Random thought.. Why the closed Cold Air Intake?

[13COBRA]

Why did Ford decide to put a closed CAI on the Boss while Shelby chose to go with an open CAI on the GT500?

I understand that they were made by different design teams, but what is the difference? I know back in the old days that people would take off the 'box' before they even left the dealership and put on an open one. But I have seen several vehicle engineers come out and explain that an open CAI gives no benefits over a stock closed CAI...

 

[65sohc]

Here is one theory. Noise. I have a Steeda CAI on my Boss and there is no way it would meet Ford noise standards. You'll notice that when Ford went to an open element system on the Shelby they also added a silencer between the filter and the throttle body. Because of the engine layout on the 5.0 there is no room for an intake silencer. One thing is certain. They didn't put a closed box on because it flows better. It's already been shown that the 5.0 box flows less than the 4.6 box.

 

[86merc]

It's already been shown that the 5.0 box flows less than the 4.6 box.

links? Thanks

 

[13COBRA]

It's already been shown that the 5.0 box flows less than the 4.6 box.

Waiting for proof... I don't buy it. :sleeping:

The noise was an interesting thought...but I have never really noticed a huge difference between an open and closed CAI..

Maybe it's just for the 'cool look factor'? Or the 'this isn't factory' statement.

I was hoping there was a reasoning behind this, but oh well. Hope everyone had a great Thanksgiving!

 

[Smileyboy]

If i had to make a guess it could have something to do with IATs. From the looks of the CAIs on the market, most look like they draw their air from the engine bay while the closed system seem to pull its air from the front of the car. Just my observations.

 

[kbroush]

If i had to make a guess it could have something to do with IATs. From the looks of the CAIs on the market, most look like they draw their air from the engine bay while the closed system seem to pull its air from the front of the car. Just my observations.

I would agree with this. I also think that a lot of it comes down to cost and the nvh issue as well.

 

[cloud9]

If i had to make a guess it could have something to do with IATs. From the looks of the CAIs on the market, most look like they draw their air from the engine bay while the closed system seem to pull its air from the front of the car. Just my observations.

I'm betting you're right. Right or wrong as far as the rationale, your statement is accurate. On my GT500 with an open CAI, IATs run about 10 degrees above ambient. On my Boss with the stock closed CAI, they're either equal to or within a couple degrees of ambient.

 

[Ray Lucca]

It's based on the Carb rules.. No new car has an "open air" Cai anymore except the GT 500, and it was grand-fathered in. [Notice the Camaro, or 'Vette doesn't have one either]. Earlier many after-market Co's had Carb approved Cai's for the older Cars, don't see that with the newer ones.

 

[Silver TT]

I'm betting you're right. Right or wrong as far as the rationale, your statement is accurate. On my GT500 with an open CAI, IATs run about 10 degrees above ambient. On my Boss with the stock closed CAI, they're either equal to or within a couple degrees of ambient.

Based on that reasoning would you make more power with lower IATs or more flow? (assuming the open design flows better even if it does draw warmer air from engine bay vs. cold air from front/side of vehicle)

 

[Silver TT]

If you want to see the Ford Mustang Chief Engineer discuss the open vs. closed intake, check out this link:

2013 Mustang Boss 302 - Jay Leno's Garage - YouTube

 

[65sohc]

links? Thanks

cnlperformance.com

With an open element there is a whistle every time you crack the throttle, not to mention the roar at WOT. No way Ford would approve that. They would have thousands of customers complaining to dealers their cars were making weird noises. I tested the pressure drop of the stock system vs. the Steeda. My results were virtually identical to C&L's: 21 inches of water vs. about 5 at the same cfm. Some know-it-all has already challenged this on another forum. Whatever, it's a fact. As far as IAT, I always monitor this on my '13. Sitting at a traffic light for two minutes on a 100 degree day I have seen temps as high as 145 degrees with the stock box as well as the Steeda. How much power does it take to maintain an idle? Maybe 10? Once you start moving and open the throttle IAT comes down. Faster with the stock box but eventually they are about equal.

 

[Davemcc]

If you want to see the Ford Mustang Chief Engineer discuss the open vs. closed intake, check out this link:

2013 Mustang Boss 302 - Jay Leno's Garage - YouTube

LOL at 6:30

 

[suaveflooder]

if i had to make a guess it could have something to do with iats. From the looks of the cais on the market, most look like they draw their air from the engine bay while the closed system seem to pull its air from the front of the car. Just my observations.

this!

 

[65sohc]

The Steeda CAI connects directly to the factory grill duct so once the car is moving the filter is pretty well-ventilated with outside air. IAT reading has more to do with airflow through the system. Idling with almost no airflow results in skyrocketing IAT. When you get on the throttle IAT drops instantly. I still think noise is the main issue. They designed a system to meet NVH and packaging standards and still produce their target horsepower level. Same thing with the shifter and the 2 inch ID resonators. Reasonable compromises all.

 

[13COBRA]

Thanks for all the input!

 

[TX04WhiteL]

Closed box prevents air from the engine bay entering. Correct me if I am wrong, while the open filer produces more noise the main thing that silences the intake is the baffles on the tube. Eliminating them usually causes the car to make more intake noise.