True. But that isn't always an option for customers ...

 

Oh right. I didnt know you were doing this for someone other then yourself.

 

Well, this specific instance is my personal car. But some customers want ECU boost control as well ... I'm just trying to make sure I can offer them the most reliable solution.

 

I like that thinking, if you can get a BWGDC to be pretty much on the money AND TBEC that is also a good shape, then you're pretty much sorted. So you to do this you would have to run a poor BWGDC to get the TBEC table well defined.

MB

 

Bingo.

From my experience the TBEC table is much more important for stable boost year round than the BWGDC table. A nicely tuned BWGDC will aid in year round stability since the curve shouldn't change much throughout the year ... the WGDC needed should move up or down a similar amount for every RPM value. This defined BWGDC curve should aid the TBEC table in correction even if you are way off the defined BWGDC values themselves.

So, in a perfect world, you tune your TBEC and BWGDC perfectly and then temps drop. You now need 10% less WGDC to reach your desired load. Technically, the TBEC would only need to correct for the 10% one time and then actual WGDC will follow that defined BWGDC curve (at -10% of defined) for stable boost.

 

Remove the spring on the WG and get a smaller pill. A number 67 should suffice. Another thing you should try is number 1 setting, zeroing the entire negative side of the TBEC and the top 2 of the positive side, and increasing your WGDC. You do not want the TBEC to step in unless your target load goes way high. Then, you want the TBEC to remove WGDC to protect the engine.

 

If your BWGDC is accurate, your BDEL is accurate by +/-5, and the negative side of the TBEC is turned off, I see no reason why your boost will fluctuate by temp/altitude. I am trying to understand why, but drawing blanks. Can you explain why this would happen?

 

A denser air charge requires less WGDC to reach a desired boost level. I've described my findings in another thread, but I basically saw a swing of ~20% WGDC from my summer when temps fell this winter. I retuned before they got any further off.

Consider it this way ... tune a perfect BWGDC curve and leave error correction off ... boost will be really nice at that temp and probably 5-10* either way. Temps change more than that you'll be overboosting or underboosting.

A smaller boost pill will help hold boost just like upgrading the solenoid or the actuator ... I'm simply adding WG spring tension in a cost effective way. Would you tell someone to remove the Forge actuator they installed and use a smaller pill instead?

 

Thanks for the explanation. Here in SoCal we rarely see such temp swings. I guess that is why I have not seen the boost behavior you describe.

I have not tried the Forge actuator, but I did produce 2 number 67 pills and I am planing on testing them and posting my results. Currently, with the number 65 pill I can hit 19.xx psi by redline with the BWGDC almost maxxed out.

I want to see how much I will have to lower the BWGDC to achieve a similar boost curve to the number 65 pill. I am guessing that 5% less would do the trick. After that I want to run higher octane gas (we have 91 pisstane) and see what boost 100% WGDC will give me up top. I am guessing that I should be able to hit 21-22 psi @ 7000 rpm or above.

 

Swings here in the Southeast can be pretty drastic. Temps in July are around 100* to 110* and super humid ... winter isn't too bad, but it gets to the 20's. I think the humidity is a big factor in the WGDC swings as well ...

Sorry that I was a little short with you on the spring thing ... I'm just a little tired of hearing that suggestion ... I haven't even had a chance to test it, and most people telling me to take it off likely haven't tried it either. Plus, it's all been in this thread that has nothing to do with the stupid spring anyway ...

 

don't worry bud. This thread inspired me to do the spring mod. I popped it on today and I'll do some logging tomorrow. I use a Hallman MBC, so I'll letcha know what happens w/o all this crazy ecu-boost nonsense (don't mind me, I just hate tuning ecu-boost). [I didn't adjsut the WGA arm length, just added the spring]
lol, sorry for the OT, but I figured you could use some encouragement.

 

NP .. thanks. It's odd that my car acts stupid and inspires you to perform the same mods. lol. I can only assume that the OT wastegate discussion was the convincing factor.

I didn't adjust the arm length either .. only added the spring. Adjusting the arm length could possibly lead to boost creep since you are possibly reducing the available travel of the actuator spring and therefore the WG flapper itself ...

 

Log from tonight ... same tune as last night except for lower TBEC values for +17 and +20 error ...



Odd, huh?

Closer to desired ... especially in the low/mid range but still off up top. Load error still seems to be off though ... does anyone know if load error logging needs to be modified when the load target is changed to match 2-byte?

 

TB,

Could you please post the actual log? I can read it better that way.

 

http://www.frameleft.com/tuningStuff/4thGear_046.xls