The curious case of the Atom 4 Cooling

[Mrlizard]

my coolant runs at 96deg just cruising about, doesnt seem to get noticeably higher when pushing it a 'little' but surprised to see people running in the 80's...

Anything in the 90s does seem rather high when simply cruising around.

I've just looked at a recent log of temps over a 13miles fairly spirited pleasure run on rural B roads and the coolant temp varied between 79 and a max of 86degC.

Do you have the uprated cooling package?

It does have the hot weather rad on it.

an FYI - 90s temperatures cruising around is totally normal... that is a temperature that is across the board of manufacturers. Cars run alot hotter these days!

Yer im not too concerned, my m2c runs at 110 quite happily on track regardless of how long/hard you push it. Just seemed a bit odd the difference (appreciate the weather is a bit warmer though). Im off to Donny next week so will report back.,

[plip1953]

an FYI - 90s temperatures cruising around is totally normal... that is a temperature that is across the board of manufacturers. Cars run alot hotter these days!

Fair comment, although how does that explain the radiator fan coming on at 82degC? Is is standard to expect a fan to run constantly during normal running?

Our logging of temps for road trips, even in reasonably warm ambient conditions, is for coolant temps to stay in the 80s, but at soon as the car goes on track they climb quickly and will readily exceed 100degC. Our highest recorded value thus far is 108degC (as I believe others have witnessed too) and of course at that kind of temp the boost pressure is restricted back to around 0.8bar from the normal 1.25bar.

[Curves Junkie]

Gentlemen - you are comparing apples with pears.

All newer vehicles are operated at over 100°C in normal operation. This is due to the emission regulations. Also the new engine oil for these vehicles is as thin as salad oil to reduce the resistances and thus save gasoline and to protect the OPF.
At full load, these new cars, the water temperature immediately drops into the 80-90°C range and stays there.

Our Atom's - no matter what generation - must not go much above 100°C.

[mention]plip1953[/mention]
If your boost pressure drops from 1.25 to 0.8 bar, it has not only to do with the high water temperature of 108°C, but your charge air is too hot and therefore the ECU regulates the boost pressure down to protect the engine.
The hot charge air also inevitably increases the water temperature and probably also the oil temperature.

[plip1953]

@plip1953
If your boost pressure drops from 1.25 to 0.8 bar, it has not only to do with the high water temperature of 108°C, but your charge air is too hot and therefore the ECU regulates the boost pressure down to protect the engine.
The hot charge air also inevitably increases the water temperature and probably also the oil temperature.

I'm familiar with how intake temps are taken into account, although our logging of these suggests they actually stay within reasonable bounds (thank goodness!). So I believe it really is the coolant temps that are the main trigger for boost pressure cuts. Oil temps do not become excessive either.

[plip1953]

These are datalogs of individual laps from a recent trackday at Snetterton when ambient temps were in the low 20s.

The first is of a relatively gentle lap and the second is when trying much harder. In each instance I've placed the cursor line to coincide with the end of the Bentley straight and the individual parameter values relate to that track position. As as can be seen the boost/manifold pressure is significantly lower when temps reached 105degC compared with when they stayed below 100degC, and yet intake temps on the faster lap were actually lower.

[Monza]

Clearly the first problem with Atom 4 is the water temp on track every time (and even with the latest upgrade), the intake temp is only the second problem and not every time.
What is surprising me a lot is that the oil temp seems to stay very good.

[plip1953]

Clearly the first problem with Atom 4 is the water temp on track every time (and even with the latest upgrade), the intake temp is only the second problem and not every time.
What is surprising me a lot is that the oil temp seems to stay very good.

We were very pleasantly surprised by the relatively low oil temps. One car has an oil cooler, but the readings from that compared to one with no oil cooler really don't show any material difference.

[robfitz]

Do the cars you are monitoring have wings as those seem to have more of a cooling issue?

[Curves Junkie]

[mention]plip1953[/mention]

I want to understand this log. Must of the datas are not plausible. How do you get the data? Own sensors installed, read out the ECU?
ECT is Water temp
AIRT is Air intake temp
ManifoldPressure is the intake pressure from the Turbo

What is Distance (ft) 1ft=30cm
But what distance - Snetterton on the track? Please show a log of an entire lap from start to finish.

[plip1953]

@plip1953

I want to understand this log. Must of the datas are not plausible. How do you get the data? Own sensors installed, read out the ECU?
ECT is Water temp
AIRT is Air intake temp
ManifoldPressure is the intake pressure from the Turbo

What is Distance (ft) 1ft=30cm
But what distance - Snetterton on the track? Please show a log of an entire lap from start to finish.

Not plausible in what way?

The data is taken directly from the AIM dash using a Smart Logger connected to an AIM Channel Expansion Module that also has connected to it a GPS aerial and a Smartycam. What is shown in each instance is a full lap of the Snetterton 300 circuit. I've honestly no idea why the X-axis units appear in the way they do because the actual distance round the circuit is nearly 3miles or 4.8kms. With the AIM analysis software you can display distance or time across the X-axis and here is the quicker lap with the same data plotted against elapsed time - so an overall laptime of 2mins. Does that make more sense?


ADDED - the X-axis distance units show as ft (feet), but in actual fact is seems they must be miles ie because one lap of Snett 300 is just under 3miles. Why it is shown as it is a mystery to me!

[Curves Junkie]

If I look at the circuit map http://www.snetterton.co.uk/media/65500 ... p_both.pdf I will say that at RPM the "U" beginning my red line you are driving "Williams corner" at that moment. Your cursor shows the end of the "Bentley Straight".
Is this correct?

Logging data from Snett 3.jpg (343.03 KiB) Viewed 1181 times

In my red arrow the ECT raises up at the Bentley Straight where you have full throttle.
This shows me that your water cooling is not very effizient because the air pressure to the rad is here at the maximum.
You see at this section the AIRT is falling.

At Brundle and Nelson corner the ECT is falling but the AIRT is raising very rapidly. His very rapid increase surprises me.
Possibly the aftercooler eats the hot air of the water cooler. Try to install a horizontal cover at the front behind the rad so that the hot air does not come under the car, but is only discharged to the side.

I agree with [mention]Monza[/mention] that the coolant temperature problem must be solved first.
Because I think that's why the ECU is cutting the power to protect the components.

The efficiency of the intercooler is also not great, because at an ambient temperature of 20° it just cools down to 40-45°C.

Now make my suggestion above and then show the log again.

[plip1953]

If I look at the circuit map http://www.snetterton.co.uk/media/65500 ... p_both.pdf I will say that at RPM the "U" beginning my red line you are driving "Williams corner" at that moment. Your cursor shows the end of the "Bentley Straight".
Is this correct?

Logging data from Snett 3.jpg

In my red arrow the ECT raises up at the Bentley Straight where you have full throttle.
This shows me that your water cooling is not very effizient because the air pressure to the rad is here at the maximum.
You see at this section the AIRT is falling.

At Brundle and Nelson corner the ECT is falling but the AIRT is raising very rapidly. His very rapid increase surprises me.
Possibly the aftercooler eats the hot air of the water cooler. Try to install a horizontal cover at the front behind the rad so that the hot air does not come under the car, but is only discharged to the side.

I agree with @Monza that the coolant temperature problem must be solved first.
Because I think that's why the ECU is cutting the power to protect the components.

The efficiency of the intercooler is also not great, because at an ambient temperature of 20° it just cools down to 40-45°C.

Now make my suggestion above and then show the log again.

Yes, Williams, the sweeping right hander, on to the Bentley Straight. My cursor line is positioned towards the end of the Bentley Straight, but shortly before the braking point.

And I agree totally that the cooling system simply isn't able to cope with the demands being placed on it and it's exactly that we are seeking to address. Several different options are being considered, the first of which was in operation at Snetterton, but clearly didn't work. A second version will be trialled next week, but there are a couple of more radical options also being considered. But none of these include shutting off the option for hot air from the radiator to exit downwards, but it's certainly something else to consider.

It would be great if intake temps could be lowered too, but at this point they do not appear to be high enough to result in the ecu feeling the need to take any positive action to limit power eg by retarding the ignition or cutting boost. What is somewhat odd though is how the intake temps appear to spike to really high temps when off throttle. This isn't what I've observed from other turbo cars and I'd be grateful to hear from anyone what the explanation might be. But I don't believe it's actually having any effect on power.

[plip1953]

Do the cars you are monitoring have wings as those seem to have more of a cooling issue?

The way the front wing is attached does impinge slightly on the airflow in through the nose cone and a number of people have improvised a deflector to try to counteract this.

Whether the wing somehow acts in a way that further restricts air getting to the radiator (or away from the radiator) does seem to be a possibility and next time out we plan to runs back to back sessions with the wing on and wing off.

[Yorkshire]

I also understand that the fuse for the electric pump has a tendency to blow, so checking before any kind of track action would seem like a good idea.

Thanks for this i checked mine and the fuse had blown. Spoke to the factory and they suggested changing it from 10amp to 15amp which i have done.

I am out in my Atom at Blyton Park on sunday so should know fairly quickly whether the "Race Ready" no antifreeze coolant i have in mine has made any difference. I was also going to try the deflector plate in front wing see if that alters anything and may even try no front wing again to see if any difference.

Will report back once i know

[Curves Junkie]

Possibly the aftercooler eats the hot air of the water cooler. Try to install a horizontal cover at the front behind the rad so that the hot air does not come under the car, but is only discharged to the side.

But none of these include shutting off the option for hot air from the radiator to exit downwards, but it's certainly something else to consider.

It's a consideration of mine.
At the moment I can't find an explanation why after the Bentley section the AIRT rises so much and especially so fast.
My suggestion is thought, according to the exclusion method, that it is not due to the hot air running along the underbody.

Just take a cardboard cut it to size and tape it to the horizontal tubes with a panzer tape.
It may be that ECT rises even further - but it doesn't matter in this case - we want to know only how AIRT is doing.

I hope you understand my bad English.