NZ, I am not saying that creep cant still happen to the point you will reach decent boost very late in the power band. But a properly setup WG should not allow any creep, if you are still getting creep after porting the WG you need to go to plan B .. cause that is not a propper setup. A properly setup WG should be able to relieve all boost preasure above stock (at least), that is the purpose of a wastegate. And I still think it makes a big differnce creating boost to begin with when it's open at all times, not just when relieving. I am also not saying the WG is his only problem, but I am convinced it needs to be fixed before looking at the other possiblities.

My point with this whole arguement is just that; A propperly porportioned WG will limit maximum boost on any vehicle, it is the purpose of the wastegate valve. His circumstance may, or may not fall into the catagory of properly porportioned.

-Robert

 

Correct, but you should still check it. The flap's not supposed to be sitting up like that, so you should fix that problem now that you've found it. Left like that it'll increase turbo lag. Have you tested the actuator like I described in my first post?
The twin-scroll system works well with a stock turbo. Leave it alone, at least until you fix your boost problem.

Have you checked that the twin-scroll system is working properly? The system is fail-safe (if anything fails the flap should stay open), but you should check it as per the FSM instructions anyway.
Make sure it spins freely, there's minimal shaft play and the wheels aren't touching the housings. Pressure-test the wastegate actuator if you can.

BTW, try to take your photos in focus.

 

In a perfect world you'd be right. But this is far from your ideal wastegate. Just because he's ported it doesn't mean it's suddenly turned into this perfectly performing wastegate. Ask any S4 owner who has only ported to the limit of the stock wastegate flap. With a decent exhaust it still creeps. It doesn't matter how far open the flap is, it'll still creep in high gears.

With this wastegate and the other mods on the car, the position of the wastegate flap is not going to be holding boost at 2psi.
Of course it does, it causes a lot of extra lag. You probably won't get near full boost in lower gears because the turbo takes so much more time to spool up. In higher gears where you hold the gear for much longer, you will eventually reach full boost.
It definitely needs to be fixed, but something else is holding boost down, not this.

 

lol, thanks for the advice ANyways Here is some pics of the engine. The twin scroll stuff is gone so I think It's really not even worth having the twin scroll stuff on the turbo right?

 

one more

 

Wait a minute. Where's the twin-scroll actuator? Have you just removed it now or was it never there? With it bolted in place and connected to the arm, the flap is always held open. Without it connected the flap can swing freely, and exhaust pressure hold most likely hold it closed. This will severely restrict engine breathing.

Personally I think you should reinstall the actuator and plumb the solenoid and check valve so the system works properly. If that's too much work, either reinstall the actuator or remove the flap from the manifold. Don't leave it like it is!

 

******besides the wastegate right? *******

I'd say the exaust sys is clogged somewhere along the line since you say the turbo itself is ok.

I saw what NZ saw and almost said something.....but from the words I figured you had by now removed the flap?scroll? what ever its called, and put a bolt or welded over the actuating device. I find it odd that that small amount of unseated wastegate could be the cause of a major problem. Looking at the picture of the atuator rod.....yeah, that thing is off center quite a bit. Maybe bend the actuator housning to align things????

 

I missed this question earlier. With the wastegate flap disconnected from the actuator, instead of being held closed by the actuator's spring, it can move freely. Exhaust pressure will simply push it open and hold it there. Since the maximum amount of exhaust gas is being bypassed all the time, the turbo will spool up much slower, but it will eventually reach max boost if you can hold WOT long enough (i.e. higher gears).

 

the twin scroll actuator is still there its just on the bottom of the car right now. I thought there was more to the twin scroll system than just the twin scroll actuator and the flap? Also would the angle of the wastegate actuator be causing this problem? I was thinking of getting a hammer and banging the bracket that holds the wastegate actuator to where it is strait. If it is strait then the door will close all the way.

 

But your photo shows the flap closed. Until vacuum is applied to the actuator it should be sprung open. If it's not, you've probably found the cause of your boost problem.
You need the ECU-controlled solenoid valve and the check valve, connected to a vacuum source on the UIM. See the schematic on the FSM (page 4B-53).
No, but it does need to be fixed.

 

I think what I'm going to do is fix the wastegate actuator problem and then just get rid of the twin scroll system all together. Would you recomend that?

 

People remove the twin scroll system. They have their reasons. Personally I'd advise someone who is thinking about doing that, to try it out first. Like a girl friend. When the vacuum is not applied to the actuator...the flap in your picture is Spring Loaded To The Open position. Sort of like it wasn't there. Then you can experience the thrill of driving without a twin scroll. Or the lack of thrill of driving without a twin scroll.

This subject is very, very, similar to the throttle body mod. If you want to experiece the thrill of the secondary throttle plates opening instantly instead of being dampened by the damper, just back off the damper from the black plastic cam. Walla. Spring loaded open with little or no effort. Now if someone does not know what the damper is or the black cam....I can see why. The fsm talks little to zip about it. Just rambling on.

 

The reason the twin scroll flap is closed in that picture is because I disconnected the twin scrool actuator from the engine however left it connected to the arm. So basicly the arm is still attached however the two bolts holding on the actuator itself is off so the actuator is just dangaling. Anyways if I where to bolt the actuator back on right now it should make the flap open right?

 

The stock turbo performs best with the twin-scroll system working properly. The car will drive fine without it, but you'll just have more turbo lag.

If you can't be bothered plumbing it back up to work properly (which is easy), then remove it. It's your choice.

You still haven't answered my question. When you were driving around complaining of low boost, was the twin-scroll actuator connected to the flap (i.e. the flap was held open), or was the flap just moving freely and blocking off half of your turbo?

 

oh, no it wasn't disconnected. It was connected and from what I understand working fine. What I might do for now however is buy this s5 tII that I have been looking at that has been sitting for a little while at a mechanic shop. The ladie wants 500 bucks for it so I think I'm going to get it and take the turbo and mani out and put it in mine. The engine is siezed so I will have to be rebuilding it anyways. This way I can just get it out of the way with.

 

Well i just bent the bracket that holds the wastegate actuator back into place and now the wastegate closes tightly! The only thing is is when I was putting the rear plate back on if there is a gasket that is supposed to go from the turbo to the rear plate? Just woundering? Thanks.

 

Not sure if there is a gasket there or not, my guess is no. But i leave the turbo work to the experts.

But I can sugest fixing the motor before worrying about the turbo

-Robert

 

There's no gasket under the rear plate.

 

The engine is fine just boost is bad.

 

thanks nz

 

What engine is this you are talking about? The one the lady has?

if so, make sure that the turbo did not eat a seal before buying it. Inspect it good, if n apex seal went, chances are parts o it went through the turbo.


-Robert

 

ok well 500 bucks for a tII is worth it to me in my oppinion however I'm putting my turbo back in to test it out and see if it works. I found two things wrong with the way it was setup before that may have caused by boost leak problem.

1. wastegate bracket bent so that the arm was only holding it 3/4 of the way closed.

2. there was a piece of an old copper gasket from the mani to the turbo that was only on half the mani so obviously exhaust had to be leaking through there.

What do yall think? my turbo should spool right now huh? Anything else to try before putting it back on this weekend? Thanks.

 

just talked to a master mechanic at toyota, his son works with me at the computer shop, and he said that with that wastegate being open like that it wouldn't build any pressure so hopefully when I put this turbo back in it will spool like a mad man. If it does spool then I will post so if anyone else has this problem they will know what it is.

 

Is that not what I have been telling you for the last 10 Posts

-Robert

 

yeah but other peeps keep saying that it will just later on. Well how can it if the wastegate is open? THat post was not for you