[WedgePerformance]

Hey guys, looking to see if anyone has ever had there N55 boost just fine until you get to 4 to 5000 rpm and then boost just dumps.

It's almost like the DV opened and dumped all boost. I have change the electronic DV, the Boost Solenoid, the MAF sensor..

Everything is o-ring and I'm not dropping boost in midrange, still make 23 psi for 1000 rpm before it falls on it's face.

If you haven't see an issue like this before, don't post. Want to keep this clean if possible.

BTW, I do have a PS2 with GFB DV+

Update: So the issue is the PI system pushes the intake over just enough to cause the bottom of the intake hose to pull away at the bottom and suck closed which restricts the airflow. From looking at it, it didn't look to be an issue. I don't know how many times I had that apart, but from day 1 Jesse from Pure told me that was the issue. Guess I should have put the other intake back on. Would have saved me a lot of money and time trouble shooting this issue.

So... Conclusion... If you install a port rail, make sure you switch intakes as you'll run into issues as the clam on the intake cannot put enough pressure on the oval pipe to keep the bottom half of the hose from pulling loose and restricting air flow at high boost levels.

[bradsm87]

Is boost target still staying high but the boost itself drops? Does PID try to raise WGDC or is it like the DME is telling boost to drop? Any logs?

[weehe126]

Log or pic of log would help to see how fast boost is dropping.

[JETmn]

Have you done a boost leak check? PS2 could overcome a pretty large boost leak in the mid range, but would run out of steam up top. I agree a log would be very helpful to see how fast it drops off.

[Newguy123]

Your stock intake coupler is suctioning itself shut. Ask me how I know. Slide over an extra rib then clamp it down. Gaurentee that's the issue.... Running the Injen intake eliminates that POS coupler BTW

[houtan]

Originally Posted by Newguy123

You stock intake coupler is auctioning itself shut. Ask me how I know. Slide over an extra rib then clamp it down. Gaurentee that's the issue

+1. Big boost problems haha. At least it's an easy fix. Pull that rubber elbow tight!

[WedgePerformance]

Update: So the issue is the PI system pushes the intake over just enough to cause the bottom of the intake hose to pull away at the bottom and suck closed which restricts the airflow. From looking at it, it didn't look to be an issue. I don't know how many times I had that apart, but from day 1 Jesse from Pure told me that was the issue. Guess I should have put the other intake back on. Would have saved me a lot of money and time trouble shooting this issue.

So... Conclusion... If you install a port rail, make sure you switch intakes as you'll run into issues as the clam on the intake cannot put enough pressure on the oval pipe to keep the bottom half of the hose from pulling loose and restricting air flow at high boost levels.

[JETmn]

Originally Posted by WedgePerformance

Update: So the issue is the PI system pushes the intake over just enough to cause the bottom of the intake hose to pull away at the bottom and suck closed which restricts the airflow. From looking at it, it didn't look to be an issue. I don't know how many times I had that apart, but from day 1 Jesse from Pure told me that was the issue. Guess I should have put the other intake back on. Would have saved me a lot of money and time trouble shooting this issue.

So... Conclusion... If you install a port rail, make sure you switch intakes as you'll run into issues as the clam on the intake cannot put enough pressure on the oval pipe to keep the bottom half of the hose from pulling loose and restricting air flow at high boost levels.

Ken, this is with the stock intake? If so, that proves that the stock intake is definitely a restriction at higher boost levels if there is this much of a vacuum being caused. I am going PS2 shortly so I guess I will but this on the buy list. Thanks for sharing!

[houtan]

Originally Posted by JETmn

Ken, this is with the stock intake? If so, that proves that the stock intake is definitely a restriction at higher boost levels if there is this much of a vacuum being caused. I am going PS2 shortly so I guess I will but this on the buy list. Thanks for sharing!

It has nothing to do with restriction of the stock intake. HPA posted results on the stock intake and regardless of filter, the restriction is the same.

It has to do with running a PI rail that is a spacer. The PI pushes the stock airbox back a little bit, which in turn, stretches the OEM rubber coupler slightly, making it either more narrow or not fully reaching both sides of the intake pipe. So under full boost, the rubber elbow either collapses on itself or one part of it gets pulled into the intake, basically causing a kink.

Running the BMS intake solves the issue because it just sits on top of the motor and doesn't need to stretch to align with the stock airbox, that is it. You can also still run the stock intake, but you have to pull the coupler so its one rib past where it would normally be, so it is super taut which will prevent it from collapsing.

[houtan]

Originally Posted by WedgePerformance

Update: So the issue is the PI system pushes the intake over just enough to cause the bottom of the intake hose to pull away at the bottom and suck closed which restricts the airflow. From looking at it, it didn't look to be an issue. I don't know how many times I had that apart, but from day 1 Jesse from Pure told me that was the issue. Guess I should have put the other intake back on. Would have saved me a lot of money and time trouble shooting this issue.

So... Conclusion... If you install a port rail, make sure you switch intakes as you'll run into issues as the clam on the intake cannot put enough pressure on the oval pipe to keep the bottom half of the hose from pulling loose and restricting air flow at high boost levels.

Glad you got it figured out!

[JETmn]

Originally Posted by houtan

It has nothing to do with restriction of the stock intake. HPA posted results on the stock intake and regardless of filter, the restriction is the same.

It has to do with running a PI rail that is a spacer. The PI pushes the stock airbox back a little bit, which in turn, stretches the OEM rubber coupler slightly, making it either more narrow or not fully reaching both sides of the intake pipe. So under full boost, the rubber elbow either collapses on itself or one part of it gets pulled into the intake, basically causing a kink.

Running the BMS intake solves the issue because it just sits on top of the motor and doesn't need to stretch to align with the stock airbox, that is it. You can also still run the stock intake, but you have to pull the coupler so its one rib past where it would normally be, so it is super taut which will prevent it from collapsing.

So it is the physical movement of the engine under power that is causing the kink and not a vacuum being pulled?

[orteeze]

So, when are we going to a get an inlet similar to N54's for the N55's? Is MAF still necessary when running JB4 BEF?

[mpls_M3]

Originally Posted by WedgePerformance

Update: So the issue is the PI system pushes the intake over just enough to cause the bottom of the intake hose to pull away at the bottom and suck closed which restricts the airflow. From looking at it, it didn't look to be an issue. I don't know how many times I had that apart, but from day 1 Jesse from Pure told me that was the issue. Guess I should have put the other intake back on. Would have saved me a lot of money and time trouble shooting this issue.

So... Conclusion... If you install a port rail, make sure you switch intakes as you'll run into issues as the clam on the intake cannot put enough pressure on the oval pipe to keep the bottom half of the hose from pulling loose and restricting air flow at high boost levels.

So does that mean that you'll be calibrating MaF for aftermarket intakes?

[houtan]

Originally Posted by JETmn

So it is the physical movement of the engine under power that is causing the kink and not a vacuum being pulled?

Suction is part of the reason. But the reason why it collapses is because of the PI rail. It pushes the bottom side of the air box further away, making the top part of the intake reach further to get clamped down. This causes one of two things to happen from what I have seen:

1. The rubber elbow is stretch just enough for when the suction gets really strong, it pinches together causing a bottleneck. The fix is to pull the elbow further onto one side of the intake pipe, basically stretching it some more, but it is taut enough that it won't collapse under boost.

2. From what Ken said, one side of his rubber elbow was not reaching fully and was getting sucked in under boost, causing the bottleneck.

If you are not running PI, stock intake should still be fine with PS2.

[Mike@N54Tuning.com]

To prevent having this issue and having to over-tighten the coupler just use the BMS intake but do not use the mounting bracket for the airbox. Instead use a zip-tie to the fuel rail to secure it.



Mike

[JETmn]

Originally Posted by houtan

Suction is part of the reason. But the reason why it collapses is because of the PI rail. It pushes the bottom side of the air box further away, making the top part of the intake reach further to get clamped down. This causes one of two things to happen from what I have seen:

1. The rubber elbow is stretch just enough for when the suction gets really strong, it pinches together causing a bottleneck. The fix is to pull the elbow further onto one side of the intake pipe, basically stretching it some more, but it is taut enough that it won't collapse under boost.

2. From what Ken said, one side of his rubber elbow was not reaching fully and was getting sucked in under boost, causing the bottleneck.

If you are not running PI, stock intake should still be fine with PS2.

So to my earlier point and your #1, if there is that big of a suction, then yes the stock intake/filter is a restriction. If it wasn't a restriction there would not be suction. The vacuum created is the engine wasting HP trying to get air in to itself (pumping losses).

I am going PI and PS2 in the near future, so I want to have a good solution to install at the same time. I may be fabbing something up myself as I can't fathom spending $600 on a couple of pieces of plastic from AFE and I want cold air intake.

[houtan]

Originally Posted by JETmn

So to my earlier point and your #1, if there is that big of a suction, then yes the stock intake/filter is a restriction. If it wasn't a restriction there would not be suction. The vacuum created is the engine wasting HP trying to get air in to itself (pumping losses).

I am going PI and PS2 in the near future, so I want to have a good solution to install at the same time. I may be fabbing something up myself as I can't fathom spending $600 on a couple of pieces of plastic from AFE and I want cold air intake.

Again, it's not the suction, it's because the PI rail makes the coupler cover a longer distance.

Here is testing from HPA: http://www.e90post.com/forums/showthread.php?t=452870

The Issue is not the filter, issue is the coupler. The reason why the elbow doesn't collapse with the BMS intake is because the BMS intake just sits on top of the airbox and does not stretch the coupler.

Either way, you are going port injection, so the easiest solution is an aftermarket intake. You can still use the stock intake, but you will have to stretch the elbow about half an inch further onto the pipe. It looks goofy because the hose clamp is nit on the indented part where it's supposed to be, but it works.

[WedgePerformance]

Ok, let me clarify because we have a few comments which jump to conclusion which is completely incorrect. The stock airbox on the N55 is NOT restrictive. The rubber coupler is not long enough to clamp when you install a port rail between the engine and the intake manifold. Because of the angle change with the lower and upper pipe, the bottom part of the rubber coupler is too short and pulls out from under the clamp. Regardless of what filter system you put on a turbo car, there is always suction. And like water, air under vacuum will take the path of least resistance. So as soon as that happens, the air flow collapses the rubber coupler and restricts the airflow causing boost to fall off.

I have installed the BMS intake and so far all is good. I personally DO NOT like the way the clamps hold the oval coupler hose and will be looking for a better hose. Any airflow that doesn't pass through the MAF will cause the car to run very inconsistently. After fixing the issues, my car is running extremely well. I'm thinking that this was an issue all along with the intake and I'm contemplating just taping it to ensure it's sealed until I can get another solution.

I have to admit, the few weeks this was an issue I truly missed the power the Pure Stage 2 turbo makes. The car is an absolute monster. I can't wait to get the s55 flywheel installed and really turn up the boost.

[JETmn]

^ Perfect, thank you Ken.

[houtan]

Originally Posted by WedgePerformance

Ok, let me clarify because we have a few comments which jump to conclusion which is completely incorrect. The stock airbox on the N55 is NOT restrictive. The rubber coupler is not long enough to clamp when you install a port rail between the engine and the intake manifold. Because of the angle change with the lower and upper pipe, the bottom part of the rubber coupler is too short and pulls out from under the clamp. Regardless of what filter system you put on a turbo car, there is always suction. And like water, air under vacuum will take the path of least resistance. So as soon as that happens, the air flow collapses the rubber coupler and restricts the airflow causing boost to fall off.

I have installed the BMS intake and so far all is good. I personally DO NOT like the way the clamps hold the oval coupler hose and will be looking for a better hose. Any airflow that doesn't pass through the MAF will cause the car to run very inconsistently. After fixing the issues, my car is running extremely well. I'm thinking that this was an issue all along with the intake and I'm contemplating just taping it to ensure it's sealed until I can get another solution.

I have to admit, the few weeks this was an issue I truly missed the power the Pure Stage 2 turbo makes. The car is an absolute monster. I can't wait to get the s55 flywheel installed and really turn up the boost.

This is what I have been trying to say all along! Just with the wrong words and not as clearly as you explained lol. I updated my post a little bit.

You could have still used the stock intake as I explained above as well. Newguy did for many miles until he got the injen intake.

[NRigs]

Originally Posted by Mike@N54Tuning.com

To prevent having this issue and having to over-tighten the coupler just use the BMS intake but do not use the mounting bracket for the airbox. Instead use a zip-tie to the fuel rail to secure it.



Mike

I am going to do this next time I have to take off my BMS intake, getting that mounting bracket on was such a pain in the ass.