7MGTE Boost Issue

[MKIIITurbo88]

I have installed a HKS EVC and whenever i get above 6psi, i get boost surge; I have my target boost set to 10 psi, and it will hit 10, drop to ~7, back to 10, then to 7 etc.

When I un-install the HKS, it only runs 5psi. Is this common for wastegate pressure?

I'm beginning to think I may have popped the diaphragm in the wastegate actuator;

Any thoughts?

 

[Compton74]

is the car automatic or stick?

 

[Orion ZyGarian]

I'm just going to put this here as a "just in case"

http://www.supramania.com/forums/showthread.php?163023-Correctly-controlling-boost-levels&p=1861525

 

[MattTerror]

I'm just going to put this here as a "just in case"

http://www.supramania.com/forums/showthread.php?163023-Correctly-controlling-boost-levels&p=1861525

This is great info. I just ordered a MBC myslef. I know how to hook up the MBC the regular way. How would i go about doing it the way you described in your write up? I assume you ignore the hose on the compressor housing and go straight to the intake?

 

[MKIIITurbo88]

is the car automatic or stick?

Manual transmission

I'm just going to put this here as a "just in case"

http://www.supramania.com/forums/showthread.php?163023-Correctly-controlling-boost-levels&p=1861525

Thanks for the write up; I'll try this and see if it resolves my issue. However, I find it odd that this goes against the manufactures instructions on how this think should be hooked up. Also, it's not that my boost is tapering off, it is surging, like this:

 

[Orion ZyGarian]

Thanks for the write up; I'll try this and see if it resolves my issue. However, I find it odd that this goes against the manufactures instructions on how this think should be hooked up.

I'm not entirely certain that it will fix it, but it might at least help. I'm also not sure why manufacturers say to use the nipple on the compressor housing, when science says the density of the air after the intercooler will change how it affects the boost signal. Maybe they dont expect lots of boost, and through a bar and plate design..? I'm just relaying the info I have found. In this case yes, you'd block off the compressor housing source.

 

[Turbo Habanero]

That's awesome info

Thanks Orion.


I have a few questions.

So I'm still running a CT26 turbo and stock wastegate setup.

Currently setup up using the factory nipple on the turbo.

My question is

Since ill be running one line from the wastegate to the solenoid and the other to from solenoid to intercooler pipe closer to the throttle body, now what do I do with the open nipple on the turbo ?

Should I just put some vacuum line and block it off with a screw ?


I posted this same thing over in your thread Orion and then realized that maybe I'm not suppose to post under that section.

 

[IndigoMKII]

That's awesome info

Thanks Orion.


I have a few questions.

So I'm still running a CT26 turbo and stock wastegate setup.

Currently setup up using the factory nipple on the turbo.

My question is

Since ill be running one line from the wastegate to the solenoid and the other to from solenoid to intercooler pipe closer to the throttle body, now what do I do with the open nipple on the turbo ?

Should I just put some vacuum line and block it off with a screw ?


I posted this same thing over in your thread Orion and then realized that maybe I'm not suppose to post under that section.

Why not just hook it back up to the turbo? You'll get a more 'accurate' reading as to the output of the turbo itself and be able to see the PSI lost in the IC/piping.

 

[Turbo Habanero]

Why not just hook it back up to the turbo? You'll get a more 'accurate' reading as to the output of the turbo itself and be able to see the PSI lost in the IC/piping.

I guess I'm not understanding something correctly...

Stock the port on the turbo has a line running to the port on the wastegate. With this mod ill be using the wastegate port and a new port on the intercooler pipe in place of the port on the turbo.

So thus leaving a open port on the turbo correct? So i was wondering what I should do with this port?


I thought the whole point of doing this mod was to avoid boost drop off?

 

[IndigoMKII]

Doing that will avoid boost drop off but also make the turbo work harder per say to keep up with the drop off.

 

[Turbo Habanero]

Doing that will avoid boost drop off but also make the turbo work harder per say to keep up with the drop off.

So what do you recommend ? Is it going to be bad for the turbo in such a way one shouldn't do it ?

I don't have much boost drop issues but i have a avcr that i can adjust by rpms to help keep the boost where I want it.

 

[teedoff00]

Try reducing the gap on your spark plugs, if they are set a stock gap. You are likely to to get surging at higher than stock boost levels without reducing the gap. Happened to me a few years back, may be worth a try.

 

[IndigoMKII]

So what do you recommend ? Is it going to be bad for the turbo in such a way one shouldn't do it ?

I don't have much boost drop issues but i have a avcr that i can adjust by rpms to help keep the boost where I want it.

If you don't have a huge PSI loss in the IC/piping then I'd leave it like normal.

 

[Orion ZyGarian]

Doing that will avoid boost drop off but also make the turbo work harder per say to keep up with the drop off.

..uh, what?

 

[MKIIITurbo88]

Thanks all for the thread bombing - back to my issue. Besides the ic pipe 'mod' (rather than using the compressor housing nipple), and potentially re-gapping the plugs, what else could cause surge? Is there an easy way to test the BPV and then wastegate actuator?

I initially thought I might have a boost leak, but this does not make sense as 0-5 psi holds steady (wastegate pressure); after that, I get the boost oscillation.

 

[IndigoMKII]

Thanks all for the thread bombing - back to my issue. Besides the ic pipe 'mod' (rather than using the compressor housing nipple), and potentially re-gapping the plugs, what else could cause surge? Is there an easy way to test the BPV and then wastegate actuator?

I initially thought I might have a boost leak, but this does not make sense as 0-5 psi holds steady (wastegate pressure); after that, I get the boost oscillation.

Does the 0-5 psi hold steadily with a boost leak test? Or while you're driving?

 

[MKIIITurbo88]

Driving - holds 5 dead steady when 3/4 throttle - 100%; that's when I have the boost controller set to 5psi or off (running wastegate pressure). As soon as I try and exceed 5psi, I get the oscillation

 

[IndigoMKII]

Driving - holds 5 dead steady when 3/4 throttle - 100%; that's when I have the boost controller set to 5psi or off (running wastegate pressure). As soon as I try and exceed 5psi, I get the oscillation

Have you tried to boost leak test your piping? Sounds like you've got a leak opening at higher PSI.

 

[teedoff00]

You can test your WG actuator with any bicycle pump with a gauge. Stock WG crack pressure is around 5.5 to 6psi if I recall correctly. However, if you your wastegate actuator is seized, you will either never build boost, or build way too much. Don't think this is your issue. Try the plugs, I was stuck until IJ pointed me in this direction and it 100% fixed my issue.

Good Luck!

 

[MKIIITurbo88]

You can test your WG actuator with any bicycle pump with a gauge. Stock WG crack pressure is around 5.5 to 6psi if I recall correctly. However, if you your wastegate actuator is seized, you will either never build boost, or build way too much. Don't think this is your issue. Try the plugs, I was stuck until IJ pointed me in this direction and it 100% fixed my issue.

Good Luck!

My only doubt with this is that it only occurs sometimes; If the plugs were the issue, this should happen anytime the car is under boost. It holds fine at 10 psi, and then out of nowhere, it will hit 10, and oscillate between 7 and 10psi