Hey guys I just bought an fd that is mostly pretty clean and fully functioning except i have discovered that my boost gauge is reading extremely low compared to what it apparently shouldbe. I am going to take it in to the dealership on monday because apparently theres an rx7 guru that works there but in the meantime i am trying to narrow down what could be wrong. this is my first experience with turbo cars so bear with me and thanks in advance for any help!

1) there is a hose missing off of the air box and i cant find a meaningful diagram and i am curious as to if this could be one of the issues....anyone know what this hose is???



2) the vacuum lines look like they have been replaced with blue silicone lines which i have read is a farely common mod, but maybe something is hooked up wrong.

3) a boost leak somewhere else in the system??? no clue where or how to start

 

not sure if this would help with diagnosis of ur problem but have u been pointed to where to download repair/service manuals yet? should have diagrams for vacuum hose routing to check to see if everything's correct.
Foxed.ca - Mazda RX-7 Manuals

 

That missing air hose on the side of the airbox is just the port that the air pump air that is dumped goes out.

First point of call is checking there are pills in the wastegate and precontrol lines from the turbos to the 2 actuators on the turbos.

It is extremely likely there is a problem if someone has messed with the car by putting silicon hose on.

FYI It might be a common first mod but I would never be using any hose but an OEM quality rubber vacuum hose such as gates brand.

 

thanks I will check and see if the pills are in there as ive read this could be the issue in opening up the secondary turbo. Would the primary turbo make 6 psi across the rpm range though if the secondary turbo is not kicking on?

 

OK so I go to taking apart some stuff and lo and behold there were no line pills in the wastegate or turbo precontrol actuator lines....I will try to fabricate some myself but does anyone know of something else I can use?

 

Fixed!!!! I took the lines from the wastegate actuator and turbo precontrol actuator off and made some line pills with factory sized orifaces for ~$6 of parts from lowes. heres how if anyone is interested....

Supplies needed:

1. 1/4" id silicone tubing
2. 1/4" x 3' aluminum rod from lowes
3. drill press(or steady hands and a vice)
4. dremel tool or hacksaw (for cutting aluminum rod)
5. 1/16" drill bit (.0629" for wastegate line pill)
6. 1.5mm drill bit (.0590" for precontrol line pill)
7. vice grips






1) remove factory air box and all tubes attached, locate and remove both the wastegate and turbo precontrol vac lines



2) grab the aluminum rod and use a vice or vice grips and measure about 3/8" from one end

3) use your preferred cutting method to chop off that piece. i used a file and bench grinder to clean the cut a bit.

4) use the 1/16" drill bit to create the wastegate line pill using the drill press and the 3/8" piece you cut off the rod





5)cut a piece of silicone tubing to the same length as the wastegate line and insert the finishe pill into the line to about the middle of the tube.

6) repeat with the precontrol line and the 1.5mm drill bit and place the lines back on the car.

this completely fixed my boost issues!

 

excellent! what's ur boost pressure now?

 

Between 10 and 12 psi at wot