Going to Nordstern DE this weekend at BIR. The rules have changed back to windows up. I am curious: I am planning to now run my a/c..am I sacrificing significant power/hp loss by doing so? I searched posts and could not find anything.

 

Yes, there is some parasitic loss by running the AC. How much depends on the size of the compressor. Will it be noticeable depends on how much the loss is and how much power your engine makes. Some AC systems disengage at WOT, so you may not notice much if this is the case.

 

In a DE situation does it matter if you lose a couple of HP?

 

A/C on full tilt will consume at most 1kw (12000 btu/hr) which is 1.5 hp more or less. The trouble is, positive displacement refrigerant compressors start under full pressure which is higher, but this lasts only a very short time.

Belts and pulleys will consume 0.25 hp

I keep my A/c on, especially when forming up to go on-track.

 

Thanks. You confirmed my thoughts that hp loss is minimal..essentially no effect on a DE event.

 

I'm curious. What is their reasoning for windows up?

 

I thought that the AC Compressor clutch disengages on full throttle and I'm not so sure that it would be all that good for the AC compressor to be spun near redline for extended periods of time...BUT, I could be wrong here.

 

Curious here as well. How in the world is that safe?

 

You could be right but I find that very very hard to believe. If it were true, you wouldn't feel the loss in a 120 hp civic either, but experience proves otherwise.

 

It keeps arms/heads in the car in case of rollovers.

 

Sorry, but that glass ain't gonna make it in a rollover. Wearing a 6pt will address most of that anyway. The last thing you want is to have the windows up and have a NON rollover incident that results in fire and then have the windows up as well. What happens if your window switch is fried? This has misinformation written all over. I imagine it will be changed back pretty quick (after an incident).

 

It has been windows up for years. This year it was changed to windows down and was a big controversy. Then it changed to windows up again.
BIR is a fast track and does have occasional roll over’s.

Many of the DE participants do not have 6 pt harnesses or window nets.

Please note that I am not stating my opinions here.

 

I'm with you. I've seen enough car fires to know that you will be blinded in about 2 seconds if smoke enters the cockpit. Add to that the toxins/lack of oxygen and you could be out before you could get the car pulled over.

 

Precisely. Have to wonder what goes on with the decision makers of this policy.

I realize that. Just commenting on the policy makers

 

Wears that glass hammer when I need it.