Question for those still running a stock airbox on the 5.0

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Question for those still running a stock airbox on the 5.0

April 04, 2014, 02:43:39 PM

I'm looking to tinker a bit. Got a question.
The stock airbox. What's the inner and outer diameter of the tube section that connects to the air intake tube? Anyone know?

Question for those still running a stock airbox on the 5.0

Reply #1 – April 04, 2014, 03:27:34 PM

Ill get it for you tonight.

Question for those still running a stock airbox on the 5.0

Reply #2 – April 04, 2014, 04:17:38 PM

You mean the tube on the box or that goofy short tube between the airbox and the MAF?

I'm fairly certain it's all bigger than 70mm, which is the size of the throttle body I'm running. As long as it's bigger than that it "shouldn't" be a restriction.

Question for those still running a stock airbox on the 5.0

Reply #3 – April 04, 2014, 06:10:00 PM

Lou, the tube on the box itself. Hoping for 3" or larger, but yes over 70mm on the inner diameter will do.

I'm planning on re-installing a stock box and opening the hole against the wall and match it with the fenderwell (remember it is just a tad smaller). That and a nice SMOOTH tube up to the throttle body. Something rubber preferably.

Question for those still running a stock airbox on the 5.0

Reply #4 – April 04, 2014, 07:25:43 PM

its bigger then 3".. I used a 3" plumbing connector, and had to crimp the stock pipe to make it go in to it

Question for those still running a stock airbox on the 5.0

Reply #5 – April 04, 2014, 08:25:58 PM

Guess that means I gotta grab one. Need to go hunting for a good replacement inlet tube too.

Question for those still running a stock airbox on the 5.0

Reply #6 – April 04, 2014, 09:01:15 PM

I measured the extra airbox I have in the garage. The inside diameter of the opening is 3.25 inches which is about 82.55mm so much bigger than 70mm. I wonder what the area of the hole in the fender for the airbox is? I'm thinking about measuring it and if the area of the hole is the same or larger than 70mm I don't think it would be worth it to make the hole bigger, at least for me. The throttle body I have is 70mm (the Explorer GT40 upper I have had a 69.5m opening so I took out the Dremel and opened it up to 70mm) so as long as everything in front of that is bigger there should be no restriction.

As for replacing the stock rubber inlet tube between the MAF and TB it should help. I have one of those cast C&L 76mm inlet tubes. I ran it back to back with the stock tube at the track. On my 3700lb Thunderbird it was worth .5mph and .05 second in the quarter over the stock tube. So in my case it added about 5hp.

Question for those still running a stock airbox on the 5.0

Reply #7 – April 04, 2014, 09:18:23 PM

Quote

I wonder what the area of the hole in the fender for the airbox is? I'm thinking about measuring it and if the area of the hole is the same or larger than 70mm I don't think it would be worth it to make the hole bigger

I was thinking more on the airbox itself. A "gasket matching" of sorts. Pretty sure the fender hole is bigger than the hole in the airbox that mates to it.

I'm running an Edelbrock 70 mm TB with a 73 mm C&L.

Have I mentioned I hate how clean your engine bay is? My Mustang is that clean, but she don't see the wet stuff.
Wish my wipers and window cowl panel looked like your too. Still getting out from the body shop under the hood. Rained all day....No progress.

Question for those still running a stock airbox on the 5.0

Reply #8 – April 04, 2014, 09:35:08 PM

Quote from: V8Demon;431847

I was thinking more on the airbox itself. A "gasket matching" of sorts. Pretty sure the fender hole is bigger than the hole in the airbox that mates to it.

I'm running an Edelbrock 70 mm TB with a 73 mm C&L.

Have I mentioned I hate how clean your engine bay is? My Mustang is that clean, but she don't see the wet stuff.
Wish my wipers and window cowl panel looked like your too. Still getting out from the body shop under the hood. Rained all day....No progress.

Actually the hole in the fender is smaller than the hole in the airbox base. To gasket match it you would need to make the fender hole bigger.

I'm actually running the exact same MAF and TB you are. Small world eh?

The only reason the engine bay is that clean is that, like your Mustang, it never sees rain. It keeps from splashing all over the place.

Everyone here seems to complain that the engine bay of my Thunderbird is too clean. You're not the first

Question for those still running a stock airbox on the 5.0

Reply #9 – April 04, 2014, 09:45:23 PM

Quote

Actually the hole in the fender is smaller than the hole in the airbox base.

Hmm....Cut-off wheel, touch up paint, some of that door edge protector plastic strip stuff.... Although I'm fairly certain the fender hole area is far larger than a 70 mm circle so I guess I'll see when I match them up.

Question for those still running a stock airbox on the 5.0

Reply #10 – April 04, 2014, 10:18:48 PM

Quote from: V8Demon;431849

Hmm....Cut-off wheel, touch up paint, some of that door edge protector plastic strip stuff.... Although I'm fairly certain the fender hole area is far larger than a 70 mm circle so I guess I'll see when I match them up.

I know the hole in the airbox is about 1/4"-1/2" bigger all the way around than the hole in the fender. I've thought about making the hole in the fender bigger to match the hole in the airbox but I don't have a cutoff wheel at home and, well, I haven't got the gumption up to do it.

Now I'm curious how big the area of the fender hole is and if it's bigger than 70mm. The area of a 70mm circle is 3848.45mm (A = pie(mmm pie) x radius^2). Can you measure the area of the hole in the fender of your Cougar? The formula for the area of an oval is Area = (Width x Length) x 0.8. So if it's the same or bigger than 3848.45mm making the hole larger "shouldn't" result in a gain in power.

FWIW a 70mm TB flows ~750cfm.

Question for those still running a stock airbox on the 5.0

Reply #11 – April 04, 2014, 11:15:25 PM

I think the hole in the fender is the same size as the pipe, its just oval, and the airbox opening is way bigger then that hole.
I have a pic of it but I cant seem to post a link with this version of the forum

Question for those still running a stock airbox on the 5.0

Reply #12 – April 04, 2014, 11:47:09 PM

One must take into account that it must pass through a filter barrier as well. Interesting article on how they stack up.....

http://www.nicoclub.com/archives/kn-vs-oem-filter.html

Question for those still running a stock airbox on the 5.0

Reply #13 – April 06, 2014, 10:13:59 AM

I've seen a couple people that cut out the back side of the air cleaner and also a large rectangular hole in the fender well...

Question for those still running a stock airbox on the 5.0

Reply #14 – April 06, 2014, 09:04:41 PM

Yeah, dig this one from another thread... Note the fender hole. Good execution actually. The hoodliner SHOULD make a decent seal in this application. I want a sealed box though.

I figure once I get everything here I'll do some measuring, and then some more measuring, and then some cutting.
Obviously I'll be using a stock style panel filter with this. I think with a large enough opening there should be negligible restriction with a stock paper element filter.