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Discussion Starter · #1 ·
2015 WRX Base
Mishimoto CAI
Nameless Axleback
Perrin Pitch Stop
Perrin 25mm Rear Sway
Perrin Front Strut Bar
(Last three added for kicks...not relevant to post)

Okay, so I have the Mishimoto CAI w/Box and no tune. I have not had any huge issues out of the car and had a decent power gain, except when the temperature gets up into the 90s. Once that happens it feels like it isn't getting enough fuel as the power kind of "flatlines" and I accelerate far more slowly. It is still driveable in this condition, but only if I keep my foot out of it. I do not have any CELs, there are no lights on the dash which should not be on, I will be checking my hose clamps on the intake and if those are tight I will be reinstalling the factory airbox and seeing if that fixes the issue. I was hoping that someone could tell me if it's probable that the intake (due to the increased CFM flowing through) has caused a premature failure of the BPV, as I can hear a LOT of air rushing around on the DRIVER'S side of the car. The intake system being mounted from middle to passenger side, I do not expect it to be the hoses. This has me highly concerned as I do not currently have the cash to shell out for a major repair without dipping into my savings (which will be used to pay for repair to my '92 Miata soon) and I am trying at all costs to avoid that. Combined with the fact that our only other car is my wife's which she needs to get to work.

So in summary:

PLEASE HELP ME FIGURE THIS OUT.

Thanks all, and I hope none of you are experiencing this kind of nerve wracking potential parts failure:eek3:
 

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You have to have a tune for that intake, no options. If it hasn't cause damage yet it will. So your options are tune the car or remove it. The only grey area right now that I've seen was ETS. They have purposely designed their intake to flow like the stock box and have provided data to back that up.

You could easily have a boost leak, it isn't uncommon at all. Or you could have gone lean often enough to damage a piston and have low compression. So I would have a boost and vacuum leak test done and a compression and leak down test done. Good luck

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Discussion Starter · #4 · (Edited)
I agree with XJ. I am also curious what you mean by "rev limit" at 4k rpm?
It was topping out at 4k and acting like it was bouncing off the rev limiter.
UPDATE: I took the CAI off and reinstalled the factory box and it's still doing it, just not as loudly. I have concluded that it is likely that I have a boost leak.
Any tips on where I should look for common fail items?
I read up on a few other instances where people had a boost leak and they said something about a small hose on the BPV that came off while driving??
Also the boost will not exceed 10psi which is why I'm leaning towards a leak instead of something internal being damaged...REALLY hoping nothing is messed up.
And in case anyone is interested in knowing, it is completely possible (with the proper application of a swivel socket and a few extensions...as well as small forearms to prevent burns from the head) to remove and install an intake system on this car in less than an hour :thumbup:
 

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If it's literally stopping at 4k under full throttle and cutting fuel or ignition you've got a problem that sounds like some sort of limp mode.

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Discussion Starter · #6 ·
If it's literally stopping at 4k under full throttle and cutting fuel or ignition you've got a problem that sounds like some sort of limp mode.

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Yeah, but it only does it if I try to build boost and it gets a LOUD air whoosh sound on the driver's side/center area
I'm discussing possibilities with a friend who has a shop and we came to the same conclusion on it being some kind of weird ass limp mode that doesn't throw a CEL (at least not yet).
 

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I would stop driving it immediately. Have it towed to a shop, sell the intake to find the repair. You possibly blew a hose loose or something.

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Discussion Starter · #8 ·
I would stop driving it immediately. Have it towed to a shop, sell the intake to find the repair. You possibly blew a hose loose or something.

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That's what I'll be checking for in the morning before doing anything else is checking for a loose connection or a hose that is completely off somewhere. I saw something in another thread about that happening to someone while they were going down the interstate at like 75 so I'm HOPING that is all that's happened here is a loose hose.
 

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in for update

you try resetting the ECU?
also put MAF on the back burner to check if hoses check out
 

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Discussion Starter · #10 ·
in for update

you try resetting the ECU?
also put MAF on the back burner to check if hoses check out
No reset necessary.
UPDATE:
After the sun came up this morning and I could see, I took a look under the hood and discovered that the intercooler coupling had come off on the driver's side opposite the charge pipe. Popped the intercooler off along with the coupling, seated the coupling onto the intercooler and reinstalled. Took her for a test run and everything is running quite nicely. I'll take the loss of the turbo sound from the CAI if it means I have reliable power and won't be damaging parts.
Big thanks to that first response from XJMan telling me that it DOES require a tune (even though the manufacturer says otherwise...and I went with it over my common sense). I had that intake off in less than an hour and I felt a LOT of power come back during the test run. I hadn't realized how dumbed down the engine had gotten trying to compensate for that thing, but I won't be doing any more mods like that without a tune or buying an AccessPort package.
Thanks all! Glad to have the help.
 

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No reset necessary.
UPDATE:
After the sun came up this morning and I could see, I took a look under the hood and discovered that the intercooler coupling had come off on the driver's side opposite the charge pipe. Popped the intercooler off along with the coupling, seated the coupling onto the intercooler and reinstalled. Took her for a test run and everything is running quite nicely. I'll take the loss of the turbo sound from the CAI if it means I have reliable power and won't be damaging parts.
Big thanks to that first response from XJMan telling me that it DOES require a tune (even though the manufacturer says otherwise...and I went with it over my common sense). I had that intake off in less than an hour and I felt a LOT of power come back during the test run. I hadn't realized how dumbed down the engine had gotten trying to compensate for that thing, but I won't be doing any more mods like that without a tune or buying an AccessPort package.
Thanks all! Glad to have the help.
Ask the manufacturer for a flow analysis for the intake if it isn't exactly the same as the OEM part it requires a tune. Pretty simple stuff. No gray area. If the flow is any different the maf is not scaled for it and the car starts to run lean.

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