Go Back   EcoModder Forum > EcoModding > EcoModding Central
Register Now
 Register Now
 

Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 08-23-2022, 01:16 AM   #41 (permalink)
Master EcoModder
 
Ecky's Avatar
 
Join Date: Dec 2011
Location: New Zealand
Posts: 5,027

ND Miata - '15 Mazda MX-5 Special Package
90 day: 39.99 mpg (US)
Thanks: 2,878
Thanked 2,520 Times in 1,559 Posts
I could use an opinion on a small plastic piece that pokes out from the rear fender liner. I suspect it's more to catch rock chips than anything. Can anyone think of a valid aerodynamic purpose? It has a bit of a scoop shape on the inside.








Also a pic of the car from my drive today. If you look closely you may be able to see the deflector.


Attached Thumbnails
Click image for larger version

Name:	PXL_20220819_015523540.jpg
Views:	9
Size:	67.5 KB
ID:	32781   Click image for larger version

Name:	PXL_20220819_015534693.jpg
Views:	8
Size:	48.7 KB
ID:	32782   Click image for larger version

Name:	PXL_20220822_010212138.jpg
Views:	8
Size:	38.4 KB
ID:	32783   Click image for larger version

Name:	PXL_20220823_021945476.jpg
Views:	10
Size:	89.3 KB
ID:	32784  
  Reply With Quote
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 08-23-2022, 01:47 AM   #42 (permalink)
It's all about Diesel
 
cRiPpLe_rOoStEr's Avatar
 
Join Date: Oct 2012
Location: Porto Alegre, Rio Grande do Sul, Brazil
Posts: 12,571
Thanks: 0
Thanked 1,628 Times in 1,453 Posts
Quote:
Originally Posted by Ecky View Post
I put in a few hours of driving today. Subjectively, the buffeting, which was already low, is reduced. With the windows up (top down still) it's virtually zero, and there is almost zero wind noise.
So that's why once in a while I see folks riding convertibles with the windows up, even though the top is down... Well, most of the times I see a convertible with the top down, so are the windows anyway.
  Reply With Quote
Old 08-23-2022, 08:52 AM   #43 (permalink)
wdb
lurker's apprentice
 
Join Date: May 2008
Location: the Perimeter
Posts: 942

PlainJane - '12 Toyota Tacoma Base 4WD Access Cab
90 day: 20.98 mpg (US)
Thanks: 504
Thanked 226 Times in 173 Posts
Quote:
Originally Posted by Ecky View Post
I could use an opinion on a small plastic piece that pokes out from the rear fender liner. I suspect it's more to catch rock chips than anything. Can anyone think of a valid aerodynamic purpose? It has a bit of a scoop shape on the inside.
Absent a wind tunnel I can only speculate, but I do know that carmakers are using some very subtle tweaks these days to improve aero. My WAG would be aero aid first, added to pass some obscure wheel well / tire coverage law second.
  Reply With Quote
Old 08-23-2022, 11:41 AM   #44 (permalink)
Eco-ventor
 
jakobnev's Avatar
 
Join Date: Oct 2010
Location: sweden
Posts: 1,635

Princess - '92 Mazda MX-3 GS
House of Tudor
Team Mazda
90 day: 53.54 mpg (US)

Shirubāarō (*´ω`*) - '05 Toyota Prius Executive
Team Toyota
90 day: 54.88 mpg (US)

Blue Thunder - '20 Hyundai IONIQ Trend PHEV
Team Hyundai
Plug-in Hybrids
90 day: 587.16 mpg (US)
Thanks: 75
Thanked 704 Times in 446 Posts
Send a message via MSN to jakobnev
Those plastic bits may be due to legalities regarding bans on open wheels.
__________________




2016: 128.75L for 1875.00km => 6.87L/100km (34.3MPG US)
2017: 209.14L for 4244.00km => 4.93L/100km (47.7MPG US)
  Reply With Quote
Old 08-23-2022, 01:24 PM   #45 (permalink)
Batman Junior
 
MetroMPG's Avatar
 
Join Date: Nov 2007
Location: 1000 Islands, Ontario, Canada
Posts: 22,521

Blackfly - '98 Geo Metro
Team Metro
Last 3: 70.09 mpg (US)

MPGiata - '90 Mazda Miata
90 day: 52.71 mpg (US)

Even Fancier Metro - '14 Mitsubishi Mirage top spec
90 day: 70.75 mpg (US)

Appliance car - '14 Mitsubishi Mirage ES (base)
90 day: 52.48 mpg (US)
Thanks: 4,077
Thanked 6,965 Times in 3,606 Posts
Those rear wheel arch nubs are on a LOT of cars these days. I've wondered myself, been too lazy to do the research.
__________________
Project MPGiata! Mods for getting 50+ MPG from a 1990 Miata
Honda mods: Ecomodding my $800 Honda Fit 5-speed beater
Mitsu mods: 70 MPG in my ecomodded, dirt cheap, 3-cylinder Mirage.
Ecodriving test: Manual vs. automatic transmission MPG showdown



EcoModder
has launched a forum for the efficient new Mitsubishi Mirage
www.MetroMPG.com - fuel efficiency info for Geo Metro owners
www.ForkenSwift.com - electric car conversion on a beer budget
  Reply With Quote
Old 09-03-2022, 01:41 AM   #46 (permalink)
Master EcoModder
 
Ecky's Avatar
 
Join Date: Dec 2011
Location: New Zealand
Posts: 5,027

ND Miata - '15 Mazda MX-5 Special Package
90 day: 39.99 mpg (US)
Thanks: 2,878
Thanked 2,520 Times in 1,559 Posts
While waiting on some supplies to come for building a temporary coroplast belly pan and diffuser, I installed a hitch, rated for 900kg/2000lbs. The receiver bar mounts sandwiched to the end of the frame rails, and has braces that extend underneath and forward to prevent twisting torque. It has a clever extendable (and removable) receiver, that I plan to leave detached most of the time, to shave a bit of weight. When not attached, nothing hangs down under the car in the airstream. Total weight is around 10kg (22lbs) with the receiver elbow attached, a bit less without (didn't weigh it).

I got some good underside pictures as well, to better plan my pan.







Attached Thumbnails
Click image for larger version

Name:	PXL_20220903_012231921.jpg
Views:	2
Size:	83.9 KB
ID:	32816   Click image for larger version

Name:	PXL_20220903_010313838 (1).jpg
Views:	4
Size:	115.1 KB
ID:	32817   Click image for larger version

Name:	PXL_20220903_010332729 (1).jpg
Views:	8
Size:	101.3 KB
ID:	32818   Click image for larger version

Name:	PXL_20220903_010340919 (1).jpg
Views:	6
Size:	116.0 KB
ID:	32819   Click image for larger version

Name:	PXL_20220903_011226158.jpg
Views:	8
Size:	100.0 KB
ID:	32820  

  Reply With Quote
The Following User Says Thank You to Ecky For This Useful Post:
freebeard (09-03-2022)
Old 09-03-2022, 02:00 AM   #47 (permalink)
Master EcoModder
 
freebeard's Avatar
 
Join Date: Aug 2012
Location: northwest of normal
Posts: 27,849
Thanks: 7,815
Thanked 8,634 Times in 7,112 Posts
You scared me. I guess it all goes back together?

Maybe because I'd just seen this Lincoln four-door the other day:

__________________
.
.
Without freedom of speech we wouldn't know who all the idiots are. -- anonymous poster

____________________
.
.
Moore’s Law suggests that good things come to those who wait. Wright’s Law says that good things come to those who act.
  Reply With Quote
Old 09-07-2022, 09:44 AM   #48 (permalink)
Master EcoModder
 
Join Date: Dec 2010
Location: USA
Posts: 1,170

Sport Utility Prius - '10 Toyota Prius II
90 day: 52.98 mpg (US)

300k Sequoia 4WD - '01 Toyota Sequoia Limited 4wd
90 day: 20.19 mpg (US)
Thanks: 352
Thanked 265 Times in 212 Posts
Quote:
Originally Posted by Ecky View Post
I could use an opinion on a small plastic piece that pokes out from the rear fender liner. I suspect it's more to catch rock chips than anything. Can anyone think of a valid aerodynamic purpose? It has a bit of a scoop shape on the inside.
Least ugly mud flap. Yup its for rock chips. But you can do what Toyota (and probably other manufacturers) does and put clear bra on the rock peck prone areas instead.
__________________
"I feel like the bad decisions come into play when you trade too much of your time for money paying for things you can't really afford."
  Reply With Quote
Old 09-08-2022, 02:20 AM   #49 (permalink)
Master EcoModder
 
Ecky's Avatar
 
Join Date: Dec 2011
Location: New Zealand
Posts: 5,027

ND Miata - '15 Mazda MX-5 Special Package
90 day: 39.99 mpg (US)
Thanks: 2,878
Thanked 2,520 Times in 1,559 Posts
Made a small coroplast panel today for just behind the engine, and took some more measurements / made some more cuts for some rear panels. I'm not willing to cover the exhaust with it like the aluminum ones do, and I'll probably end up replacing it at a later date, but for now it's a small improvement.



Attached Thumbnails
Click image for larger version

Name:	PXL_20220908_041431950.jpg
Views:	7
Size:	36.1 KB
ID:	32830   Click image for larger version

Name:	PXL_20220908_032845204.jpg
Views:	12
Size:	47.1 KB
ID:	32831  
  Reply With Quote
The Following 2 Users Say Thank You to Ecky For This Useful Post:
freebeard (09-08-2022), hayden55 (09-13-2022)
Old 10-05-2022, 06:10 PM   #50 (permalink)
Master EcoModder
 
Ecky's Avatar
 
Join Date: Dec 2011
Location: New Zealand
Posts: 5,027

ND Miata - '15 Mazda MX-5 Special Package
90 day: 39.99 mpg (US)
Thanks: 2,878
Thanked 2,520 Times in 1,559 Posts
I got around to ordering all of Verus Engineerings' underbody panels plus diffuser.

They also sell canards that attach just in front of the front wheels which actually reduce drag as per their testing, in addition to just increasing downforce. Their explanation is that it reduces turbulence caused by the front wheels, and creates a low pressure zone right around the rear wheel wells, but they honestly look too racey for me. At some point I may fabricate a deflector, but that day is not today.




Once the underbody panels are in place, many of the eccentric bolts used to align the wheels will be inaccessible, so I took the car in for an alignment as well. Here's what I picked out, and what I got:

Before:

Rear camber L: -2.19°
Rear camber R: -1.35°

Rear toe L: -1.5mm (negative means toe out)
Rear toe R: 1.3mm
Total rear toe: -0.2mm (negative means toe out)

Front camber L: -1.12°
Front camber R: -0.34°

Front toe L: 1.7mm
Front toe R: -1.4mm (negative means toe out)
Total front toe: 0.3mm

Front caster L: 8.35°
Front caster R: 8.08°

~

The alignment on the car was pretty neutral, really. Almost zero toe. It was set for a lot of caster, which gives a heavier steering feel and better self-centering, but this was causing the front left wheel to rub the fender liner when turning right, because it was pushed so far forward in the well. The camber was a bit off, but nothing too crazy.

Here's where it landed after the alignment:

Rear camber L: -1.24°
Rear camber R: -1.20°

Rear toe L: 0.6mm
Rear toe R: 0.8mm
Total rear toe: 1.4mm (toe in)

Front camber L: -1.25°
Front camber R: -1.21°

Front toe L: 0.7mm
Front toe R: 0.7mm
Total front toe: 1.4mm (toe in)

Front caster L: 7.27°
Front caster R: 6.59°

~

Overall, the front and rear got a hair of toe-in, but less than what is called for by the factory specs. Toe in tends to make the car very stable, while toe out tends to make it very eager to rotate. Any toe (in or out) causes tire scrub and reduces economy. I can reasonably expect the front to toe out just a hair at highway speeds due to bushing flex. The rear will toe in more under power. The factory spec is ~3.2mm rear toe in, and I had it dialed back to half of that.

Camber is now square around the car. I don't weigh enough to really throw the balance of the car off, and I often have a passenger anyway.

I haven't taken too many high speed corners yet, but the car feels marginally less squirrely.

Caster was dialed back around a degree on both front tires. The steering feel difference is minimal, but as predicted it's both a hair lighter and has a bit less self-centering when you let go of the wheel.

~

In a couple of weeks I'll begin drilling holes in the frame and installing rivet nuts, onto which to attach the underbody panels.

I also ordered an ultra lightweight LiFePO4 motorcycle battery that should have plenty of CCA. It weighs 2.3kg (5lbs) compared with the lead acid currently installed, which weighs 13.6kg (30lbs).

  Reply With Quote
The Following User Says Thank You to Ecky For This Useful Post:
MetroMPG (10-07-2022)
Reply  Post New Thread


Thread Tools




Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright EcoModder.com