Light Ecomodding: spats, active grille shutters, underbody pans

You are right that Florida is pretty flat. The only hills we have here are called overpasses and bridges. I have had OV tune for over a year and it helped greatly by not downshifting to 4th every time I went over a bridge. There have been 5 boost kits announced in the last month and I plan on getting one but haven’t decided which one yet. I will likely go with one of the OV kits since it will not cost any extra for the tune. Magnuson, Harrop, and URD are all coming out with S/C kits which will be great for the competition. I will be adding boost only for the fun factor and not the mileage.

It is really cool that you fly an experimental aircraft. I grew up just a few miles from Oshkosh where they have the EAA annual fly in every summer. At my age I would be concerned about the safety of those things but I know you must have a blast flying them. Good luck with your mods.

 

I’ve gotten my all time best fuel economy when I’ve been forced to drive backroads, under 60mph and in areas where I can maintain speed without stopping a lot.
I remember seeing a presentation a few years ago about the Shelby Daytona development. Peter Brock had built the body and designed it for maximum aerodynamics. He also designed and sells an enclosed race car trailer that is lightweight and aerodynamic. With both of them, he concentrated on getting the airflow around the back axle underneath the car. Said it was the most forgotten place to look for aero savings! I’m guessing our rear axle, spare tire, and underside of the bumper could all use that attention if another mpg was desired.

 

good idea. besides the ideas you already had a 2 inch lowering kit should also help.

 

It is a pickup truck. For picking up things. But things add weight. Therefore, don't ever pick up anything for 200000 miles.

In fact, remove the entire bed and sell it. One-time mod, no additional expense and weight for mod parts. In fact, makes you money.

Could see 30 mpg.

 

Carrying a load and attempting to maximize mileage aren't mutually exclusive. But you be you.

 

Ive seen those "spats" if that is there technical name, on vehicles before and thought there purpose was to help prevent paint chips in front of the rear wheels. Ive had older toyota trucks that got chipped bad in that area.

 

You are right. They are not. Your enthusiasm is laudable, but the ratio of effort spent to outcome realized is akin to picking pennies out of the gutter to fund retirement.

Good luck.

 

On level ground aerodynamics trumps weight. On hills it's the other way around. The other effect isn't negated in each circumstance, just minimized so adding things that improve airflow can help and no, Toyota doesn't do everything possible to maximize economy or the 5-lugs wouldn't have steel wheels. If Snugtop made a spoiler I'd probably get one. Make the roof rack easily removeable and take it off when you're not using it. That's easily 1-2 mpg right there. As a carpenter I sometimes carry longer stuff so I added ditch tracks to the cab so I could mount one of the Thule bars there or both on the cap but they come off and get stowed in the cap when not needed and every tank they're up there mileage takes a noticeable hit while varying the load carried inside doesn't do as much. I'd expect the chassis pan to have the most effect of the mods mentioned but don't know what effect trapping the exhaust heat will have on the cats or plumbing.

Altering driving styles is easily as effective as weight or aerodynamics so to maximize economy you'll want to improve all 3.

 

I have the same concern. When you look at modern cars most of them have underbody panels to improve airflow and reduce noise, but they have a cutout so the exhaust is not covered. This may be beyond my fabrication skills.

Spats is the industry name, which is also the term used for covering the wheel’s side like on the older Insight. I think they might sometimes also be a protective feature like you suggest, but when I see them on the Colorado I have to imagine they’re there for minor airflow improvements.

 

No. Covered in post #1.

 

Yes, once I reviewed it, I saw that you made that clear.

That is why I responded with this earlier:

"You are right. They are not. Your enthusiasm is laudable, but the ratio of effort spent to outcome realized is akin to picking pennies out of the gutter to fund retirement."

Good luck with your time investment, regardless of my inability to comprehend it.

 

I would look at lowering the truck. You can achieve much of the effect of a pan, just by being closer to the ground. My biggest MPG hit, after heavier tires, came from a 1.5” lift. I’m guessing if I lowered the truck 1.5”, I’d have seen a noticeable improvement.

 

I installed a flex-a-lite electric fan and gained about 2mpg

 

Options:
1: Remove roof rack. and use a 2in receiver carrier for extra luggage. Easier access. Remove when not in use.
2: Remove side steps. Not needed since you removed your roof rack.
3: Tonneau cover. I got better gas mileage dispite the added weight. It reduces turbulent wind flow.
4: I saw better MPG when running 93 octane in my 4.0L however actual financial net gains depend on how much premium gas costs. If its $0.60 difference you will always be in the red.
93 octane reduces pre-detonation. If you have a domestic engine with a low (8.5) compression ratio there is absolutely zero benefit to run premium because compression is not high enough to ignite fuel.
The 4.0L old Tacoma engine was a 10.5 compression ratio. OEM mfgs recommend premium fuel when their engine compression gets higher than 11-12 ratio.
Pre-detonation occurs @ low rpm high load so when your trying to lug up a hill and not mash the pedal, pre-detonation may be adding additional drag.

 

Working on gaining mpg on a truck is a little strange I’ll agree. But maybe we should all look at it like a hobby. Modifying a stock vehicle for better performance has always been seen as a hobby. People rarely question when someone tries to make a slow car faster instead of simply buying a faster version or an off-road vehicle handle terrain better when an atv would be more appropriate.
All the different automotive modifications genres don’t excite me. I don’t care for ricers, hot rods, low riders, etc but I do really have an appreciation for the time and effort the owners devote to using the existing vehicle and changing it to better suit their needs or desires.

 

Whatever you drive can do better or worse. I drive a truck because I need to but there's no reason not to get the most out of that necessity. It helps me make money so helping keep more of it is a good thing.

 

That seems like a big number. For 2mpg Toyota should have made it like that.

 

Have any more details on this? I installed corvette e fans on my old trailblazer ss, was a nice mod.

 

Loose five or ten pounds if needed. It’s a win, win.

 

Can you share some additional details? That sounds promising.