Some members are getting discouraged with mods,and I've been thinking of foibles that could be associated with the "magic" of the Scan-Gauge.------------------------------ The "up-shot" of the electronics is that they give instantaneous readings,without burning alot of fuel for results.---------------------------------------- One concern,is that "scanners" may be seduced into taking readings before their vehicle is in a position to provide useful data.-------------------------------------- Here's the rub.A vehicle requires 22-miles (35.5 km) of continuous driving before it reaches equilibrium temperature.------------------------------ Tires will come up to temp in about 5-miles (8 km ),however,coolant,engine oil,transmission and differential require a full 22-miles before their viscosity reaches it's final status.--------------------------------------- Any testing conducted without the "warm-up" has the potential of such a great amount of variables as to render results,dubious at best.-------------------------------- "Ideal" testing,is conducted at 75-degrees F,no wind,flat road surface,no turns,and "special" lubes".( don't ask!).--------------------------------------- City vs highway mpg can vary by a factor of 100%.--------------------------------A 4-mile cold start test could show 40% below your actual mpg.----------------------------------------A 2-mile test could show 55% below your actual mpg.---------------------------------- A 1-mile test could show 75% below your actual mpg.----------------------------------- Wind can effect mpg by (negative) 17%,to (positive) 19%.---------------------------------------- Road grades can effect mpg up to 55%.------------------------------ Rain can cost 1 mpg.---------------------- A 50-degree F test day will cost you 5% mpg.If temp drops to 20-degrees,your looking at a loss of 11%.It's easy to lose 3.5 mpg during any winter.------------------------------------- I hope everyone is tracking "tank" mpg,to go along with their Scan-Gauge results.--------------------------------- I'm not into anybody wasting any additional fuel during testing,but there's a reason for the warm-up,and I'm afraid many modders will suffer needless disappointment if they inadvertently stray from the rule-book.
Some members are getting discouraged with mods and I've been thinking of foibles that could be associated with the "magic" of the Scan-Gauge.
The "up-shot" of the electronics is that they give instantaneous readings, without burning allot of fuel for results. One concern is that "scanners" may be seduced into taking readings before their vehicle is in a position to provide useful data.
Here's the rub.
-A vehicle requires 22-miles (35.5 km) of continuous driving before it reaches equilibrium temperature.
-Tires will come up to temp in about 5-miles (8 km ),however coolant, engine oil, transmission and differential require a full 22-miles before their viscosity reaches it's final status.
-Any testing conducted without the "warm-up" has the potential of such a great amount of variables as to render results, dubious at best.
"Ideal" testing, is conducted at 75-degrees F, no wind, flat road surface, no turns, and "special" lubes".( don't ask!).
-City vs highway mpg can vary by a factor of 100%.
-A 4-mile cold start test could show 40% below your actual mpg.
-A 2-mile test could show 55% below your actual mpg.
-A 1-mile test could show 75% below your actual mpg.
-Wind can affect mpg by (negative) 17%, to (positive) 19%.
-Road grades can affect mpg up to 55%.
-Rain can cost 1 mpg.
-A 50-degree F test day will cost you 5% mpg. If temp drops to 20-degrees, you’re looking at a loss of 11%. It's easy to lose 3.5 mpg during any winter.
I hope everyone is tracking "tank" mpg, to go along with their Scan-Gauge results.
I'm not into anybody wasting any additional fuel during testing, but there's a reason for the warm-up, and I'm afraid many modders will suffer needless disappointment if they inadvertently stray from the rule-book.
__________________ I am not trying to save the planet, just trying to hurt it a little less
Thank you for doing this. I will quote your message
...
aerohead -
Quote:
Originally Posted by digitaldissent
Some members are getting discouraged with mods and I've been thinking of foibles that could be associated with the "magic" of the Scan-Gauge.
The "up-shot" of the electronics is that they give instantaneous readings, without burning allot of fuel for results. One concern is that "scanners" may be seduced into taking readings before their vehicle is in a position to provide useful data.
Here's the rub.
-A vehicle requires 22-miles (35.5 km) of continuous driving before it reaches equilibrium temperature.
-Tires will come up to temp in about 5-miles (8 km ),however coolant, engine oil, transmission and differential require a full 22-miles before their viscosity reaches it's final status.
...
I'm not into anybody wasting any additional fuel during testing, but there's a reason for the warm-up, and I'm afraid many modders will suffer needless disappointment if they inadvertently stray from the rule-book.
To me, this 22 mile warm-up is a big incentive to get an engine block-heater for use in *any* climate. If I were to do this, I would want to figure out the "virtual gasoline hit" for my fuel log. To do this, I think I would need to :
1 - Use a Kill-A-Watt to figure out my outlet energy usage
2 - Assume worst-case-scenario power plant efficiency for calculating energy usage. For example, if the power plant were a gasoline power plant (verrrrrry unlikely), how much gas would be burned to power my engine block heater for X minutes?
I think power plant thermal efficiency tops out around 32 %.So about 68% of the fuels(whatever fuel they use)energy is lost right at the powerplant.An additional 7% of the electric production is lost within the powerlines according Ohm's Law.They can't boost the voltage and get current down to reduce the loss do to increased EMF caused by high-voltage alternating current,which has been linked to human healthcare issues.If the powerplant WERE burning gasoline,I think it has an average energy content of about 124,000 Btu per gallon.Wind and solar would be the hot ticket!
1 - Use a Kill-A-Watt to figure out my outlet energy usage
2 - Assume worst-case-scenario power plant efficiency for calculating energy usage. For example, if the power plant were a gasoline power plant (verrrrrry unlikely), how much gas would be burned to power my engine block heater for X minutes?
CarloSW2
Why not just calculate the dollar cost, at your electric rates, of the electricity you use for the block heater during the tank, convert that to gallons at the same $/gal you paid, and add that to the tank?
Why not just calculate the dollar cost, at your electric rates, of the electricity you use for the block heater during the tank, convert that to gallons at the same $/gal you paid, and add that to the tank?
-A vehicle requires 22-miles (35.5 km) of continuous driving before it reaches equilibrium temperature.
-Tires will come up to temp in about 5-miles (8 km ),however coolant, engine oil, transmission and differential require a full 22-miles before their viscosity reaches it's final status.
I'm not entirely sure I believe all of this. In fact, I'm not sure that it even makes sense to talk about the "final status" of the viscosity of the fluids unless the car is being driven at a constant speed and load for a long period of time.
My one way drive to work in a 2003 Protege5 is about 7.5 miles and takes 20 minutes. The radiator is up to equilibrium temperature in about 4-5 minutes and the car switches from open loop to closed loop at that point. This transition can often be felt because when the car is idling the transition causes a very brief engine stumble, with the RPM dropping a bit and then immediately recovering. Anyway, once the car has gone closed loop and the temperature gauge is fixed at midpoint I am pretty sure the coolant really is at a stable temperature. That temperature is pretty darn hot so I imagine whatever tiny separation in water vs. other coolant components which has taken place overnight will have been thoroughly remixed by that point. So what physical mechanism could possibly account for a delay of 15-16 minutes from this time before the coolant's "viscosity reaches its final status"? On the other hand, the viscosity of the coolant isn't going to make all that much difference in anybody's test results, unless they are running the test in Anchorage.
Oil, on the other hand, could well take 20 minutes to reach a stable temperature. The outside of the motor is definitely not yet at its equilibrium temperature in 5 minutes, and the oil is flowing through various parts of the motor and pump which are at different temperatures, so it is reasonable that it would be warming up more slowly. I googled for a while and could not find a plot of engine oil temperature versus time. Perhaps someone here has one? Anyway, 20 minutes sounds about right for the oil/motor to come to equilibrium temperature for the given load. And there's a problem - I'm certain the viscosity is lower the higher the temperature of the motor, and the temperature of the motor can go up and down depending on the load.
The transmission, like the motor, will heat up and cool off depending on how much work it is doing. Especially if it is an automatic running at speeds below torque converter lock. The differential I'm not so sure about. It would tend to heat up (lowering viscosity of the lubricant) with speed, but that would be offset by the air blowing past many differentials, which would tend to cool it.
What I'm trying to get at here is that I don't think a long warm up period is going to guarantee the reproducibility of test results. I do think that the test conditions should as closely as possible match the warm up conditions. Specifically, driving around town for half an hour warming up the car, and then going out on the highway for an A-B-A-B with 5 minutes each leg, could result in a fair amount of variation from the car moving from the in town temperature equilibrium to the highway speed temperature equilibrium. I suppose this is obvious, but for the first A to be comparable to the last B, the warm up period before A should be as closely as possible the same conditions as for the first test.
This also may be relevant to block heaters. If the point of heating the block is to get the oil up to temperature and so reduce its viscosity, it would seem like it might be more effective to attach some sort of (regulated!) heater to the bottom of the oil pan. That is, heat the oil as directly as possible in order to get it to a lower viscosity as quickly as possible. It should take a lot less power and time to heat up the oil in the oil pan to a nice toasty temperature than it would to warm up the big chunk of metal that is the motor. Block heaters work the slow way on purpose because they are used in places that are very cold - shooting very hot oil into a very cold motor is not a good idea!
Today
Other popular topics in this forum...
