Boost Levels for GT3071r on 2.0L Build

[00black1.8t]

OK so I have been working with my tuner Sam 613B6. AWESOME GUY! We have gotten the car up to 23/24 psi and every things been looking great. Here are my questions...

1. Boost tappers about 2 sometimes 3 psi between 5000 and 7200 rpm. Pressure tested up to about 20 psi and no leaks. Is this normal for Denver (mile high) and the 71?

2. Now that I have hit 25 psi it acts like my wastegate is shuttering for a couple seconds once hitting peak boost (25) and to goes away before redline. Believe its the boost controller/wastegate. Not sure. This is not a surge or coil pack shutter. Purely boost pressure fluttering

Any of the goo roos have any suggestions or thoughts?


Relevant MODS
2.0l stroker
2000 converted to 2001 ME7
JE Pistons 9:1
Scat Rods
ABA Crank
AEB Head (slightly ported and gasket matched)
Walbro FP
Injector Dynamics 1000cc
GT3071r
Tial 38mm with (large blue and small red springs)
Tial BOV Q with -10.00 psi spring
Custom 3" exhaust
2.0l coil packs
NGK-BKR6E-11 (.44 gap)
Hallman Pro Kit Boost Controller

[Davdraco1]

I would preasure test it again to something higher then what you intend on boosting too. I would try another WG too. See if it fixes it. The only other thing I can think of its a tuning issue.

[00black1.8t]

Some build pics for the pic lovers :)
http://smg.photobucket.com/user/snow...Engine%20Build
General Car Pics
http://smg.photobucket.com/user/snow...rary/Audi%20A4

[ray4624]

love the engine build pics.
are you running just the external oil cooler or the stock and external combined?
also, what manifold is that? Polished turbo looks amazing in the bay

[00black1.8t]

External Mocal cooler off the filter. No stock coolant cooler any more. Keeps temps a lot lower for sure. The other cooler is power steering.
Treadstone SS Manifold (newer version) it makes the turbo placement a little difficult. I have to customize the back of my headlight to allow for my cobra hose to fit. Ill try to get a picture as Im sure a lot of you guys would like to see the work. I removed the auto leveler and re designed the back of the headlight for more clearance. I have a ton more pictures of the build ill try to add to that album.

[00black1.8t]

I would preasure test it again to something higher then what you intend on boosting too. I would try another WG too. See if it fixes it. The only other thing I can think of its a tuning issue.

Not sure how it can be a tuning issue as all the boost control is manual. The boost pressure flutters not the engine so much. Its defiantly an external engine issue, not fueling or tuning. My belief is waste gate shutter. But I have the higher rate springs already in there. I would hate to buy another WG... just to try. :(

[MetalMan]

Just some general comments, not really sure if they will help but am curious.
1) Have you considered N75 for boost control instead of the Hallman? If your tuner is good he can do a good job with controlling boost. I realize though that to effectively control boost past ~21-22 psi requires a different MAP sensor, and the tune to be configured for it.
2) Spark plugs. Heat range 6 that you're using is the stock heat range I believe. Have you played around with a colder spark plug (NGK BKR7E or 8E) to see if that does anything? Maybe also try closing the gap a little?

[00black1.8t]

Just some general comments, not really sure if they will help but am curious.
1) Have you considered N75 for boost control instead of the Hallman? If your tuner is good he can do a good job with controlling boost. I realize though that to effectively control boost past ~21-22 psi requires a different MAP sensor, and the tune to be configured for it.
2) Spark plugs. Heat range 6 that you're using is the stock heat range I believe. Have you played around with a colder spark plug (NGK BKR7E or 8E) to see if that does anything? Maybe also try closing the gap a little?

1. We tuned with the N75 until we reached 21 psi. Then we switched to the BC to get higher. That worked just fine up to 23 psi. I am not familiar with other options.
2. I was told to use those plugs for the 2.0 coil packs. I used to use the 7E before I changed the coils. I could always go back. What gap then? I haven't ran into misfires yet but running colder could defiantly do no wrong at higher boost levels and no water/meth yet.

[Avant Nate]

Is your WG hooked up correctly? Your current spring pressure is 20.3lbs, so even with no boost control you should be around where your at.

[00black1.8t]

Is your WG hooked up correctly? Your current spring pressure is 20.3lbs, so even with no boost control you should be around where your at.

Yeah its right, min boost pressure is 16 psi with the boost controller turned all the way down. Everything adjusts just fine. Everything functions perfect until 25 psi.
I guess Ill verify that and see but I doubt its wrong.

[M-Hood]

Sounds very much like compressor surge, your exhaust manifold pressure is overcoming your WG spring pressure. Have you checked to make sure your BOV is not opening right when you hit 25psi?

[00black1.8t]

I completely agree that its the waste gate by the sound. I will confirm the BOV can hold that 25 psi by pressure testing past the 25 psi for a very short time. Makes me nervous to test sustained psi that high on the system. I am sure it will be fine as I am 100% emission free and still have all my check valves between the brake booster and such. Ill report back. Thanks Mike

Any suggestions to alleviate the problem?

[viceprp]

The WG isn't hooked up wrong. You would see massive boost creep. I hooked mine up wrong once and saw 30+ psi before boost cut.

I'm leaning towards the BOV or compressor. What springs do you run in the bov? I would clean them if you already have them off.

[00black1.8t]

What springs do you run in the bov? I would clean them if you already have them off.

-10.00 psi = -16in/hg to -19in/hg
http://www.tialsport.com/documents/w3_tial_qqr_sp.pdf

[M-Hood]

-10.00 psi = -16in/hg to -19in/hg
http://www.tialsport.com/documents/w3_tial_qqr_sp.pdf

Is that the amount of vacuum you see at idle? If so then the BOV shouldn't be the problem unless you have a leak in the vacuum line that goes to the BOV.

[00black1.8t]

Is that the amount of vacuum you see at idle? If so then the BOV shouldn't be the problem unless you have a leak in the vacuum line that goes to the BOV.

-19in/hg exactly and defiantly no boost/vacuum leaks in the system. :)

[BlueBoostedAudi]

-19in/hg exactly and defiantly no boost/vacuum leaks in the system. :)

I would try another boost leak test to insure there is no leak.
This is what I did;
1) I plugged the intake piping right after the turbo, my piping is 2.5" so I just used a soda can that was full and put It in the other end of my silicone coupler w clamp
2) hooked up my air compressor with a Air blower fitting with a trigger to blow air
3) unhook a hose from one end off intake manifold, make sure that It will fit over the air blowing fitting
4) cap the nipple that the hose came off of
5) while watching the boost gauge trigger the air blower nozzle
6) I always test þ psi more then I will be boosting. If i boost 30psi I will pressurize it til 35-40
7) have soapy water in a spray bottle and spray down the intercooling piping w soapy mixture. You will see bubbles from where its leaking at. When I did this I had to go over alot of my piping and hoses. After you have all the leaks gone there will be no more bubbles when u spray.
8) put it back together better than it came apart!

Also from my experience, my shuttering/fluttering has been; loose injector rail, loose spark plug, loose clamp on intercooler, and a loose intake. Crazy how all of them things just rattled loose and all gave the same shuttering problems
Good luck hope this helps

[00black1.8t]

I actually have a piece of pipe welded with a fitting on it for testing. Thanks for the detailed description.
I tested the system last night up to 26 psi and only found two very small leaks. One was slightly bigger then the other(Injector). Other then that no problem

Had to file my fuel rail spacer down a little as it was allowing two injectors to leak when I wiggled them. They leaked at 5 psi so that is a very probable cause. The other was a very small leak at the inner cooler piping I just had to tighten up the t-clamp a little more. So now all is good again. Ill drive it after work and report back.

ANOTHER QUESTION. There is conflict in which way I should route my boost controller. Which way should I route it? Tial says option 2 and Hallman Controller says Option 1. I have always done Option 1

OPTION 1


Option 2

[M-Hood]

Option 2 tends to be how you do it with a EBC since the controller is cutting pressure off to open the WG by releasing the pressure that is holding it closed. This is a dual port setup and has pressure on both top and bottom parts of the WG.

Option 1 is how a MBC and N75 valve would be setup since those allow pressure to be passed thru to open the wg at a set pressure.

[BlueBoostedAudi]

Glad to hear it is boosting again! Are u able to go over 25 psi?
As far as the way u hook up ur boost controller, how ever u wanna hook it up.
I always done it with the first option, turbo to mbc to extrenal wastegate.

[00black1.8t]

I have not ran it yet, just the pressure test last night. I'll see how it runs here in about an hour when I get home from work.

[Seerlah]

Is your compressor housing port shrouded? If not, may be your issue.

[00black1.8t]

Is your compressor housing port shrouded? If not, may be your issue.

nope

[00black1.8t]

Here are the two videos, one below 25 psi third gear.
the other above 25 psi (probably the worst of the flutter here). I varies at times depending on outside temps and so forth.
I have been able to hold 25 with out flutter or very minimal at times.

Below 25 psi
http://youtu.be/lj3EvuocN0o

Over 25 psi Flutter/Surge
http://youtu.be/bf8UWK0dLX8

[viceprp]

Should really have a boost gauge that can read that high. All I saw was the gauge fluttering but no vibrations/misfire from the bay area.

[00black1.8t]

Should really have a boost gauge that can read that high. All I saw was the gauge fluttering but no vibrations/misfire from the bay area.

I do plan to buy a larger boost gauge. Its defiantly the engine/boost that is fluttering. I strongly believe the wastegate is the issue.

[M-Hood]

Here are the two videos, one below 25 psi third gear.
the other above 25 psi (probably the worst of the flutter here). I varies at times depending on outside temps and so forth.
I have been able to hold 25 with out flutter or very minimal at times.

Below 25 psi
http://youtu.be/lj3EvuocN0o

Over 25 psi Flutter/Surge
http://youtu.be/bf8UWK0dLX8

With colder temp your idle vacuum will tend to increase since the air gets denser, so that could be 1 issue. When it is colder outside have you checked to see if your vacuum is higher then 19 inHG?


If you aren't feeling any actual misfire, it could just be that your gauge can't handle pressure above 25psi. Won't know if that is the case till you get a gauge that reads higher.

[00black1.8t]

I have not seen any idle vacuum above 19 inHG. But I was worried that it was defiantly in between what spring ratings are.

I will buy a new boost gauge and see if that does it but I defiantly hear the flutter/air release from the engine bay. It does not cause misfires or bucking from the engine. That's why I believe its more so the waste gate than bov. I plan to disassemble the wategate spring and verify I don't have a broken spring or anything. I should see a base boost of 20 psi and not the 16 I get when I turn the boost controller all the way down. All I can think of is that I have a bad spring or something.

[00black1.8t]

So I was trolling around here after a few years:
Update for anyone wondering, I have concluded its just that the turbo is working at the edge of its limits. After all the math to find my intake vs exhaust ratios I have determined I am at the turbos limit of efficiency.

Update: This is not correct. See most a few lines down.

[ktsimp721]

So I was trolling around here after a few years:
Update for anyone wondering, I have concluded its just that the turbo is working at the edge of its limits. After all the math to find my intake vs exhaust ratios I have determined I am at the turbos limit of efficiency.

I dig this thread I’m gonna have to be doing the same at some point but I know I’ll be happy 21psi for some time I just wanna get the thing on the road again... happy boosting man !


Sent from my iPhone using Audizine

[00black1.8t]

To clear it up for everyone what the problem I was having was..... I tore the engine down to rebuild the head and finally install my Supertech valve train components before xmas. I knew the AEB head I purchased was high mileage but not sure how high when I purchased it. The valve guides were bad and then I pulled the pistons to examine how the rings seated. It looked like the guy that helped me build the engine in the past overlooked the ring gap a little. I he read it as "min ring gap" which is true. But looking at it now it looked like they were the wrong rings because the gap was over 4-5 times greater then JE specs. So needless to say I had extreme blow by on the rings as well as the head. So the turbo was operating out of its P/R ratio to keep up with the requested boost. At high boost my catch can would actually blow oil out from the boost blow by. Pretty crazy. The turbo was capable of keeping up with the 23-24 psi as well as one boost leak I found while tearing it down.

So in short the turbo was working at its max to do what it could with the horrible inner boost leaks. Now that I have it rebuilt, my boost controller is barely turned up and running great boost at 20 psi until I get some more miles on the engine. Before it was turned way up. So that answers that. :) I also upgraded to the Gen2 GTX3071r while i was at it.