Losing boost at 6400rpm. Help!

[suprahero]

As I stated earlier.......I think I posted it, if not here it is. The last time I was at the dyno I made four pulls back to back to back to back, and they were all within three tenths of one horsepower of each other. I just can't see any boost leak being that accurate. It just about has to be something in the way I have the AVCR set. I'll mess with it tomorrow and see if anything helps.

Ian, go drive your car and make us a video...........don't come back until you do.........:icon_bigg
please don't ban me.

 

[jdub]

Where is your valve timing (cam gears) as compared to the previous 1J set-up that detonated?

Refresh my memory on your cam specs...specifically what's on the cam card.

You are absolutely certain you have no boost leak...it could be one that shows itself above 10-12 psi.

Do you have your Tial set up like this:
http://www.tialmedia.com/documents/w3_tial_wginstall.pdf

 

[Turbo Drifter]

I thought you checked for boost leaks already? Most boost leaks will not show at low boost unless you leave a clamp right off and even then it takes a few PSI to leak. If you have a cut intercooler hose that may do it, the only problem with that idea it the over boost you get before it falls off.

Just to make sure, you have run a vac line strait from the Intake manifold to the lower port on the WG with nothing else on the line right. Also make sure that the upper port on the WG is open.

This cant be that hard to figure out, its got to be somthing easy.

Jeremy

 

[jdub]

The Tial diagram shows the lower hooked up to manifold pressure, the upper hooked up the the EBC to modulate manifold pressure. There is also a vent between the EBC valve and the WG.

 

[suprahero]

Where is your valve timing (cam gears) as compared to the previous 1J set-up that detonated?
I degreed the cams before I installed the engine with the help of Brian(slow66). I don't remember the specifics, but anyone with the crower cams can chime in with their specs. I think I have my cam card in my degreeing wheel case. I'll check later.

Refresh my memory on your cam specs...specifically what's on the cam card.

You are absolutely certain you have no boost leak...it could be one that shows itself above 10-12 psi.
I have replaced every intercooler pipe, coupling, and clamps, as well as every vacuum line. I have found any leaks and I've searched several times.

Do you have your Tial set up like this:
http://www.tialmedia.com/documents/w3_tial_wginstall.pdf

I printed it off and I'm going to check in a few minutes. I did talk with Ian and I have it hooked up exactly like he said it should be installed.

I thought you checked for boost leaks already? Most boost leaks will not show at low boost unless you leave a clamp right off and even then it takes a few PSI to leak. If you have a cut intercooler hose that may do it, the only problem with that idea it the over boost you get before it falls off.

Just to make sure, you have run a vac line strait from the Intake manifold to the lower port on the WG with nothing else on the line right. Also make sure that the upper port on the WG is open.

This cant be that hard to figure out, its got to be somthing easy.

Jeremy

Jeremy, I did run a vacuum line straight from the throttle body to the side port yesterday and I made a run,but I had to get out of throttle right at the rpms it normally starts to drop in. I'll do it again this morning and log it. I'm hoping to have some better answers this evening. Thanks again to everyone.

 

[p5150]

I just did a pull but I couldn't get passed the dreaded 6400rpm mark and still have room to stop my car. I live near a two lane road and the speed limit is 40mph. I was probably doing closer to 110mph just guessing. With the wastegate hooked up and the boost controller not, it still spooled to 18.347psi with a 14psi spring. At 6413rpm, it still had 17.9847psi when I shut her down. I wish I'd went another second so I would know for sure if it was going to lose it.

As I look back at one of my last dyno runs, I had 17.187 psi of boost at 6396rpm and then it drops as follows:
RPM............pressure.......Ign timing...........TPS........Injector ms.............Engine Temp
6462.............16.969.........17.8................100...........22.34......................154.4
6524.............16.607.........18.0................99.8..........21.78......................159.8
6591.............14.286.........18.2................100...........17.942.....................181.4
6681.............12.256.........19.0................100...........16.988.....................172.4
6764.............11.095.........19.2................100...........16.306.....................167.0
6837.............10.443.........19.4................100...........15.068.....................183.2
6897.............10.805.........19.4................99.8..........15.364.....................176.0
7026.............11.893.........19.2................37.4..........17.208.....................165.2

This was a log I did back in August 8.2008 on the dyno.

Jay, looking at your chart I am wondering why the injector pulse drops so much at 6591 rpm. Did you try adding more fuel at that point?

You also said that you are using an AVCR to control the boost level. Is there a discrepancy between what the avcr is reading and what the Stinger is logging? What kind of pressure sensor is on the AVCR and have you changed it yet?

 

[ForcedTorque]

6591 would also be the sight of the largest change in ignition timing and engine temp. Engine temp has a pretty big spike compared to all other changes.

 

[hottscennessey]

Jay, looking at your chart I am wondering why the injector pulse drops so much at 6591 rpm. Did you try adding more fuel at that point?

I disagree, only because the boost dropped by ~20%, the fuel dropped by ~20% as well. I know these can't always be compared linearly, but the injector pulse dropped because it's based on manifold pressure.

 

[IJ.]

Scott: Ditto that's my take as well.

 

[suprahero]

Yeah I also agree. Just about everything on my stinger is controlled by the boost pressure per rpm. If my boost drops then the timing and fuel also changes. Here is a log I just made with the wastegate hooked up to the throttle body and the top port left open.

RPM............Pressure.............Ignition................TPS...............Injector ms..............ET
7053..............12.836...............18.6..................92....................18.834.............129.2
7092..............12.980...............18.2.................90.6...................18.956............96.8
7033..............12.763...............18.8.................89.1...................18.824............132.8
6900..............11.676...............19.4.................98.2...................17.544............150.8
6848..............11.240...............19.4.................97.2...................17.016............145.4
6752..............12.473...............19.2.................98.4...................18.462............122.0
6702..............13.561...............18.6.................97.2...................18.822............149.0
6655..............14.141...............18.4.................97.1...................18.976............132.8
6618..............15.374...............18.4.................95.9...................19.486............154.4
6601..............15.592...............18.4.................93.4...................19.538............123.8
6534..............17.042...............18.0.................92.8...................20.206............158.0
6467..............18.057...............17.8.................92.5...................21.562............141.8
6435..............17.840...............18.0.................92.5...................21.294............138.2

I probably didn't have the accelerator completely pressed down is the reason my tps is reading shy of 100% but I did this pull out on the road in front of my house in third gear. It's a fourty mph zone and I was going a little bit faster than that.

Could all of this be caused by my turbo? I took my turbo apart and the fins look great to me, but if it does this without the boost controller hooked up then it can't be related to the AVC-R. I'm just wondering if the turbo can't keep up with the flow.

Cade, the boost controller thinks it's holding the boost steady at 17psi, but the datalog shows differently.

Thanks again to everyone trying to help solve this issue. For those that aren't reading this, they can kiss my ...................:biglaugh:

 

[jdub]

I'm beginning to suspect the WG spring Jay.

 

[IJ.]

He's had 2 different gates on it John and without the AVCR he said it was pulling full boost.

 

[suprahero]

I have two working wastegates doing the exact same thing, so unless both of them went out then that's not it. The wastegate has a 13-14lb spring in it so is it normal for it to let me get 18psi of boost?
Could the turbo being losing it's mojo?
It's almost like the turbo can't keep up................:dunno:



I only know of one more option...............::hang::

 

[IJ.]

^ NOT normal

Do you have a pic of the WG and how it's plumbed back into the exhaust?

 

[suprahero]

^ NOT normal

Do you have a pic of the WG and how it's plumbed back into the exhaust?

Ian, I'll get pictures first thing in the morning and post them up. I'm at my sisters house waiting on a football game to come on. I'll post them up first thing and you guys can tell me if it's screwed up. Thanks again. Hopefully we'll come up with something soon, although my car is still a blast to drive..........I mean, it's no Fatty or anything, but it's o.k................:biglaugh:

 

[IJ.]

Pics will help

 

[suprahero]

If you're lucky, I may even throw in a picture of me................:naughty:

 

[IJ.]

my eyes my eyes ......

 

[suprahero]

cameras charging and I'm heading off to bed for my beauty sleep. I'll post pictures up first thing in the morning.................Roll Tide!!!!!!!!

 

[ForcedTorque]

Well Jay, at least the Tide could Boost up and hold it. Maybe that takes a little of the pain away.