Cold Air Intake, any measured differences?

[paintdudeluke]

Feel the components under the hood after you park and shut it off. Feel the fan. Feel the intake tube. Feel the firewall. Feel the mass airflow unit or air cleaner. Put a can of soup on the engine and after you get home it'll be too hot to hold. Headers melt things and kill starters on some cars if they're too close to it.

WIKI QUOTE: "In most modern automobiles, internal combustion engines "breathe" under-hood air or air ducted from under the front bumper through plastic and rubber tubing. The high operating temperatures in the engine compartment result in intake air that is 28°C (50°F) or warmer than the ambient temperature, and consequently less dense. A hood scoop can provide the engine with cooler, denser outside air, increasing power."
'
On the subject though, I have contemplated fabricating a good ram air intake. That's a nice charge of positive pressure at 70+ mph. At 100 you might pick up 10 HP depending on design and air capture.

This guy picked up over 30hp and 5mpg on a dodge 2.2: Not sure I'm convinced of that number though.
http://www.karlsnet.com/mopar/ramair.shtml

[RoyBatty]

The Mooney 201 M20J had a ram inlet that could be opened to bypass the induction air filter once you were at cruise altitude.
Consider that this plane could travel at around 150 MPH or so, and it was found that the ram air effect only gave about 1" increase in manifold pressure. Sure the cool air was better to run, but the filtered air was running thru the same plenum at roughly the same air temps.
Later the factory gave the owners the option of doing away with this feature due to the negligible performance increas as compared to the maintenance costs of the system.

[Daniel]

Maybe we should contact Mythbusters and see what they come up with? The facts on cold air induction seem to vary
a lot from the articles I've read on the issue. The dyno is the only true way to find out.

[paintdudeluke]

Difference in top speed would suffice for a test. Maybe these folks that claim a huge difference are simply benefiting from upgrading from a really crappy restrictive intake to simply being able to breathe.

[Tobi]

Maybe we should contact Mythbusters and see what they come up with? The facts on cold air induction seem to vary
a lot from the articles I've read on the issue. The dyno is the only true way to find out.

http://www.youtube.com/watch?v=gCi2yo4UqPI

[paintdudeluke]

Nice cold air intake test. Results? They suck. So much for easy power gains.

[paintdudeluke]

Lets try nitrous!

[v6spider]

Making more horsepower takes money... No doubt about it!

Rob

[MrJD]

Making more horsepower takes money... No doubt about it!

Rob

yea... lets be honest with ourselves: if you have a US spider, the elephant in the room is the compression. Changing that is not cheap.

[chrisfiat]

as anyone who lives in a 4 season area, ie new england for instance, knows. cold air makes a huge difference. i live in New Hampshire, and on days like last week, and this week, where our daytime highs are 85, and our 10:00 to 11:00 pm temps are in the high 50's there is a noticeable difference in power going up my hills in the evening / night temps

[FiatMac]

Maybe we should contact Mythbusters and see what they come up with? The facts on cold air induction seem to vary
a lot from the articles I've read on the issue. The dyno is the only true way to find out.

http://www.youtube.com/watch?v=gCi2yo4UqPI

This "mythbust" test was done with a turbocharged and intercooled engine and is not applicable to a normally aspirated engine.
The intercooler wipes out most of the temperature difference. A typical intercooler is 85% efficient so a 15 degree inlet temperature difference becomes a 2.25 degree difference exiting the intercooler. You will note that in the video that they confirm this fact at about 6 minutes 50 seconds in when they say that the manifold temperature difference was only about 2 degrees.

Also this work was done on an inertial dyno. The engine doesn't see the load long enough to demonstrate real life underhood temperatures.

[timinator]

10deg.F change in intake air temp. causes a 1% drop in horsepower with atmo. pressure and humidity being constant. Large changes in power are not therefore going to be seen in a moving car under cruise conditions. If you install an IAT in your intake manifold plenum it is easy to record actual air temp. Sealing your air cleaner off from under hood air is always good. Not so much because of the 200deg. air off the radiator but the up to 1000deg. air coming off the exhaust manifold under prolonged hard acceleration. Hot air packs under the hood which is where most air filters are located.

I pull air from outside the car for best results. On the exhaust side of my turbo car the paint on the the hood bubbled up even though the IAT usually reads around 100deg. intake air temp. with 1300deg. EGT with 70deg. ambient air temp. under full throttle acceleration.

[carl]

Maybe the ideal solution is a pair of IDFs with tall velocity stacks poking up through four holes in the hood! If it rains you get water injection.

[Redline]

Fiat's solution anyway draws air from behind the radiator...

[csi2000s]

I've almost finished fitting a cold air intake system along with a load of other upgrades on my 1974 spider. My car is RHD so I have twin DCOE 40mm Webers mounted to a Ritmo Abarth 130 TC inlet manifold. It a very compact manifold with short inlet tubes which has liberated a lot of room for the carbon fibre air box.The air filter is a K&N Apollo which will be piped to next the radiator where there a couple of factory holes in the support panel leading to the grille. I'm going to seal off this section from inside the engine bay so the system on only draws in cold air from the grille.

Other new parts fitted include Mark Allisons computronix ignition and 95 amp alternator. Millers Mule pulleys up front and a few other bits and pieces. I'm currently doing the final fit up and getting the linkages sorted. I'll keep you posted on the hopefully massive improvement.