Accent coasts poorly, but why?

[theholycow]

Originally Posted by Eyeteaguy

Hey, the gearing is quite poor. At 55 MPH it revs at 3,000.

I thought my car was bad, 70mph at 3,000rpm.

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.

Coroplast has been used successfully for that exact problem.

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

Not a problem. Weight is just NOT as big of a deal as most people make it out to be. See the link about weight in my sig; see also Basjoos car:
http://aerocivic.com
This guy tacked on loads of stuff to his car to lower his aerodynamic drag. It's got to have considerable extra weight, and it's on a car that is known to be sensitive to weight. Reduced aerodynamic drag thoroughly pays for any efficiency loss to weight.

I suspect that your low-geared car will not be bothered by 100 pounds of modifications. If you do mostly highway driving in that car, then you might as well load another 800 pounds in the car...it will barely make a dent in your fuel economy.

[GasSavers_maximilian]

Originally Posted by theholycow

Coroplast has been used successfully for that exact problem.

So THAT'S what that stuff is called. Cool.

[theholycow]

Yup. Besides abandoned campaign signs, it can be bought in large sheets from sign shops.

[GasSavers_maximilian]

Used to come across it at an art supply place where I went to college. Never noticed the name though.

[brucepick]

Use real fasteners on coroplast, if you do use coroplast.
A couple summers ago I built some coroplast aero mods with duct tape.
I spent a lot of time fixing where it came apart while driving. And only recently did the last of the gross residue go away.

Metal screws would theoretically corrode if they are not the same material as your car's sheet metal. Since the car is likely galvanized steel, and the screw would contact both the steel and the galvanized skin, I think corrosion is nearly guaranteed. I'm considering using rubber well nuts (aka expansion nuts) for my future/hopeful underbody mod projects. I used them for mounting license plates and they held up very well.

[GasSavers_maximilian]

I fortunately have a plastic hex grille to attach to, so no galvanic reactions to worry about.

[theholycow]

IIRC, stainless steel fasteners would resist reacting with various other metals and are the appropriate choice when fastening reactive metals together. However, galvanized steel is galvanized with stuff whose job it is to NOT react with steel (not sure what they're using on cars but nails get zinc), and plain steel or galvanized screws should work fine. Of course, the plain steel ones would corrode where exposed to the environment anyway...

[GasSavers_maximilian]

Found the Accent gear ratios online (figures, now that I wasn't looking for them):

First Gear Ratio (:1) 3.62
Second Gear Ratio (:1) 2.05
Third Gear Ratio (:1) 1.37
Fourth Gear Ratio (:1) 1.03
Fifth Gear Ratio (:1) 0.84
Reverse Ratio (:1) 3.58
Final Drive Axle Ratio (:1) 4.06

Tires are 23.6" in diameter so that's...uh...2914.46 RPM at 60 mph. That matches very well with what I observed.

[keenzTDI]

Originally Posted by maximilian

Found the Accent gear ratios online (figures, now that I wasn't looking for them):

First Gear Ratio (:1) 3.62
Second Gear Ratio (:1) 2.05
Third Gear Ratio (:1) 1.37
Fourth Gear Ratio (:1) 1.03
Fifth Gear Ratio (:1) 0.84
Reverse Ratio (:1) 3.58
Final Drive Axle Ratio (:1) 4.06

Tires are 23.6" in diameter so that's...uh...2914.46 RPM at 60 mph. That matches very well with what I observed.

So would it be at all possible the change the 5th gear? To drop the RPM? I travel on average 110kmh+ (70MPH)
I also I have a 2009 Accent. I get so far an average of 30 US MPG (7 L/100KM)
I do mostly hwy driving. I like the accent it's a great cheap-o car. I Guess I expected miracles going from a '03 Buick Regal (3.8L v6) to this Accent (1.6L 4)

[GasSavers_maximilian]

There have been some other threads about changing the transmission gears. Expensive is the problem, apparently. I would love to see your gaslog. Have you considered creating a garage profile? Is yours a manual and if so, how have you found neutral coasting performance? I'd love to get another data point.