Cowzzz

I finally got my christmas presents in , my boost gauge, air fuel ratio gauge, and my boost controller. My boost gauge only reads like -1 vacum and when i floor it, it goes up to 5 and then when i put the clutch in to shift it spikes to 10. Do you think i hooked up somthing wrong? or is that just how a rotary works?!?! thx for any help.

Cowzz

SpeedFreak03

First, is it PSi or KPa or something else? What is it at on idle? And WOT is 5 then? What does the stock boost gauge say? And where did you tap for the reading (what vacuum line)? I don't think it should spike to 10...that might have something to do with the boost controller. Is it manual or electronic?

Cowzzz

ITs a manual boost controller, at WOT it stays at 5 and when i let off the gas it spikes to 10 for a second and goes back to 0. i went of the vacum line that goes from the boost controler to the turbo, would it mater if i went from the boost controller to the wastegate accuater???

SpeedFreak03

What do S4 turbos run at stock (ive only owned an S4 NA, but I know S5s run like 9PSi)? I think that your boost gauge is probably getting an accurate reading, its most likely your boost controller having something to do with the spiking. Turn up the boost little by little and see if your readings change. BTW what does the stock boost gauge say?

Cowzzz

Ive read 7psi stock, and i was thinking the same thing so i turned the boost up on the controller when i first drove it, and it went to 5 and spiked at like 6-7, then i turned it up again and it went to 5 and spiked at 9-10. By then i was like wtf is going on, the stock gauge stays at a constint spot. Does it mater which vacum line i tapped off of to get the boost vacum??? The boost gauge came with this pos line and i went and got some good vacum line and i just put the boost gauge line into the line i bought and put a screw on thingy to hold them together, could i of tightned it to much and the gauge isnt getttin a good reading(im prolly making no sence )??

SpeedFreak03

Well honestly im a little confused about how its all hooked up, so I made a diagram in MS Paint. Is that how its all hooked up? If so, I think you wanna have it on the line going from the MBC to the WG actuator. Im not 100% sure though. Its worth a try I guess. But tell me if my diagram is how your car is setup, and we will go from there.

SpeedFreak03

BTW just want to add, I hope you have a FCD (fuel cut defender)...It will render your stock boost gauge useless, but if you plan on running at higher-then-stock boost levels you need one.

Cowzzz

yes thats how my setup is(thx for goin to the trouble of drawing that pic), and of course i have a FCD but thanks for checking =) So do you think i should switch the tee to the wate gate accuater side?

SpeedFreak03

Yea give it a shot, vacuum line is cheap . But before you do that make sure all lines are in good shape and hooked up well (like clamps and stuff) before you switch it. Good luck!

NZConvertible

Why are you connecting a boost gauge to the wastegate line? It's supposed to be measuring manifold pressure, so it needs to be tee'd into a post-TB vac line. The most logical one is the line to the pressure sensor, since that's the point where Mazda decided to measure manifold pressure.

Cowzzz

wow that accually makes sence NZConvertible thx alot . ill try that tomarrow and post on how it goes

Cowzzz

and btw i was teeing it off of the line from the boost controller to the turbo