Executive Summary:
The stuff is extremely stable. Much more so than any water based combination I've tried to date. It keeps my temperature MUCH more consistent. My
oil temp appears to have climbed about 10-20 degrees on average, however. This confirms my suspicions that the reduced specific heat capacity of the NPG+ DOES HAVE AN EFFECT!
Oil temps during spirited cruising run about 205-210.
Oil temps during hard driving rise to 220-230. Oil used to run about 180-190 normally, up to 210-215 on hard driving. Water temp is very stable. Cruise temp (78-80F ambient air) is 160-180 and very steady and predictable. 160 when puttering, 180 when flogging. Period. A little cool for my taste but there is no thermostat with this system.
The Nitty Gritty Details:
$28/gallon from the State 8 Motorcycles here in NE Ohio. Got 5 gallons. Shop said I did not need to run their flush fluid. I drained the radiator and attempted to drain the block. The block plugs were not moving. So I ran a hose out one front coolant passage and a shop vac in the other hole. I blew a bit out of the block and sucked some more out with a narrow hose on the end of the shop vac.
I ran one gallon of Evans NPG+ into the re-assembled cooling system (had it apart for some other work) and fired up the motor. Let it run for about a minute (maybe 2) and shut it down. Opened the radiator plug and out came the NPG - nearly crystal clear and no new color. Looks like I got most EGW out of the block!
The fluid itself is a similar viscosity to a regular Ethylene Glycol. It is clear and slightly brown colored. Slimy on the fingers. Looks like a very low viscosity motor oil. I filled the system until the level was at the baffle in the expansion tank. Cut the bottom seal off a radiator cap and ran a hose from the overflow line into an empty NPG jug. I probably blew out about 4 cups of the coolant while bleeding the system. However, I don't think it was because the level was too high. I think it was because there is no thermostat and the coolant just shot right up and out the cap. After 5-10 minutes of idling, I removed the cap (pressure was being relieved due to my "custom" cap) and checked the level. It was as low by as much coolant was in my jug. I emptied the hot coolant in the jug back into the system, capped it (16#) and said goodnight. The radiator cap is still used at that pressure because of the lack of thermostat. Hi-Vol pump, overdrive pulley, will blow off a lower PSI cap. The system does not run pressure, but some will happen in the expansion reservoir due to the location.
First run was pretty easy stuff. Takes a bit of time to get the oil temp up with no thermostat. Oh well. At idle, the water will go straight up to 210 and then the fans kick on. 210 in the manifold, 195 in the radiator (cold side). Fans cycle on and off at this point. I also wired in a fan override switch while I was at it. With the override and that great SPF radiator, I can make sure the coolant temp never goes above 180. Even after a flogging and then immediately stopping and idling.
Once I had confidence in the system, I ran the car very hard. Repeated trips through the gears to redline, one extended rev-limited fish-tailing burnout, and lots of very spirited driving. During the easiest of the driving, the coolant temp stuck right about 165. Mildly spirited driving, 175. Hard driving, 185 was the top mark I saw. Steady, slow rises and drops, predictable . . .
When I ran water, the gauge would stair-step up to alarming temps. I'd get into it, and it would shoot from 160 to 190. I'd lay off, and it would settle back down to 170. Then from 170 to 200, and back to 180. And so on. Go to
www.evanscooling.com and read up on nucleate boiling. While water is a superior cooling fluid to NPG+ or ethylene glycol, once it reaches its boiling point, it loses ALL cooling capacity. Period. When I would boil water on the surface in the water jackets, I would lose all cooling capacity. Boiling would slowly begin, air pockets would form, water would push out through the cap. Repeat vicious cycle.
I believe that my internal temps are hotter by a little bit, but that they will never get out of hand. The NPG+ will simply not boil over and not lose its cooling capacity. It will keep doing its job. This is not an advertisement - it's from experiences I had.... YESTERDAY.
If you have a consistently hot set-up, and it JUST RUNS HOT all the time, NPG+ probably won't be your cooling epiphany. My motor would run cool, but when flogged, it would run quite hot, and a water based system was too unstable. NPG was my solution. It alleviated my stair-stepping temperature issues. My overflow bottle stays high and dry. My coolant level stays consistent. After a hard day's drive, my surge tank has nice clear fluid in it. I'm not staring down my dry gooseneck into the intake anymore. I like that.
If you have any questions I may not have answered about my experience with Evans NPG+, ask me. I'll do my best to share my experiences or create them on the road so that I can answer your questions. The stuff is very very cool, but probably not a solution to every problem. And if your system runs perfectly well on water, well... if it ain't broke.....
This solved some issues I was having and wanted to address. If you experience similar cooling issues, $150 bucks... really cheap insurance. Seems ridiculous that coolant could cost that much, but think about it. I can run extremely hard now and watch the ROAD instead of my temp gauges. Peace of Mind..... you put a price on it! $150 fit the peace of mind budget for me!
