Ok, I've been reading through the hundreds of pages on here about controlling the wg duty cycle and other things in order to raise or lower boost. I have an '03 evo 8 and out of curiosity I pulled out the restrictor pill near the boost solenoid to see what it would jump to (while keeping a close eye on my wideband). Seeing that I was semi in-town I never really got a hard load past the middle of 4th gear, but I saw it jump to roughly 23psi and stay pretty steady until the higher rpm and then start tapering off to around 19 or 20psi. Now I realize that for right now I'm only going off the mechanical gauge so it's not 100% accurate, so don't burn me because of it.
Basically what I'm trying to find out is how to lower the peak pressure slightly back down to 21 psi, and try to keep it semi-close to that through the rpm and load range. I've read alot about changing the '03 fuel pump once I start jumping up the pressure, but so far it's actually been in the 10.8 afr range on whatever the stock map originally had (which I'm not 100% sure if it is the original, the rom info says it's a 2004 base) so for now I'm not too concerned, it's plenty rich for safety reasons seeing this is pretty much my daily-driver. I did have a slight flutter at first in 1st gear, but it went away. Which table should I look at to lower the pressure? The load offset currently sits at 60, so I'm guessing that the error correction table would be the one I should modify? All the other max wg d/c tables currently say 100%, should I mess with the desired engine load wg tables?
Sorry for the questions, I'm still learning the program and such, and wanted a better way to control boost other than a MBC.

 

If you are going to get a JDM MAP sensor see here:

https://www.evolutionm.net/forums/sh...d.php?t=293981

If you don't want to get one see here:

https://www.evolutionm.net/forums/sh...d.php?t=288408

But basically you can tune all 3 the WGDC tables. Whereever the boost is too high for your tastes you lower the value (assuming they are stock).

You also should tune the 3 BDEL tables since that is what tells the car what load it should aim for (and basically helps the car spike in the first place).

TBEC is the one that is supposed to help control the load if it exceeds what you specify in the BDEL tables but you have to be careful tuning this since it can make you end up with a very "wavy" boost profile.

Read the above 2 posts first though they should be able to point you in the correct direction. If you can you should modify your rom to log WGDC and Error correction...they are dead useful while trying to tune the stock BCS.

 

Thanks for the help. I have to admit though I'm a little confused as to why there are 4 boost desired engine load tables, which ones control what? Or would I be better off just changing the boost error correction to achieve where I need it set? I'm sorry it seems like I'm asking the same questions over and over, I'm just not sure why there are 4 tables for BDEL and MWDC. So far I haven't even touched the rom or added the 2 byte option (mostly because I'm not sure what it does lol). Maybe for now I'll leave it alone or try drilling the pill out a hair larger.

 

Its speculated that they are used for various engine conditions: warmup, normal operation and then limp/error mode. Thats why people change all 3.

TBEC can help curb the spike but relying on it too much will lead to a very "wavy" curve since it will curb the spike by decreasing WG but at the same point, it lets that stay decreased too long and then boost drops it. It then corrects that by increasing WG and then the whole process starts all over again.

Ideally you want a combination of tuning BDEL, WGDC and TBEC tables go get the boost relatively stable.

 

Ok, thanks. One more quick question...something I noticed when going through my car's stock rom values. Why does the Boost Limit table look so weird to me?

I think tomorrow I'm going to re-download the stock map to make sure nothing got screwed up.

 

Some of the 03 Roms have wrong defs for the Boost Limit table.

If all you have done is take out the solenoid side pill and want to get rid of some of the spike, the easiest first step is to reduce Wastegate duty cycle at the RPM points you are seeing the spike.

Stock the WGDC tables are 100%. I would reduce them to about 85-90% from 3500-4750.

 

Thanks bro, that's pretty much what I needed to know for now. I'll adjust the tables tonight and upload them tomorrow and see how it goes.