Boost leak: fixed!

"Noah - Now with more boost." (antriebverliebt) 01/25/2018 at 12:32 • Filed to: None

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The hose in question is only a few inches long. It’s the big one underneath all of this clutter, with the shiny hose clamp.

The EJ’s throttle body to intercooler hose is a notoriously shoddy design that rears its ugly head when you crank the boost up. So of course, shortly after reflashing with an Accessport, it started whistling like a tea kettle under full boost. The culprit was obvious: one of the hose clamp adjusters was so loose that it turned when I was simply trying to get the flathead screwdriver in there.

For now, the boost leak is gone! No more tea kettle in the engine bay. And perhaps this is placebo, but it feels significantly faster. Given how loose that hose was (ready to be pulled off if I wanted to) I bet I was down at least one or two PSI, AKA back down to stock power levels and just didn’t notice it. There are more cracks and pops on upshifts/downshifts now too, which also supports my hypothesis. More boost = more fuel!

The part is only $70 new and I’ll definitely be replacing it when I go for a catless downpipe/intake setup which involves another PSI of boost after the reflash. That will be around 320-330 at the crank, which is comfortably below the limits of the WRX 5 speed. I’ll be stopping there for the sake of the trans, and my wallet too.

Wrong Wheel Drive (41%) > Noah - Now with more boost. 01/25/2018 at 12:54

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I have this exact problem in my STi after replacing my starter. This required removing the intercooler. The hoses were such a pain to get back on that I must have torn the edge of one of the hoses in the process since I am getting that tea kettle whistle as well even though I am totally stock. Its not resulting in a noticeable loss in power but it is annoying. I plan to upgrade those hoses when I install an oil catch can at some point.

Noah - Now with more boost. > Wrong Wheel Drive (41%) 01/25/2018 at 12:58

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Ugh that’s too bad, the whistle is incredibly irritating. A reminder that you’ve got an unaddressed issue every time you want to have fun. I should investigate the catch can mod, haven’t read up on that.

SmugAardvark > Noah - Now with more boost. 01/25/2018 at 13:05

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Boost leaks were a big part of what convinced me to sell my Mazdaspeed Protege many years ago. Mazda used cheap rubber and plastic, and it degraded rather quickly on my car. After two years, it felt like i was having to track down minuscule cracks and pinhole leaks every damn weekend.

So frustrating. Glad you were able to solve yours.

gawdzillla > Noah - Now with more boost. 01/25/2018 at 13:21

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catch cans are better than AOS imo

it catches all the crap that you dont want but u’ll have to remember to drain it every now and then, depends on how much blowbys you have

saikou michi makes a good dual can, moroso also have a good dual

gawdzillla > Wrong Wheel Drive (41%) 01/25/2018 at 13:23

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I had get a good silicone hose and that slide on / off effortlessly got it from intakehose.com or something. upgrade the clamps while you are at it

Sovande > Noah - Now with more boost. 01/25/2018 at 13:29

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On my old Volvo V70 T5M I had to replace the stock intercooler hoses when I tuned it. The stock rubber hoses would collapse under 17 psi of boost. I replaced them with silicone hoses and the issue was gone. I replaced the hoses on my C30 preemptively for the same reason. I replaced the stock turbo intake piping on both as well to do away with the stock accordian fittings in favor of smooth, larger bore silicone fittings. One of the side effects is glorious intake sounds.

I would urge you to keep a cat in place. At the hp levels you are aiming for you will lose no more than a couple horespower and you will not stink up the joint. You can get high flow cats that will still work without robbing any real power.

Noah - Now with more boost. > gawdzillla 01/25/2018 at 13:48

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sounds like a good investment, I’ll check out that saikou

Noah - Now with more boost. > SmugAardvark 01/25/2018 at 13:50

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Yikes, that sounds really frustrating. This is the go-to part to check when you have an EJ boost leak, I’m even wondering if its designed like this on purpose so something more difficult to address doesn’t pop before this does.

Noah - Now with more boost. > Sovande 01/25/2018 at 13:52

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lol. I want to stink up the place because that involves shooting flames :) my first daily was a 635csi so I’m down with a little exhaust funk.

Wrong Wheel Drive (41%) > gawdzillla 01/25/2018 at 14:06

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Yup, silicone hoses were my plan! I just didnt want to hassle with it until I had another reason to remove them.

Wrong Wheel Drive (41%) > Noah - Now with more boost. 01/25/2018 at 14:07

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I have gotten used to it. Its my “poor mans boost gauge” lol. Since when its whistling, it should be building boost, which I dont want if I want to save fuel. When I am just having fun, I could care less what sounds its making, the more sounds the better. I do wonder if it sounds really silly from the outside though.

Wrong Wheel Drive (41%) > gawdzillla 01/25/2018 at 14:09

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Hmm I was wondering if an AOS would make more sense so that I could at least not replace the oil that gets lost, it would already go back where it belongs. Seemed like a lot more permanent of a solution. But also a bit more complicated with coolant hookup and oil lines instead of just one in and one out air line. Pretty sure both are not CARB legal anyways and the catch can would be far easier to remove for inspections.

Noah - Now with more boost. > Wrong Wheel Drive (41%) 01/25/2018 at 14:10

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I always wondered about the outside sound too. Sticking your head out the window to check doesn’t really work lol.