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Discussion Starter #1
So this issue is consistent every time. Start the car up, let it get to operating temp, start to drive, lay into it, boost about 10-11ish psi, do 2 more pulls no issue, drive a little, lay into it again, car sounds NA and weird. Boost about 8-9psi and falls off with RPM. Think the turbo's are going out? Engine has 180k miles. Pretty weird though? Heat is the obvious factor hmm
 

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Could be a weak wastegate, try this
 

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Discussion Starter #3
This sounds like my symptoms.. will let yas know in a few days. I just think of how simple a big single setup is.. ugh.

""Best mother fuckin' mod I did for $1!!!!!!

THis whole time I thought I had a boost controller problem. TUrns out its the freakin' wastegate spring being to week.. No wonder it would only boost at first starts caus the spring isn't hot enough yet to get weak. Oh man, I am sooooo happy now.
""
 

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Discussion Starter #4
So yea.. my car has never held boost this steady at oem levels for the 3 years I have owned it until I just put this dinky spring across the wga. lol unreal
 

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Figured I would add my 2 cents here. I imported a TT Mk4 supra from Japan last year. Completely stock. When I hit boost on the 2nd turbo shortly after it would fall flat on its face ( around 4500 - 5000 rpm). Got that 3 dollar spring put on now it pulls all the way to redline. So simple but damn does it work.
 

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Reminds me of the time the clip that retains the wastegate flapper to the actuator arm fell off my front turbo...

"Man, this thing feels really laggy all of a sudden!"

Didn't have the heart to tell my neighbor that I outran his 4th gen F-body with only one turbo. :p
 

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Discussion Starter #12
Alright I have a solid update. The spring mod did not fix my issue. After a lot of time and research of trying to understand the system it made me realize how vital the vsv's actually are. So turns out the vsv's are dead, no continuity when the car is warm, did not bother to check when cold. So I bypassed the vsv's and I have a whole different car. All of us know what a 2j is supposed to sound like in boost, that deep exotic sounding rumble as you spool up.. I dont want to stop driving this car.. I just want to keep going. The method in which i bypassed was the quick way, pressure source to iacv and pressure source of egcv directly to the valve. So the system has to actually pressurize itself before it's TRUE twin mode. Moving forward I will most likey disconnect the arms and force the valves, wideband, bcc, and turn it up. Car spins 2nd now through an auto. Omg a 2j sounds so beautiful through an auto. I have a 2j through an r154 on my mk3 but it doesnt have that deep loaded up sound.. Complete different car.
 

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How did you determine that your VSVs did not operate properly when hot? Mine test properly with the correct impedance and 12v jumper, so I just assumed they are working at all times. Yet, my boost also seems to fall off.
 

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Stock twins are great! I have a straight pipe, hks intake, spring mod, boosting to about 15ish psi and today at SIV 2019 I was the only one with stock twins. The Car made 411 HP (91 octane pump gas) on the Mustang Dyno... I was happy it put down a little more HP than the MKV’s. Not too shabby at all... -Matt you where not there but you would of been proud.
 
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