Oil cooler diverter valve

[Mike R]

I'm only throwing ideas out there .

The standard arrangement is supposed to be 3000cfm as is the SPAL, but I image that the standard arrangement is its peak, where the SPAL does this as soon as it comes on, so perhaps it is this fact that causes improved heat recovery that the Yanks are mentioning.

Think about it logically, WOT, huge thermal loads, come to a corner, reduced revs, reduced fan efficiency and then WOT again, so continue this for several laps and gradually the thermal load overcomes the cooling.

However change the set up so that the 3000cfm is running all the time, the car slows down at the end of the WOT, but the cooling remains constant, it recovers briefly, then WOT, huge thermal load, followed by brief recovery and repeat. Perhaps it is the way the standard set up works in that it doesn't allow that brief recovery (instead, it's actually putting even more thermal load into the engine), as instead of a period of high flow at the end of the WOT, it is getting a reduction of flow as the rpm drops.

So maybe an electric water pump and an SPAL fan would be the cure?

[shimmy]

Remind me of what happens to the a/c fan and viscous fan at different temps and speeds.

Obviously the viscous fan stops pushing air once it cools (e viscous bit) and doesn't the a/c fan stop running above certain speeds ?

[shimmy]

Just checking Alexk old post and Auxillary fan (fitted to both a/c and non-a/c cars, builds up but then stops working at 87.5mph. Above that speed it I guess revolves and is driven partly by the air speed of air entering the car grille.

When does Viscous fan start/stop running?

[Mike R]

Originally Posted by shimmy

Remind me of what happens to the a/c fan and viscous fan at different temps and speeds.

Obviously the viscous fan stops pushing air once it cools (e viscous bit) and doesn't the a/c fan stop running above certain speeds ?

I'm new to CSLs so can't give that info LOL.

If it was for Cossies though, that would be easy (but it uses an electric fan as standard, which I have upgraded to higher flow SPAL items). And it is purely temperature controlled.

The Escort one comes on half speed at 93 deg and then full speed at 99 deg (switching back off at 87 deg). This is because being a newer car than the original Sierra, it is subject to more strict emissions regulations, so is deliberately run hotter. However, this causes overheating on track, as it allows the water temps to get too high because the fans come on ful speed too late.

The Sierra runs a single stage fan switch, which comes on full speed at 93 deg, so we fit these to the Escorts, which maintains the temps at an acceptable level for much longer.

I'm sure you're now going to educate me on how the BMW arrangement works, which is going to blow my theory out of the water LOL.

[shimmy]

Mike

See other thread, I wasn't trying to catch you out, I'm not technical enough to know or remember tbh.

I think froUS forums they overcome the problem by ditching viscous fan, removing electric and fitting a high speed SPAL That is controlled by temp level s(and doesn't go off at speed)

But they do then occassionally get overheating at low speeds/traffic in hot weather.

[Mike R]

Originally Posted by shimmy

Mike

See other thread, I wasn't trying to catch you out, I'm not technical enough to know or remember tbh.

I think froUS forums they overcome the problem by ditching viscous fan, removing electric and fitting a high speed SPAL That is controlled by temp level s(and doesn't go off at speed)

But they do then occassionally get overheating at low speeds/traffic in hot weather.

Obviously the key would be to having both the data of the electric fan and viscous fan and see what CFMs these create when running together at slow speeds. And then see if this can be recreated by changing the switch on points in the map?

Perhaps switching it on at a lower temp will prevent it from climbing so rapidly. In my experience it is far easier to prevent the water temps from getting too hot, rather than trying to reduce them when they do .

[shane@mbtech]

Originally Posted by Mike R

Obviously the key would be to having both the data of the electric fan and viscous fan and see what CFMs these create when running together at slow speeds. And then see if this can be recreated by changing the switch on points in the map?

Perhaps switching it on at a lower temp will prevent it from climbing so rapidly. In my experience it is far easier to prevent the water temps from getting too hot, rather than trying to reduce them when they do .

Every little helps.

But I'm adamant on a track like spa for instance. The fans will be doing bugger all.

[shimmy]

Originally Posted by lawsy

Every little helps.

But I'm adamant on a track like spa for instance. The fans will be doing bugger all.

If BMW turn off the aux fan at 87.5mph then for 75% of the time that is off and the other 25% just adding abit of air flow

Viscous fan, I have no idea!

[AlexGTT]

Originally Posted by lawsy

Every little helps.

But I'm adamant on a track like spa for instance. The fans will be doing bugger all.

As Shane said, fan is fuck all to do with it. Only reason for any fan is to cool at standstill and very slow town speed traffic. Above 20mph when airflow takes over a fan is next to useless.

Ideally the solution is something like this but not really possible on CSL without major modification. Sealed inlets and outlets. Example not the configuration suitable for E46 but you get the theory.

[alexk]

What if we open outlets on the plastic cover under the chassis ?