Yea I knew what you meant, AFAIK, those are the only boost related "protection" elements built in. Meaning, the only thing that can change boost related to temp.

At least from what we have found, what I have seen so far...

 

Yeah, I agree. I don't know of another similar safety feature and know nothing about disassembly so will likely never find one. That's just what it seems like to me ... it's confusing as hell.

 

Exhaust manifold pressure increases as rpm increases, even if boost if held completely constant.

It has to do with the turbine's ability (inability, actually) to swallow increasing levels of exhuast flow.

Just tap into the exhaust manifold with a pressure gauge to see how crazy backpressure can get. If you want to get fancy, I posted some time ago a Ford p/n for a factory 0-5v exhaust backpressure transducer.

 

As I do appreciate all of the insight in to wastegate mechanics, that's not really what this thread it about guys.

My trouble shooting methods for this evening are as follows:

Clear any codes with ScanTech
Reset the ECU by disconnecting the battery
Flash the ECU with a non-Tephra'd ROM
Try some different WGDC correction delays
Try different TBEC values
Remove the additional WG spring

I'll also log load error since that will actually give some decent insight on the actual load target. I meant to do that this morning but forgot.

 

I still think you should first take the WG spring off. That is the one mechanical thing you have changed from last time.

 

I see where you are coming from, but does it really seem like a mechanical problem to you? It seems very much like an ECU issue to me and that's why I'm hesitant to remove the spring first.

 

I have just returned from logging my car. I am running a 3 port, ECU controled, with a stock actuator. I am hitting just over 20 PSI, this is on a JDM 7, which has a 9.8 hotside and stock turbo dump pipe. Your car should easily hold 21 psi on the IX turbo, I suspect the BCS cannot bleed enough air from the system to stop the actuator operating.

Jcsbanks experimented with actuator pre load and found he was getting boost creep with increased pre load. With normal preload he was able to run some decent boost at the top end no his AVCR setup. So assuming your actuator is OK, them the stock BCS is likely to be the limiting factor.

I think we were both saying pretty much the same thing regards turbo flow etc.

The reason for the load issue seem still elusive.

MB

 

A good 3 port (like a GM solenoid) can hold more boost up top than the stock factory solenoid. I've seen it on many Evos. A 3port also is much more responsive overall, which also means you need less spread in your error correction.

The most I have seen a stock evo 9 turbo hold, logged, is 23psi at 7000 or so. This was a ported stock evo 9 turbo, ported exhaust manifold, 02 housing, FP actuator, cosworth cams, GM 3 port solenoid, open filter.

An upgraded actuator does wonders on the stock turbo, just keep in mind you will be retuning all your boost maps.

Evo 8's can actually hold more boost up top with the stock BCS compared to Evo 9's with the stock BCS, mod for mod, from my findings.

 

Thanks for the info. According to my logs there are no signs of creep. I'm not sure why I can't hold more than 19 psi or so up top ... I actually flow more than other 9's with similar mods, but I'm also still on the stock intake and paper filter. Even so, I generally hold a slightly higher lb/min/hz up top than other IXs with MBCs and sometimes EBCs. Even if the BCS can't vent quite enough up top, the added spring tension will make up for it and hold better than stock.

The spring addition seems to be working so far and I'll be able to really test it after we get this load issue straightened out. I'll report back this evening with the results of my troubleshooting.

 

At the most basic level, the additional spring I've added does the same thing as an upgraded actuator. It increases spring tension without reducing the available travel in the actuator itself. It might not work as well as a nice aftermarket actuator, but it's a $5 mod ... I wouldn't expect it to.

I plan to upgrade to a 3 port solenoid soon because of the response characteristics. that should allow the TBEC table to work more as it is intended.

 

A open filter will also allow the car to hold more boost up top.

 

open filter as in no air filter at all,
well that test is just plain idiotic. worthless since nobody in their right mind is going to run an open filter

 

Open filter as in a cone filter replacing the airbox. If it was no filter, I would have stated no filter. Which I didn't.

 

My guess is that you fall out of the range of TBEC (-20, +20) because your WGDC in tables is that much off the required WGDC for your requested load. Your base WGDC seemed to be 60% originally, now it's only 50.
So maybe you fall out of the loop, and it only looks like Load follows the requested load because after 5500 rpm's your base WGDC starts increasing, therefore increasing your load and it looks like it follows some other load.

I also agree with you, that spring has nothing to do with it.
A good test would be to still have a flat requested WDGC, but maybe 60% instead of 50%.

 

Alrighty ... I think I fixed the problem ... I can't verify this 100%, but a little throttle in 4th gear on the way home this evening showed ~1.7 on the stock gauge and holding strong ... that's right where I should be.

I think the boost control load offset value was not being calculated correctly ...

If you look at the actual load curve in comparison to the desired, it seems to follow the same curve.



It clicked with me that it's acting almost just like it would with a lower BCLO value. Also, the BCLO is the only boost control value I hadn't modified while troubleshooting ...

So, we all know that the ECUFlash only updates the sections of the ROM that have been modified. It seems that the ROM to ECU comparison didn't catch that small amount of data being changed so the BCLO value was never overwritten from what was on the ECU, even though I flashed the car several times.

So, I flashed my stock ROM back to the car, essentially overwriting 90% of the data in the ROM. This included the BCLO value. I then put my current ROM back on the ECU and it seems to be working correctly.

Again, I do still have to verify that the issue is resolved. Also, it's only speculation that the BCLO table really was the issue. I could have easily tested it by changing the BCLO specifically rather than rewriting the entire ROM, but I went with the better safe than sorry approach just in case more values had been somehow changed in the ROM.