Hypermiling: A new hobby for gas savers & environmentali

Our "pub" where you can post about things completely Off Topic or about non-silent PC issues.

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kaange
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Post by kaange » Sun Jun 22, 2008 12:01 am

aristide1 wrote:The coasting with the engine business is taking way too many risks. What if something or someone bolts in front of you?
Horses for courses. You drive a 3200 lb car while mine is considerably lighter.

If I can brake hard enough to pulse the ABS and turn hard enough to cause tyre squeal, I don't consider too much of my safety margin has been compromised during EOC.

bonestonne
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Post by bonestonne » Tue Jun 24, 2008 8:05 pm

quikkie wrote:the liquid that comes out of the exhaust is water - water being one of the by-products of combustion. If it was petrol/gasoline it would flame as soon as it hit the hot exhaust pipe. Remember the Ferrari F40? on a downshift the overrun was so bad the fuel went straight through to the exhaust and that's what caused the flash of flame from the exhaust pipe.

Oh and in the UK we get a choice of 95 (regular) or 97 (premium) - none of that anaemic stuff you Americans can get ;)

As for running at peak torque I think I'd cry if I had to do that... on my car that works out as 5K rpm! Granted it's a lot more "fun" but a lot less silent 8)
the older a car gets, the worse its diaphrams get, and therefore you always have the inefficiency. what comes out the back is a mixure of water, unused gas, rogue oil, and if you use octane boosters (they're all snake oil type stuff) it pretty much goes right through.

the only exception is hydrogen fuel cells, which only pure water comes out of the exhaust pipes. sure you have the condensation from the catalytic converter, but don't think your engine is 100% efficient and does not have waste fuel in the exhaust.
Covering the upper grill was the biggest improvement: ~2-3mpg.
its a truth that few car manufacturers are coming to realize. if you only filter the amount of air your car needs for combustion, your fuel injectors will slow down because of the combustion ratio (most if not all newer cars should be able to sense that).

also, by covering the upper intake you're forcing the engine to take cold are from right next to the true intake (which is not always where the filter is) and that means that the Ambient Air Temperature will be lower...which is always better for a car.

also, mad props to aristide1...Mobile 1 synthetic oil is the best stuff on the market because even after 30k miles (like in my dads 1996 minivan) its still doing the same job it was the day it was put in. natural oil begins to break down in the heat much faster than the synthetic crap. 10W30 all the way...unless you're in a racecar (my friend puts 15W50 in his).
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Post by NeilBlanchard » Wed Jun 25, 2008 4:51 am

Hello,

Actually, higher octane fuel has less potential energy...

The benefit of the covered grill comes from improved aerodynamics -- I doubt that it affects the temperature of the intake air. I have a so-called cold air intake that has it's K&N filter inside the lower left front corner behind the bumper.
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kaange
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Post by kaange » Wed Jun 25, 2008 7:12 pm

NeilBlanchard wrote:Actually, higher octane fuel has less potential energy...
Er no. Higher octane fuel often has less potential energy due to the nature of the additives that are often used to prevent knock but there is no inherent property strictly tying in octane and the energy density of fuel.

The strict definition for octane ratings (from 0 - 100) are based on 2 hydrocarbon molecules, n-heptane (c7H16) and iso-octane (C8H18), with almost identical chemical composition (and hence energy density) but markedly different molecular structure. The difference in molecular structure makes n-heptane much more likely to explode under compression but this does not mean it has more potential energy.

Gasoline being a varied mixture of hydrocarbons (and other chemicals) can have batches with varying energy density for a large variety of reasons (including the seasonal variations used to maintain consistent vapourisation).

aristide1
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Post by aristide1 » Fri Jun 27, 2008 6:58 pm

bonestonne wrote:also, mad props to aristide1...Mobile 1 synthetic oil is the best stuff on the market because even after 30k miles (like in my dads 1996 minivan) its still doing the same job it was the day it was put in. natural oil begins to break down in the heat much faster than the synthetic crap. 10W30 all the way...unless you're in a racecar (my friend puts 15W50 in his).
Mad props? I use Mobil 1 to cut friction and improve full economy. The fact that it lasts so long is less of a factor. A normal oil filter simply can't last that long. I will probably switch to just a filter change every other change, I dump it all now.

I use 15-50 in the summer, I think the oil's viscosity is a tad low at running temperatures. Last winter I used Castol Synthetic 5-50 because Mobil 1's 5-30 or such stays awful thin, and we get warm spells in the winter. Castrol is more suited for that, but those idiots refuse to sell 5-50 in a 5 quart container. :(
kaange wrote:Horses for courses. You drive a 3200 lb car while mine is considerably lighter.

If I can brake hard enough to pulse the ABS and turn hard enough to cause tyre squeal, I don't consider too much of my safety margin has been compromised during EOC.
It's more than that. I drove a '69 Chevelle 396 with manual steering. Yes, they actually made it that way, and despite F60-15s in the front and this massive engine it steered easily at speed. Parallel parking was another story, but my point is even my current car with manual steering would be easier than that Chevelle. As it is now I tried EOC and it's harder at speed than the Chevelle, but OK for small course corrections. I don't know any car sold in the States has manual steering anymore, and frankly for the lighter cars I don't see why. But as overweight Americans I don't see many cars being sold under 2500 pounds anymore either. Even the Honda Fix.

Yes I did EOC. Out of 10 one-way trips to work and back in a week, about 12 miles each, I can coast a little over 2 miles per day, or about a 1 way trips worth a week. But that won't save me an average of a trip's worth of gas, because all my coasting is downhill or flat, and a trip to work involves going uphill as well. I can't say what it will save me because I never liked looking at my in town mileage. :?

Higher octane fuel has the potential of creating more horsepower in an engine that is designed to take advantage of it, but from what I recall more refining meant less fuel created to begin with, no?

Propane is the winner here. Morgan continued to make their sports car for years without pollution controls by switching to propane, and propane's octane rating is very high from what I recall.
quikkie wrote:Oh and in the UK we get a choice of 95 (regular) or 97 (premium) - none of that anaemic stuff you Americans can get .
Is your octane rating based on R+M/2? The average of the two available ratings? If not the comparison is not valid.
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quikkie
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Post by quikkie » Sat Jun 28, 2008 1:55 pm

aristide1: you are absolutely correct, europe just uses RON and I just recently found that the US uses the average of RON and MON. So UK standard fuel is (roughly speaking) 90-91 in US equivalent - wikipedia and a bunch of other sources seem to corroborate that figure.
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