|12-19-2007, 11:32 PM||#26|
Join Date: Feb 2002
Location: sugar land, katyVehicle:
2002 2.5L WRX Wag.
I'll throw this in here just incase someone is struggling with a similar issue.
I had to replace all my boost control hoses because they were hard and cracked. I had done the 3/16 mod years ago, and figured why not make all of it like that(also it was all I had) so I replaced all of the hoses and the little T with 3/16 hose and fittings. Yes, I did put the pill back in the right spot. I am still trying to hammer out the effects of this with my FBC. I have dropped down to 50% Max WGDC and it still overshoots in 3rd. I can hit my max boost of 16.5psi in1st and 2nd, so I know I have a ways to keep going.
maybe I just gave myself more headroom for more boost, ha ha. or I have made the issue impossible and need to replace it with the 1/8" hose and fittings
edit: After struggling for almost two weeks to get the boost set right, and dropping my TDC numbers to almost 20% of the stock values...I gave up and went back to 1/8 hoses. With the smaller TDC numbers, it was close almost spot on when it came to control, but it was over boosting like a mother, and dropping my max WG% early on did nothing but make spool up supper slow. Maybe if I had more time...but I figured two weeks was enough. perhaps I should have gone with bigger numbers...but I found it compouded the problem and the slightest over boost meant a massive dump.
* Registered users of the site do not see these ads.
Last edited by Wheeler Bement; 12-29-2007 at 10:23 PM.
|12-19-2007, 11:52 PM||#27|
Join Date: Aug 2006
2005 LGT Wagon
When tuning boost on a new setup, I do the opposite.
1. First thing I do is set reasonable boost targets. You should have a rough idea based upon other people's performance with your particular turbo. I usually shoot for about 1 psi less than what others have achieved. (Then examing boost plots in 4th gear plus plots of MRP vs load, I adjust the target boost later.)
2. After setting up the boost target, I set up the TD parameters. On a 2 port system, I use a very slightly modified stock TD.
3. Then I set WGDC initial to 0 across the board and I use a very high WGDC max. Datalog from 2000 rpm to redline in all gears and then keep increasing WGDC initial until you hit target boost.
4. Once you can hit target boost, adjust WGDC max so that WGDC max = WGDC init + 10% in the partial throttle region and in the far right column set WGDC max = WGDC init + TD Integral max + 5%. TD integral max is usually 15%.
4a. Make sure that the difference between WGDC init and WGDC max is constant or monotonically decreasing as rpm rises.
5. Adjust boost targets based upon accel and MRP vs load, etc... and redo.
6. Datalog starting from 3000 and/or 4000 rpm in 3rd and 4th gear. Check for spiking. Adjust TD accordingly.
|05-05-2010, 02:36 PM||#29|
Join Date: Sep 2007
Location: St. LouisVehicle:
2005 Lotus Elise SC
94 Legacy Rally Car
Bringing up a thread from the dead. But what kind of timing/AFR are you guys using during spool-up?
|05-19-2014, 09:53 AM||#30|
Join Date: Oct 2010
Location: Ithaca, NYVehicle:
Back from the dead.
This is a great read. I have been reading all kinds of boost tuning info for the 32-bit ecus which is pretty worthless for a 16-bit.
So for a 16-bit ecu, why would you even set the max WGDC differently on any cell? It seems like you could just pick one number and put that across the board, along with some reasonable boost targets and it would try to hit your boost targets automatically, unlike a 32-bit ecu which has that initial WGDC you have to accurately set to avoid initially over-boosting/under-boosting.
Obviously you want the max WGDC to reflect what it typically takes to reach the target for safety (plus some margin for error). Does anyone just do the following:
1. Set up a reasonable boost target table
2. Set max WGDC to some constant across the board
3. Log to see if target in each cell is reached and if so at what WGDC.
4. Adjust max WGDC up in cells that did not reach target boost, and set it to the WGDC that was required to reach target boost + 10% or so in cells where target was achieved.
5. Repeat 3 and 4 until you get all max WGDC 10% above the max WGDC you observe.
|Thread||Thread Starter||Forum||Replies||Last Post|
|Question on Boost Targets and Wastegate Duty on initial tune of GT30R||roybfr||Engine Management & Tuning||0||06-09-2006 05:25 PM|
|The theory around boost target||srf||Factory 2.5L Turbo Powertrain||1||09-24-2005 01:42 AM|
|Cobb stage 2... not hitting boost target level...||WRXVII||Engine Management & Tuning||37||06-06-2004 12:14 AM|
|What happened to the HiVisibility @ Target thread?||NeoteriX||Texas Impreza Club Forum -- TXIC||3||03-30-2003 07:04 PM|
|HEY!!! What happened to the Cobb/Vishnu tuning infor/debate thread!!!!||davidm_sh||Factory 2.0L Turbo Powertrain||1||07-18-2002 04:18 PM|