HHR Warm air mod

[HotRodEconomist]

As the cold (relative, since I'm in central TX, cold is anything below 60 degrees) temps here in Austin I've been noticing how much the cold air effects my MPG on my '08 LS 2.2L manual.
For instance:
On my way to work in the afternoons the ambient temps are ranging from 65-75 degrees
and I average around 33-36 on the highway (Most of my commute is highway) at 60-70mph.
However on the way back home, around 10pm, it's much colder ambient temps...usually around 40 degrees.
I can barely average 30 mpg on the way home going 60mph.
I realize my tire psi's are slightly lower in the colder temps, but they're not much.
In the heat, the tires are at 35-37psi...in the cold they're at about 32-35. I hypermile as much as possible.
I realize this is still normal for the HHR, but I can' just leave something alone if there's a possibility to improve it.
So here's my idea:
Move the stock air intake hose (the flexible one) from the hole in the fender to directly below where it attaches to the airbox.
I ran it down the fender well as to get the warmer air coming off the exhaust manifold.
I realize that warmer air is worse for performance but it's better for MPG. The colder, denser air
requires more fuel to atomize correctly at 14.7:1....conversely, warmer air is thinner and requires
less fuel to reach the stoichiometric goal. The trade off is that the less fuel, the worse performance....but it's an HHR.
Like I was telling my wife, my HHR is my mileage hot rod. I want my go-fast cars to go as fast as possible....
I want my HHR to get the best mileage possible.
I won't get to test it out until Monday, but what are y'alls thoughts?

Here's where the stock intake hose went:


Here's where I moved it to:

[Cobb]

Cold air takes more effort to move it out of the way. Use of the heater takes GAS to keep the water warm. In my experience warm air intakes help if you drive is like 10 miles or less, hurts if its more. It can cause your computer to reduce timing, increase the afr to reduce or prevent detonation, knock, etc. The second problem is the gas stations move to a winter blend which gives less mpg. Sounds like you know its just the air temp currently. You know, I have a block heater, but I cant measure any changes in mpg using it with my drives.

[pletby]

Originally Posted by Cobb

You know, I have a block heater, but I cant measure any changes in mpg using it with my drives.

It must be warm where you live. Block heater makes a huge monster freakin mega difference in my mpg, how long it takes to get heat out of the block of ice that is my engine, and just the way it sounds when I start it. I don't have a short commute. 2 hours each way, city highway mix.

Looks good HotRodEconomist. Noticed your intake temp change?

[awcook]

Here in Oklahoma it doesn't get cold enough to use a block heater. Sometimes I think that it would help, but then my engine jumps up and heats up quickly.

Cobb, I don't think the block heater would help you too much anyway (with a hybrid).

HotRodEconomist, looks good. Not too sure how much it would help down in Texas, but it should help a little, as long as it doesn't heat up the engine so much that the radiator fans start turning and causing drag on the alternator.

[oil pan 4]

I am in New Mexico and I use the crap out of my block heaters when I use my diesel suburban. Just because you are in texas or newmexico doesn't mean we don't get a winter.
For example in new mexico I see almost a 130 degree temperature difference between the hottest summer days and coldest winter nights and a 80 degree temperature difference easy during winter between cold nights and warm winter days. Just recently here with in the last 2 or 3 weeks we have gone from -8'F nights to just shy of 80'F for a high during the day. 2 or 3 weeks ago it was -8'F at night, these past few days the high was just shy of 80'F. In 2010 we went from 80'F days to -16'F nights in less than a week.

Even in OKC I have been there when the high for the day was less than 20'F.

[Snowman9000]

I have a 2013 Focus SFE, and I'm just shocked at how much the MPG has gone down in the past several weeks due to cold weather. From a typical 38.5 MPG in warmer weather, I've lost 5 MPG! Yikes.

[thomason2wheels]

Originally Posted by Snowman9000

I have a 2013 Focus SFE, and I'm just shocked at how much the MPG has gone down in the past several weeks due to cold weather. From a typical 38.5 MPG in warmer weather, I've lost 5 MPG! Yikes.

We here in va regularly lose about 10% give or take fuel economy during the winter...it sucks but at least the vehicles run in the cold weather. I bet the folks in alaska really suffer...

[HotRodEconomist]

Well we had a cold front come through last night, so any testing will be a little skewed because the ambient temps will be much less than me previous tests.
If the mod works, however, results will be mostly immediate.

[HotRodEconomist]

Got inspiration from a member on here about putting a quick grill block on his Civic...so I did the same before I leave for work. Literally took me a half an hour...including the 15 minutes I let the black spray paint dry.

[awcook]

Nice grille block. What is it made out of?