2016 4Runner SR5
Senior Member
Ah, and, I hope you all like the new title of this thread
Intake restrictor / insert / reducer / delete from air box
- Thread starter 2016 4Runner SR5
- Start date
4Rocker
Junior Member
A manufacturing engineer's speculation: the tube the OP perceives as a "restrictor" does two things:
1. Smooths the airflow coming into the airbox (as has already been mentioned)
2. Allows Toyota to use the same bottom filter box molding in the 4runner as the 10+ FJ cruiser which is identical save the addition of a cyclonic pre filter in the same location as the 4runner's tube. (Common base to lower the airbox assembly cost)
I'd be willing to bet that if someone did the math to calculate the engine's volumetric airflow at red line speed, the diameter of the stock airbox opening would be plenty sufficient to achieve that flow. My butt dyno detected no power loss after swapping in the FJ airbox base. I'll take the extra filter life over imagined power gains anyday!
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1. Smooths the airflow coming into the airbox (as has already been mentioned)
2. Allows Toyota to use the same bottom filter box molding in the 4runner as the 10+ FJ cruiser which is identical save the addition of a cyclonic pre filter in the same location as the 4runner's tube. (Common base to lower the airbox assembly cost)
I'd be willing to bet that if someone did the math to calculate the engine's volumetric airflow at red line speed, the diameter of the stock airbox opening would be plenty sufficient to achieve that flow. My butt dyno detected no power loss after swapping in the FJ airbox base. I'll take the extra filter life over imagined power gains anyday!
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Why delete? This is a very entertaining thread. This thread is a very scientific posting more so than the daily posting of "Should I get a TRD INtake?" or "I LIke LEDs Where Can I buy?"
wfo9
New member
I think I understand that, but maybe my question was a little different. (Granted, my mechanical knowledge is limited, and dangerous when I comment here)
It's not like this "restriction" is an adjustable valve of any sort, like the throttle valve in a carburetor, but if it is a restriction then would it have any venturi effect at all? Could it help create suction through the accordion filter*? (similar to the restriction before the throttle valve in a carburetor?)
Now I'm confused which side of the filter it's on, but oh well
No there would be no reason to venturi it there for performance reasons... That type of stuff happens down in the intake runners. This is way too far back to make any difference. It is only there for distributing air across the filter media...IMHO.
If one wanted to eek a little restriction out.. they would remove the carbon filter on the lid.. but even that will make no major difference in the pressure drop.
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2016 4Runner SR5
Senior Member
I didn't delete anything at all. I just changed the name. it used to be titled "intake restrictor delete" but I now changed it to cover all the different names this little plastic insert has been given lol.
83Mule
New member
As the OP said, it won't hurt anything and is easily reversible so go for it! I doubt Toyota failed to spec enough flow for the intake but clearly sound suppression was the priority over performance so why not experiment. I built my own cowl induction for my Mule and eliminated all the stock ''suppression junk'' and it made a noticeable change as well as raised my fording depth. I love to ''Try'' stuff!:thumb3:
2016 4Runner SR5
Senior Member
Carbon filter has been removed also, I think I forgot to post that. I agree, I'm sure it's a very small improvement in restriction but improvement is improvement.
As far as removing restriction, I absolutely did notice a difference in performance when removing the huge stock paper air filter and replacing it with the AFE Pro Dry filter. If no one takes anything away from this thread, at least listen to that one piece of advice.
TRUSTYAXE
New member
Does anyone else get dirt trapped in one small section of the air filter more than anywhere else? I know I do and from the pic on page 1? of the Titan filter they do too. So is the engine trying to suck air through this one small area more than anywhere else? Is this caused by the intake nozzle/restrictor? I don’t know but I am willing to try it out. Fun, quick, free, reversible mod.
there's actualyl a flow test somewhere on the world wide internet that proves the charcoal filter hardly barely restricts the intake system... too lazy to dig for it.. good luck
so in theory once that corner of the air filter gets caked with dirt and dust, air would have to flow through the next path of least resistance: the rest of the filter. So why not just take it out entirely and let it flow freely
Altim8
New member
Don't forget that improvement in one part of the breathing/exhaust system doesn't affect the other that much.
Yes, modifying the stock setup or adding a CAI will help with some gains. However, unless you swap in free-flow headers, high-flow cats, and a catback, you aren't going to see the gains that you would expect. Each restriction down the line lessens your possible gains by significant percentages. You can put a ton more air in, but if that air is restricted on the way out....
Yes, modifying the stock setup or adding a CAI will help with some gains. However, unless you swap in free-flow headers, high-flow cats, and a catback, you aren't going to see the gains that you would expect. Each restriction down the line lessens your possible gains by significant percentages. You can put a ton more air in, but if that air is restricted on the way out....
what I need is a hot air intake .. at home in the cold north east 14.5MPG.. down here in sw Florida 20 MPG .. need warmer air into the engine that will save much of gas....back home ..winter .
like the old carb days air cleaner temp divert er ..
on my 2016 the air filter box has no restrict-or .. just checked it out 2 weeks ago. all open .. I did notice when I took out the air filter , it did have some discoloration in certain areas , the rest was very clean 10K miles.
like the old carb days air cleaner temp divert er ..
on my 2016 the air filter box has no restrict-or .. just checked it out 2 weeks ago. all open .. I did notice when I took out the air filter , it did have some discoloration in certain areas , the rest was very clean 10K miles.
2016 4Runner SR5
Senior Member
So I've been averaging a consistent 14.0 MPG here lately with winter gas. I've put 175 miles on my truck since this mod and as of today, I'm averaging 14.7 MPG Anyone else notice any kind of gains? If so or if not, what filter are you running and do you have any exhaust mods? Need to know everything in order to paint a clear picture.
its winter dude.. i bet your 4runner takes forever to reach optimal temp..
TRUSTYAXE
New member
To be honest I’ve been getting on it a little more lately to see how it acts. So I haven’t even looked at mpg. Ordered the URD MAF tuner to compliment the intake and exhaust mods. I can tell you when I kick down to pass it pulls harder.
Borla cat back.
2016 4Runner SR5
Senior Member
5 minutes maybe. These trucks warm up very fast, one of the things I love about it. Either way, that has nothing to do with the improved economy. It was a week ago when I did the mod, still winter lol. Lets hope it keeps climbing and isn't a fluke. I will fill up at the same gas station for the next few tanks just to be sure.
2016 4Runner SR5
Senior Member
So picked this up to add to this mod. The way I see it, with the restrictor removed, carbon filter removed, AFE Pro Dry drop in filter, and the TRD air accelerator, I'm damn near the TRD intake for about $75 and a little time. No I don't have the smooth intake tube but I'm OK with that for a savings of $300+ I'll be installing this Friday night and I'll post updates and pictures after the install. BTW the TRD air accelerator is $10 from the dealer.
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rayofsi
New member
the notches don't line up, but you can still have it fit. No noticeable difference. I have this on stock airbox with all the mods.
2016 4Runner SR5
Senior Member
Yep pretty much figured it was a waste of $10 but it's a $10 feel good part so I'm OK with that.
