For the little time it takes for the dyno run it dosen't need it. It's not much diffrent than idling at a stop lite.

 

Yea OK

 

have quite a bit of heat capacity in them. Eventually, the water will heat up and then it will be an issue. But because the water can act like a heat sink, it can "store" coldness (yeah I know, not a real term) until when it's needed. The amount of dyno runs you can do before degradation is a function of how often you do a pull, how much water is in the cooling loop, and how much (if any) air flow is going over the w2A radiator. But for sure, the systems are more forgiving......

Matt

 

The last time I had it on the dyno I had a power difference was about 2HP over 3 runs in about 20 mins. It was like looking at a single line on the chart.
I had some friends run there's at the same time but with air cooled IC's and the difference was about 10 to 15 HP for the same runs.

 

well that certainly says something - doesn't it.