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RB25Detonator

Mamba Internal Wastegate Diaphragm Leaking?

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I've got a brand new Mamba Adjustable Internal Wastegate on my highflow RB25 turbo. I did a boost leak test and it leaks a lot of air from the wastegate's diaphragm out through the hole that the wastegate has. I've attached a video showing the massive boost leak. 

mamba.JPG.e067cf95c90ca1da279785dccca06baf.JPG

My question is, Is it suppose to leak air like this? The stock nissan wastegate doesn't have a hole that leaks air out of the wastegate.

Maybe the hole is there to save the engine? I don't know.... :35_thinking: 

I have a EBC that uses a mac solenoid. My second question is, there ment to be air going through the mac solenoid if the car is off or EBC switched on? If not, then I'll know my EBC or mac solenoid is stuffed.

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After reading your post, I'm beginning to suspect this f**king POS wg is the culprit I can't build a steady boost and not because of my turbo housing which I personally instructed a shop to modify. I can't guarantee it is the cause of my boost issues for sure but prior to using this POS gate I had no issues with my ebc set up using even the stock iwg. BTW I was even using the most hardest spring that came with it!!!

But thanks for sharing your findings. something for me to look into now.

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I would suggest that you have torn the diaphragm.  That hole is to make sure that the back side of the diaphragm is open to atmosphere so you don't get any pressure in there when the diaphragm is moved forwards/backwards by the boost signal on the connected side.

An EBC solenoid valve is a calibrated leak from that signal line, so yes, air should be able to pass to the wastegate, regardless of the state of the solenoid (on, off, working, broken).

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Ok, I've figured out what was causing the boost leak in the wastegate. Turns out that my actuator arm was sitting on a funny angle when connected to the turbo's gate, forcing the air to push past the o-ring in the wastegate. I've attached a video to show what I mean. So in the video, I've connected compressed air straight into the wastegate with the arm disconnected and testing the operation of the wastegate with no air leaks. Then I connect the arm onto the turbo's gate with no pre load and blew air into the wastegate and it then fouled on the turbo's outlet (something to look out for). Then I rotated the arm slightly so that it won't touch the turbo's outlet and when I blew air into the wastegate, it leaked air past the o-ring because of the arm being pulled to one side. 

I've got it working now without any leaks. I actually took the actuator arm out of the wastegate and bend it to where it wants to be. And then I tested with the arm connected to the gate and it operates freely now with no leaks.

I suggest to everyone to test your internal wastegate's operation by connecting compressed air directly to it.

Edited by RB25Detonator

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Argh default_sad.png&key=60edf0cfeb1b5687d093da59e19dcb4bc4ca5078c255acb1c3a47ac6adc5cc5e have to scratch that now.

On a side note came to think of it, I actually remember having issues with the arms not aligned properly. Did you bend it yourself or something

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8 minutes ago, -S- said:

Argh default_sad.png&key=60edf0cfeb1b5687d093da59e19dcb4bc4ca5078c255acb1c3a47ac6adc5cc5e have to scratch that now.

On a side note came to think of it, I actually remember having issues with the arms not aligned properly. Did you bend it yourself or something

Yeah, I took the arm out of the wastegate and bend it by putting a pipe over it and then jamming the other end into a something els (my stock strut bar lol). 

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Manage to find my old video where I made sure there was no restriction with the iwg movement. From the looks of it, it looks like I have to find my boost issue else where since you proved its not the iwg :( 

Have been hesitant to get a boost leak test like what you've done in your video but oh well... 

BTW dumb question but your leak was blown through the iwg and not the intake right? 

 

 

Edited by -S-

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3 minutes ago, -S- said:

BTW dumb question but your leak was blown through the iwg and not the intake right? 

Yeah, my leak was only coming out of the internal wastegate. The other hissing noises in the background is my shitty air compressor leaking. When I connected my stock nissan internal wastegate, there were no boost leaks.

 

I can't believe I've been boosting with the gate stuck in the closed position. It actually runs shit now haha. Can't boost past 6psi because the gate can now open. I'll try preloading the arm even more. I reckon this was a major cause of why my engine has low compression. O-welll, I'm chuckin a RB30 in it soon :7_sweat_smile:

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I found the Mamba ' bolt on wastegate for rb25 stock turbo" a bit of a joke, didn't even come close to fitting nicely. Anything that looked like it might reach the flapper connector was pulling the piston off on a bad angle as RB25 Detonator said. And then when trying to bend the wastegate rod, it just snapped. I ended up making a new arm out of 6mm steel rod and then welding it to the remains of the Mamba rod...as they used some weird-ass thread size rather than a standard m6 x1. Now fits perfectly and no issues with the wastegate operation, just for me, wasn't " bolt-on "  as advertised. Their spring pressures seem to be way off though; I found they were consistently 2-3 psi lower that what they rated them as....which wasn't a bad thing, just meant more testing/swapping time. 

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