[thunderjet302]

Any cold air system that does not place a 90 degree bend on the inlet of the MAF is better than one that does. I like systems that use the air box to make the turn into the fender. This is less restrictive than making the turn with a small pipe. This isn't even mentioning the havoc a bend on the inlet of of a MAF causes to the signal.

Remember that having longer pipe with more bends is VERY restrictive.
You lose more than you gain from the "cold air" or the "ram air" by having a complicated tube that is long and turns and bends into the fender well.

This is why I use the March box. I have a short section of 3.5" pipe between the MAF and throttle body and then the filter on the end of the MAF in the March box. The stock fender opening (where air comes through) on a Fox is actually larger than the opening in the bottom of the air box on a '11-'14 Mustang (I've measured the opening in my wife's '12 V6 Mustang. The 3.7 and 5.0 cars share the same lower air box and ducting).

I've kind of figured that the scoop and hose would actually be more of a restriction than just pulling air from the fender opening. I think the only way it would make sense is if it somehow pressurized incoming air, which unfortunately it does not accomplish.

 

[Ssp 363]

I don't know but that is a nice clean engine bay.:wink2:

 

[russ3747]

I had a 93 GT convertible with an AOD it had a crome cold air intake with the filter in the fender. It would pick up a .1 in the 1/8 when I removed the corner light.

I talked to a guy who had a ram air set up I asked if he could tell a diffrence. He said it helped over 80 mph, but who knows....

 

[Flyin Ryan]

My ram air does wonders on my kawawaki but then again it doesn't have three to four feet of ribbed flex tubing running from the intake port to the airbox like the March kit does

 

[FISHTAIL]

I ran one of those things for years. Aside from being a major pain in the can to remove the box, the only other thing it did for me was pickup interesting things off the highway. Pebbles, leaves, discarded butts, and the occasional frog.

 

[DELL37]

I know this is a stupid old thread but I figured I'd post my experience since I got to do this exact test as I bought a car that came with the that March Ram air kit already installed. Let me begin by saying that I read this thread a couple years back and it was the bases for me doing what I did at the track.

The car is a nothing special 1990 LX 5.0 that has been swapped from a 5-speed to a Performance Automatics AOD by the previous owner. Car has 3.55 gears, Edelbrock Performer Intake, 70mm throttle body, EGR, shorty headers, H-Pipe, Pypes 2-1/2 exhaust, electric fans and a good Alternator. It really needs heads and a cam to wake it up but that's another day. Best pass since I bought it was a 13.07 @ 107.9 mph on a 255/60/15 radial so the car dead hooked every time with no spin.

When I got the car it had the full March ram air setup with scoop, tube and box installed. Like other have mentioned, cleaning out the airbox after every drive was a PITA.

All passes were made same day over about a 3hr. period. First pass was around 11:00am and the last was around 2:00pm and it only got warmer as the day went on.

I had just installed a new replacement K&N cone filter a few days earlier as the old one was junk. Made two passes and the best pass on the full setup was 13.36 @105.2mph.

I decided to remove the Scoop and hose. Again I cleaned out the air box as it had picked up rubber and other misc. crap just driving around the track. To get the hose off I had to remove the box. What I found when I removed the box was that the previous owner had opened up the hole in the fender but still had the tiny opening in the March box.

Next passes were with only the box and the filter. No scoop and no tubing. Made two passes and the best was 13.24 @ 106.1 mph. I dropped .12 and picked up .9 mph.

Next I tried removing the box altogether and doing what we did back in the day with running an open filter. This was a bad idea. The first pass was 13.54 @ 101.1mph. The car just felt lazy and I think it might have stumbled at one point. I Let it sit about 20 mins and tried again. This time it stumbled badly and I got out of it. It really didn't like the open filter. Not sure if it was heat from the motor or the electric fans were messing with the mass air but it was unhappy.

The track was getting busy so we wanted to run one more time. I decided to open up the side of the March box to match the opening size in the fender. This was easy enough with just a razor knife. I made it pretty when I got home with the Dremel. The one and only pass on this combo on this day was 13.18 @ 106.9mph.

Over all I dropped .18 et and picked up 1.7 mph. It's clear that the scoop and hose are a restriction and not a benefit. Considering that the track was getting warmer and the air quality was going away I think this is worth the time and we had a hell of a lot of fun. What have I learned. First, don't run an open filter on my combo. Second, the scoop and hose are useless. Last, enlarge the opening in the airbox to fit the opening in the fender.

It's also worth mentioning that the car sounded completely different. It has an annoying whistle coming from the intake that I never could track down until I removed the hose and suddenly it was gone. It now has more of that old 4 bbl carb sound from outside the car.

 

[Cougar5.O]

The track was getting busy so we wanted to run one more time. I decided to open up the side of the March box to match the opening size in the fender. This was easy enough with just a razor knife. I made it pretty when I got home with the Dremel. The one and only pass on this combo on this day was 13.18 @ 106.9mph.

I've been running the March air box for at least 15 years now. In my Cougar, the scoop was mounted within the front valance as it has slots in it. I felt that air would be directed in through funneling at high speeds. I thought this would help get more power at the top end of the track with the Kenne Bell which isn't known for it's top-end power. Any reduction in vacuum in front of the blower, and the cooler the air, the better. At least I didn't pick up much road debris.

My slips at the track showed an unusual gain in power at the top end between the 8th and 1/4 mile. Ram air effect? Maybe, but lets fast forward a decade to 2017 after I broke the Kenne Bell 306 for the final time and decided "there's no replacement for displacement". If I stressed about getting enough air for 450 HP, now I needed to get air for 600+ HP.

No real issue using the same 4" silicone elbow and 85mm TB, after all the 662HP '13-'14 GT500 has an air inlet that tapers from a 106mm MAF to 90mm just before the TB, and the dual 60mm TB is equivalent to an 80mm Accufab airflow-wise.

Now, about that scoop and hose. One day I decided to actually measure the oval flange of the March airbox where the ram-air hose mounts in the fenderwell. The oval had a tiny equivalent area of about a 75-80mm diameter hose. Explains the weirdly insufficient 8th mile time/MPH with the Kenne Bell and the nice MPH @ the 1/4 mile.

After this discovery, I removed the scoop from the valence, the hose and cut the inlet flange off the March box. I then scribed the full oval opening in the fenderwell and cut the March box to match. Even then it's barely sufficient for a 428 cubic inch engine (trying to recall, but something like 4" - 4.5" equivalent hose diameter?)

Moral of the story, I learned what DELL37 and other have learned, the ram-air part of the setup is more of a detriment than a benefit.

Edit: '10-'14 GT500 intake has a 106mm MAF, not 113mm. I should have measured it myself versus take the word of some internet jockey.

 

[90trunk]

Roughly two years ago I installed a March air box and enlarged the opening to closely mirror the fender apron opening. Having the air box match the apron can only help things.

Edit: You can see the original March ram air hose attachment point was 5.5” x 2.125”.

 

[DELL37]

Roughly two years ago I installed a March air box and enlarged the opening to closely mirror the fender apron opening. Having the air box match the apron can only help things.

View attachment 1070000

View attachment 1070001

Edit: You can see the original March ram air hose attachment point was 5.5” x 2.125”.

View attachment 1070002

Since my car in put away for the winter I can't take pics so I marked up your pic to show how my fender was cut.

When I removed my air box for the first time I was surprised that the fender had been opened up the way it had. While it was very neatly done and looked professional I was still surprised. Basically there was a huge hole as marked below. My March airbox was held on with a metal flange that had been attached to the front of the box that used the two hole forward of the opening. When I opened up my airbox I simply traced a line from the fender opening to the side of the box and started cutting.

 

[superirish]

You can pass your entire throttle body opening through the factory hole in the fender.
Block that hole off, remove your headlight while at the track, and make a boomtube.

 

[Zookistang]

Years ago I had one of these on my ‘93. I put a manometer fitting in the air box. Without the scoop attached there was -2 inches of water measured. At 100 mph with the scoop attached the scoop pressurized the airbox(pre filter) 2 inches or water. 1 psi equals roughly 28” of water, so there was roughly 4 inches water difference, or 1/7th of a pound.

 

[Cougar5.O]

Years ago I had one of these on my ‘93. I put a manometer fitting in the air box. Without the scoop attached there was -2 inches of water measured. At 100 mph with the scoop attached the scoop pressurized the airbox(pre filter) 2 inches or water. 1 psi equals roughly 28” of water, so there was roughly 4 inches water difference, or 1/7th of a pound.

Good info, thanks for posting. I bet this partially explains the HP growth I saw from 8th to quarter mile. Kenne Bell blower acts like a multiplier of whatever it sees for pressure in front of it, so differences in pressure before the S/C are amplified.

1/8th mile = 404HP
1/4 mile = 459HP