Gents, I am getting belt slip over 6500 engine revs and suspect that the water pump and alt speeds are too fast and taking too much power to drive. I will measure all pulleys tomorrow, but just need some speeds to work towards. I have been told that an alternator can happily run between 3000 and say 8-10,000 even up to 30,000, but the higher speed will chew 15 HP and achieve nothing in extra charge especially when I only have to run avionics and charge the battery. Water pump has a speed whatever that is over which it just cavitates and does nothing. What is that speed for the RX8?? Neil. -- Homepage: http://www.flyrotary.com/ Archive and UnSub: http://mail.lancaironline.net:81/lists/flyrotary/List.html