Cold air intakes? What have you tried?

Trying to think outside the box here on this. Maybe slightly heat/melt the plastic and then form your custom ‘flare’ on the rim of your existing intake. I’m assuming the ‘flare’ is the magic design detail we are trying to achieve?

 

The flare is called a velocity stack. It creates smoother airflow and faster movement of air. This improves cylinder filling at both part, instantaneous and wide open throttle.

https://en.m.wikipedia.org/wiki/Velocity_stack


Anyways, you cannot re-form the current tube without cutting the hole in the inner fender larger to fit it through. Which would somewhat defeat the purpose as I still want to pull only then cooler air outside the engine bay.

Different shape and it has a larger diameter iirc. 2nd/3rd gens have a different airbox and fender opening.

 

Either way you’d have to cut the inner fender whether you purchased a new ‘stack’ or you modded the existing one with ‘flares’.

Porting the inner edge of the intake inside the filter box with a file would also help? Might as well.



I don’t have the time right now to mess with this, but it doesn’t look too difficult to melt that ABS with a heat gun and flare the edges out using a smooth piece of rounded wood. The flared edges may be flexible enough to fold/bend and stuff into the existing hole without cutting the inner fender. Not sure as I’ve never removed my Air Box.

The other option is remove the quarter panel and push it in that way. Or, fab up a metal blocking plate and slip it over the enlarged inner fender hole/new intake and tape or caulk it in place against the inner fender for a somewhat clean fitment upon Air Box reinstall.

While one is at it one could block off those holes and other hot air entires that already exist on our inner fender side panel.

Question for me is: Is this worth it all? I’m not spending money to find out, but might try this using what I have no money out of pocket style.

 

Seeing that the k&n actually moves the mass airflow sensor it “might” add some performance. Because changing the diameter of the tube the sensors in will trick the maf into reading incorrectly which can mean more power... but I don’t have one to actually see what the difference is

 

I’m going under the assumption that @assassin10000 is trying to find a stack end that fits the existing OEM Air Box set up on the pre-filter intake side. Didn’t realize we are changing tube diameters other than the Stack Tip. I’m confused now. I’ll sit back and learn some more.

 

Computer is programmed for the maf to read based off air velocity tuned to the size of the stock tube where the sensor sits. Larger or smaller diameter will make the readings appear incorrect. Which can trick the ecu into adding or removing fuel.

 

Will flaring the just the tip on the Pipe entry trick the ecu? Or, will it just make the air flow more efficient? Or both?

So, we’d need a tune with a new tip? We can’t tune our trucks ecu I thought?

 

Anything before the sensor won’t mess with readings, but you will get smoother airflow which may help a bit

 

This sounds plausible. Smoother flow helps anything. I’ll sit back and watch and maybe tinker in a few weeks.

 

Ah, but here's the trick with the TRD 'air accelerator'. As I am to understand it's flexible (rubber I think). I'm hoping it will both compress to fit through the existing hole and form to the airbox inlet shape.


Yeah, it may be possible to reform the airbox but abs plastic becomes even more brittle when reheated and reshaped iirc.

Correct. I'm just interested in adding better flow into the airbox currently.

^ This is what he was getting at talking about CAI and the K&N setup specifically. Not what I was doing.

No trick to adding a velocity stack to the entry of the airbox (or on flaring it). It just adds a little more efficiency.

The maf/tube diameter at the top of the airbox hasn't changed, so the stock tune (fuel tables) still apply. No change to the accuracy of airflow readings.

So no tune or retune necessary.

This is the goal.

The 1st gen Tundra airbox is near the same inlet size as the 4th gen 4runner with a larger engine. Increased flow to the airbox may help a bit more on our 4.7L than the smaller 4.0L. That's my current thoughts on this.

I'm also looking at a drop in filter to go along with this. Leaning towards the AFE Pro S washable dry filter.

That and maybe some 12 hole injectors too.

 

The K&N plays tricks in a few ways.
1) maf is further up the tube vs being right off the box.
2) maf has a little foam spacer that pushes it out of the pipe a bit.
3) the opening of the tube within the filter is slightly smaller than the stock tube if I remember right, but the tube gets a bit fatter as it gets toward the maf.

I'm not sure which airboxes you guys are eyeballing, my Tundra box looks like this. I hacked the end off the tube long ago and just left the part that pokes through the fender. Measures right at 3" ID


The rib with the foam is what presses against the fender. Option A is to fit a velocity stack onto this part of the pipe. Option B is to remove this section of pipe completely and run the biggest pipe possible into the box with a velocity stack on the end (in the fender). You would need to peel back the inner fender to attach that pipe, I don't have any inner fender to worry about.

Freshly trimmed nails for the amateur hand modeling points.

 

That AFE is pretty damn good quality. I also really like the AEM dry filter (K&N is the parent company but AEM are better). I have an Airaid filter and its pretty badly designed, less filter surface area than stock.

 

If the spot the MAF is in is the same diameter as the OEM airbox, it should read the same. It doesn't matter if it's closer or further from the filter. The foam spacer may just be their seal/gasket.

The only reason I can think they probably moved it further away, is the airflow may be more turbulent from the cone filter vs the panel filter, which can cause odd issues to occur.



Looks like your airbox is different than mine. Mine has that odd shape and is a little larger works out to about 3.5-3.75" I.D. vs your 3" I.D.

Perhaps a non-VVT-i vs VVT-i difference?

 

What if vvt-i is a fraud and Toyota just made the intake bigger

The K&N lifts the sensor and seems intentional. Aside from the foam, which does seal in place of the o ring, the pad where the maf mounts is a bit elevated. I'll maybe get it down off the shelf to get some pics this week.

 

I drew inspiration from watching swimsuit models arching their backs on the beach.

 

The ol Nantucket finger arch

 

Took a peek a do down through the inner fender holes. The 2002 has a shape like this.

 

Here's a few pics off a '00 that still had the lower part of the airbox at the junkyard.





Not applicable to me but may help someone else out.



Anyone fitted a filter minder on their truck and how long until you needed a filter? They also come on the fancy TRD intakes.

 

That, from what I could see via the holes on 2002, is what mine looks like.

 

Yup. Thats what mine looked like before I circumcised it. No idea why Toyota aims them backwards, as if you'll need ram air when hitting reverse.

 

Factory shape is likely to keep it quiet and keep dirt and water out. Not much performance to be gained here that doesn't sacrifice the ability to do it's job, which is filter contaminants out before they get to the motor. The fact that a million mile example of this motor exists (2 in fact) points to the factory design being effective. I'll be leaving mine stock as I have no plans to replace this vehicle. Ever.

 

This Rib Design seems futuristic. Guessing it adds 5hp.

 

My best guess would be in case the bumper/fender is off, the scoop doesn't become a debris/snow/sand catcher.

___________________________________________________


Ordered one over the weekend and picked it up earlier today.

This will only work with the oddly shaped 05 & 06 VVT-i airbox inlet. The earlier ones are smaller in diameter.





Test fit into the fender was successful.


Picture is of the 1st cut with about 1/2" to 5/8" lip remaining. I cut it further back to about 1/4" after removing the foam tape.


I also had cut the bottom portion except for a lip off of the rubber TRD stack. If you look at the 1st pic, basically I trimmed the part with the rectangular hole that helps retain it to the TRD CAI.

Looks like this in the fender now:



Whether or not it makes a difference is hard to say without a dyno. Maybe worth bragging rights? It was only $8.


I did a MPG check.


MAF Gs / Load %, Est. MPG and # of readings averaged.

2075rpm 65mph 5th
34.4/34.8 19.1 x27

2200rpm 70mph 5th
39.9/38.3 17.6 x20

2375rpm 75mph 5th
48.2/43.0 15.7 x10

w/TRD

2075rpm 65mph 5th
34.0/34.9 19.2 x32

2200rpm 70mph 5th
40.4/38.4 17.6 x32

2375rpm 75mph 5th
46.9/42.3 16.0 x13

Possibly gains at 75mph. Makes sense as the velocity stack doesn't help much until air starts really flowing. I'd need a dyno to see how it helps on max hp, acceleration, mid-range and tip-in.

 

Cool write up @assassin10000

I’ll remove my box this weekend as it will give me a good reason to Feather Dust underneath it. Might put some Ric Flairs on the outer scoop using a Heat Gun as described earlier.

Thinking out loud here that it looks like the Original Opening on the OEM Pipe has a larger surface area opening ‘scoop’. Your new one has a smaller area scoop. I’m measuring the angle of the dangle on the OEM pipe vs. the squared off new one.

 

Added some curves to the Intake Tip using a Heat Gun to slightly melt the ABS and shaped it with a wooden implement. Prior, I ported off the square edging around the rim to give the air some taper.

 

Ported the top portion of the Air Box Inlet Pipe. Next step is adding a ‘Ric Flair’ on the MAF Inlet.

 

Hopefully it works for the better. MAF sensors can be super picky about turbulent air flow and do strange things.