My boost shutter/stumble issues past 15psi

[A_USER_NAME]

Edit: Thread is no longer about the air intake.



Is there a "max" vacuum pressure it can handle? I don't know if I worded that right so ill explain...

Basically im asking if the stock rubber intake can only handle so much air being pulled through it before it collapses?

My car feels like its starving for air after 17psi on a e316g. So I turned down my boost to 15

Just a thought I had.

Thanks.

 

[bryanwheat]

It's not going to collapse, it is just restrictive at a certain point. Do you have the correct fuel mods to run the 16g at that psi?

 

[A_USER_NAME]

It's not going to collapse, it is just restrictive at a certain point. Do you have the correct fuel mods to run the 16g at that psi?

Enough and then some. Compared to my mods list my stock intake is

Fuel mods are fuelab fpr and filter, dw300 pump and fic bluemax 1250's running on e85
Well, is my pump too small?

 

[WES_393]

I'm at 25psi on a small 16g and I have no issues with the stock snorkel. Over 30 lbs/min of airflow is getting pulled through it, which is audible from inside the car. The most restrictive part about the stock intake is the recirculation tube that runs clear through the snorkel. Check out this link for more info:

Cut the BOV dump tube on your DSM (2G)

I have to agree with Bryan though, if your car seems like it's "starving" for air, then you likely have issues with the tune/supporting mods.

 

[A_USER_NAME]

I'm at 25psi on a small 16g and I have no issues with the stock snorkel. Over 30 lbs/min of airflow is getting pulled through it, which is audible from inside the car. The most restrictive part about the stock intake is the recirculation tube that runs clear through the snorkel. Check out this link for more info:

Cut the BOV dump tube on your DSM (2G)

I have to agree with Bryan though, if your car seems like it's "starving" for air, then you likely have issues with the tune/supporting mods.

Sounds good. I have already completed the free mod. Maybe my issue lies deeper within a fuel issue or spark or tune. Hmm. My issue started at a random time after a run up a nearby mountain.

Maybe a bunch of crap got sucked into my fuel filter and its not flowing to well. Ill check it out.

 

[Dsmkauai]

Or maybe you have a boost leak, I would do a blt to first before anything else.

 

[A_USER_NAME]

Or maybe you have a boost leak, I would do a blt to first before anything else.

I do need to do a boost leak test. But I don't think its a boost leak. I am able to push 28psi if im not wot. The second I go wot my car stumbles/studders/craps itself. But I will do a blt and check it out.

I can only hold wot to redline if I turn my boost controller to around 15psi. If I do a blt and can't hold past 15psi would that confirm its a boost leak?

 

[99ECLIPSEGSXDSM]

If your car stumbles/studders/craps itself at wot have you checked/replaced your plugs and wires?

Some times boost leaks don't pop up untill a certaint psi. I always Blt at least 5-10 psi higher the I actually run just to mKe sure!

 

[Dsmkauai]

You can have a leak that is more present at higher boost levels. I would do the test to alittle about what you plan to have boost set at. Start with like 20 and see if it holds then go to 25 and see if it holds. Sounds like you have a leak honestly, when doing the test check all around the throttle body, and any couplers in the intake path. Also what plugs are you running at the moment and how old are they.

 

[ENZ5573]

i am running 24lb on my stock intake with a gt35r..no problem here..

 

[A_USER_NAME]

Yeah ill go ahead and test to 30-35.

I have already done the spark plug game . Bought ngk 6's 7's and 8's and the issue is the same with all of them, also tried different gaps from 20 to 28. But I am currently running the ngk7's, with 800 miles on them. Replaced wires with ngk's at the same time as plugs.

Unless my coils are bad, I don't believe I am losing spark

I have searched and searched on my issue, maybe I didn't catch what the issue could be. I will get a BLT done before I add to my list of what I believe it could be.

You can have a leak that is more present at higher boost levels

This is what I am confused about, I can boost to 28psi, if I am giving less than WOT. But if I push my pedal another half inch to WOT it starts to stutter.

Could it be my pedal angle sensor or something? Trying to go past 100% throttle making the computer crap its brains out?

 

[DSMnOOb00]

Im having a very similar issue, car runs strong but as soon as I hit boost and gas pedal is all the way to the floor, the car starts to shudder, I have a small 16g with the waste gate hooked stright up to the J-Pipe.

 

[DSMnOOb00]

Although I haven't done a BLT, I did replace all my couplers with 4ply silicone and tbolt clamps.

 

[99ECLIPSEGSXDSM]

Just rule out the blt and then we can go from there

 

[A_USER_NAME]

I dont have access to a compressor at the moment.

BUT, I was tinkering under the hood just checkin things out and I noticed my fuel pressure was low, 39-40, so I bumped it back up to 43.5 and the car runs a bit better, my issue arises at about 19psi now instead of 15.

So I dont know if this possibly points to a fuel issue, filter/pump/lines, but I though I would add the info in case it gives someone else an idea of what it could be. (Im still going to do a BLT)

Thanks.

Edit: One more note, im seeing boost creep, if I have it set at 14psi and do a third gear pull, at around 5000 rpm it starts creeping up until I let off.

 

[A_USER_NAME]

Wooh its fixed, but I still have a question.


I installed an fp 4 inch intake, and an oil catch can. My catch can is routed from the left side valve cover breather, to the catch can, to my intake.

So this disproves one of two things: my stock intake was indeed collapsing (it was very weak) or I was sucking in oil from my valve cover. Then the oil was either A: oil hitting my turbo causing it to slow down, or B: oil was introduced through my intake, and combusting causing a crappy detonation in my cylinders. Possibly a combination of both.

So yeah, happily boosting at 28psi again!