:driving: Turbo Boost Gauge readings

[Phoenix7]

you won't build boost in neutral....with stock injectors you should not see more than 10 psi but, like I said, you won't build boost without load.

[nvno1]

Originally Posted by Phoenix7

you won't build boost in neutral....with stock injectors you should not see more than 10 psi but, like I said, you won't build boost without load.

great, however what should the Hg be at 750, 1000, 1300?

[RETed]

Vacuum reading don't really matter except for maybe at idle.
When driving, when you see vacuum on the gauge, it just means the turbo isn't working to produce boost.
Trying to see your vacuum numbers while driving is a royal waste of time.


-Ted

[nvno1]

Originally Posted by RETed

Vacuum reading don't really matter except for maybe at idle.
When driving, when you see vacuum on the gauge, it just means the turbo isn't working to produce boost.
Trying to see your vacuum numbers while driving is a royal waste of time.


-Ted

Wow Ted, i feel so honored you replied on my post. I'm not driving the car right now, my main reason for asking about the vaccum is the idle is not set and i wanted to know if at 1000rpms, if the reading is right? I have checked for vac leaks and nothing has surfaced, however i dont have another way of verifing there is no leak. So i figured the vac reading on my boost gauge would fall as a back up.

[vex]

Originally Posted by nvno1

Wow Ted, i feel so honored you replied on my post. I'm not driving the car right now, my main reason for asking about the vaccum is the idle is not set and i wanted to know if at 1000rpms, if the reading is right? I have checked for vac leaks and nothing has surfaced, however i dont have another way of verifing there is no leak. So i figured the vac reading on my boost gauge would fall as a back up.

Ah, the mysterious missing vac leak, where you know you have one, but just can't find it.

Try to get a smoke machine. That should show you exactly where your vac leak is. I am in the process of doing this, but have a few things to do first before I do (mainly earn money).

as for boost and vac readings. Are you sure your gauge is grounded properly? Not having a proper ground will give you very messed up readings. If you have, expect to have anywhere from 14-20+inHg in vac. I'm currently pulling in around 14inHg on a fresh rebuild (though compression is absolutely fine). Good luck though.

[nvno1]

Originally Posted by vex

Ah, the mysterious missing vac leak, where you know you have one, but just can't find it.

Try to get a smoke machine. That should show you exactly where your vac leak is. I am in the process of doing this, but have a few things to do first before I do (mainly earn money).

as for boost and vac readings. Are you sure your gauge is grounded properly? Not having a proper ground will give you very messed up readings. If you have, expect to have anywhere from 14-20+inHg in vac. I'm currently pulling in around 14inHg on a fresh rebuild (though compression is absolutely fine). Good luck though.

Hey thanks for the info. The gnd is good but my Vac readings are not that high(if memory serves me right). With the smoke machine the smoke will be inserted to a opening in the intake somewhere and pressurized through the system with the vac leak showing up by means of escaping smoke?

[vex]

Originally Posted by nvno1

Hey thanks for the info. The gnd is good but my Vac readings are not that high(if memory serves me right). With the smoke machine the smoke will be inserted to a opening in the intake somewhere and pressurized through the system with the vac leak showing up by means of escaping smoke?

Not quite. With the engine running (and you're reading low on vac) start the smoke machine. Point the stream over the engine and look for locations where the smoke enters the engine where it shouldn't be. Gaskets, Hoses, connections, etc are good places to look.

[Flooder]

Originally Posted by Phoenix7

you won't build boost in neutral....with stock injectors you should not see more than 10 psi but, like I said, you won't build boost without load.

Sure you will, just not very much. You can still make your BOV vent when in neutral.

[nvno1]

Originally Posted by Flooder

Sure you will, just not very much. You can still make your BOV vent when in neutral.

matter of fact it did...my boost gauage hopped up to nearly 5psi. it was pretty cool to see.

[nvno1]

OkAy SOoooo...like my Hg rading are low..i got video coverage of the issue, no dvd player on the wk pc and dont have internet access else where right now. so what i decided to do is block everything off with block off plates, get another BAC, change all the remaining hoses, upper to lower intake gasket and check the fuel injectors. from the information you guys have given me the Hgs are to low. i am sure that it HAS to be a vac leak somewhere. oil pressure good, not getting hot, no bubbling at the rad, no sweet smell out exhast, and hard to start unless i play with the trottle.

[RETed]

Originally Posted by nvno1

from the information you guys have given me the Hgs are to low. i am sure that it HAS to be a vac leak somewhere. oil pressure good, not getting hot, no bubbling at the rad, no sweet smell out exhast, and hard to start unless i play with the trottle.

I doubt that's the case.
I put money it's something else.

Other causes that can "fool" your boost gauge to show improper vacuum while driving:

* ignition problems
* fuel delivery problems
* misfire
* hurt motor


-Ted

[nvno1]

Originally Posted by RETed

I doubt that's the case.
I put money it's something else.

Other causes that can "fool" your boost gauge to show improper vacuum while driving:

* ignition problems
* fuel delivery problems
* misfire
* hurt motor


-Ted

Ted i'm not driving;(, I got strong spark, getting good signal from the cas, plugs are good, coils seem good, good clear fuel flow, 85psi on front and rear and it doesnt backfire.