Boost coming on at 4k rpms

[James Bondage]

Hey all I have a '92 tsi awd and I am trying to figure out why my boost isn't kicking in utill 4k rpm's. I have searched and found nothing. I have a K&N filter, 3'' DP, 2.5'' catback walbro 255 FP and a Greddy BOV.

Thanks in advance for any help.

 

[b4christ15]

Have you performed a boost leak test recently? If not, start out by doing one first and then posting the results.

 

[2fast4]

It's your wastegate rod disconnected. Hook it back up and put a cotter pin in & be done.

 

[Maverick3169]

It's your wastegate rod disconnected. Hook it back up and put a cotter pin in & be done.

What??? Please don't post misinformation!

 

[Maverick3169]

Have you performed a boost leak test recently? If not, start out by doing one first and then posting the results.

Now, I agree with this. Do a boost leak test, it could easily be the problem. Also, try checking for any kind of cracking on your exhaust manifold. Let us know!

 

[2fast4]

What??? Please don't post misinformation!

How do you figure it's misinform?
Either it's intake leak or exhaust leak. Could be both, though.
It's a "classic" symptom of boost coming on late and slow.
If the wastegate is open you WILL NOT get boost until late, like the poster said.

So I figured to start from the simple steps first, since the intake leak was suggested prior.
Have you driven with the wg rod disconnected? Huh?

Let's face it...if there is intake leak, idle would be all outa whack to indicate this. Lots of people suggest intake leak check, but rarely no one suggest exhaust side.

So don't post confusion, it's very common than you know

 

[dr1665]

The first thing I would do is check for any boost leaks. It's discussed many times in the past around here. So much so, that even my NT ass has heard of it. I would say that, until you do the leak test, any other suggestions are more speculation based on personal experience.

At the same time, I think it would be helpful if those who report potential misinformation actually make mention of the situation in their report. "Set the record straight" isn't very helpful to some. Thanks.

 

[DSM90AWD]

Many times it's just that the wastegate flapper is not fully closed at rest and/or severe cracking around the WG flapper's seat. The first case is easy to check. Just disconnect the actuator arm from the flapper lever and see how it aligns with the flapper fully closed.

If the actuator arm hole is exactly aligned or slightly ahead of the pin in the flapper lever, then you need to add more pre-tension to hold it shut. Can do this easily if your actuator is adjustable, if not you can add washers to shim the actuator mounting bracket.

As well as boost/exhaust leaks, incorrectly set cam and ignition timing will also affect boost onset

 

[oldman]

I will try and set the record straight. If the actuator arm is completely off then boost will probably not come on until 5k plus if any at all. I have experiemented with this 2 years ago while porting to get rid of boost creep on my 16G. Prior to porting the turbine housing and the actuator arm off, I was able to build 7 psi by 5.5k, after porting I was only able to build no more than 2 psi by 6k. That said, a defective actuator causing the flapper not to close COMPLETELY will result in slower spool. In conclusion, boost leaks, exhaust leaks and defective actuator are what need to be look into here so all three of you are pretty much right on.

 

[oldman]

Beaten by John.

 

[DSM90AWD]

Beaten by John.

sick-o

BTW, welcome back to the Tuners

 

[oldman]

BTW, welcome back to the Tuners

Now I just have to relearn everything.

 

[steve]

Now I just have to relearn everything.

Try to learn it correctly this time

Steve

 

[oldman]

Try to learn it correctly this time

I guess getting a new teacher this time around would be a good idea then.

 

[supravw]

How do you figure it's misinform?
Either it's intake leak or exhaust leak. Could be both, though.
It's a "classic" symptom of boost coming on late and slow.
If the wastegate is open you WILL NOT get boost until late, like the poster said.

So I figured to start from the simple steps first, since the intake leak was suggested prior.
Have you driven with the wg rod disconnected? Huh?

Let's face it...if there is intake leak, idle would be all outa whack to indicate this. Lots of people suggest intake leak check, but rarely no one suggest exhaust side.

So don't post confusion, it's very common than you know

at your first post.... That was misinformation.. Wastegate arm fallen off results in max boost of 7 psi and a much slower boost like stated above. If he said that he couldn't hit his max boost then you might have been correct but he didn't. It is either a boost leak, wastegate cracks or his cams are off a tooth. I'm leaning towards a boost leak because I my gsx hit full boost of 15 psi by 3200 rpm with the exhaust side was cracked all the way through with cracks around the wastegate...

 

[2fast4]

If you're getting that much cracks you're running hellish lean. And that also indicates pretty good spool of 3200rpm despite your all the cracks you got. If he's got boost leak, I'd say he'll see boost rising even in 3k rpm range. And max boost in mid 4-5k range.

But it seems to me there's something going on with the turbine side. All it takes is wg rod hanging off and all the gas rushing off the wg... a very classic case I've seen. And max boost is atainable if he keeps the pedal to the metal to redline.
If boost leak, he'd see a lot of smoke due to running pig rich.

Either way, as you demo'ed here it's not misinform .

Btw, your cracked exh is calling you

at your first post.... That was misinformation.. Wastegate arm fallen off results in max boost of 7 psi and a much slower boost like stated above. If he said that he couldn't hit his max boost then you might have been correct but he didn't.
It is either a boost leak, wastegate cracks or his cams are off a tooth. I'm leaning towards a boost leak because I my gsx hit full boost of 15 psi by 3200 rpm with the exhaust side was cracked all the way through with cracks around the wastegate...