newt28,won't go under 13psi, - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

Rich Druash · 06-29-2005, 12:51 PM

I was wondering if anyone knows what the wastegate is supposed to be set on on the s15 t28.I just installed a brand new s15 daul bb t28 on my s13 motor. I have stock injectors, ecu, and maf with a frontmount and a walboro 255 fuel pump. I had my car with the stock t25 running 12 lbs and it ran fine, I just unpgraded to the t28 and my car all the sudden wanted to boost all the way to 1.5 bar,(over 20lbs) and it would get there by 4000 rpms, it would probobly go even higher if i reved it all the way out. I tried bypassing the boost controller to try to isolate the problem and running the vacuume line directly to the wastegate actuator and i was boosting between 12 and 13 pounds. Does this seem unusual at all. With stock fuel the car is not runing right on 13 pounds, it feels like it's missing or back firing or something, I was guessing my injectors were passed dutycycle and the fuel cuting out. I was trying to run the t28 on less boost instead of the t25 on high boost until I could afford an enthalpy ecu and 550 injectors but now can't get it to boost any lower. Could my wastegate actuator be to tight or something.

rim_bender · 06-29-2005, 01:01 PM

I have an s15 T28 bb on my s13 sr. Stock boost is 7 psi for the s15 turbo. You might want to check the actuator. Hook up a pump and see if it moves at 7 psi.

Rich Druash · 06-29-2005, 05:22 PM

what do you mean by hook up a pump

Rich Druash · 06-29-2005, 05:26 PM

I just installed a DNA boost controller and it is going over 20 pounds when it is all the way closed. Is my wastegate not opening or is this just a bad actuator or what? I checked all my vacuume lines and everything.

rim_bender · 06-29-2005, 05:33 PM

you can pressuer test the system with a homemade device, search and im sure you'll find a how to on it. Also make suere there is no leaks from the hose going to the actuator.

sr240mike · 06-29-2005, 07:40 PM

With the manual boost controller closed its never going to allow the wastegate to open. Running a vacuum line directly to the wastegate was what you did and it still boosted to 13 psi. More than likely you have either a bad actuator or an aftermarket one with an upgraded spring inside or adjustable rod. Can you take any pics of the actuator or see if the rod is threaded?

Rich Druash · 06-29-2005, 11:48 PM

The rod is threaded but if you try to extend it to the right length it will screw off the end. I think it's probobly the actuator because when I take the arm off the actuator it won't boost at all. I was thinking off ordering an hks one.

06-29-2005, 12:51 PM	#1
Rich Druash Leaky Injector Join Date: Mar 2005 Location: Virginia Posts: 52 Trader Rating: (0) Feedback Score: 0 reviews	newt28,won't go under 13psi, I was wondering if anyone knows what the wastegate is supposed to be set on on the s15 t28.I just installed a brand new s15 daul bb t28 on my s13 motor. I have stock injectors, ecu, and maf with a frontmount and a walboro 255 fuel pump. I had my car with the stock t25 running 12 lbs and it ran fine, I just unpgraded to the t28 and my car all the sudden wanted to boost all the way to 1.5 bar,(over 20lbs) and it would get there by 4000 rpms, it would probobly go even higher if i reved it all the way out. I tried bypassing the boost controller to try to isolate the problem and running the vacuume line directly to the wastegate actuator and i was boosting between 12 and 13 pounds. Does this seem unusual at all. With stock fuel the car is not runing right on 13 pounds, it feels like it's missing or back firing or something, I was guessing my injectors were passed dutycycle and the fuel cuting out. I was trying to run the t28 on less boost instead of the t25 on high boost until I could afford an enthalpy ecu and 550 injectors but now can't get it to boost any lower. Could my wastegate actuator be to tight or something.

06-29-2005, 07:40 PM	#6
sr240mike Zilvia FREAK! Join Date: Apr 2004 Location: California, Norcal biiaatch Posts: 1,185 Trader Rating: (0) Feedback Score: 0 reviews	With the manual boost controller closed its never going to allow the wastegate to open. Running a vacuum line directly to the wastegate was what you did and it still boosted to 13 psi. More than likely you have either a bad actuator or an aftermarket one with an upgraded spring inside or adjustable rod. Can you take any pics of the actuator or see if the rod is threaded? __________________ TWO IN THE COOT, ONE IN THE POOT

06-29-2005, 01:01 PM	#2
rim_bender Zilvia Junkie Join Date: Jan 2004 Location: Ga Posts: 441 Trader Rating: (0) Feedback Score: 0 reviews	I have an s15 T28 bb on my s13 sr. Stock boost is 7 psi for the s15 turbo. You might want to check the actuator. Hook up a pump and see if it moves at 7 psi.

06-29-2005, 05:22 PM	#3
Rich Druash Leaky Injector Join Date: Mar 2005 Location: Virginia Posts: 52 Trader Rating: (0) Feedback Score: 0 reviews	what do you mean by hook up a pump

06-29-2005, 05:26 PM	#4
Rich Druash Leaky Injector Join Date: Mar 2005 Location: Virginia Posts: 52 Trader Rating: (0) Feedback Score: 0 reviews	I just installed a DNA boost controller and it is going over 20 pounds when it is all the way closed. Is my wastegate not opening or is this just a bad actuator or what? I checked all my vacuume lines and everything.

06-29-2005, 05:33 PM	#5
rim_bender Zilvia Junkie Join Date: Jan 2004 Location: Ga Posts: 441 Trader Rating: (0) Feedback Score: 0 reviews	you can pressuer test the system with a homemade device, search and im sure you'll find a how to on it. Also make suere there is no leaks from the hose going to the actuator.

06-29-2005, 11:48 PM	#7
Rich Druash Leaky Injector Join Date: Mar 2005 Location: Virginia Posts: 52 Trader Rating: (0) Feedback Score: 0 reviews	The rod is threaded but if you try to extend it to the right length it will screw off the end. I think it's probobly the actuator because when I take the arm off the actuator it won't boost at all. I was thinking off ordering an hks one.