K&N intake 57-9027

Currently a lot of chatter going on about intakes and pipes. Decided to buy one and play around with it. And having done nearly every 1GT NA performance mod worth a damn, why not end at the beginning? The air intake system. True to form, I've installed the easiest and most common speed part last.

Enter this thread with these facts in mind:
-Everybody knows oiled filters are no good for MAF and throttle body cleanliness.
-Every 1GT owner knows that the factory pleated paper air filter performs better on the dyno and cleans the intake air better than aftermarket.
-Smooth intake pipes tend to make more power than stock 'accordion' or chambered pieces.

Those facts stated, our 1GT factory intake piping is internally smoother than other vehicles I've worked on and only features a large chamber in the center. Other vehicle makes state these chambers act as a harmonic resonator, intake noise dampener, or an 'air reservoir' for throttle transitions.

The chatter going on currently is about how to get the best of both worlds. Factory filter efficiency with better flowing piping.

Airaid used to offer a kit to replace the stock piping while utilizing the stock airbox. K&N purchased Airaid and those kits are NLA. Some members have been able to buy the Airaid pipe only, but not anymore.

Here comes the K&N 57-9027. Uses the factory box, albeit modified to fit a goofy square based conical monstrosity of an oiled filter. Key to this stupid experiment is that it replaces the stock intake tube.

First thing was to throw away the directions. Don't need those. We're going to see how to make this work to suit the 1GT ideal.

The kit is intended to relocate the MAF further down the intake stream vs. the snout of the intake box. My assumption is with the airbox modification and squared cone filter this causes additional air turbulence, moving the maf further down the intake tube puts it into smoother flowing air.

Not going to do that. We'll be using the unmodified air box, OE filter, and factory MAF location.

I used the kit's MAF adapter plate and stock location MAF plug on the opening in the pipe. If this causes any driveability issues I will change it to the K&N intended location.



Everyone knows how to install an air intake kit, so I did. Used the kit's supplied silicone couplers, hose clamps, NPT to barb fittings, and replacement vacuum hoses. The kit reuses the factory vacuum hose for power steering idle switch.





Zip tied the OE hoses and clamps to the stock air intake pipe and tossed it in the box with the K&N frankenfilter that comes as part of the kit. In case I ever need it.



Kit comes with a CARB Compliant sticker for you left-coasters. I live on the right and correct coast so I don't need it but put the sticker on my truck anyways.

While cleaning the spot for the CARB sticker my mind wandered. I bet there are some criminal minded fellows in this world that would gladly sell a CARB sticker that they don't need to someone trying to pass an emissions inspection. But everyone knows that smog dodgers eat corn the long way, enjoy Snickers dick vein side down, and are generally unsavory people not to be trusted.

Anyways, our resident 1GT guru @Shifty' has been able to purchase K&N and Airaid intake tubes. Without buying the whole kit. I bought the whole kit just to throw away the expensive filter because I can't be assed to source individual parts. Maybe he'll be kind enough to chime in with links to his posts in the Lunchtable thread.

If you choose to do a DIY 'best of both worlds' intake you need parts from K&N manual and local sourced:

https://static.summitracing.com/glo...cQFnoECB0QAQ&usg=AOvVaw0EzPSfPnZO9sFXskXT_Aj7

From K&N parts - C, L, O, N, and K from the above link's installation diagram.

Local sources -1/4" NPT to 1/2" barb, qty 2 - 1/4" NPT to 1/4" barb, qty 2 - 3.5"ID x 2"L hoses, qty 4 - 3.5" hose clamps, 1 foot of 1/4 vacuum hose, and 1 foot of 1/2" vacuum hose.

I'll post a reply in a few days to see how the stock MAF location jives with this kit. I probably wont dyno this. But I probably will too. Haven't decided yet. If the butt dyno feels like a big improvement, I'll book a dyno session.

 

Watching...

 

Now this is how you make a thread, bringing together all the chatter in various other ones.

If I get my airaid just-the-tube, I'll write a full report.

I'll also just note that the K&N CS agent said they are working on an airaid tube replacement part. No further details. Not sure why, when nobody mainstream brings out new parts for our trucks these days, and K&N themselves already have this kit you got.

Looking forward to reading about your results.

 

Correction to my parts list: For the 3.5"ID silicone hose that attaches between the airbox and pipe use either a longer hose or the bubble type shown here. You need additional flex here as the airbox is stationary while the engine moves side to side with throttle.

 

Oh, one other question I had. What does the MAF port look like on the inside of the tube? Is it a turbulent looking spot with just the block off plate?

 

The OE piece looks like this. Didn't take a pic of the K&N side.



K&N side should be pretty smooth. The MAF adapter plate doesn't enter into the pipe and the MAF plug is shorter than the MAF plate.

The threads for the MAF plate screws may extend into the air space by a minimal amount. I would guess by less than 1/4" - 1/8".

 

I’ve been ditching my oiled filter every two years for smog here in Ca. With the Airraid intake I used to replace the tube and everything for smog. Removing the intake but, leaving the tube in place with stock airbox a few smogs back. Passed no problem. The resonance always sounds cool but……. @shifty` knows best. Airraid tube with stock air box definitely feels more punchy.

If you can find an Airraid kit, jump on it. Time to clean my engine bay!

 

Hey all. Rounding things out with the Airaid Tube, part number KIT981T. The only real alternative to buying the K&N in the title thread.

I received what K&N purports is the last KIT981T tube that they had. They did say that that part number is discontinued, but it is referencing a new PN in their system, something currently in development, no other details. If you can and mention KIT981T, they can see the new PN and may have an update in the future. This could be BS, and their supersession might just be the K&N kit itself? I dunno...

So, I ordered the tube, and both of the rubber pieces. I sourced the rest myself. Below is a breakdown of parts, but some clarifications first....

Airaid has a few kit numbers that contain the same tube, as noted other places on the internet... Two easy to find kits, if you JUST want the tube are 510-781, and 511-781. The only difference is the air filter. HOWEVER, 510-781 has the tube part number listed wrong. Irritatingly, 510-781 has BETTER descriptions of all of the parts needed, it gives better dimensions for tubes, hoses, connectors, etc etc. I'll try to summarize below. K&N will also only sell you a limited number of parts when you a la carte, so you may not be able to buy everything from them.

KIT981T: Modular Intake Tube. It is my impression that the parts below will also work with the K&N tube, but honestly, you should probably just buy the kit instead of piece mealing. The vacuum situation is different tho!

KITHUMPS03: (Intake tube to air box) 3 1/2”x3” Hump Hose. I got theirs, but there are a few options on summitracing.

KITRDCR04: (Intake tube to throttle body) 3 1/2” To 3 3/8” Reducer. There are also options on summit racing, mainly one from Vibrant Performance. K&N had a hard time finding this PN in their system. PN might be KITREDUCER04. @shifty` I have an extra one of these if you want it.

KITHOSE01: Easy to source any old place, 1/2x13" is a touch long on my truck. Connect this to valve cover and large barb on tube.

Misc pieces and hardware:

- Hose clamps. I got NAPA ones down the street from me: 7051026. These clamps are slightly too wide for the grooves in the hump hose but they will hold. I will probably get OEM ones, because I want them to have Phillips and a 10mm head, not standard close to 8mm and a flathead. PN 90460-99010 will match your two other clamps.

- 1/4 x 4" hose. Also an easy source. 4" seemed correct.

- 1/4”x1/4”x1/8” Vacuum Tee. I got a cut to fit tee, because it was available at my parts shop. I will probably replace it with Dorman 493-047. Note that the small fuel line/Breather doesn't fit well onto the barb, so I added a tiny Constant Tension Band Clamp (see photo below). Sorry I don't have a size.

- 1/4” Barb x 1/8” NPT Fitting. I dont know if this is the same on the K&N or even other Airaid tubes, but my threads were tight and in danger of stripping. I chased the plastic threads in the plastic tube with a 1/8-27 (NPT) tap. Then an old 1/8" NPT screwed right in. I used Gates G37100-0402 but there are options on summit too.

- Washer and Bolt. I just picked up a shorty 1/4x20 (coarse thread) bolt. I may change it out. It bugs me that this isn't METRIC.

Some other observations... The stock tube is very smooth inside. The large baffle box on the back where the vacuum lines go into... Is just a hole on the inside, maybe 1/2"? The air does not get routed THROUGH this portion. The intake is MUCH more straightforward than my LM7 stock intake was. Thusly, the sound "improvements" are not as great as on my Silverado. There is some sound improvement, mostly growl between 2K and 3K, above that the truck was already loud and sucking for air. My E-rated tires, loud concrete interstate, old front hubs, and wind noise, kept me from really hearing it above 60MPH.

As far as increased performance? Based on the inside of the stock one, and this new one? None to me, although it might "feel" like it cause big truck go vroom vroom now. Oh, lastly, I left my charcoal filter in place, didn't seem that restrictive to me and I didn't have the heart to break it out yesterday.

All I really wanted was a little more sound. I got it, but I thought I'd get more. I'm glad I didn't pay for something more expensive, as I would have been pretty disappointed to have spent more money. The tube and two couplers were like $150. (The K&N couplers were cheaper than online) and the rest of the hardware was like $20 and some scrap tubing.

I'll drive more and try to remember to report back.

 

Looks good. My main goal behind this isn't performance, it's engine bay cleanup. Honestly. I want to reduce clutter in the bay, and if there's a side perk of smoother airflow into the truck, that's a bonus all day long.

 

I agree with performance gains. Feels minimal. Driving around town the last couple days it feels like there is a slight bump in partial throttle torque. Haven't done any WOT blasts yet.

 

Makes sense. I'm not totally convinced on the smoother flow! Do you want my extra reducer tube?

 

I shot K&N an email today asking about parts. I expect they won't reply for a day or three. It almost doesn't make sense to send it, if they're doing free shipping, it may be cheaper just to buy it? What was their item cost on the reducer?

 

I think it was less than $20.

 

Just dropping this in this thread because it's another example of modified intake tube from @Baller: https://www.tundras.com/threads/k-n-stock-air-box.157312/

 

Thinking about these setups, I wonder if the inlet to the airbox is the Achilles heal. We can put big smooth tubes from the airbox to the TB, but it all loses function if the inlet to the airbox can't provide the volume of air needed to really run. Has anyone made the inlet bigger?

 

TRD made an intake trumpet that sits in the fender for our factory air box. Maybe someone with a 3d printer could reproduce it, or a larger diameter version.

 

It may help smooth out the fluid flow into the intake, but Bernoulli told me increasing the holes diameter is the real answer. Ideally, the inlet diameter of the box should match the outlet.

 

For the vvti 1st gens, the TRD "air accelerator" (velocity stack) works with some mods.

 

From what I can gather, none of that opens up the inlet. At best, it just reshapes it.

 

That's why I said someone with a 3d printer should recreate it with a larger diameter.

Or just buy some stubby ITB velocity stack that will fit in the fender and allow one to enlarge the intake hole in the air box.

 

The '16+ Tacoma one is larger I.D. 4.33" vs 3.98", approximately.

 

Summit sells a shallow 5-1/4" aluminum velocity stack.

https://www.summitracing.com/parts/ofy-5315