Accent coasts poorly, but why?

[GasSavers_maximilian]

Would an alignment issue I can't really notice effect coasting significantly?

[dkjones96]

I typed a long explanation about why there is a difference and it didn't post, so here is the gist of it.

The Aveo weighs 8% more so its city suffers. The Aveo 1.6L, however, makes peak torque 1100 rpm lower than the Accent 1.6L so the Aveo is more efficient on the freeway.(Peak efficiency is at the torque peak and on the freeway the engines hang closer to 3400 than they do 4500)

[GasSavers_maximilian]

OK, just put on my summer tires and gave the wheels a spin while I was at it. The rear ones spin very freely, but the front ones resist. Of course I'm turning the half shafts when I spin 'em so I imagine it would resist somewhat. Way below a level I could use my torque wrench to measure. If I had to guess I'd say both fronts had about the same resistance. How much resistance is normal?

[dkjones96]

If you can't measure it with your torque wrench it isn't enough to worry about. I'd expect your front tires to have resistance because of the cv shafts, disc brakes, and differential up front.

Even though you aren't spinning the other tire you are still spinning everything after the planetary assembly within the transmission.

[GasSavers_maximilian]

Went out to run some errands and the coasting, while still not as good as my other cars, is still a lot better with my summer tires. So that's something anyway.

While I was at it I got the engine RPMs vs speed. 60 mph @ 2950 RPMs. I took a digital picture of the tachometer rather than trying to stare intently at both gauges at the same time. This is with my summer tires on again, so the tire size is matched to the speedometer.

[Eyeteaguy]

Hey, the gearing is quite poor. At 55 MPH it revs at 3,000. That is part of it. They geared it for city driving. Quick starts with a small engine.

I also did some testing 2 days ago. We had 40 km/hr winds and they were blowing right down the road I take. (it is normally a crosswind).

I did the same stretch of road at 60, 80, 100 and 120 km/hr(don't tell the cops)
It is aero for sure. The speed dropped very quickly from 120 and 100 down to 80 where it slowed. At 60 it never really dropped off at all even with a headwind.

The next day was calm and I did the same test. 120 and 100 the speed dropped off, but 80 and 60 the speed stayed constant.

If I coast starting at 40, the car seems to want to go forever.

I can only guess the hollow bumper is making a scoop and the faster you go, the smaller the bubble of air from the front is and the air is getting into the rear bumper.

And to clarify. The autobody guy was talking about wanted a sheet metal belly tray, quite heavy. I'm going to see him again next week and ask himif a plexi, or fierglass tray might be feasable.

[GasSavers_maximilian]

Originally Posted by Eyeteaguy

The autobody guy was talking about wanted a sheet metal belly tray, quite heavy.

What gauge metal was he suggesting?

[dkjones96]

The weight of it only matters when riding around town. I doubt even a 100# pan would cause issue.

[bowtieguy]

maxi,

check out this idea by dracofelis...

http://www.gassavers.org/showthread....wheel+bearings

might help you a bit anyway.

the use of synthetics to decrease rolling resistance is not a novel idea.

[GasSavers_maximilian]

Interesting thread, but they didn't seem to reach any particular conclusions. At first I questioned the quality of the bearings, but my mechanic told me that was unlikely it. He also told me that if I was getting greater than 40 mpg in the summer on these hills that I shouldn't waste any more time worrying about coasting!