[1955oval]

Installed a New South boost gauge and took it out for a ride. At idle I'm at 20 in vac. and everything seems steady. Took it out for a ride and it will spike to 18 but when I'm steady at 55mph I have 10 in vac. Does this sound right?? The only time I have boost is if I give it gas. Just doesn't seem right to me. I used hose clamps where I could and zip ties where I had to. I tapped off the FPR.
Thanks for the help.
steveo

 

[Big_Tom]

:facepalm:

 

[logiCReversed]

It's normal.

But put on your flak jacket . . .

 

[1955oval]

It's normal.

But put on your flak jacket . . .

That's OK, I can take it.:beer: I'm still learning. The reason why I posted is because I've seen replies where guys spike to whatever and then they hold a certain number. I understand I'll see boost when I give it gas, but it just didn't seem right to have vac at 55 mph.
Thanks
steveo

 

[cincyTT]

Its because the throttle body is almost closed when cruising. You only make psi when giving it a good amount of gas and the throttle body is open.

 

[1955oval]

Its because the throttle body is almost closed when cruising. You only make psi when giving it a good amount of gas and the throttle body is open.

Thanks...So when people say they spike to 20 and hold 12 does that mean that they spike to 20 in 1st gear and then thru the gears..2-6.. they are boosting to 12??? If that's the case..I understand now.
steveo

 

[cincyTT]

no. They mean they spike at about 3k and around 5k the psi keeps dropping to about 12psi at redline. This is all at wot and in one gear.

 

[20vturbslo]

This is obviously your first turbocharged motor. Which is great :thumbup: But it will take some time and you will understand all the ins and outs of these motors. You are in vacuum maybe 75% of the time while driveing (varies on how heavy your foot is) now that other 25%, you will be in positive pressure (boost). At this time while you are giving it a lot of fuel and air, it begins to build pressure in your system. Now factory settings are mapped at around 8-10psi spike and then tapers off around 5psi. Very whimpy I know. Boost spike is when the turbo initially builds up pressure that is normally an uncontrollable turbine that would keep on building pressure until its capacity. This is where your waste gate releases exhaust from hitting the turbo and bleeds it off. The reason for spike is your cars ECU controlling it. It spikes, then the N75 bleeds off the extra air.
Ha, sorry I wrote so much but it seemed like you needed some education :laugh:

 

[1955oval]

Gotcha...Thanks to everyone for the help/definition..Actually this wasn't bad, I put my kevlar on for nothing:laugh:
thanks again
steveo