Hello, guys!
I have an Airtrek Turbo.
Main specs to give you understading:
Stock 4G63T engine (components are weaker than stock Evo's)
Stock Evo 8 cams
Stock Evo 9 turbo (TD05HR-16G6C-10.5T), barely new (about 5000 km) with stock actuator
Intake: Apexi power intake + Greddy Spec-LS
Exhaust: Stock Evo manifold, Invidia outlet and full 3" exhaust without narrows
Subaru STi 560cc pink injectors

The problem is that it overboosts after about 5000-5500rpm, especially in high gears.

I checked the actuator with compressor - it works as it should. The BCS is disconnected, so the actuator is connected directly to the nipple on the compressor housing.

When I've just builded this setup, it was overboosting (1.6-1.7 bar) in second gear. I've decided that it is because of very small hole in the outlet (made in China) that connects wastegate duct with the main one. So I've replaced that outlet with the stock Evo one - it got better. Than I've ported this noname outlet and it got even more better, but it was still overboosting (about 1.5 bar in the end of the third gear). Recently I've installed Invidia outlet that has the biggest wastegate duct that I've ever seen, but the problem persists

I've tried to throw off actuator rod, so the wastegate opens easily even in idle - I've got slooooow spool but on WOT it overboosts anyway in the end of the second and especially third gear (I don't drive fast enough to test in 4th, but it will be definitely worse, huh).

EGT is normal (about 820-830*C), AFR is about 10.5, load mut 2 byte shows corresponding values to boost sensor (about 250% on 1.5-1.6 bar). Timing belt is installed correctly.

Everything points to the fact that it is easier for exhaust to pass through turbine wheel than through opened wastegate port, but I have no idea why that happens.

The only one thing that is working incorrectly is bypass valve, which is likely to leak on boost (in the intake, not in the atmosphere). Will replace it shortly, but I don't think that will solve the problem.

Should mention that the problem solves by closing exhaust valve a bit (I have xforce varex muffler with remote controlled butterfly valve), but it affects sound, spool and perfomance and it isn't normal at all.

Sorry for such a huge description and for my bad English

 

Today I've thrown off actuator rod and tied wastegate wicket to the part of cylinder head, so it was opened all the time. Spool was around 4000 rpm. But in the second gear boost hit 1.5 bar.

 

It makes no sense to me. I'd be curious to know how you fix it.

Turbos are fairly simple things, if the wastegate is fully open then it is the path of least resistance for exhaust gas and boost should drop off (I realise that you know these things - just thinking aloud)

What bypass valve are you running? My standard Airtrek (plastic) BPV would not hold boost above 14psi so you must have changed it to something else.

If you go back to the stock BPV does it still over boost?

Have you eliminated a faulty gauge / sender?

You are not using BCS solenoid so the ECU settings are irrelevant..

That's all I can think of...

 

Also, I see you are using STI Pink injectors - what scaling and latency settings are you using?

I have a set ready to install so ome initial settings would really help me.

 

I use stock BPV by now, will install new one soon.
Load mut 2 byte in logs corresponds to my boost gauge readings, so it is OK.

I will try to install evo 7 gta turbo to check whether it is a turbo problem (maybe something wrong with wastegate duct, maybe it is production related, don't know what else).

STi pink: scaling 513, latency base 0.528 (or 22 in uint16), battery latency 6.12, 3.84, 1.608, 0.96, 0.672, 0.432, 0.24

 

Thanks for the latency and scaling settings.

Unfortunately on your turbo problem I can't offer a solution. The BPV should open well before those boost levels if it is stock (i think) but your wastegate should also do the same.

I have just fitted a new turbo to my Airtrek, i went for the TD04HL-19T to make it more simple and I am having what I hope are temporary high boost problems and I am tuning it down.

My issues (I think) are caused by the fact that the previous setup had a tactric 3 port bcs that I thought I had tuned via baseline wastegate duty cycle to give the correct boost levels. When I changed the turbo, I also changed to the Evo metal BPV and suddenly my boost is so high that the intercooler joiners blow off at just over 20psi. Now that's not a problem, just better T-Clamps but it highlights that the plastic BPV was limiting my boost.

In your case, I am wondering if the stock BPV is always closed (if that is possible) and your high boost is happening on throttle let off or gear change (although you said you were testing in 2nd or 3rd gear) or is the high boost holding steady?

If the high boost is only a spike then that is different in my opinion to steady high boost and may be BPV related.

I am just guessing here as your issue defies logic.

 

It is steady, not BPV issue...

 

Well you have me stumped...

Maybe trying another turbo is the answer, although all I can really think is that the wastegate isn't opening but you say you have it open, so I don't have a clue..

 

Did you ever fix this?

 

I've installed Invidia outlet (this is the one with the largest wastegate duct available on the market). By now it's overboosting at about 1.1-1.3 bar in third gear, so it is OK for me. Maybe also outside temperature affected it - now it is about +10*C, in winter it might overboost more easily.