Does anyone have a clue what size orifice greddy uses for their pressure sensor on their boost controllers?

When I log my boost its really jumpy not very linear, I realized they use a restrictor to regulate the fluctuations of pressure and give you a smoother reading. On mine I have nothing, a straight line from manifold to the sensor.

 

Are you getting manifold pressure from the front OEM port on the plenum? If so, that one is very instable. When we log boost on the dyno, its very jump when we use that port. We source from the back of the plenum and the boost curve isn't as jumpy.

 

I am getting it directly from the manifold, from a aprox 2mm nipple. I have a FWD manifold. In this pic, the hose you see at the bottom of the picture.

 

Interesting. It's also in that corner. Wonder if retapping somehwere towards the back...closer to the TB would be worth a shot?

 

Yeah I am going to try a couple of things, right now i replaced the line from manifold to the pressure sensor, put a thinner vac line, I was using a big plastic line (same one you use for meth/water injection), also put a little restrictor from autozone. later one will see if it did anything.

If that dont work, then I will tap a new area in the manifold towards the center/back.

 

Does the length of tubing between the plenum and MAP sensor cause these issues?

Is it better to have the MAP sensor as close to the Plenum?

Reason i ask is because i have the MAP sensor hidden in the brake/master cylinder compartment, so the vacuum hose is about 1 metre long.

 

Not sure, but mine is alot further than that. comes from the manifold into the firewall by the driver side, then goes across to the passenger side below the glove box.

 

Length should not be the problem here - I frequently run them inside the vehicle for to onboard map sensors. I believe the nipple you are using is likely to blame. Try a large port on the intake manifold or tap a new port w/ fitting, and don't bother with all of the adapters and things you were trying to add.

 

What size barb would you recommend hal? I might just go ahead and tap a new one.

 

^ I tap 1/8 NPT and use 3/16 barb.

 

Cool, thanx alot. I will be doing that then. So I need a barb with 1/8th npt thread and 3/16th barb. Shoudlnt be too hard to find at local home depot, I got a NPT 1/8th tap in my hand right now. Will do this tomorrow.