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06 LGT wastegate duty at 0%

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Second Update: The noise under the hood sounded somewhat like an elephant and found it to be a leak on the throttle body pipe (pretty easy fix). Still no wastegate though. Possibly a bad boost control solenoid?



UPDATE: I put the stock wastegate acutuator on and it didnt do anything. the car runs perfect and sounds fine UNTIL i get on it. when i get to about 9 or 10 pounds of boost it sounds kinda like an elephant letting air out. Wastegate is still at 0 and target boost stays at -1. HELP????? I attached a datalog of 1st gear although its kinda long.




Hi. So ive been working on my car for a while and I just replaced my blown vf40 turbo in my 06 lgt and while im running it, the wastegate duty stays at 0%. I'm confused as he** so i would really appreciate honest help. I am running it on Cobbs economy 91 map with AP3 and Ive hit 11.4ish psi (I removed the restrictor pill in the vacuum tube). when i let off the gas it makes a really loud kinda whining noise like the BPV just got really loud. Yet, earlier, when i got on it, it overboosted to 17psi (with restrictor pill in) and was EXTREMELY loud pssshhhh sound, didn't quite sound like wastegate flutter or a compressor surge though. The turbo i put in was the stock vf40 type but it is a JM turbo. I noticed that the actuator rod is MUCH harder to push forward by hand than the stock one so maybe that's causing it not to open? I'm gonna put the stock actuator on tomorrow to see if that does it. Is it safe to run at 0 wastegate duty? Thanks so much for thoughts and advice!!! Sorry for posting like such a noob...

Mods include catless up and high flow invidia catted dp.


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Uhm... you're on the economy map. Of course it's at 0%.


What did you think was going to happen, that your car is going to run just as fast as before but miraculously get better mileage?


I hope for your sake that you are running the correct stage 2 map as well. I am unsure if the wastegate actuators are the same or different but I expect that if they are both labeled as VF40 they should be the same. If the new actuator IS actually stiffer than a USDM VF40 then you have to be careful of overboosting. A stiff actuator will make it so that the wastegate is LESS open, and consequently there will be MORE exhaust gas driving the turbine.


Also, leave the restrictor pill in if it's the correct one. Cobb OTS maps are meant to be run with the restrictor pills in.


As far as the whining noise, I don't know what that is. You'll have to record the sound.


Strongly advise you search and read a lot before you do something that blows up your car. Yes, you're a noob, but at least you're asking the questions.


Don't use the forum search. Instead, go to google and type in your search terms and then add in "site:legacygt.com" at the end (without the "s). Much better results.

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No I guess I'm paranoid from the blown turbo so I didn't want to push it too hard to start so I didn't think of the economy mode being the reason for no wastegate. I'll put the pill back in tomorrow and flash back to stage 2.


Sort of a side note but on my new turbo the wastegate flap is a little bigger so with my invidia divorced dp it pressed it shut, thus the wategate wouldn't open. So I ground down the dp and it fits now. This flap is what caused my turbo to overboost on my first run and I assume that's why the throttle body hose became loose and started making noises.


The noises just ended up being the throttle body hose being loose on the intercooler.


I'm 99% sure I'm running the correct maps so I shouldn't have any problems there (cobbs. OTS Stage 2 91 ATv300)


Also thanks for the search advice!! Trust me, I've been doing ALOT of searching!!!

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0% WGDC means your wastegate opens as much as possible to prevent the turbine from seeing exhaust gas. It helps to think of the percentage as how much exhaust you are giving the turbine to drive it. Higher numbers mean the turbine is being driven harder. Read that entire article. Trust me, it's excellent.


There isn't a percentage that's hard set for stage 1 and stage 2. Each map is different. Offhand, I don't know what the WGDC is for stage 2 COBB specifically.



1) Running a stage 1 map on stage 2 hardware will cause overboost.

2) Running without a restrictor pill on a map designed for a car that has a restrictor pill will cause underboost. (assuming no other changes were made)


You did BOTH of the above, so I have no idea what your outcome would be, but whatever you did was NOT right. As I said, don't go pulling and changing maps and hardware and stuff because it seemed like a good idea in your head.

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Thanks for the link! I got everything back to normal and its set up correct for stage 2 and its running great! No leaks so far and everything seems fine! I'll just have to drive it more to make sure. Thank you SO much for helping me out!!!
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You're welcome. Now that all your hardware is reinstalled and you have the right map it's a good time to make a log. 1st gear logs are next to useless. You should be doing your log in 3rd or 4th (can't remember what it is for automatics).
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K so i ran my car for a couple days. Found a coolant leak and fixed that (bad clamp). Car seems to run pretty well but i did a few logs and found that im getting -2 feedback knock every now and then. sometimes during WOT and sometimes after i let off the gas from normal driving. There is one log where i have -1.4 Fine knock learn also. On all of these, the knock shows up and goes away after a few seconds. Should I be worried? If you could look at my 3rd gear log id appreciate it. Also a 5th gear log with normal driving fine knock.


Cobb OTS stage 2 91 map with 91 fuel. catless up and high flow invidia catted dp. Thanks!


-1.4 fine knock.csv

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