Dumb things people say about cars.

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My stock Civic Si with a Bosal muffler and Ebay CAI will blow your Trans Am out of the water. (TPI, ported runners ans upper, long tubes, shift kit, massaged heads, mild cam..) Yeah, but VTAAAAAAAAAAAAAAAAAK son...
 
A customer said that I shouldnt run 10W30 in his old ford because it makes a 20 weight. He wanted straight 30. Also stating that our anniversary 29.99 Valvoline oil change was a "rip off"......
 
I admit to using a paint pin on a timing belt.... cheap insurance if anyone spun a pully over through stupidity while I was taking a leak.

And cuts the install time to under three hours.
 
"I once ran very low on oil, the engine started knocking and the light on the dashboard lit up. My engine is so great that I put in three quarts of oil and it's still running to this day, though the engine does smoke a little..."

Said by my friend who was telling me how great foreign engines are.
 
Originally Posted By: PeteTheFarmer
"My car gets its best mileage at 75 mph.", which is usually followed up with "No, it's true, the new cars are geared like that."


It's uncommon, but it's actually possible for this to be a case. Given a fairly aerodynamic vehicle with very tall gearing, the gains from going faster and getting the engine into its efficiency peak can outweigh the losses from the worse aerodynamic drag at higher speeds.
 
^ Tee hee hee you believe it too.
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Aerodynamic drag is exponential, it's hard to overcome that without deliberately poisoning the low-end power. With VVTi etc now it's even harder.
 
Originally Posted By: PeteTheFarmer
"My car gets its best mileage at 75 mph.", which is usually followed up with "No, it's true, the new cars are geared like that."


Yep pure silliness. In testing most cars were most fuel efficient at a steady speed of around 35 mph. You would expect the car to be tuned to be most efficient at the lowest speed it slips into top gear around 40 mph, but 35 mph and the next to the highest gear usually is most efficient it appears. Although a few cars have been slightly more eficient around 55 mph.

I think they are confusing the steady speed highway efficieny with the higher speeds, but why they'd claim 75 mph is more efficient than say 55-65 mph is really baseless.

http://editorial.autos.msn.com/article.aspx?cp-documentid=1090496
 
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Originally Posted By: mechanicx
... but why they'd claim 75 mph is more efficient than say 55-65 mph is really baseless.

I talked with a local engineer who explained to me that engine parameters are maximized for 70 mph by design. That doesn't mean the car gets the best gas mileage at that speed, just that all controls are optimized and the engine runs most efficiently at 70 mph.

I think people may have heard something similar, but then they turn around and misinterpret what they heard, and repeat something different.
 
Road friction is fixed, regardless of speed, AFAIK. Drag through bearings is also fixed. Wind drag goes up as the square of speed. As pointed out, it might be possible to gear it so that the engine is at its sweet spot at 70. [I think it was on here that I read GM got into trouble for leaning out the ECU at 70mph? Below that speed, it ran richer to meet EPA requirements. May have been the typical internet controversy, though--I've never seen data for that assertion.]

I'd think that would make it look bad on the EPA test cycle though, since that means it's always "not a peak", since EPA doesn't get to 70mph AFAIK.
 
not sure how relevant it is... but GM did do a bit of that in the late 80s/early 90s.... in a couple of calibration, "highway fuel" mode will bump up the spark advance a little and lean out the AFR to ~15.4 when at relatively low load above 50MPH...

the EPA caught onto that pretty quickly though.

the old EPA highway cycle never actually hit 70 IIRC. they do have a visual of the speeds they put them through, but i don't know where to find it off-hand. the new tests do hit 70 from what i remember, but not for a very long period of time.

EDIT: here we go:

http://www.fueleconomy.gov/feg/fe_test_schedules.shtml
 
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Originally Posted By: Kestas
Originally Posted By: mechanicx
... but why they'd claim 75 mph is more efficient than say 55-65 mph is really baseless.

I talked with a local engineer who explained to me that engine parameters are maximized for 70 mph by design. That doesn't mean the car gets the best gas mileage at that speed, just that all controls are optimized and the engine runs most efficiently at 70 mph.

I think people may have heard something similar, but then they turn around and misinterpret what they heard, and repeat something different.

But engine efficiency at a certain engine/road speed is not really the stated issue. It is fuel efficeincy/consumption (mpg) at a certain speed. Because it takes more power to travel at 70+ mph than at 55-65 mph, 70+ mph is less fuel efficient despite engine efficiency. It's hard to make blanket statements as various years and models are tuned and geared different, ie some (few) cars actually get peak mpg at 60 mph, others at 55 mph, 35 mpg etc. But I've never seen test of a car that got better milage at 70-75 mph than at 55-60 mph mph and lower speeds.
 
Originally Posted By: dwcopple
Originally Posted By: css9450
Originally Posted By: RobertISaar
i've washed paint off before.... GM had issues with certain colors in the late 80s-late 90s...


Not just GM.
I remember the days when I'd see (and still do
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) white Chrysler minivans and Chevy trucks and Lumina's with the paint flapping in the wind, literally coming off in sheets LOL.

The 1985-1988 Nissan Maxima had that problem. Underhood heat was not well controlled, and it would burn off the factory paint after a few years. It also burnt to death numerous parts under the hood of those cars.
 
CL ad "I have 1998 honda civic hx it has 217,000 miles but runs real smooth! you cant even feel the transmission shift gears!"

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The only auto trans with that year HX is a CVT - I guess they're kinda right
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