--------------------------------
Quote:
Originally Posted by Mike
Re: Your tips.
I was reading some of your tips, and have some feedback on them.
1. Some of them are untrue.
2. Some of them are very unsafe
3. Some of them will cause your car to break down early (I'm a professional mechanic.)
As for the untrue ones. Driving with your lights on does not decrease your fuel
efficiency. On any vehicle the alternator is turning at the same relative speed as
the vehicle's engine. That means that it's going to continue charging the battery
and shunting the excess voltage back into the alternator. Only when you're using a
HECK OF A LOT of power is it going to start using battery voltage to power it all.
|
Not true, the field circuit weakens the field (am I saying that correctly?) reducing ouput and therefore load. If it were true, then why would some race cars install devices to weaken the field when at WOT?
Quote:
Originally Posted by Mike
And by a heck of a lot I mean neons, a sound system, and a multi-screen DVD display
in the car all running at the same time.
|
I noticed that this is false before I was in to Fuel economy, my Supra went for 17.5~18 down to 16.5~17 When I used my car computer + 15" display + 2000 watt stereo + Neon + dual power seats + . . . .. (over 100 amps continuous draw when maxed draining from a 90 amp alternator, which didn't last long) I tried a tank with everything switched off and fuel economy returned to normal, from then on I used electrical accessories when needed.
Quote:
Originally Posted by Mike
Also, when a vehicle is warm it does have greater efficiency in fuel usage, true,
but at the same time, the warmer the tires, the more they stick, causing a decrease
in mileage.
|
Well this is partially true, however tires don't get very hot from driving efficiently. And you are ignoring hot grease, hot transmission fluid, hot transfer case fluid. I can tell that my car is significantly easier to push (by hand in my driveway) when hot than when cold, couple that with a cold / less efficient engine and you have significantly worse fuel economy (30% in my case; your mileage will vary)
Quote:
Originally Posted by Mike
To be honest, Cold Air Intake systems usually increase mileage because
of the cold air, the warmer the air the more of it has to pass through to get the
same effect as a smaller amount of cold air, and the amount of fuel injected depends
on the amount of air passing through. So down to about 30 degrees or so it's
actually more efficient to drive in the cold than the warm.
|
Someone else will reply who knows more about this subject, but in general the idea is to decease the effective engine size, thereby running it at a higher throttle which is typically more efficient, at very least, it warms the engine up faster.
Quote:
Originally Posted by Mike
You also seem to like turning the engine off. While that does save gas to coast it
also takes an approximate fuel/air mixture of 8:1 for a cold engine and a mixture of
10:1 for a warm engine, compared with pedal to the metal acceleration of 12:1 ratio
and optimum cruising ratio of 16.7:1.
|
My Wideband make sit look like my supra starts lean . . . 15~16 to 1 ish. Diesel doesn't have an O2 sensor, so I can't comment.
You are also contradicting yourself about colder engines being more efficient
Quote:
Originally Posted by Mike
As for unsafe ones, turning off the engine is the most obvious one here. It kills
|
Quote:
Originally Posted by Mike
the brake lights,
|
False, go outside get someone to put their foot on the brake pedal (with the key in their pocket) and look at the brake lights, in every vehicle I have ever seen they have stayed on
Quote:
Originally Posted by Mike
kills power steering (not many vehicles without it now),
|
True! This is where someone needs to know their vehicle, some drive fine without power steering, some do not, some situations are safer with it, some don't matter.
Quote:
Originally Posted by Mike
kills power brakes,
|
False, I get at least 3 full stops without adding vacuum to the booster (tested in mountains) and you will need to start the engine once you are stopped, replenishing your vacuum reservoir.
Quote:
Originally Posted by Mike
takes out any warning lights/indicators,
|
Mixed. On some cars the indicators will stop, this is an issue if turning. I have modified mine to always work. As far as warning lights they will work at all times.
Quote:
Originally Posted by Mike
and wears out your drivetrain
faster because oil is not circulating as designed.
|
Debatable, if you are leaving the engine off for several minutes there is some oil drain back, but assuming that your anti-drain back valve is functional (inside most oil filters) then it will be only a few drops. However all those hours that your engine is not idling, it is also not wearing at all.
Quote:
Originally Posted by Mike
As for killing the engine but leaving the key on. Your power steering and brakes
are still gone, plus that will kill your sparking system.
|
False on modern engines; True for points; (When was the last time you saw a car with points? my 66 bus was swapped to electronic as soon as I burnt the coil up leaving the key on to run the stereo), which may (if the engine stoped in the wrong spot continue charging the coil, and overheat it (ask me how I know).
Quote:
Originally Posted by Mike
If the vehicle had points it'd be fine, but most have pulser coils now, and if they're powered but not being
used (as in engine off key on) it kills them fast.
|
Absolutely False, see above
Quote:
Originally Posted by Mike
Engine troubles also abound with putting the transmission in park after your key is
turned off. The engines now a days are almost exclusively fuel injected. That
means they have different fuel settings for different statuses/gears/etc. A vehicle
needs to be able to adjust for that, hence why the idle temporarily jumps when you
put it in park or neutral. It also prepares the electronics to be shut off.
Neutral while stopping. It may seem like a good idea, but it's doing the exact
opposite of what you want it to.
|
Umm, I do not know if I am following you, or not, but I believe you are claiming that the ECU will be confused by early shut down, not know what gear you are in and perform poorly? I don't have iny information other than that I tried to do odd things with rental cars shifters, and they all reacted in the best way I could think of. . . .
Quote:
Originally Posted by Mike
If you look at your tachometer while you're idling
at a stop sign in drive it drops down to about 800 RPM on average. That's lower
than the average of 1000-1200 RPM for neutral.
|
If your car behaves that way, I would suspect either a faulty Throttle Position Sensor, or sticky Idle air Control valve. Some older cars will take a second to "adjust to load" but most newer cars do it so quickly that the engine does not rev/ accelerate a noticeable amount.
Quote:
Originally Posted by Mike
It also wears out your transmission
faster, instead of lasting 150K miles it might last 80 or 100K.
|
Can you provide any information about this? there are additional shifts, but they are low load, and in general you will be reducing load on the transmission, therefore if I had to guess I would think that the transmission would last as long or longer.
Quote:
Originally Posted by Mike
Other than the ones I pointed out I agree with and utilize most of those in my daily
driving. I drive a 1997 Toyota Camry that's completely stock with over 120K miles
on it and get an average of 20 MPG in city and 25-28 highway.
|
A good fried of mine has a 97 camry V6 auto not a bad car IMHO, that's about the mileage she gets.
Quote:
Originally Posted by Mike
Also, if you have any responses or would like to refute my claims, please feel free
to contact me, I'm always open to debate and learning. And who knows, I may be
wrong on something and too thick to think about it! Have a great day!
Ryan
|
Thank you for the invite, I'll say that some of the things on the list are way out on left field, I'd use them in competition, but in daily driving, there are probably only 75 or so I use.