Losing boost at 6400rpm. Help!

[Turbo Drifter]

OK one last thought (been bugging me all night) on the IAC there is a check valve in between the IAC and the manifold. Is it there or maybe installed backwards? I cant see it making that big a diffrence but at this point anything it worth a shot.

One last one is there any chance the BOV is getting pushed open?

It really sounds like you have one of two things going on. 1) a exhaust blockage or restriction. 2) a intake (turbo to cyl.) air leak or restriction.

Jeremy

 

[suprahero]

It is there and it is not installed backwards, but I was thinking about replacing it if I can find one. The BOV is a brand new Tial and I've watched it while it was on the dyno and it never opens until he gets out of throttle. Thanks for the suggestions.

tlo........He's been resting long enough. It's time for him to wake his ass up.

 

[10secdream]

I am stumped on this too. Did you do a pull and log it yet?

 

[turbodriz]

Suprahero. I have seen this before so if u don't mind I'll put my 2cents in. I am assuming that u are running the same exhaust maniforld as before so in saying that check for a small crack around where the wastegate mounts to the manifold. Make sure that u have a good seal at the mounting area 2. Last but not least I know u have a new wg but that doesn't mean that it doesn't have a faulty spring. I would like to believe that if it was a fuel issue that ur car would be breaking up not loosing boost.

 

[ForcedTorque]

A flash drive may help you transport your info Jay.

Sorry for not having much technical help for you here. Your tuner had no idea? How bout Ricky? If you bought the Tial because you suspected a problem and you wanted a Tial anyway, can you not put your old one back on to see if it makes any change. That could rule out or pinpoint whether the Tial is defective or not.

 

[Turbo Drifter]

I would find it really hard to belive its a bad spring, I have sold 100's of Tial WG's and never had a single problem with them. Tial's QA is next to none and as long as its a genuine Tial I cant see it being at fault.

You have had the same problem with two diffrent WG's I cant see that happening. I guess at this point anything it worth a try lol.

Jeremy

 

[RacerXJ220]

Try another turbo?

If you want to drive over to my house, I'll let you borrow my GT40R.

 

[suprahero]

I am stumped on this too. Did you do a pull and log it yet?

No not yet, but I will in a few minutes. I just got home from work and I would love to sit on the couch and relax for about fifteen minutes.

Suprahero. I have seen this before so if u don't mind I'll put my 2cents in. I am assuming that u are running the same exhaust maniforld as before so in saying that check for a small crack around where the wastegate mounts to the manifold. Make sure that u have a good seal at the mounting area 2. Last but not least I know u have a new wg but that doesn't mean that it doesn't have a faulty spring. I would like to believe that if it was a fuel issue that ur car would be breaking up not loosing boost.

I had the same problem with my HKS copy wastegate, so I bought the Tial. I had to have a new vband clamp welded onto my manifold so I know it isn't leaking. They did a great job on the weld, so I doubt that's the reason, plus it was doing it before at the same rpm. I doubt it's the spring either since I was having the same luck with a different wastegate.

A flash drive may help you transport your info Jay.

Sorry for not having much technical help for you here. Your tuner had no idea? How bout Ricky? If you bought the Tial because you suspected a problem and you wanted a Tial anyway, can you not put your old one back on to see if it makes any change. That could rule out or pinpoint whether the Tial is defective or not.

Scott, I think I have one of those but I've never used it. I bought a little thingymajig that plugs into my laptop so I can copy things from it and install it onto my computer. If that's what a flashdrive is, I have one.........:icon_bigg

Blake, the tuner and Ricky both have tried to come up with a logical explanation, but logic owns all of us.

I would find it really hard to belive its a bad spring, I have sold 100's of Tial WG's and never had a single problem with them. Tial's QA is next to none and as long as its a genuine Tial I cant see it being at fault.

You have had the same problem with two diffrent WG's I cant see that happening. I guess at this point anything it worth a try lol.

Jeremy

Thanks Jeremy, and I agree one hundred percent.

Try another turbo?

If you want to drive over to my house, I'll let you borrow my GT40R.

Is your gt40Ra t4 flange'd turbo? If so, mine is a t3, but thanks. If not, I'm on my way........:biglaugh:

 

[RacerXJ220]

T4, sorry. I don't know if the housings will swap out either.

Do you know your EGT's when the RPM's start to drop? Are your cams dialed in?

When the block was rebuilt, did they correctly install the 12 point crank sensor?

Heck, I dunno, I'm stumped too and those seem basic.

I'm still agreeing with what others have posted regarding flow, but I think the problem may be in the turbo or with the turbo.

 

[suprahero]

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.

 

[IJ.]

^ My birthday

What's the AR on the hot side J?

 

[Turbo Drifter]

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.

Ok one more thought looking at that log. Look at were your boost starts to fall off, what else is changing at that point?.......timming. I'm not sure if that added timming would make the boost drop like that not likly but have you tryed setting the timming up there too say 16-17 deg? I cant remember from doing EFI classes if the Timming can have a effect like that on boost but you never know.

What killed the first 2j block if you dont mind me asking? Did it do the same thing? Was the timming changed a lot or anthing else in the tune other adding fuel? Waht A/F are you running when the boost falls off?

We need to fix this its keeping me up at night!!!

Jeremy

ninja edit: what size AR on the turbine are you running?

 

[suprahero]

It's a .82turbine housing.
I think the timing changes due to the boost and not vice versa. The first 2j block detonated four pistons. It had the wrong head gasket, way too much clearance between bore and pistons and the timing was a bit too aggressive I think, but other than that I can't tell you why it blew apart..........:biglaugh:

For the record it did make it all the way from Texas to Bama doing about ninety miles an hour for eleven hours straight, and then I put it out of it's misery........now it's filling me full of misery.

 

[Turbo Drifter]

Yeah thats makes sence, well I'm done. Good luck and I hope you can fix it, then you sick it right back at that damn thing (25psi and drive it like you stole it :evil2.

Jeremy

p.s. you do not have one of those exhaust silencers in the muffler do you?

 

[tlo86]

so unplugging the wastegate doesnt do anything?

 

[turbodriz]

The crazy part about it is that it's proably something so simple. I have a friend with a honda who had the same problem but in his case it was just a real cheap exhaust manifold. I know u don't have one of those but it just keeps leading back to something between the manifold and the turbo. Maybe a bad gasket or something simple.

 

[suprahero]

The crazy part about it is that it's proably something so simple. I have a friend with a honda who had the same problem but in his case it was just a real cheap exhaust manifold. I know u don't have one of those but it just keeps leading back to something between the manifold and the turbo. Maybe a bad gasket or something simple.

I also replaced the turbo gasket yesterday. I'll do some pulls tomorrow and see what it's doing. It may be the turbo, but I took it apart and it looks brand new. I have no shaft play at all even after running this turbo for two years. As accurate as it is, I think it's got to be in the boost controller, but I'll have to do some pulls with the wastegate only to verify that it still does or doesn't drop off.

Keep the suggestions coming please.

 

[IJ.]

Wonder if you're in the same boat as I am with a .8 housing J......

 

[suprahero]

Wonder if you're in the same boat as I am with a .8 housing J......

The only thing Ian is that it's always ran perfectly with the other setup. When my car was 1jz and even with the first 1.5, the car never quit pulling all the way to 7300rpm. On all of my dyno graphs it was still climbing when we shut down. Their is something screwy going on and I know I'll find it, it's just going to take some time. I'm going to drive it to the golf course tomorrow morning and do a log or two on the way while it's cool outside. It'll be about 85degrees in the morning, but it'll get to 95 soon enough. I'm not really trying to run it hard with it so hot out. I'll post up how it runs tomorrow and see if anyone has had anymore brainstorms. Thanks for all of the comments.

 

[IJ.]

1J wouldn't have been moving as much Air J.

I still think there's something going on with the management.

I don't think it's a mechanical issue.