Very slow boost spool

[giles712]

Car description is in my signature. I'm running MBC @20psi in parallel with oem n75 valve. As far as deletes, pretty much everything that can be removed has been removed.

It was running perfectly for a couple days then today I let it idle in my driveway for 20+ minutes. When I took off I mashed the throttle in 1st gear and boost spooled extremely slow from 0-15psi then snapped to 20 like normal. Normally the second you step on it the boost will snap right to 20 and do the normal k04 taper off to 15lbs bullsplit. I know that I have an exhaust leak from my head to manifold gasket because I used a crappy Felpro gasket when I rebuilt the head.

When I got back I sat in the driveway listening to it, when I rev it up it sounds fine, but when it comes down from rev, i get a nasty high pitched rattle from the downpipe area.

Idles at 18.5"hg
forge 007 yellow spring 1 shim
ball/spring boostvalve mbc
rpturbo k04-001 pos w/ 6000 miles(already leaks oil...)
unitronic 2+
I have non-registered vag-com with codes:
Camshaft position sensor(replaced before I cleared the codes)
secondary o2 sensor(catless)


Any ideas?

[giles712]

help me pleaseeeeee

[armymech666]

mine is doing the same thing and I haven't really checked yet, but I am thinking it is an exhaust leak pre-turbo. I have no boost spike at all. just slow building boost.

[groggory]

know that I have an exhaust leak from my head to manifold gasket because...

That'll do it.

Your turbo spools because of the high pressure differential between before the turbine and after the turbine. If you have a pre-turbo exhaust leak you're letting pressure out from behind the turbine THUS reducing the pressure differential.

Less pressure before the turbo = less energy to spool the turbo.

Less energy = slower spool

Slower spool = sad panda.

[giles712]

That'll do it.

Your turbo spools because of the high pressure differential between before the turbine and after the turbine. If you have a pre-turbo exhaust leak you're letting pressure out from behind the turbine THUS reducing the pressure differential.

Less pressure before the turbo = less energy to spool the turbo.

Less energy = slower spool

Slower spool = sad panda.

This. I'll definitely replace my exhaust manifold gasket asap. any ideas about the noise i'm hearing?

[groggory]

This. I'll definitely replace my exhaust manifold gasket asap. any ideas about the noise i'm hearing?

exhaust leaks in that area get loud real quick.

I left an o2 bung open for a minute and started it up and the car sounded like a tractor. That's a ~ 1" hole in the downpipe.

I think getting all the leaks out of your exhaust will fix a lot of the noises you're hearing.

[giles712]

okay. i'll get on it and report back. thank you so much!

is there any way to replace the manifold gasket w/o removing the turbo?

[groggory]

okay. i'll get on it and report back. thank you so much!

is there any way to replace the manifold gasket w/o removing the turbo?

Not to my knowledge. Sorry.

[giles712]

turns out my wastegate was sticking. soaked the rod with pb blaster then soaked with some graphite lube. runs mint now! other than my exhaust manifold leak. the rattle is because one of my heat shields fell down slightly and is tapping my exhaust.

[groggory]

turns out my wastegate was sticking. soaked the rod with pb blaster then soaked with some graphite lube. runs mint now! other than my exhaust manifold leak. the rattle is because one of my heat shields fell down slightly and is tapping my exhaust.

Cool.

But just FYI...your car is going to run much better once you have no more pre-o2 exhaust leaks. Your spool will go faster, your car will run better, your car will idle better, and your fuel economy will go up.

[87vr6]

But just FYI...your car is going to run much better once you get rid of the rpturbo.

Fixed.

Sorry OP, you already knew that... If that wastegate, which comes with the turbo, only has 6k on it and it's already sticking, it's only a matter of time before it completely fails. Get a Borg Warner unit sooner rather than later.

You noted in your sig you made 180~ BHP? That's what the factory motors are rated at...

And for the record, 6k and it's failing? I've owned two 1.8t powered cars, one has 90k (current 20th) and the last one had 135k with a 185k turbo. Factory turbos, no problems with the wastegate on any of the three turbos (two on the older car)

[giles712]

yeah the 180hp is sarcasm because everybody craps on k04-001 turbos, i have no idea what i'm actually putting down for power but my butt dyno says its pretty quick. I know very well that my rpturbo sucks bad. cash is tight right now(college sucks) or i'd have a borg warner k04-001 at least. Saving for waterfest right now i cant really afford the extra ~500-700 for a good used one.

[babarber]

frankenturbos are a good reliable upgrade that will cost you about the same as the oem turbo so when your ready to replace ur pos rpturbo do yourself a favor and give doug a call

[forcefedjetta]

What dp are you using I had the same problem and found the flex joint in my ghl collapsed and was about the size of a quarter