Ford Focus Forum, Ford Focus ST Forum, Ford Focus RS Forum

Ford Focus Forum, Ford Focus ST Forum, Ford Focus RS Forum (
-   MK3 Focus (
-   -   Factory Air Box vs. Short Ram testing (

newmission 07-16-2011 10:08 PM

Factory Air Box vs. Short Ram testing
So I was curious about the actual numbers comparing the factory bread box, to the much put down short ram intake set up. I have read countless arguments from those that say the short ram just sucks hot air and is useless, but never had any numbers to prove their point. So here you go.

I'll start by saying that the factory air box is as close to a true cold air intake as you're going to get. The air that feeds it is drawn from in front of the radiator, and the box itself is as close to the intake as you can get. No pipes running down the side of the engine next to the trans or what have you. So I'm going to consider this a CAI to SRI comparison. You may disagree, and that's fine with me. But I have numbers. :)

The constants:
-84 degrees ambient temp. Partly sunny. No accessories on.
-Wide open throttle until reaching cruising speed of 60mph.
-5min cruise at 60mph maintained.
-Factory filter.

The variable:
-With factory box, without factory box. (completely removed)

I began by removing the air line that feed the valve cover. Then inserted the probe from my Fluke meter, and taped closed. The probe was monitoring the air from behind the MAF sensor. I thought this would be the best area to gather real numbers.

I then went for my drive. The most consistent reading came to 89.9 degrees at 60 mph maintained over 5 mins.

I returned home. Put the complete factory set up back together and went for my second drive in the same manner.

88.3 degrees

A difference of 1.6 degrees isn't quite that much to cause all of the complaining about short intakes sucking hot air. At least not in my "daily driver" book.

In my looking around with the air box removed. I notice there really isn't any place at all for fresh air to get in. Imagining where the CAI (once released) would draw from, the only place I could think of would be to remove the backing to the driver side triangular part of the grille. I can only imagine the issue with water now flooding into the engine compartment. Especially with the low air dam still on.

I've considered drilling holes in the plate, and purchasing a 90 degree elbow to point my filter downward, remove the box completely, and fabricate a stainless steel bracket to hold the filter/MAF combo. I'll take pics when it's done. :)

mattlqx 07-17-2011 12:24 AM

From my experience with readings in other cars...

Engine bays at speed typically heat up intake temps around 10-15 degrees above ambient.

The big problem is in stop-and-go or idle. A few minutes stopped can raise the engine bay temperature drastically (think 130 degrees intake temp on a 90 degree day). Then when you get going again, you're sucking in all that hot air if you have an open element.

Air intakes on this thing won't get you much but sound and maybe an extra HP or two. I know there will be people that will SWEAR it's SO MUCH FASTER and it's a WORLD OF DIFFERENCE but I really wish those people would practice some science and go prove it on a dyno.

Time and time again, intakes claim to be amazing pieces of equipment and at most yield an extremely modest improvement (and that's ones that suck air from the fender well or some other non-open routing).

vmaxbaby 07-18-2011 05:21 PM

Sound is nice makes me feel I am going faster LOL.

All times are GMT -5. The time now is 05:06 AM.

Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.1
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.