flyrotary@lancaironline.net Mailing List Archive

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NPG will continue to pressurize your system if you leave the cap in place. It expands somewhat more than 50/50 when heated so your system can still be pressurized. In fact, Evans recommends a 7 psi cap just to seal the system. Ether way, you do need an overflow tank.

One problem with NPG is that it is quite viscous - a negative attribute. This would tend to slow the circulation with your EWP even more.

I also feel that NPG would be less tolerant of a slowly circulating system because that would just exaggerate the temperature rise in the engine block.

That being said, with the temps you are showing I thing you could tolerate it and still come out ahead with NPG.

Dave Leonard

I just thought about this more in the shower (where I do my best thinking, apologies for the mental image)... I have a very simple system, with nothing more than a pressure cap, and overflow bottle. I'll probably leave the cap in place, though it will never get activated, and run my hose from the makeup bottle to a fitting on the lower hose (suction side) of the water pump housing. I'd also like to install one of those neato level switches on the overflow bottle, to alert me if the level drops.

With any luck, a leak would be a much slower problem with a non-pressurized system. Hopefully, the level sensor would warn me in time to get to an airport. Heaven help you trying to find Evan's NPG+ at an airport though.

I use the low oil sensor in the pan, and would probably put the low coolant light next to it. I've already got a label for the pair of lights, that I stole from the RX-7 list. Some of the RX-7's (at least the FD) have a low coolant light. Several wags have joked that it's in fact the "change engine light" :-) I can verify that this is a valid label for the low oil light.

Another odd though that came to mind. Wouldn't NPG be much better to have if you lost coolant flow? At least I can imagine that it's much better for a low flow situation. Since I believe we can all agree that EWP's work, I think we can also agree that Todd has demonstrated that the flow is less than what the stock pump puts out (not bad, just true). Would NPG make the EWP's lower flow rate more appealing to the disbelievers? Still thinking this through, but thought I'd throw it out there for comments.

Cheers,

Rusty (no Dave, I'm not tasting it)