I never trusted advertised dyno runs on intake kits. Think about a dyno run. The hood is open and a big fan is blowing air across the front of the truck. That pretty much rules out any under hood heat factors. Seeing real world numbers is nice.

The roush intake kit totally encloses the filter except for the front. Nice design and good price on ebay while they last.

Other guys have used a mac intake tube in conjunction with either the roush kit or the stock box. Bigger tube for flow yet no "growl". Speaking of the growl- I thought I was the only one that liked to hear himself think while driving. lol. I think you and me are about the only ones concerned with it.

Now to my question- I want to use my stock air box for storage- tow strap. I want to cut my intake 6-8" shorter so the filter ends before the box. Air comes in from the hole in my hood so heat is not a factor. I'm curious about your thoughts on a shorter air tube. The research I did led me to a honda that was running the salt flats. At high rpm they could get a higher mph with the short tube, but they lost at low rpms. They devised a bypass valve (kind of like an exhaust valve) that would change from a short tube to a long tube. I'm curious to your thoughts on running a shorter tube, keeping n mind heat is not a factor.

 

[QUOTE=wydopnthrtl]Yep.. just a simple make-shift box that sealed off all air except from behind the headlight and inner fender./QUOTE]

First off thanks for the great research and you have the right idea!

....and so did ford with the oem air box that came stock on your truck, but you have managed to solve the daunting task of fitting a round peg in a squre hole.

An oem box can be used as a templet and by cuting the top off, most cone filters will fit inside(if the snokle is cut/removed.) All that is needed to finish the custom heat sheild/box is a little fiberglass tunnel over the new filter. If anyone would like pics I've been running this set up for about a year. i

Thank you Rich for puttng your time and effort in.

 

I hear what your saying / asking.

It really comes down to how you use the power and what you want to maximize. If your a slow speed off road-er type. I'd think that small efficiencies like this "CAI" really would not be a concern. I'd think mud/water infiltration would be most important.

Assuming you did want to maximize low end TQ with a true CAI.. you need to understand what the heat in the engine room does. (I've done a lot of studying on this subject with my Mustang & Lighting) Using temp sensors and yarn I've studied what does what.

The engine room heat flows in different directions at different times. The majority of it goes out and down past the headers. Even though heat rises.. this is where it goes when your moving. When your going 5-10mph it still flows rearward but not much. Sitting still and the heat pretty much rises until the engine room is full. Then it bleeds out around the hood and fenderwells. An e-fan when turned on will start to push heat out and down past the headers about like when moving 5-10mph. The heat coming off the rad pretty much bleeds out the front and heat soaks everything around it until air starts moving.

Adding a open and foward facing hood scoop does'nt really change this other than when sitting still. It does however pull less air across the radiator when moving! So does raising the rear of the hood or adding a cowl induction hood that's not sealed off. I found this very interesting actually! If you raise the rear of the hood or have a non-sealed CI hood.. the air will flow in in that area and sweep down past the firewall. This will lower temps overall but it pulls less air across the rad and front of the motor!

From a pure power standpoint on a 4.0L ranger driven at speeds under 80mph.. shortening the intake tube length won't mean squat. The TQ is mostly developed from the long intake runner lengths. Anything up streap of the TB really does'nt matter very much.. other than temps.

Since you have that scoop.. I'd shorten the tube as you like. Then encase the filter with a box and have the top open. Make a fiberglass panel that ducts the hood scoop air to the filter.

Rich

 

Not a problem. As far as modifying the stock box. Well.. that would most likely work for the majority of ranger guys. Especially the off roaders.

I on the other hand will be/have increased air flow over a stock setup. Anytime you feed a pump "more" you make it more efficient. I want to make it as large as is possible not only for this.. but I'm going to be mounting a little something in/on the new box.

Also, the larger the volume of air in the box.. the less of a delta T you get when you do sit still. It's a larger volume so heat doesn't transfer in as quickly. And.. to a small degree heat will transfer out of it quicker because you have a greater surface area. The only time a larger box will hurt me is in a true heat soak condition. But.. I live in michigan and when at the track the hoods open. :D

Rich

 

I am mostly there, just need to finish up. Thanks for the info. I figured I would need to seal the box to the hood via some compressable weather stripping. Sounds like that may not be neccessary based on the air movement you dscribed. At least while moving.

 

Yeah looks like your all over it.

On my Lightning I actually found that flooding the area with cool air is 90% as good as a truely sealed off box. In the south, closed hood, and slow speeds might dictate a true sealed off box. But.. if you don't get that hot IMO it does'nt have to be anything more than a "flood" of outside air.

Rich

 

the thought had always been a sealed enclosure with a removeable port in the bottom that I could pull out in the rain. Along with an outerwears cover. In an offroading situation I figured I would be gold unless water came over the hood. At that point I would have a visual to react to a problem before it happened. Couldn't imagine getting to that point though- getting in that deep. I'd be engineering for something that would never happen. Flooding air seems simpler than sealing it.

 

That's what I wound up doing on my Lightning. Besides the blower on that thing is so loud you would never hear the differance of a box or no box.

Considering it all.. I am pretty supprised that I gained a solid 10ftlbs TQ at first WOT. That is certianly something to consider for not only the track. But in daily driving too.

Once I get the box done and working. I'll post pics and power results. Hopefully I'll get this all done Thanksgiving weekend.

Rich