It just depends on the radiator and it's efficiency ;) Cooling systems are over sized for that worst case scenario (in this case, hauling something big and heavy up a mountain in the desert :p).

Despite there being a grille block, you're still going to have some airflow - BUT, depending on the car, the difference is "how much" and is that "enough" ;)

But the nice thing about making it removable/adjustable... If you notice things are running hot (as you did), you can easily pull over make an adjustment and then move on :thumbup:

Had a good run today. I'll answer the questions first, then move onto my stats, and then a question.


Questions/Concerns - yes it is probably not much of a hauler at this point. But entire upper grille block honeycomb section pops out in under 2 minutes with the use of a flatblade screwdriver. So when I need to haul, or the NC summer heat gets a little too much, then I have that option. I typically dont haul much, but when I need it, I have a truck - which is why I bought a truck. Now - 3 years later, Im finally thinking about fuel economy and working with the vehicle I have.

Air is still let into the engine - between the hood and bumper is a 1/2" - 1" slit all the way across. Some air is getting in there, as described below.

Thanks for the positive feedback on the asthetics...my wife thinks Im a little nuts I think.

I drove 400 miles up hwy 95 today. I had a great run. The engine temp only increased about 15-20 degrees. before lower grille block, it ran at 188. Today it ran between 200-206 with the lower part added. I was also always moving of course. In stop and go traffic (which I am in very little of, if ever) it may inch up a bit more. But it was fine today, and that was with a NC high of 90!

without the lower grille block, my SG tests showed an average of 22mpg in testing. Todays run with the lower grille / bumper seam block added, I averaged 24.7 mpg, running between 60-70 mph. Then I hit DC...lol. got through ok, and kept my average up for the whole trip at 24.1. I am very pleased with this. Additionally, the last manual tank calculation I made was 17.5mpg on the tank. Todays manual tank calculation, made up of mostly highway but some local, was 22.4. Im very excited to see these mods payoff. I usually use an entire tank on this drive, but today only 3/4 of a tank. Round trip I have saved 1/2 tank. The great part is, I still have some more mods to make! 32mpg may actually be attainable!

Question time. I used cruise control most of the time today and noticed late in the trip that if I let cruise fully control the throttle while on downhill coasts, the SG would report back 50-60-70mpg. BUT if I used the cruise button, it felt like it disengaged the transmission and SG would report 120-130-140 mpg. I only used this for the last 50 miles of the trip, which is when I discovered that there was a difference. I also tried to just put it in N myself and coast, but SG reported the same 50-60-70 numbers. It was really weird, on the same hill, in cruise, without me using the crs button, SG = 50-60-70. Id hit it, SG = 120-130-140, Id let go, and back to 50-60-70. Any thoughts on whats going on\? Is SG confused, or do you think its making a difference?

I guess Ill know for sure on the leg back home Wednesday - as Ill be trying to use that button as much as possible and see if I arrive back with 1/2 a tank rather than 1/4.