Air intake on my 91?

Hi guys, I’m new to this forum and am wondering if anyone has any thoughts on adding a air intake to my 91’ 4 runner. It’s a 4 cylinder. Are they worth the money and if so does anyone have a link to a good one. Thanks.
Sol

 

Never been big on aftermarket intakes. They can help on some engines but I think most are just a placebo or for looks. This is an option for you https://www.knfilters.com/cold-air-intakes/toyota/pickup

 

Waste of money l

 

Save your cash. The only true CAI is the factory air box which actually draws air from outside the engine compartment. If you want some real gains on the 22re get a header.

 

Hey this is a mod I have just done but it is for a 3VZ-E. The 57-9006 kit is a hot air intake for sure and being that the 22R and the 3VZ-E share the same basic Air Flow Meter this might spark some ideas as the OEM air filter and air box is quite a bendy proposition in getting the air to the TB. I think the 22R goes across the engine compartment to the air filter, right?

I have until yesterday been running the K&N 57-9006 kit as designed and supplied by Summit for a cheaper price but as a hot air intake. I have been getting an average of 11 to 13 MPG and nearly getting 150 to 175 mile from a tank full. This is usually with 5K pulls on the tachometer and then shift. It seems to get to 85+ MPH with little effort and doesn't require WOT to do this.

The eureka moment was when I decided to reinstall the OEM funnel that goes behind the headlight that is part of keeping the OEM air cleaner shrouded with air from the front of the truck and not from inside the engine compartment. Here is what I did with my 57-9006 kit.

Funnel's plastic provides a nice surface to seal the clear lid against. Sticky foam backed insulation with foil lines the inside of the aluminum sheet metal frame I fabricated with a jigsaw and some creative bending with my vice and some T section channel from a garage door opener track. I screwed this to my work bench and it acts as a bending tool edge with vice grips and c-clamps.

I sealed up the large NPT in the K&N's casting and put a filter on the muffler box for the air injection. I re-purposed the supplied K&N brackets to mount the muffler-box to the structure.
Will this get failed for smog in two year time will be the question. The path from the AFM to to the TB is certainly more direct to the engine. The pressure drop across the air filter is symmetrical with the opening to the AFM's square flapper port with nice radii that the casting provides. Now only cooler outside air from around the headlight goes into the filter chamber. Sure wish K&N had done this when they created the kit!

 

Wont give you any detectable gains

 

Sure it will there are at least two 90° bends in the OEM air filter and the pipe running to the TB has three in it. Any pressure drops incurred with a naturally aspirated engine hurt when all you have to begin with is 1 ATM at sea level. Those losses can be directly attributed to the minor loss coefficients for bends inside the intake plumbing. The same thing goes for the exhaust as well. The 57-9006 kit improves getting the air into the AFM because it is a straight shot through a larger conical air filter that is located equally around the casting that is fixed to the AFM's square flapper port. The full radius at the entry to the flapper port is an excellent improvement in reducing another minor pressure drop in getting the air to flow into the AFM. This is way better than the OEM design were the air is turning to get into the AFM port after it had to turn to go up through the air filter. The K&N kits path after the AFM removes about 1-1/2 bends on the way to the TB. The friction loss coefficient value for an elbow is 0.3 or 0.2 for a long sweep. The change in pressure as a minor loss is equal to the minor loss coefficient x density of the air x flow velocity squared / 2. So you will not feel this when the engine is coming off idle but when its humming above 3K things get a lot more interesting because the flow velocity is squared in the equation and so when you can remove some of these minor loss pressure drops from the intakes design, the engines ability to make as much power as it can is enhanced because it is getting more of that 14.7 psi into the plenum. Fewer minor pressure drops mean more air and the ECM will deliver more fuel which results in more horsepower. With about 5K miles on my recent engine rebuild and a heavy right foot the tank full is lucky to clear 150 miles. This recent CAI shrouding is in the hope of keeping the air density as high as is possible by drawing the cooler outside air from behind the headlight bucket. We will see what the next couple of tank full yield in range with a true K&N 57-9006 CAI design.

 

Again nothing detectable you have to have sizable gains to really see numbers change. An exhaust and intake wont do that.

 

2016Pro,

You are being a real downer. As for nothing detectable you are not driving a 1990 with OEM exhaust and a 1991 with Thorely and 2-1/2" FlowFX-CAT-Back side by side for comparison both with 3.0L V6's.
When Ivan Stewart was making the rounds with the PPI Toyota as a class 1 SCORE entry in the mid 1980's, I was racing in SCORE 7S in a Toyota with my good friend Mike Falkosky. Our sponsor-ship ranged from Downey Off-Road Manufacturing, BFG, Doug Thorley, Doetsch-Tec Suspension, Fab-Tech, Jamar to name some of them. That V6 in Ivan's PPI Toyota was mostly a 3VZ-E. Sure the heads were worked and the cams were tweaked. Oh But I remember that sound like it was yesterday. And I tell you this 2016Pro, the 3VZ-E likes to rev and make power. Sure its not going to ever by a torque monster but the 1991 4Runner I purchased and drove home as stone stock with 230K is nothing like the ride I have now with 241,556.