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

Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 05-28-2019, 08:48 AM   #21 (permalink)
Master EcoModder
 
kach22i's Avatar
 
Join Date: Jul 2011
Location: Ann Arbor, Michigan
Posts: 3,295
Thanks: 4
Thanked 2,108 Times in 1,483 Posts
Quote:
Originally Posted by aardvarcus View Post
My mental dyno tells me the drag coefficient of the vehicle hasnít changed drastically, however I can tell the rear end feels much more planted in turns which I attribute to reduced rear lift.
I felt that way about the first huge air dam chin spoiler I built on my van back in 1983.

The added stability in cross winds made the effort well worth it, and it looked cool too.

__________________
George
Architect, Artist and Designer of Objects

1977 Porsche 911s Targa
1998 Chevy S-10 Pick-Up truck
1989 Scat II HP Hovercraft

Chin Spoiler:
http://forums.pelicanparts.com/off-t...effective.html

Rear Spoiler Pick Up Truck
http://forums.pelicanparts.com/off-t...xperiment.html

Roof Wing
http://ecomodder.com/forum/showthrea...1-a-19525.html
  Reply With Quote
The Following 2 Users Say Thank You to kach22i For This Useful Post:
aardvarcus (05-29-2019), slowmover (05-29-2019)
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 05-29-2019, 08:02 AM   #22 (permalink)
Master EcoModder
 
slowmover's Avatar
 
Join Date: Oct 2009
Location: Fort Worth, Texas
Posts: 2,311

2004 CTD - '04 DODGE RAM 2500 SLT
Team Cummins
90 day: 19.36 mpg (US)
Thanks: 1,306
Thanked 667 Times in 507 Posts
Quote:
Originally Posted by kach22i View Post
I felt that way about the first huge air dam chin spoiler I built on my van back in 1983.

The added stability in cross winds made the effort well worth it, and it looked cool too.
This goes to the heart of the thing. Handling adverse winds. I can run down the road with a 53í van behind me (full skirt & tails) and it is more the position of the tandem trailer axles that alerts me to this adversity (tandems positioned to even out weight of load with the Drive Axles) as leverage increases with length past those axles position.

In other words, most of the time I donít notice the effect of the tail (3.5í deep). Not until wind loads increase. Itís only judging by the Current Fuel Economy readout that the advantage is obvious in every driving situation.

I think ABBA testing not a big deal. If fill up is possible at same station pump every time to first auto-shutoff itís more than enough. That also rules out fuel blend changes per brand.

Reading engine hours is the last. Calculation of Average MPH per tank is handy. Accounts for operator changes. Keeping it at or above 26-mph is the key to long-term engine life and FE.

Same fuel, same basic routes, same average mph covers ďtransparencyĒ.

Aero aids are cake icing. Operator inputs FAR outweigh it as this is a metro-mobile, not a highway runner. The margin added is in keeping MPG high versus weather penalties per tank.

.

.
__________________
2004.0 DODGE Ram QC/LB 2500 2WD/NV-5600 305/555 ISB. 7,940-lb. Stock. 200,000 miles/5000-hrs @ 40-mph average.
1990 35' Silver Streak TT 7,900-lb.
11-cpm solo & 19-cpm towing; 21-mpg average past 54k-miles
Sold: 1983 Silver Streak 3411
  Reply With Quote
The Following User Says Thank You to slowmover For This Useful Post:
aardvarcus (05-29-2019)
Old 06-13-2019, 01:39 PM   #23 (permalink)
Master EcoModder
 
aardvarcus's Avatar
 
Join Date: Apr 2012
Location: Evensville, TN
Posts: 560

Deep Blue - '94 GMC Suburban K2500 SLE
90 day: 23.75 mpg (US)

Griffin (T4R) - '99 Toyota 4Runner SR5
90 day: 25.43 mpg (US)
Thanks: 189
Thanked 458 Times in 248 Posts
I donít have extreme confidence in these numbers yet, but I have collected a few similar mostly highway tanks with and without the shell, same route, same pump sort of thing. Three of these tanks without the shell averaged 25.4 two tanks with the shell averaged 26.6, implying a 4.7% increase.

The reason I donít have extreme confidence in the numbers is that I have noticed that both stop and go traffic and use of AC seem to drive fuel economy down, more so than I have experienced in other vehicles. I am not sure what to think of that fact yet. I am going to be doing plugs/wires/sensors on the engine soon. Also I plan to put heat rejecting tint on the windows and add some cab insulation to reduce the AC use.

I still feel the transition from the body to the shell is hurting me, I am planning on adding some thin aluminum strips formed to the contours to cover this gap, which would stop right at the front of the factory hatch. These would be attached to the shell mechanically. I tried to do something with fiberglass in this area when I initially created the shell but had issuesÖ

I am still trying to form a good plan for the underbody coverage, one area of particular drama is between the front and rear tires. I am thinking running a flat bottom from the frame all the way out to the tires outside edge, turning up and forming a box shape, turning back in where the rockers pinch seam is, basically boxing in the area where the side steps usually go. This would give me a good surface to mount my tire spat flaps on.
Attached Thumbnails
Click image for larger version

Name:	G1.jpg
Views:	31
Size:	22.8 KB
ID:	26174   Click image for larger version

Name:	G2.jpg
Views:	35
Size:	30.7 KB
ID:	26175   Click image for larger version

Name:	G3.jpg
Views:	34
Size:	41.3 KB
ID:	26176  
  Reply With Quote
The Following 2 Users Say Thank You to aardvarcus For This Useful Post:
aerohead (06-19-2019), slowmover (06-14-2019)
Old 06-13-2019, 02:34 PM   #24 (permalink)
Master EcoModder
 
freebeard's Avatar
 
Join Date: Aug 2012
Location: northwest of normal
Posts: 13,524
Thanks: 3,291
Thanked 4,494 Times in 3,579 Posts
Beware the breakover angle.
__________________
.
Haiku are easy
But sometimes they don't make sense
Refrigerator

_________________
  Reply With Quote
The Following User Says Thank You to freebeard For This Useful Post:
aardvarcus (06-14-2019)
Old 06-14-2019, 09:40 AM   #25 (permalink)
Master EcoModder
 
slowmover's Avatar
 
Join Date: Oct 2009
Location: Fort Worth, Texas
Posts: 2,311

2004 CTD - '04 DODGE RAM 2500 SLT
Team Cummins
90 day: 19.36 mpg (US)
Thanks: 1,306
Thanked 667 Times in 507 Posts
Quote:
Originally Posted by aardvarcus View Post
I donít have extreme confidence in these numbers yet, but I have collected a few similar mostly highway tanks with and without the shell, same route, same pump sort of thing. Three of these tanks without the shell averaged 25.4 two tanks with the shell averaged 26.6, implying a 4.7% increase.

The reason I donít have extreme confidence in the numbers is that I have noticed that both stop and go traffic and use of AC seem to drive fuel economy down, more so than I have experienced in other vehicles. I am not sure what to think of that fact yet. I am going to be doing plugs/wires/sensors on the engine soon. Also I plan to put heat rejecting tint on the windows and add some cab insulation to reduce the AC use.

I still feel the transition from the body to the shell is hurting me, I am planning on adding some thin aluminum strips formed to the contours to cover this gap, which would stop right at the front of the factory hatch. These would be attached to the shell mechanically. I tried to do something with fiberglass in this area when I initially created the shell but had issuesÖ

I am still trying to form a good plan for the underbody coverage, one area of particular drama is between the front and rear tires. I am thinking running a flat bottom from the frame all the way out to the tires outside edge, turning up and forming a box shape, turning back in where the rockers pinch seam is, basically boxing in the area where the side steps usually go. This would give me a good surface to mount my tire spat flaps on.

Cylinder Pressure. Is everything.

.
__________________
2004.0 DODGE Ram QC/LB 2500 2WD/NV-5600 305/555 ISB. 7,940-lb. Stock. 200,000 miles/5000-hrs @ 40-mph average.
1990 35' Silver Streak TT 7,900-lb.
11-cpm solo & 19-cpm towing; 21-mpg average past 54k-miles
Sold: 1983 Silver Streak 3411
  Reply With Quote
The Following User Says Thank You to slowmover For This Useful Post:
aardvarcus (06-14-2019)
Old 06-16-2019, 12:49 PM   #26 (permalink)
EcoModding Apprentice
 
Join Date: May 2019
Location: California
Posts: 103

Hyhoe - '08 Chevy Tahoe HY2
Thanks: 0
Thanked 15 Times in 15 Posts
Quote:
Originally Posted by aardvarcus View Post
Purchased a 1999 Toyota 4Runner, 3.4L V6, 5 Speed R151F Transmission, 4x4, 4:10s. It was selected because it has real 4WD, stick shift, 4 Doors, will fit two car seats and two adults, capable of towing and hauling, smaller than my Suburban, and has a comfortable ride. My wife has a similar one and I enjoy it (other than the missing clutch in hers). This vehicle will be for daily driving and moderate off-road use.

I am not going to mess with the powertrain on this one, mainly just some aero add-ons and a few off-road related items. I am putting this in the Aero subsection since that is the focus of this thread.

Currently planning the following:
Aero Mods:
Swap 265/70R16 Cooper AT3 to 245/75R16 Michelin LTX (in progress)
Remove roof rack, rear deflector, side steps, and fender flares.
Small boat tail attached to the rear hatch. (Fiberglass over foam)
Belly Pan/ Skid plates (1/4” Aluminum)
Tire Spats (Conveyor Belt)
Grill Ducting

Other Mods:
Change all fluids and stop oil cooler O-ring leak (in progress)
Upgraded Sway Bars
Front and Rear high clearance hitches, with winch on cradle.
255/85R16 tires on extra wheels to swap for dedicated trips.
Extra Insulation/sound deadening in interior.

Dream wishlist:
E-locker axle swap.
Dyna 5th gear swap in transmission during future rebuild.

I am open to suggestions, please give me your ideas on what all I should do/not do to this vehicle. I will post some more details below of my planned aero mods.

front clip from 2002 toyota prius
  Reply With Quote
The Following User Says Thank You to Tahoe_Hybrid For This Useful Post:
aardvarcus (06-25-2019)
Old 06-19-2019, 11:50 AM   #27 (permalink)
Master EcoModder
 
aerohead's Avatar
 
Join Date: Jan 2008
Location: Sanger,Texas,U.S.A.
Posts: 10,253
Thanks: 15,519
Thanked 5,447 Times in 3,223 Posts
confidence

Quote:
Originally Posted by aardvarcus View Post
I donít have extreme confidence in these numbers yet, but I have collected a few similar mostly highway tanks with and without the shell, same route, same pump sort of thing. Three of these tanks without the shell averaged 25.4 two tanks with the shell averaged 26.6, implying a 4.7% increase.

The reason I donít have extreme confidence in the numbers is that I have noticed that both stop and go traffic and use of AC seem to drive fuel economy down, more so than I have experienced in other vehicles. I am not sure what to think of that fact yet. I am going to be doing plugs/wires/sensors on the engine soon. Also I plan to put heat rejecting tint on the windows and add some cab insulation to reduce the AC use.

I still feel the transition from the body to the shell is hurting me, I am planning on adding some thin aluminum strips formed to the contours to cover this gap, which would stop right at the front of the factory hatch. These would be attached to the shell mechanically. I tried to do something with fiberglass in this area when I initially created the shell but had issuesÖ

I am still trying to form a good plan for the underbody coverage, one area of particular drama is between the front and rear tires. I am thinking running a flat bottom from the frame all the way out to the tires outside edge, turning up and forming a box shape, turning back in where the rockers pinch seam is, basically boxing in the area where the side steps usually go. This would give me a good surface to mount my tire spat flaps on.
The old-school,SAE testing protocol was to drive at a constant highway speed,with and without,on the same route,same day,as soon as possible.This reduces variables down to one,about as much as we could hope for.In mixed driving,you'll get a composite number,but it will impossible to arrive at a delta-Cd.
At a steady highway speed,a 10% drag reduction is going to net you close to a 5% improvement in MPG.A two-to-one,shoot from the hip metric.
You ought to see around 10% better mpg.
__________________
Photobucket album: http://s1271.photobucket.com/albums/jj622/aerohead2/
  Reply With Quote
The Following 2 Users Say Thank You to aerohead For This Useful Post:
aardvarcus (06-25-2019), slowmover (07-03-2019)
Old 06-26-2019, 02:00 PM   #28 (permalink)
Master EcoModder
 
aardvarcus's Avatar
 
Join Date: Apr 2012
Location: Evensville, TN
Posts: 560

Deep Blue - '94 GMC Suburban K2500 SLE
90 day: 23.75 mpg (US)

Griffin (T4R) - '99 Toyota 4Runner SR5
90 day: 25.43 mpg (US)
Thanks: 189
Thanked 458 Times in 248 Posts
Freebeard,
I have measured the underbody and plotted out the points to be aware of. The 4runner has a low center belly with crossmembers dropping substantially below the frame rails, so boxing in the outer area between the tires at the frame height will still be significantly higher than the center. This is quite a bit different than other vehicles I am used to (e.g. suburban) in which the frame rails are the lowest point.

Slowmover,
I hope there is no issue with the engine beyond just sensors…

Tahoe Hybrid,
Interesting, it looks as if the widths match, I would have guessed narrower. I just replaced the front bumper though and I don’t want to mess with the crumple zone, but a novel concept nonetheless.

Aerohead,
Agreed on the suggested methodology being better, however I don’t have extra time for too awful much testing, so I just compare my tanks week to week and try to compare similar tanks/conditions to get estimates. Once I get multiple projects completed I may consider ABA for a suite of things, but I can’t do that for every change I make.
I am just surprised how much lower the “bad” tanks are from the “good” ones, it is more than I had experienced in the past.
I am not getting 10% better MPG with the kamm extension. I assume I need to fix the transition from bodywork to extension.

Everyone,
Current progress on the 4Runner has been replacing both oxygen sensors (actually air to fuel ratio sensors) on the exhaust and the throttle position sensor. Also removed the rear driveshaft and replaced the rear u-joint which was going out and vibrating at higher speeds. Carefully greased the double cardan joint to extend its life, ensuring new grease made it into each cup. Rear u-joint was a pain because the rear yoke was sloped, made it a bear to press the spider out. Eventually had to weld up custom fixtures to hold it, then it was easy.

I have done some figuring on the underbody. My current plan is to lift the vehicle a small amount (about 1”) during some upcoming suspension work, which will put the lowest parts of the underbelly about the height of the rear axle tube. From there I can run a 6 degree diffuser from behind the axle tube to the rear hitch. I picked up some materials (steel tube) for my between the tires filler panel, still doing final design on that.
  Reply With Quote
The Following 2 Users Say Thank You to aardvarcus For This Useful Post:
freebeard (06-26-2019), slowmover (07-03-2019)
Old 06-26-2019, 06:02 PM   #29 (permalink)
Master EcoModder
 
freebeard's Avatar
 
Join Date: Aug 2012
Location: northwest of normal
Posts: 13,524
Thanks: 3,291
Thanked 4,494 Times in 3,579 Posts
Put an aerodynamic bicyclist helmet upside down on the pumpkin.
__________________
.
Haiku are easy
But sometimes they don't make sense
Refrigerator

_________________
  Reply With Quote
The Following User Says Thank You to freebeard For This Useful Post:
aerohead (06-29-2019)
Old 07-03-2019, 09:11 PM   #30 (permalink)
EcoModding Apprentice
 
Join Date: May 2019
Location: California
Posts: 103

Hyhoe - '08 Chevy Tahoe HY2
Thanks: 0
Thanked 15 Times in 15 Posts
Quote:
Originally Posted by aardvarcus View Post
I donít have extreme confidence in these numbers yet, but I have collected a few similar mostly highway tanks with and without the shell, same route, same pump sort of thing. Three of these tanks without the shell averaged 25.4 two tanks with the shell averaged 26.6, implying a 4.7% increase.

The reason I donít have extreme confidence in the numbers is that I have noticed that both stop and go traffic and use of AC seem to drive fuel economy down, more so than I have experienced in other vehicles. I am not sure what to think of that fact yet. I am going to be doing plugs/wires/sensors on the engine soon. Also I plan to put heat rejecting tint on the windows and add some cab insulation to reduce the AC use.

I still feel the transition from the body to the shell is hurting me, I am planning on adding some thin aluminum strips formed to the contours to cover this gap, which would stop right at the front of the factory hatch. These would be attached to the shell mechanically. I tried to do something with fiberglass in this area when I initially created the shell but had issuesÖ

I am still trying to form a good plan for the underbody coverage, one area of particular drama is between the front and rear tires. I am thinking running a flat bottom from the frame all the way out to the tires outside edge, turning up and forming a box shape, turning back in where the rockers pinch seam is, basically boxing in the area where the side steps usually go. This would give me a good surface to mount my tire spat flaps on.
Don't use shell Fuel it's garbage mobil or chevron do the job better

  Reply With Quote
Reply  Post New Thread


Thread Tools




Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2019, vBulletin Solutions Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright EcoModder.com