-   EcoModding Central (
-   -   Warm air intake on a Focus.... (

suspectnumber961 07-03-2011 08:30 AM

Warm air intake on a Focus....
Am seeing what I think are some definite mpg gains from using a warm air intake with a Focus....after seeing a low 40s mpg trip on a 15 mile run under the conditions mentioned below....and this run involved a few stops and slowdowns for curves, etc.

This is after the car is warmed up and when ambient temps are above 80F.

My simple warm air intake results in IAT temps ~ 30F above ambient in these conditions (car warmed up/ambient above 80F) ...meaning IAT of around 110F to 120F.

So I'm thinking that if there was a way to maintain the 110F-120F intake temps or above under a wider range of conditions...mpg could be increased meaningfully.

Thinking of removing the heat shield from the exhaust manifold....and fabricating an outlet from sheet metal to allow attaching the intake tube for increased heat intake.

Not sure of the effect of removing too much heat from the exhaust tubes as far as efficiency is concerned though. Also might be an issue of too much heat for the plastic air box?

Interested in results or comments from anyone else using heated air on a Focus or other car. The Focus uses a MAF...not the MAP...which is supposed to be more effective with warm air.

kach22i 07-03-2011 10:11 AM

Sounds odd to me, because cold dense air is favored for intake. Ford even developed a cold intake system using the A/C a few years ago.

Maybe the air the body of the car is passing through is thinner?

Could this be yet another reason why the wide open spaces of the Bonneville salt flats hold all the world land speed records?

EDIT: I found an old post of mine from 2005:

Originally Posted by kach22i (Post 2135758)
Cool air intake links from bookmarks:

AEM Cold Air Intake and Short Ram Air Induction Systems

Banks System

California98Civic 07-03-2011 11:00 AM


Originally Posted by suspectnumber961 (Post 248200)
The Focus uses a MAF...not the MAP...which is supposed to be more effective with warm air.

If your Focus really is using a MAF and not the MAP then you have the effectiveness probability backwards. Apparently, nobody here has shown that a WAI works with a MAF (Sentra_SE-R ran the best test I have seen on that). I tested a WAI with my Honda's MAP sensor and found a modest gain in an ABAB test (see my signature file for the link).

In general, these benefits are close to the margin of error produced by driver variability and conditions, so a rigorous ABA test is the best way to try and see if something like this is working. When I bought my Ultra Gauge a few months ago I was amazed at the variability of my driving, even though I had been essentially hypermiling for years with the same car.


mbrac 01-20-2012 04:12 PM

I driving a 2007 Focus ZX3 - 5 sp - and tried using metal and rubber tubing to get warm air to the K&N filter that I'm running - with little success - so I'm heading down the road of adding a second heater core - tapping into the lines that connect to the heater core in the firewall - and basically setting it in front of the intake - and then the air filter on the other side of that - so in the end I will get a constant warm air intake temp year around - since living here in Indiana - can range from -10 to +100 - - CRAZY - I'll post the results later this month hopefully.

mcrews 01-20-2012 04:19 PM

ok, let me see if I understand your set up.
You took something like a heater core (looks like a small trany cooler?) and mounted it inside of the air box (infront of the air filter)
And fed hot water from the engine?

That is friggin brilliant!!!!!!!

Weather it works or not.......CONGRADULATIONS!!!!!
That is thinkin outside the box!!!


mbrac 01-20-2012 04:23 PM

Yes - that is the idea - stopping tonight to get the heater core - $20 at Advanced Auto - and hope to get going on it this weekend - I'll post results and pictures - I have a netbook pc installed in the car with the ECM connected and running ODBWiz software - so I can monitor everything and log it - it's a sweet setup!

mcrews 01-20-2012 04:28 PM

HURRY!!!!! lol

ConnClark 01-20-2012 04:55 PM

You know you would be better off warming the fuel and keeping the intake air cool. Its the fuel you want to vaporize better, not the air. A cooler intake charge also reduces combustion heat lost to the cooling system. Also a cooler intake charge results in lower NOx production.

some_other_dave 01-20-2012 05:13 PM

Warmer air is less dense, which means you open the throttle wider for the same power. That means less pumping loss to pulling the air past the partly-closed throttle valve.

I think using a heater core would be counter-productive, as that will add a restriction to flow up in the air box. It's possible that it won't be enough to matter, but my first guess is that it would be. Testing would tell, and that's why it will be great to see the results from this!


Daox 01-20-2012 05:19 PM

Increase air temps have been known to increase flame speed which increases efficiency. Also, hot air is less dense requiring a larger throttle opening to maintain the same power. So there are benefits to be had from warming the intake air.

Even if the core is a restriction, you're simply moving the restriction from the throttle to the core. If that is the case he'll notice a drastic drop in power, so it should be pretty apparent.

All times are GMT -4. The time now is 07:13 PM.

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2021, vBulletin Solutions Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright