First grill block

[BHarvey]

The car took 12 mintues to warm up as opposed to 6-7 minutes without the block. Temp stayed in the same 183-188F range throughout. No clue why. Ambient temp was 41F.

Have you guys had to make a vented block for summer or are yours 'as is' all year?

Coast distance is much better as well. I have two good reference points for coasting, one down and back up hill, and another just uphill.
The first one from 50 mph will barely get me to the 4-way stop sign. With the grill block I had 20 mph in hand. It gained speed on the downhill which gave me another 6 mph. It never did this before.

The other coast point would have me turning onto my street at 15 mph and with the block it netted 24 mph.

[Frank Lee]

I can't think of any logical explanation for 2x warmup time with a grille block. Your coasting results seem a bit extreme to me too.

[BHarvey]

I was wondering about the coast results and I guess it's from covering up that massive hole.

[brucepick]

Could be that there's massive cooling air going in through the lower "grill". Take a look at the positioning of radiator and a/c condenser also.

My car has the radiator on one side and condenser on the other, with the cat converter behind the condenser (cat is built into the exhaust manifold). I only block the radiator in winter but keep the other side blocked year 'round. ymmv, of course.

A ScanGauge will show you digital engine temp. That beats listening for the radiator fan to tell you that you have too much grill block.

[BHarvey]

The UltraGauge says 183-188F

[Frank Lee]

Originally Posted by BHarvey

I was wondering about the coast results and I guess it's from covering up that massive hole.

My money is on testing error.

[jedi_sol]

My grill block is "as-is" all year, I've never seen any major temp fluctuations (Southern California).

[BHarvey]

Running the first tank now but did do a small test of mpg. I have several places marked out around Atlanta that I have noted pure hwy mpg with cruise @55. This stretch is mainly flat with a couple of small hills. Without the block it got 41.6 mpg.
With the block it got 45 mpg.

Going to test a couple other stretches I have mapped out to see what happens.

The temp is still staying low and only comes up a few degrees if I sit idling (yes, I know).

The AIT is up quite a bit. Without the block it would stay 15-18F above ambient on the highway. With the block it stays 40f + above ambient. I think this is due to the heat soak from the motor heating the airbox up more than anything. There is a gap in the middle half of the block at the hood that is where the intake port is located so it should be getting some cool air.

On the cars instant mpg gauge at 55 on cruise it would peak out at the crest of hills and with the block it does this a bit sooner than the crest.

Everything is saying it is getting better mpg but after 10 tanks or so we will see.

[NeilBlanchard]

The temp stays in that range because that is where the thermostat is set to open. You are getting plenty of cooling air -- and it is possible that more air is passing through the radiator with the block: on some cars, air comes *out* of the upper grill.

As long as the temps are okay, you can try blocking some of the lower grill, too? Are there ways for the air to "escape" out through the chin area?

My grill blocks are year round, though I can pull them out on the hottest days.

I'm down to a 15" x 4" opening, and all the holes in the chin panel are blocked, so the air that does go through the opening, passes through the radiator.

Scion xA aero mods

[BHarvey]

Don't know if air can escape from that area, but the next plan is to block some of the lower grill as well as block off the fog light areas. The entire area behind the radiator is shrouded and enclosed pretty tight and it also has a nice pan from the front bumper back to the firewall.