus knew what they were doing targeting 82C as the water temp and ideally the oil temp will be the same and that's consistent with the data in the Porsche url link above.

BTW I don't know why you want 90C and above water temperatures in a 912 engine. Moderns might run at higher temperatures than a 912, but they have engine management to optimise combustion at those temperatures and "live on safe side of detonation". A 912 wouldn't be happy with 90+C all the time.

what temp should i be aiming for then?
thats just where it used to be and was always happy, and its middle of the gauge so assumed it would be roughly where it should be... ?
i know the MGF we have 120C oil in sump is normal, and 160C is on the hotter side...

Oz

[Lotus-e-Clan]

You should have 82C water temp (plus or minus 3 or 4C) and oil should be about the same temperature MOST of the time.

In the url link above, Porsche quote 180F -210F for oil temp (to get a 300k mile engine life! ) which is 82C - 99C.

And that's about where I am in the Clan too.

BTW this AM on the way to college doing 5.5krpm in top (about 80mph in a Clan) I had 82C water temps, 82C cooled oil temp and 97C sump temp

• ie there was 15 degrees difference between cooled oil and sump oil.

When I cruised back down at 4k rpm (about 60 mph) the sump and cooled oil were both at 82C with 80C water temperature.

[Ozzy_UK]

You should have 82C water temp (plus or minus 3 or 4C) and oil should be about the same temperature MOST of the time.

In the url link above, Porsche quote 180F -210F for oil temp (to get a 300k mile engine life! ) which is 82C - 99C.

And that's about where I am in the Clan too.

BTW this AM on the way to college doing 5.5krpm in top (about 80mph in a Clan) I had 82C water temps, 82C cooled oil temp and 97C sump temp

• ie there was 15 degrees difference between cooled oil and sump oil.

When I cruised back down at 4k rpm (about 60 mph) the sump and cooled oil were both at 82C with 80C water temperature.

thats quite interesting... thanks for the info
guess the excel should see about 95-105C sump temp then? and 85C water...
the Excel on track for 30 mins constant 4000-6000rpm has a water temp of about 79C! i normally have to come in at this point as the brakes are starting to over heat, squeel, and you can smell them in the cabin!