Developing a 67-72 LS/Fuel Injection Air intake

[siggyfreud]

Hey all,

I posted a bit back about what parts people would like to see created if I were able to start 3d-printing and designing some pieces. I appreciate all of that feedback and will be looking to it for some upcoming projects.

One of the first projects I want to do is of my own personal interest, and that is to design a cold air intake box for those doing LS/fuel injection swaps. In many of these swaps people are left to either an open filter that can and does suck in warmed radiator air, or they're left to use a universal air intake box.

My goal is to design something that fits nicely in our engine compartment, keeps the air cooler, and utilizes a factory-available air filter.

I'll be using this thread to keep people updated on the progress.

I have a few design documents going, and a list of requirements, but feel free to chime in if you think of something you'd like me to try and incorporate.

My first goal is to build something functional. After that, I'll turn some attention to tuning the aesthetics.

Tonight I wanted to mock up an idea for the Mass-Airflow adapter. The idea here is to have a piece that you can bolt a Delphi MAF directly to, after an 11" run of straight tubing to measure at the smoothest airflow. The large flange would bolt to the airbox and would be clockable (slotted on the box side) to allow fine-tuning of orientation. RIght now keeping it a circular flange makes it easier to use a slotted design on the box side, but I may change it for aestetic reasons later on.

The MAF would bolt to the other end and would utilize the factory MAF gasket.

Additionally, I have designed it to have a 1/4" air gap, as air is actually a pretty poor conductor of heat, and thus it should help keep IAT temps down by preventing the inner tube from heating from ambient air. That said, I'll be printing a tube without the shield and doing some tests to see if it helps and if the amount of help is enough to warrant the extra material and cost.

This is just a quick mockup and isn't designed exactly to spec. I'll have to buy a MAF to get the right dimensions, and pattern for the bolting surface.

I'll also be adding an optional IAT sensor port, that could possibly double for water/methanol or nitrous sprayers.

[RedRider]

Functional and aesthetically pleasing...I'm subscribed!

[siggyfreud]

Thank you! I'm excited to see how it changes as I iterate on it. One of my requirements is that hardware isn't exposed to the internal ducting, meaning that if a nut were to come loose, I don't want the engine sucking it in. Not a big problem if I use a cone filter that covers the entire opening, but then that means the intake must be rather deep.

So expect it to change over time as I continue to brainstorm a bit.

[RedRider]

Two things I learned the hard way: First, how sucking in hot air can kill power. I moved the intake as far to the side as possible, and it made a significant difference on the dyno. Then I had to move the MAF because it wasn't in a straight path of air.



These are very important factors many people don't consider as part of an LS swap, glad to see your model is addressing both.

[rowdy11]

Subscribed. Interested to see what your final design looks like!

[TA_C10]

Siggy here is the design I was talking about on my fox body stang. It's simple and worked well. Forget about the crap design of accordion style tubing feeding the S/C.... We can do better. But even this performed well on dyno and day to day driving. What I was focusing on was the placement of the MAF sensor right inside the filter housing. It's directly behind the filter so your essentially in a straight line with air flow. Then the bend happens after the sensor which on our trucks would be somewhere in the 50-85 degree bend heading towards the TB.

Just an idea here. Keeps the sensor safe from turbulence.

[WIDESIDE72]

Im in!

[TA_C10]

I got my LS Swap book out the other day and look what I found.... This is about as official as it gets. Straight from GM. Check out the top paragraph in the second pic too.

[Keith Seymore]

Originally Posted by TA_C10

I got my LS Swap book out the other day and look what I found.... This is about as official as it gets. Straight from GM. Check out the top paragraph in the second pic too.

Sounds right.

Here's my design (I did the engine air induction system for the GMT800 trucks, for the 1999 model year).

K

[siggyfreud]

Awesome info from all of you, thank you very much! I unfortunately was sick over most of the holiday and didn't get much done. I think the next step is to map out the space I have to work with, and determine how to best utilize it. I'll also build a rough core support in the program too so I can visualize spacing better.

If I wasn't in the process of selling this house I'd take apart my front end and really measure and map out the core support better, but I don't want to dig that deep into the truck at the moment.

It sounds like the approach of moving the MAF down-range of the airbox a bit though is correct, so I'll continue in that vein.

I may make that end a flange of some kind as well so that you can interchange MAF adapters, since some have different bolt patterns.

Additionally, I might not make the part that goes to the airbox a bolt-on piece, and instead have an outlet that connects to the MAF pipe via a flex coupler to give the whole unit some sway. I can't really print a flex piece very well, but using some soft coupling like used in a turbo setup could connect two pieces, and give the system some of the anti-vibration you'd want in it.

Keith thanks for that photo. Might ping you for some input once I have a better end-to-end design in mind.

Cheers all!

[siggyfreud]

TA_C10, looking at that book it looks like I could also just have a MAF boss printed right into the pipe so the use of an external MAF housing wouldn't be required, right? Are those standalone MAF sensors harder to come by?