Water Wetter, Radiator aid, Coolant enhancer - feedback.
 

Anyone used any branded coolant additive or is it something best suited to countries where 35-45c is common place or race cars only etc?

DEI claim their product cuts warm up time by 50%

its the oil you need to warm up in your impreza really not the water.
that generally warms up very quickly, noticeable by how quickly the heater starts to blow hot air.

I've sorted for lubricants, just wanted to make sure I'm not missing out on an easy few horses.

It was a genuine reply for a change.
Quite honestly its not worth it if your only concern is the speed it warms up.

I've used Water Wetter in the past to keep my Caterham cool ..... rather than speed up the warm up.
I was sufferring from running too warm and the Water Wetter certainly helped.

I wouldn't mind using it if it works. I'm either warming up or down with nothing inbetween

I only really use the car on a weekend but I occasionally do short runs midweek to ASDA where the car doesn't get to warm up, in the summer I like to drag the car and this involves a lot of hot idle running before launching.

To warm up fast and stay cooler would be beneficial for my engine with any increase in mpg/bhp a bonus.

Obviously it wouldn't be so effective on a stock 225/265 car but I'm over 300 now.

But its the Gearbox/engine oil that needs to be warm plus imprezas don't suffer from overheating anyway.
Once the engine hits a certain temp the fans kick in until it drops again....this is repeated.
Coolant will have no effect on this.

Wouldn't a thermostat with a lower temp rating be more beneficial?

But the water temp never gets too the point its a problem in an impreza.
As you say though a cooler thermostat is a good option.
If you run the strip. The best thing to do is push the car in the line with bonnet up and engine off and also fit a fmic to avoid heatsoak

Or run on 3 cylinders with the CEL light on.

Cooler stats are for bigger power cars imo, They make a difference when everything else is getting hotter quicker ;)

It's not so much stopping a car overheating but running at a slightly lower temp to help lessen heat soak into the cylinders. Cheaper than a new stat too.

Is the stat on the WRX and sti the same?

Change the thermostat for one that opens at a lower temperature.

Putting stuff in the coolant isn't going to change when the stat opens.

just wondering if the standard thermostat opens at a particular temperature for a reason? is it the optimum running temp?

Not being funny, but if you're worrying about heat soak etc when running it on the drag strip, wouldn't it be better to sort out why one cylinder is down on compression?