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how much boost can stock waste gates hold.
I have recently done usdm turbo swap on my jdm 2jz that is nestled in my fc rx7, the plus side is it no longer boost creeps. on the negative side spool up is slower, than the jdm twins. I have a custom cross pipe that connects the 2 turbos that I built, because my usdm turbos did not come with a manifold or cross pipe. my custom cross pipe has 1/3 more volume than the stock cross pipe with sequential actuator. my cross pipe flange and down pipe flange are hogged out to 3 inch, it flows real well, the rest of the exhaust it 3inch.

So my problem is I put a boost controller on it and the most boost I could get was 16 psi in the first 3 gears. So I remove the controller and disconnected the waste gates from any boost source to see what it would boost to, It only hit 16 psi in the first 3 gears, in 4th and 5th it hits 19psi, so I believe that the exhaust is forcing the gates open at about 15 psi and the extra boost I get in the upper gears is boost creep.


So my question is how much boost should the usdm actuators hold.
may be usdm supra's are able to hit higher boost levels because there cross pipe waste gate ports are restrictive causing boost creep.

please give me your ideas on what you think the problem may be.
I have a money race with an e60 m5 in a couple days and I would like to crush him.

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If the stock wastegate is in good condition it will hold quite a bit more than 16 psi...mine did for many years.

Usually the first thing to try is the "wastegate spring mod" for which there are a few threads around here, but basically you take an extension spring and attach one end to the wastegate actuator arm and the other to something nearby, so the spring is holding the wastegate closed tighter. If a weak, leaky wastegate is your problem this will improve your ability to run higher boost without leaking.
 
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