Boost creep Question

[Alibi]

After i installed a 3-inch turbo back exhaust, it looks like i began to experience boost creep. I am wandering if there is a way to hook up an mbc to fix the creep ?? I know that hooking a mbc up wrong can cause boost creep so i was wandering if it is a 2-way street ?? I have my aftermarket boost gauge i bought last night, going to install it when i get off work today.

 

[DSM90AWD]

Boost creep is caused by a deficiency in the internal wastegate to bypass exhaust away from the turbine, not the boost controller itself.

Your only remedy is to port the wastegate byass on the turbine housing exposing more of that passage to the exhaust flow, or get an external wastegate

 

[Alibi]

Thanks for clearing that up, i appreciate it !!

 

[DSM90AWD]

No problem. There's a nice VFAQ on the porting process if you wish to do this yourself

 

[project_tsi]

Heres whats happening.

Your new exhaust is flowing "too well", and actually the flow of the Wastegate cannot keep up w/ the flow of the exhaust, thus it creeps up. You can fix it a few ways.

A kind of half-ass way of fixing it would be to add a high flow catalytic converter in your system. This would provide some extra backpressure and slow down your flow a bit, thus equalling it not creeping as bad, if at all.

You could also do some porting work. You can port the shit out of you WG area, as well as port out your 02 housing., or buy a larger, 02 housing, but the turbo's WG area still needs to be ported. Also cut/port out the area where the WG arm moves up, and port it out so the arm can move an entire 90 degrees up, to allow the most possible flow.

Another thing, if you have the money, this is the best way to go. Invest in a External Wastegate system. Remove your stock wg and get your wg flapper welded shut, and get a tial 38 mm welded on the manifold. Youll most likely never have to worry about creeping again.

 

[95blackGsTurbo]

Another fix that you can do is to get an O2 dump for your O2 housing. It will help with expelling exhaust gases comming from the wastegate. But what DSM90AWD said is the best and most efficient way to get rid of it.

 

[project_tsi]

Another fix that you can do is to get an O2 dump for your O2 housing. It will help with expelling exhaust gases comming from the wastegate. But what DSM90AWD said is the best and most efficient way to get rid of it.

That still doesn't fix it. I have a internal gate and 02 dump and adjusted it many a times. And at 25+ psi, the 02 dump doesn't help internally gated. It helps a little, just not enough.

 

[Alibi]

Will putting my stock downpipe back on help at all ?? How much would this slow down the turbo spool, i'm running no cat.

 

[rowlex]

Will putting my stock downpipe back on help at all ?? How much would this slow down the turbo spool, i'm running no cat.

Yes it will. I also concur with project_tsi, an external o2 dump will most likely not help. I had an external dump on my o2 and couldnt run less then 26psi on my evoIII 16g. (Of coarse I do have a 3" exhaust with absolutly no neck downs, cat, or resonators.)

Here is a real good tech article on how to port your turbo to get rid of boost creep.
http://dsmtuners.com/forums/showthread.php?t=186525

 

[project_tsi]

Putting your stock DP back on, would help creep, but I don't reccomend doing it. Id highly reccomend porting before you put those parts back on.

 

[DSM90AWD]

Will putting my stock downpipe back on help at all ?? How much would this slow down the turbo spool, i'm running no cat.

It will help some though at the expense of some performance and a good short-term solution until you can exercise one of the two permanant fixes.

They should start putting warning lables on 3" turbo-Backs and 255HP pumps

 

[Alibi]

Thanks for all the info....I think i have decided to go with a EVO III o2 Housing. I checked out prices and they are only about 120. If i'm going to to the work to take the turbo off might as well get something new on there. Thanks again.

 

[DSM90AWD]

Thanks for all the info....I think i have decided to go with a EVO III o2 Housing.QUOTE]
The EVOIII O2 housing has a slightly different angle on the outlet than the stocker so may be a trick to install with your exhaust. Check RRE as they sell a complete kit with flange and gaskets for about that price

 

[oldman]

There is a boost creep thread and I'm not in it? Good job guys.

 

[project_tsi]

There is a boost creep thread and I'm not in it? Good job guys.

Yeah dude, where have you been? Did we do a good job at getting the job done w/out you?

 

[oldman]

Yeah dude, where have you been? Did we do a good job at getting the job done w/out you?

Good job guys.

 

[project_tsi]

Well excuse me....... J/K

 

[theSicKness]

Another fix that you can do is to get an O2 dump for your O2 housing. It will help with expelling exhaust gases comming from the wastegate. But what DSM90AWD said is the best and most efficient way to get rid of it.

id go w/ the porting or the external waste gate ....me and my friend tried to solve the creep on his 90 tsi w/ the o2 dump and it didnt help...he also had just installed his 3' exhuast


Jesse

 

[GreddyGst]

Hey guys, while we're on the topic of boost creep. I'm getting an TiAL external wastegate mounted on my manifold because i too have boost creep all thanks to my 3" turbo back exhaust.

My question is related to O2 Housing. I know i need to weld shut the flapper but would you recommend to port the turbine a lil bit anyway? and should i get a O2 housing bigger than stock size? better yet what O2 housing do you guys recommend? If i make a custom 3" O2 housing will that make a huge or little difference? could the stock O2 be ported enough to have a decent flow?

I figure if i'm going to this then i'm going to this right, so i don't have to go back and forth and I want to be able to perform at its best so what do you suggest?

 

[oldman]

If you're willing to port the turbine and o2 housing, most likely you have no need for the external wastegate.

 

[Alibi]

**UPDATE**

Aight, So I finally got my boost gauge installed, took a lot less time than i thought. I've got it tapped off the FPR, I'm reading a steady 10 psi. But it still hit fuel cut around 5200 Rpm's. I also hear a little click from the ECU about a quarter second before it hit fuel cut. That is the only time that i hear that click. So i did some reading about our ECU's and found out that they are known for going bad. Apparently (I'm sure most of you know this) there are 3 Capcitors that like to expand and eventually leak. So i talked to the guy that i bought the car from and he says that he replaced 2 out of the 3. I've got my ported 2g 02 housing ready to bolt on, but before i do i was wandering if maybe my problem is actually the ECU. Any suggestions ??

 

[kanderson111]

I would check for boost leaks, 10psi should not cause you to hit fuel cut.

 

[Alibi]

It holds boost just fine, i tested it at 20 psi. I fixed a couple leaks already.

 

[DSM90AWD]

I also hear a little click from the ECU about a quarter second before it hit fuel cut. That is the only time that i hear that click. So i did some reading about our ECU's and found out that they are known for going bad

Better to be safe than sorry. Remove the (-) battery cable and remove the ECU. Remove the four screws/cover of the ECU and examine around the Capacitors for evidence of acid damage to the traces and/or "rotton egg" smell.

As for it's affect on fuel cut, can't say for certain. More likely the damage (if any) is causing an interruption in power to the ECU resulting in a momentary "cut out" which is what you are seeing.

Are you sure your boost is not poking above 10psi and that there are no leaks when pressure testing at the compressor inlet => intake manifold?

There was a recent thread where someone's fuel cur issue was the result of the compressor o-ring gasket failing, so is important to test from the compressor inlet

 

[Alibi]

no i have extensivley read the thread you are reffering to, i did test it from the compressor inlet. I made a better version of the boost leak tester on vfaq.