Overboosting&Porting Wastegate on 2560R - recommendations?
 

Hey all, running into some boost creep issues when temps get in the 60’s. Basically can’t run the car WOT at night, and it’s getting a little annoying.

I’m running a FM turbo manifold with a 2560r, going to a 3in downpipe, and custom 3in exhaust all the way back. Catless. Soooo, too much flow for that 90 degree to handle.

My tuner (hey Shane!) mentioned getting the wastegate ported, and from the research I’ve done here, seems like many others have ported their 2560r’s.

Are there any reputable shops that you guys trust with this? Otherwise I can call around town to see if there’s any performance or machine shops that could do it for me.

You can do it yourself, its very easy with some air tools or maybe a dremel... Just grind a "channel" from the 4 bolt flange to the gate and enlargen the hole, where the flapper actually seals up.


https://cimg3.ibsrv.net/gimg/www.mia...c63357a8d7.jpg

Are you running straight waste-gate control? Or some form of manual or electronic boost controller?

I suppose I could do this myself, I have a battery dremel that I've used for interior work. May have a normal wired one at my shop. Was thinking it was more complicated than that!

I'm running EBC. Running my car with a MS3Pro PNP & the EBCS that DiyAutoTune sells.

Whoa whoa whoa, EBC is a key detail here, before you go porting your turbo... make sure your EBC settings are correct -- it took me a lot of trial and error to get EBC to be consistent, let alone consistent with weather changes. What happens when not using EBC and relying on just the wastegate?

If I remember correctly, even on wastegate, the car would still start to boost creep. It was nothing *too* crazy, but it was there.

I could retest, but I'm fairly certain this is the case.

I just finished my 2560r install with the kraken top-mount manifold and full 3" catless exhaust. Wastegate spring is 8psi, Boost creeps to 10-10.5 psi at 7k on straight wastegate control.

I want to say mine would boost creep to around 10-10.5 PSI on the 8psi wastegate spring as well.

I should note, my car is tuned for 15psi with electronic boost control enabled.

if on wastegate only you creep to 10-10.5 you should have no trouble maintaining 15psi with no creep.

Exactly. The issue is totally EBC.

I solved the type of problem you discuss by adding D to slow things down when boost comes too quickly (like cold weather).

if you are running 1.5.2, you can SD card record individual contributions of P, I, and D. This is helpful in troubleshooting.

Ted (above) has been know to do remote tune work, I understand.

Ha, thanks for the plug, but only for a select few ;)

Hmm, well good to know I might not need to port my wastegate.

Attached is images of my boost control settings. I don't have the option to change the PID settings, my boost control is open-loop. I also attached my .msq

Most of my over boosting happens right when shifting at WOT, and in higher gears (3/4th).

Maybe my problem would be solved by trying to get it tuned closed loop? Not sure what my best course of action is here - I'm not sure how to tune boost control myself. I might ask Shane from AIM to do closed loop for me.

@18psi Might a Manual Boost Controller be a good approach?

I don’t know how much throttle control of torque one loses with MBC as I’ve never driven a car with one.

18tyweslow, have you considered MBC?

DNM

Yes closed loop would be the way to go and will open the PID options, would be the best way to target overshoot and get it under control ---- there is a lot of info out there on what P I and D each do, I can't remember off the top of my head, but that is my recommendation on how to fix it

Manual boost controller could work too, but I found that it would vary based on temperatrure too and might run in to the same problem unless you undershoot boost target so that as temp drops you aren't going above your limit

TL/DR: Closed loop PID settings, start from basically nothing and make small changes -- again, it took me a lot of trial and error. But the info is out there, start reading :D

use basic, drop sensitivity slider to a low number and gradually increase till you are hitting your targets but stable, reduce "lower limit threshold" to 25 or less (this is the #1 cause over overshoot, and a mistake I see in almost every tune), populate the bias table with your open loop table values, set your minimum DC to a real number like 30 (most EBCs don't work predictably below ~ 30%, they don't work at all under about 20-25%), configure your target table, start low across the board (but keep in mind you minimum available target will be roughly WG/(1 - DC) which for a 7psi actuator and 30% minimum DC will be 7psi/(1 - 0.3) = 10psi, tune each change in the table before adding a new value, increase target at higher TPS values iteratively until you have your maximum target in the top row, revise your bias table based on what closed loop achieves for a given operating point except remove a couple/few percent (to account for changes in environmental conditions)

porting helps with boost creep, if thats what you mean by overboosting.

Record individual P/I/D contribution? Tell me more...

1.5.2 pid logging
 

Data Logging / SD Card Datalogging: Then add Log Field Selection to the selected side... pid_log_boos1_p, pid_log_boos1_i, pid_log_boos1_d (and maybe count)

Then when you SD log (do you know how?) you will see these on the log. To get the total duty cycle at any particular time, add the bias (from your table), the p, i, and d. But the primary information is a snapshot of how the controller is responding to the transient conditions.

DNM

Thanks for the info. I'm limited with a MS2PNP at the moment, but I'm hot on the trail of a MS3 Pro, so this info will be stored in my "memory bank"

I had this issue. Fixed it by spending hours and hours tuning closed loop boost control with the 3 port mac valve. Now I reach target boost wether it’s cold or hot and overboost/boost slug is taken care of by the PID algorithm.