Grill Block Poll.

[metroschultz]

Metro, I didn't realize the skirts had that much impact on your mpg.
I've blocked my torn bumper with duct tape and will make a permanent block in my new bumper, which is hanging on the wall of my garage btw. I must now go find the info on your wheel skirts so I can make my own, in my spare time on the second Tuesday next week.

[MetroMPG]

Take that graph with a grain of salt. I haven't done A-B-A on the skirts on the Firefly/Metro.

That said, I believe that skirts are going to be most helpful on cars with short rear overhangs like ours - because there's less bodywork aft of the wheel arch for disturbed flow to reattach before separating at the back of the vehicle.

[aerohead]

I believe CAR and DRIVER quantified an improvement for their "Crisis Fighter Pinto",back in March of '74.So many Big-Dogs have mentioned or recommended the practice over the decades,that I've always considered it an integral part of any streamlining project.Sorry!,I have no specific quantitative data for the solitary modification.If you'll look around,many new cars have fake grille openings.It gives the stylists busywork,and streamlines the car without the owner's awareness.

[MetroMPG]

Good memory, Phil. The Car & Driver article states that the Pinto's grille, fully blocked netted a 2.6% increase in MPG at 70 mph.

The interesting part was: when combined with their giant air dam, the full grill block resulted in a 13% increase in MPG @ 70 mph.

With the area ahead of the radiator opened up, but the sides remaining covered, the MPG advantage was 9%.

Goes to show how aero changes are not isolated. Change the flow in one area, and it has downstream (and upstream, if done at the rear of the vehicle) consequences.

[Harpo]

I made mine in concert with getting the ScanGuage, so technique over shadowed aero technology. I may take mine off for a week, and see if anything changes.

However, I recent added some baffles that restrict cold air getting to air filter inlet. Under hood air definitely has big effect on IATs now, and mileage was increased as a result. If I do take it off, I expect a drop not due to aero losses, but cooler IATs.

[brucepick]

Off topic but this sure jumped out at me:

Photo in post #14 shows that the tires need more air.
General wisdom is that with radials you can't tell visually whether they're over- or underinflated. But when seen from front or rear and they bulge out where they meet the road, to me that means they need air.

[DifferentPointofView]

I don't know, but judging by how many miles I've driven and the fuel gauge position, I'd say that I'm getting between 22-25mpg's this tank. which is better than ever. More tanks will have to confirm, but since I'm on spring break and not driving, I'll say that that'll be a few more weeks

Well, I was right, I got 22.56mpg. I can do better cause I was confused the whole time. check out the jeepin' build thread as to why, cause i don't feel like reposting it. I now know it helps.

[VWCw]

i'm obviously coming in late on this one, but my packaging tape upper grille block has helped more than i expected. i haven't filled my tank yet to get any accurate number, but my jetta usually gets ~400 miles to a (14 gallon) tank. this is nice because every 1/4 tank interval on the gauge should be about 100 miles on the trip odometer. i taped up the grille about halfway through this tank (~200 mi), and now at the 1/4 mark, i've gained 35 miles over where i would normally be (335 vs. ~300).

[k.civic.f4i]

before i added the grill block i was averaging 30-33mpg combined driving. after i installed the block i hit 35mpg for the first time with the same driving routes and techniques(with an auto transmission).

[ecocruze]

I did a partial grill block on the explorer and removed xbar on roof rack at same time. I have seen around 2.5-3 mpg improvement. I feel the grill block is mostly to credit I did one drive with xbar off and saw minimal improvement maybe .5 mpg