yep, mine was down to 6-7psi by redline from about 11@5000ish

is this characteristic because of the SWEET ass design of the exhaust mani?

small turbine/turbine a/r of the stock turbo https://www.nopistons.com/forums/pub...DIR#>/wink.png

Dude call that Rob guy, I'm tellin ya, he knows his shyte





My 7 is coming together soon, see ya on memorial

The stock turbo wont hold boost to redline. Its a very common problem that almost everybody has. They dont even hold boost to redline when theyre stock from the factory. Only way to fix it is to upgrade turbos.

It could be both. the small stock turbo will not hold boost to redline and a vac leak could easily drop boost that much but the combo of the two seems very likely too.

Are you using the stock Mazda black vacuum lines? If you're using silicon lines that is a BIG no-no. Silicon lines will swell with heat and pop off, and could easily be the problem.



Basically, it's either a vacuum line that's leaking or an exhaust leak.



My brother's T-25 in his SR20DET would spike to like 16 and settle down to like 14 until he is is in either 3rd, 4th, or 5th gear, then it's perfect. It hits 14 and stays right there. He tells me it's his manual boost controller that is causing the leak, but he used to think it was just the size of the turbo. I don't know.



I've got a T3/T4 on my S5 motor, and I'm going to have to use a manual boost controller because I'm not sure what the stock boost on that turbo will be, and I don't wanna blow my motor...:/

Interesting. I'm using some silicone vacuum lines, i've never heard of the swelling thing before. Thanks for all the points on the stock turbo, the reason i'm sure about the vacuum leak. I just always thought that if anything i would get boost creep, because you always hear people talking about boost creep with the stock wastegate.