Different approach to a snorkel

What does anyone think of the idea of routing the intake to the firewall, where the fresh air HVAC intake is, below the cowling? Assuming I can get it to fit, I don't see any reason it wouldn't work.

In addition to making room on top of the PS wheel well, creating a high-water intake, keeping a low(er) visual profile, and still sucking cold air, I also see the following advantages: I will be taking advantage of the natural high-pressure area in front of the windshield (forced-air induction), I will be opening up the intake to a full four inches (stock narrows down to three inches as it goes into the sidewall), and I will be straightening out the induction path to a single 90* bend.

Weigh in with your thoughts and constructive criticism.

I have some 4" ABS DWV pipe and fittings to test it out before looking around for proper aluminum pipe and silicone hose.

And for those who say it won't work, Tyler at Pelfreybilt has done something kinda similar by routing his intake into the passenger compartment, behind the glove box. But I *really* don't want the noise/drone that will introduce.

[Editing in progress. I'll clean this up when I get to it. Maybe.]

Got it in today. Piece of cake.
Took me about three hours, 2.5 of which was me tweaking out on getting the hole juuuust riiiight.

Parts needed:
* 4" ID 90* close elbow ("close" = one leg is just long enough to fit a hose clamp)
* 4" ID x ~12" long metal tubing (ahem, aluminum)
* 4" rubber "donut" for mounting clay pipe (Homey Despot SKU #143-175: PlumbQuik part number P44U-405)
* two hose clamps for the elbow (4"ID)
* a few dabs of paint

Tools needed:
* 10mm socket or #2 phillips screwdriver
* 12mm socket with long extension
* your choice of tools for cutting a 4"++ hole in sheetmetal (hole saw, Dremel, files, die grinder, whatever tickles your fancy)


Here's the stock engine bay:




Stock engine bay with intake tube removed:




View under the cowl:



After cutting the hole (sorry, no pics. Possible I'll snap some when I remove everything to paint the bare metal I forgot to do), assembling the tube, and mounting it all up:



You'll note that I have an extra coupler hose on there. That' temporary, as I was using off-the-shelf parts from Schlep Boys (a 6" and a 4" tube). I will be replacing the two-piece intake tube with a single piece of aluminum. The end result will be the 90* elbow and one long, continuous aluminum tube going into the firewall.


Why I did it -- or -- The real estate I gained -- or -- Check out my bad-ass compressor:
(The compressor is just sitting in there for display purposes. Nothing is mounted or hooked up yet.)





The procedure:
This is really simple enough I shouldn't need to explain it. If you're comfortable cutting the sheetmetal of your truck, you probably don't need me explaining how to do it.

Remove the intake tube. Loosen the 10mm hose clamp, unbolt the two 12mm bolts holding it to the wheel well. Remove from truck.

Attach your new elbow to your new tube, so that it is now a single unit. Use this to test-fit where you will be cutting the hole in the firewall. Note that you will very likely need to push/bend the brake lines out of the way slightly, and also note that you will be working very closely to the brake lines when cutting the hole. Pretty sure I don't need to point out just how careful you need to be to avoid cutting the brake lines. Mark where the hole will be, using your preferred method of marking (X, trace a circle, dimple, whatever). Remember to allow for the thickness of the rubber donut!

Start cutting. Again, be careful with those brake lines! Remember to cut a SMALLER diameter hole at first, as you will need to do some cleaning up of the hole, and you can always enlarge the hole with a die grinder (but can't shrink it if you overcut). I used a Dremel with a cutoff wheel, then hit it with my die grinder to get it just right -- if you have a hole saw that's just the right size, use it.

Squeeze the rubber donut into the hole, adjusting the holes size as needed. It should be a nice tight fit. Now work the tube into the donut, making sure it's also a nice tight fit. Adjust the hole size as necessary with a die grinder.

Once you're happy with the fit, and everything attaches well, pull everything out of the firewall and give the bare metal a coat of paint to protect it from rust (the one step I skipped as of this writing). Once the paint is dry, re-assemble everything, remembering to tighten the hose clamps.


The whole project as you see it in the pics cost me about $60. That will be dropping once I exchange the two aluminum tubes and the coupler (and clamps) for a single aluminum tube......I suspect the final bill will be about $30.
If you want a good source for the elbow and T-bolt clamps, let me know. The 4-ply silicone hose cost me $15, and the T-bolt clamps were $4 each.



My notes thus far on performance:
I drove about eight miles between finishing it and posting here. It was on a surface street commonly used as a bypass for freeway traffic, and it was during rush hour......and with one lane closed. Suffice it to say, I didn't get a good variable experience. I did get to mash the throttle some.
Noise: Not noticeably higher. I do sense a low growl when accelerating, but nothing of any particular note. Cruising and WOT don't seem to have changed at all.
Intake temp: No static change -- it still reads about 10* more than ambient. What I did notice was that the dynamic change improved, with the cool-down period after heat soak being significantly faster -- what I mean is that when sitting still, the engine heat tends to soak into the intake, causing the intake temp to soar as high as 50* more than ambient, but when moving all that soaked-in heat from sitting dissipates much faster to return the intake temp back down to ~10* over ambient. At some point I will likely put in some kind of heat shield along the bottom.
Airflow: I have gotten just a bit more vacuum, from ~23 inHg to ~27 inHg. I interpret this as better airflow.
Butt-o-meter horsepower: No change. I can't tell if I gained an extra 2,000 horses, an extra .002 horses, or things stayed the same. My butt's just not sensitive enough.
I will weigh back in on whether there is any effect on cab ventilation. Likewise with low-end power and upper-end power.

[Editing in progress. I'll clean this up when I get to it. Maybe.]


Updated pics post with part number for rubber donut.

Performance update:
Drove around in various on-road conditions today. The proximity of the intake to the cabin air intake does do two things: 1) introduces some noise, generally when under load and at least 40% throttle, and 2) affects the amount of fresh air reaching the cabin.
In terms of noise, it's definitely not at the annoying level. It's a very nice, powerful-sounding low note that is really only there when making the engine work (climbing hills, accelerating hard). It's not loud, but it is certainly audible. I can only imagine how loud it would be if it were routed into the cab!
Because the location of the intake is right at the intake for the cabin fresh air, the two do compete with each other for air volume. During low-throttle conditions the air blowing through the vents is like stock. But as the engine's work/throttle increases, so too does the drop in airflow through the vents. When at WOT, unless the blower is on at least speed 3, you will not be getting airflow out of your vents......except perhaps a slight negative flow. With the fan on high, you'll notice when you snap the throttle shut, because the airflow noticeably jumps.

My highly accurate but very insensitive butt-o-meter tells me that I have a slight increase in torque across the band. There doesn't seem to be any particular "sweet spot" where I get substantially more power. I do notice there is an increase in throttle response.

[Editing in progress. I'll clean this up when I get to it. Maybe.]


I won't have much of a chance to get good MPG numbers for a while. Around town DD doesn't count.


Installed a simple, basic wall to separate the two intakes (engine/HVAC). Used rigid plastic board (think plastic cardboard), attached to the two stock holes on the HVAC intake (bent up to be flush with the rest of the wall......see pic #5) with a couple of plastic removable rivets. All parts I had sitting around already.

I also trimmed the donut shorter, so that I have more clearance between the two intakes.

While I've only driven a single one-mile roundtrip since doing it, I suspect it made a difference. I seem to have less drop in airflow in my HVAC when I'm at WOT. In fact, it seems like I have *increased* airflow in my HVAC when I'm at under-40% throttle, improving upon the stock cabin-air intake pressure.

I'll keep y'all posted when I get some better readings. I'll fire up my OBD2 reader sometime and get some actual numbers with the new air dam.

[Editing in progress. I'll clean this up when I get to it. Maybe.]


Final install pics!
These were shot tonight, as the final version of the project. I've put about 8,000-10,000 miles on this setup with not a single complaint or problem.
The solution to the drop in HVAC air when opening the throttle up is to turn on the RECIRC mode.
You'll note the intake pipe I'm using is a bit ...uh...thick (.180" wall??). If I had to do it over again, I'd get **MUCH** thinner tube! Meh, oh well. It works. And it can probably stop bullets. Pretty sure this is the FleaBay seller I got it from. I bought only one foot, since the total I needed was only about ten inches.











Sorry about it being upside-down. One of the most awkward angles I've ever had to hold a camera and still reach the shutter button.
This is looking from the other side of the HVAC intake -- camera is placed roughly at the centerline of the vehicle, pointing toward the passenger side.








Even after gently bending the brake lines out of the way, it's still a tight fit (yes, they touch).






A good shot of how my engine bay looks right now, minus the jumper cables.


Exactly how my engine bay looks any day of the week, jumper cables, air chuck hose, extra oil bottles, tow strap, roll of duct tape and roll of foil tape, bailing wire, spare tire tools, and all.

 

dont see any reason it wouldnt work.
while i havent looked under the cowl (ill snap some pictures for ya since i have my fenders off and can see into the cowl opening) if it is any way similar to my old Ford Ranger, the wiper mechanism is under the cowl taking up the "free space"

 

Been under there already. No obstructions. The place I would punch through would be right at the fresh air intake for the HVAC.
The cowl comes off piece of cake. Less than a minute of no-tools work.

 

Interested, keep us posted. I was thinking snorkel but this could be a better idea...

 

Curious to see how this turns out. Sub'd

 

Are you just swapping the intake tube location from fender well to cowl and leaving the filter box in same place?

 

Use a cobra head elbow instead of a 90* elbow for better flow in a tight spot....

http://intakehoses.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=90CB40&Category_Code=CHEW

 

Think I like where this is going although I can't figure out exactly where on the truck you are referring to. Seems a lot cheaper than the snorkels though. And on the water issue, anyone re routed their exhaust to keep it from submerging?

 

Yeah, pretty much. Just removing the black rubber accordion tube.

At this point, I'm not having space issues. While there's not enough space to do a full 6" radius bend, there's also not enough space to use a cobra head. A simple close-mount smooth-radius elbow should work fine.

Punching through the upper-most part of the firewall, barely below the rubber weatherstrip, sucking air from the passenger-compartment fresh-air intake area. Where the wipers mount. Simple to find, really: just open the hood and pop up the black plastic cowling between the windshield and the engine bay. You'll see where I'm talking.
There's a good-sized space between the engine and the ABS unit (Sport model, passenger-side) that I can route the intake between, and enough sheetmetal to allow for a decent mounting point for the tube. Just have to find the parts, which shouldn't be too hard.


Speaking of finding parts, could anyone direct me to shops in the OC area that might carry 4" tubing/hose/aluminum tube for intakes? I'm going hit up the ones I know (like Hose Man), plus a contact I found on EvilBay. I try to stay away from the ricer crowd, so I don't know all that many tuner shops around here.

 

this will definitely work well. I was going to run to the cowl, but decided on running to the cab to assure its 100% water tight. I have had water go over my hood and into the cowl before, so the cowl isn't a 100% waterproof IMO - a link at RST to what I did (Tyler at Pelfreybilt got the parts list from me to do the same, but built his own adapter out of aluminum) its really not noisy at all unless you are WOT - cruising on the highway or trail no one would know or notice, no drone or noise at all. Since the truck isn't a race car, I rarely hear my intake. The only time I do is if I am trying to accelerate fast on an on-ramp or if there is a steep hill where it needs to downshift and run high RPM's

http://www.rocksolidtoys.com/forum/showpost.php?p=7920&postcount=90

(i've cleaned up the install a bit since pics - but that gives you the idea)

 

Any chance you can link the photos here? Can't see them on RST unless you're a member....

 

I've seen a lot of jeeps with cowl intakes, but not a tacoma. This sounds cool

 

this work:

 

Not for me

 

nope

 

good now?