The curious case of the Atom 4 Cooling

[Yorkshire]

I so liked the title of the brakes one that much i thought i would continue the theme with a cooling post so all the data is in one post.

I have an Atom 4 that i am in the process of tuning with various changes (more to follow).

I have made tuning changes which hopefully once i dyno on the 4th August will mean my car has over 500hp.

So as you would guess more power means more heat and hence my need to find more cooling ability.

I do have the factory fitted AIM's camera system so i can log Intake Temp, Engine Temp and Oil Pressure.

Hence once i can get on track i can see what is happening with the intercooler (to see if that is a problem regarding power loss as every 10 degree increase is 3% power loss)

Regarding the basic cooling system i have changed all my anti freeze type coolant for a race type which should hopefully see some reduction (as i was at 108 degrees last year when running 400 hp) but won't give any winter protection.

So lets see what August brings

Cheers Stuart

[jaylatti]

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500 bhp !!! Can't wait to see your write up on that ! I've tackled the heat issues with performance intercooler which is made by a top manufacturer PWR who supplies F1 Nascar etc this unit available through Ariel is alot better than the standard one. I've also fitted a Funk motorsport turbo blanket and ptp turbo elbow blanket. The amount of heat just radiating from that area heating up everything was alot, sitting in traffic now is miles better also. I've put reflective matt on bottom side off airbox also. The intercooler intake which runs right next to turbo and cat I've also wrapped in dei reflective blanket.Ive also put reflective heat resistant matt to fuel tank as this was also getting hot and hot fuel is crap. I'm now looking to fit the eventuri carbon turbo inlet pipe as this stops heat soak of the intake .

[plip1953]

Have you seen the "Water Temperature" thread.

When you say "10 degree increase is 3% power loss" are you referring to intake temps or coolant temps? My understanding is that in factory form you will have full power up to 100deg C on coolant and 60deg C on intake temps. Or are you running a bespoke map with different safety parameters?

[John Scherrer]

Nice work Jason !

I lived in Kuwait for quite a while where summer daytime temps of 47C in the shade were normal.

The best fix to stop overheating of your road car which was already fitted with middle eastern spec radiators etc was to simply remove the water thermostat from its housing.

It restricted water flow even when fully open.

[Yorkshire]

When you say "10 degree increase is 3% power loss" are you referring to intake temps or coolant temps?

Just in relation to intake temp. As a general rule i was told that every 10 degree increase in intake temp was 3% power loss. I haven't altered the factory parameters at all. I have the upgraded factory intercooler so once i get back on track i can see how it performs.

[plip1953]

When you say "10 degree increase is 3% power loss" are you referring to intake temps or coolant temps?

Just in relation to intake temp. As a general rule i was told that every 10 degree increase in intake temp was 3% power loss. I haven't altered the factory parameters at all. I have the upgraded factory intercooler so once i get back on track i can see how it performs.

The rule of thumb that I got told some years ago was 1degC of intake temp would cost approx 1bhp. But I think that was purely because hotter air is less dense than cooler air and therefore each combustion event will necessarily be less intense. But on top of that it seems normal for timing to be "pulled" (ie ignition advance reduced) once intake temps and/or coolant temps exceed certain thresholds - depending on the preference of the mapper etc.

Something else we are monitoring is oil temps, but thus far haven't seen anything above 100degC which doesn't seem especially high.

[plip1953]

Nice work Jason !

I lived in Kuwait for quite a while where summer daytime temps of 47C in the shade were normal.

The best fix to stop overheating of your road car which was already fitted with middle eastern spec radiators etc was to simply remove the water thermostat from its housing.

It restricted water flow even when fully open.

That definitely seems worth a try.

[robfitz]

You will never get up to temperature on the road though?

[John Scherrer]

It wasn’t for an Atom but for anyone’s daily drive where the ambient temps could cause overheating with just normal driving.

It just took a bit longer to come up to temperature, more of an issue in winter in European climates of course, when you could put the thermostat back in.

[Mrlizard]

is there any worry with wrapping the inlet/turbo etc that it is moving the heat to elsewhere in the chain, rather than keeping things cool. Is the exhaust backbox getting hotter because of this or is it simply stopping heatsoak?

[plip1953]

The Atom 4 (and maybe earlier models as well?) has an electric coolant pump in addition to the engine driven mechanical one. Does anyone know exactly when this kicks in? Perhaps it could be set to run constantly, especially if the thermostat has been removed?

[John Scherrer]

On the '3', the Electric Water Pump was fitted as part of the Supercharger option kit.

It was turned on when the front radiator fan started but unlike the non-supercharged car, the fan and electric pump continued to run when the ignition was switched until the water temperature had subsided.

It was fitted to reduce the water temp in traffic when there was no air flow through the radiator and ran on after engine stop to prevent heat soak causing localised boiling in the engine and cylinder head core which could cause air pocket cavitation and air locks etc.

I imagine the electronic switching/wiring is the same in the '4' ?

[plip1953]

On the '3', the Electric Water Pump was fitted as part of the Supercharger option kit.

It was turned on when the front radiator fan started but unlike the non-supercharged car, the fan and electric pump continued to run when the ignition was switched until the water temperature had subsided.

It was fitted to reduce the water temp in traffic when there was no air flow through the radiator and ran on after engine stop to prevent heat soak causing localised boiling in the engine and cylinder head core which could cause air pocket cavitation and air locks etc.

I imagine the electronic switching/wiring is the same in the '4' ?

Sounds like it's the same arrangement in the 4. In track conditions, what we've seen is that once temps get up and over the 100degC mark there is no chance of a recovery other than by backing right off. But once you do back off the temps fall quite rapidly. I'm assuming (but don't know) that the fan won't be active when roadspeed is above a certain level because a fan isn't normally thought to be effective when normal throughflow of air is strong, but maybe it would actually help (a bit) if it was?

So I'm kind of thinking that a combination of the electric pump and electric fan being forced on when coolant temp exceeds,100degC AND roadspeed is above 50mph might be worth a try? Although before that I think we are going to try to route more air directly at the radiator.

[Monza]

The electric pump on the Atom 4 was not fitted on the earlier Atom 4.
The ECU is in charge of it (if you don't have it on your Atom 4 and want to fit one, the ECU sofware has to be updated).
The electrical pump is a part of the cooling upgrade option : different radiator, electrical pump and lower temp calorstat.
If my memory is good, but not 100% sure here, the electrical pump is starting before the radiator fan or at least, at the same time, so well before 100°c.

[K20A2]

I'm assuming (but don't know) that the fan won't be active when roadspeed is above a certain level

If it helps: At least referring to the Atom 3 I could confirm, that once started the fan is running independent from the road speed.