What's this hole in my air intake?

[Yury]

I found this round hole on the intake tube which I can't make sense of.
Is it supposed to be there? It looks like a simple round drilled whole.

Seems kinda weird that engineers went through designing all the smooth ends and transitions for the air flow and just put a whole in the middle of it.





Coincidentally, when I apply throttle, at some point the intake sound goes from smooth purr to raspy.
And the gas mileage is unremarkable. It's not totally horrible, but not great either.

Anyone can see of their cars have the same hole? I am temped to tape it up with duct tape.

PS just looking at the pictures I noticed something that looks like a faint pencil mark near the hole...never noticed that before. Interesting.

[Betrivent]

I may hazard a guess that they use the same piece for multiple cars, and in our car the hole is not required, but in another application there may be a fastener there.

[Yury]

Originally Posted by Betrivent

I may hazard a guess that they use the same piece for multiple cars, and in our car the hole is not required, but in another application there may be a fastener there.

Possible, but I'd like to know whether it's present in other yarii.
However, it seems weird. If super smooth air flow is not that important why not to simply end the pipe there with a straight cut.

[Betrivent]

I think it'd only be applicable to other yarii with a 1nz-fe engine, of course smaller or larger engines have their intakes in a different location.

I presume they fitted the intake there so that debris wouldn't fall into the intake, due to the gap between the hood and front bumper allowing things to pass straight into the engine bay (water included)

[Yury]

then why isn't it cut straight at the very end?

but, that doesn't really matter. All I need is someone to confirm the same hole on their 1.5.

[Betrivent]

I have that hole in my stock intake as well.

[Yury]

Thanks. How's your gas mileage?

[MadMax]

No worries, I have the same hole in my US-specs 08 liftback...



Considering it's the air intake, I don't see any issues with having a hole that's only going to allow air to come in!

But if you do experiment with closing it, I'd be interested in your results!

Cheers! M2

[Yury]

yes, it will allow air in, and it's metered air. but my thinking is that it may create turbulence potentially lessening the air flow. stuff like that definitely matters at the throttle body, but this hole is much further away and is placed after an aggressive bend, so it's different.

i'd still roll some duct tape around there just for the hell of it. Maybe it will help the raspy sound, who knows.

anyway, I am looking for a cause of a so-so mileage I am getting and I noticed that people are getting widely different numbers. even though there is a generic statement 'results may vary depending in driving style and conditions' that is usually applied to that, I still don't understand why someone in my locale would get 6-7 mpg more than me on the same roads and climate. I drive conservatively and can't get any where near that, but they get their numbers without even trying.
I just can't quite accept that, there's got to be something not quite in order in my car.

[Altitude]

I wouldn't rule out other people's improper calculations either.

[Bluevitz-rs]

Yury, it's just bad winter gas. I had a couple of REALLY bad tanks of gas. Like I'm talking, 200km less than normal. I changed stations and was back where I normally am for the colder weather even though the weather was colder than before.

[Yury]

When I started off with this car back in September, my first tank was 24 mpg (all city driving). Then I cleaned the trottle body and that improved. At that point I started doing mostly highway and still my personal best was 33 mpg. Still on the low side, considering I drive moderately. I cleaned maf, changed the spark plugs, ran a tank or 2 of the injector cleaner. No help.
So my thinking is that if tb was dirty in such a low mileage car there can be other things. Now I am thinking i should clean injectors off car. Dirty injectors would be consistent with the past use of the car.

[Bluevitz-rs]

So is this a used car?

[Yury]

^ yes. It's a 2008 with less than 20.000 mi (29.000 km or so) on the clock.
It used to belong to my mother, who got it used in 2009 (actually I helped her find it, negotiated the price, etc). Since than she was using it for short local trips. And she is not gentle on the accelerator. To illustrate, her current ride (2010 Mazda 5, barely broken in) yields about 16 mpg. Which is the number I was getting out of a 2 ton Mitsu Endeavor suv.

I took over the car completely back in september. As I said, my first tank was 24 mpg.

[Bluevitz-rs]

Ok. There's probably carbon buildup inside the engine from the short trip use. I'd run a few tanks of high octane gas with injection cleaner and drive the piss out of it. Make sure it gets really hot too. The worst thing for a motor is operating in short cycles and not allowing the heat to burn off impurities in the oil and combustion chamber.

[Yury]

^ yep, will see about doing that. i ran a tank of Gumout once before, but doesn't hurt to repeat.
However, with my current use it may be more productive to take out the injectors and bring them for a cleaning. It takes me 2-3 weeks to burn through a half-tank of gas.

[Betrivent]

You could also take it out for a very spirited drive. VERY spirited is the key word here.

[Yury]

can do that :)

would it make sense to keep the rpm higher normal? like drive around the city on 2nd even when I can't really gun it.