how high for High Altitude Control Valve

takza · Post by **takza** » Tue Aug 16, 2005 2:51 am

I spent a few weeks between 4K and 8K with no HAC valve...did use an air bleed going into the EGR port on the carb though. You'll have more power with advanced ignition...the HAC valve is supposed to do that also...and it leans the carb.

Chris · Post by **Chris** » Tue Aug 16, 2005 9:17 am

I've had my Tercel over mountain passes in excess of 11,000 ft with no problems. So there's no need to worry. I live at 4700 ft and travel often to 8000 ft. Yes, you will notice a loss in power, but no big deal. Make sure your radiator cap is in good working order to maintain the desired pressure in the cooling system. That will keep the coolant from boiling at too low of a temperature when you're taxing the engine climbing those mountains......Have fun.

Where are you from and where are you going?

Typrus · Post by **Typrus** » Tue Aug 16, 2005 12:11 pm

I live at 5600ft and I don't see a lot of problems. I personally haven't taken it higher, but my folks drove it to the top of Trail Ridge which is... What? 12,000 feet high? A couple of times. They say it didn't too much agree with doing it but that it handled it fine. Said it had to be kept in lower gears the way up.
The original 84's engine made the trip over the Rocky Mountains from California with no HAC and no problems.