Upper grille block-off

[BigLee]

I made an upper grille block-off setup for the winter months.
It has two advantages: better aerodynamics, and possibly a little faster engine warm-up.
I had my bumper cover off last summer for a radiator replacement, and while I was at it, I cut off the tabs to the screws that prevent the upper grille from being easily removed.
I cut the plastic used to make the block-off panels from a black painted rear bumper cover core from an SUV.

I cut them down to size, and the ends that meet to fit flush with each other.
I then taped the halves together, then taped them to the inside of the grille, so I could drill both the grille and panels at the same time, to take #6 black oxide coated machine screws, 1.5 inch lenght, IIRC.

I then applied a strip of thin adhesive backed foam sealing padding to the top and sides of the grille, then attached the panels to the grille with the screws.

The grille can be snapped in and out with moderate effort.
I may add a couple of retaining screws in each upper corners at about ~75 degree angle to make sure the grille never comes out accidentally, although it seems pretty secure now.

The final result is very hard to notice.
If you zoom in on the bottom picture of the grille on the car, you can just see the screw heads..

 

[BigLee]

Just an update on this.
Its mid-July, and I still have the upper grille
blocked off in place. I've driven with ambient temps up to 95°F
and coolant temps havent risen above the normal of ~190°.
A/C still works well. This could become a permanent year round mod for me.
I'll keep you updated...

 

[yt400pmd]

Just an update on this.

Its mid-July, and I still have the upper grille

blocked off in place. I've driven with ambient temps up to 95°F

and coolant temps havent risen above the normal of ~190°.

A/C still works well. This could become a permanent year round mod for me.

I'll keep you updated...

how much of a difference in mpg does this make?



Sent from my iPhone using Tapatalk

 

[BigLee]

I honestly just dont know.
There was a temporary change to my driving route for a while due to a construction project starting about the same time I installed the grille block,
and by the time my route had returned to normal, the weather was significantly colder, so I dont have a good back to back comparison.
While I'm sure it's good for some slight gain at
highway speeds, I can't say how much.
My avg. fuel economy is up from same time last year by about 6 mpg, but most of that is certainly due to refinements to my driving technique, and I think part of it may be due to my cooler running engine. (Thermostat/fan switch mods)

 

[shoey]

Just because it works in the summer doesn't mean it's good for the engine/bay. Tons of thermal modeling is completed based on expected flow patterns and messing with that is just asking for trouble IMO (in summer months at least).

Think of the plastics and and rubbers which were specced to certain temps which now may not experience the airflow required to flow the hot engine air. You might be cutting into the life of those parts for potentially negligible benefits (according to your post).

 

[BigLee]

Perhaps.
So far, no issues there.
But my engine is running significantly cooler than stock, and I'd say that just about every plastic and rubber piece under my hood is running considerably cooler than a bone stock car does...
and for the summer, I have pulled the foam blocks at each corner of the cowling for better venting when stopped/parked. They will be reinstalled when the weather gets cool again.
Besides, I'd say that most of the heat stress on rubber and plastic parts occurs 5-20 minutes after shutdown, in which case I think this mod has limited influence.

 

[BigLee]

Just an update on this.
I previously stated that I still had the block off in place in hot weather, and the A/C still worked OK. While that was true, later study with the Torque app did reveal that refrigerant high side pressures were up noticeably from this. Once removed, the high side pressures dropped by over 50 psi, as the improved airflow allowed the condenser to work better.
Most of the A/C condenser sits behind the upper grille on the turbo models at least.
The engine temperature never went up significantly though.
So, remove the block off once weather gets warm enough for A/C usage.
This year, I plan to buy a second upper grille, so that I can just swap them out without having to install and remove the panels from the original grille twice a year.

 

[CoHPhasor]

I hadn't seen this thread before, but reading through I would have told you what Shoey said, and added that the systems compensate for worse temps on its own, like driving through a desert.
Just because it can do something, it doesnt mean you should make the car consistently do it. (Like a Dukes of Hazard jump - you ever notice the damage done in slow motion before they cut to a new hero car?)

The fan would run more often, AC presssure would be higher, perishable engine components like rubber that are susceptible to heat will fail faster, etc, etc.

 

[BigLee]

I hadn't seen this thread before, but reading through I would have told you what Shoey said, and added that the systems compensate for worse temps on its own, like driving through a desert.
Just because it can do something, it doesnt mean you should make the car consistently do it. (Like a Dukes of Hazard jump - you ever notice the damage done in slow motion before they cut to a new hero car?)

The fan would run more often, AC presssure would be higher, perishable engine components like rubber that are susceptible to heat will fail faster, etc, etc.

I understand all that. I just left it in that one time, just to see how far I could go with it. Since then, I typically remove it every spring once low temps remain above 50°F.
But like I said, I wanted to test the limits of it, and I also checked the A/C pressures to see where they were.
Nothing really came as a surprise for me here, and engine temps remained steady.
Just thought I'd update this since I realized I had neglected to years back.