Where to plumb Boost Gauge

[19GN85]

Whats the ideal spot on a hot air motor to hook up a boost gauge? Which line should I tap into?

 

[novaderrik]

ideally, you'd want it as close to the plenum as possible- the hose going to the PCV valve would be good.
but i've got mine tee'd into the line going to the fuel pressure regulator, and it reads just fine.

 

[Lee Thompson]

The hose going to the PCV nalve ?

Isn't that off the vacumn block?
IMO --the best place is the 1/8 in. NPT port that is in the front of intake sorta behind the fuel pressure reg. It has a plug in it from the factory.

 

[esinger]

Isn't that off the vacumn block?
IMO --the best place is the 1/8 in. NPT port that is in the front of intake sorta behind the fuel pressure reg. It has a plug in it from the factory.

+1 on everything Lee said. PCV is vacuum and doesn't and shouldn't see boost.

 

[19GN85]

Thanks for all the info guys...its greatly appreciated.

 

[Shortydoowop138]

I used the 1/8" port in front of the intake.. A small wrench and some teflon tape is all you need.. Less chance of screwing something up since it's on the front of the engine and easily reachable..

 

[O SO LO]

I did the same as shortydoowop138...

 

[novaderrik]

+1 on everything Lee said. PCV is vacuum and doesn't and shouldn't see boost.

hook up a vacuum gauge to the pcv line and see what it does when the boost climbs. since it goes straight to the plenum, it will see the same boost as anywhere else will.

 

[esinger]

hook up a vacuum gauge to the pcv line and see what it does when the boost climbs. since it goes straight to the plenum, it will see the same boost as anywhere else will.

You must be talking about something other than the PCV. The PCV goes from the vacuum block on top of the throttle body to a hole in the very bottom of the intake assembly that seals the top of the block. There shouldn't be any boost.

 

[Lee Thompson]

I believe

The PCV goes into the crankcase. If you're seeing boost there--you have some major blowby.

 

[novaderrik]

i was talking about the side of the pcv valve that has the hose hooked to it that goes to engine vacuum.. it goes to the vacuum block, which goes to the plenum. under boost, it will see boost- which makes it a good place to put a boost gauge.. the pcv valve is a check valve so it won't allow boost into the crankcase, but under WFO conditions the pcv valve is doing nothing to evacuate crakcase pressure- which is why you need a good breather on the inlet side of things.

 

[esinger]

I just have to ask this question. How many pounds of boost are you seeing from hooking up a boost gauge to the PCV?

 

[esinger]

Second question, is your throttle body pre-turbo or post-turbo?

 

[Lee Thompson]

3rd ?

Are you talking about an 85 or 87?

 

[my85grandnation]

The best place byfar is the port on the front of the intake. I have found thatit gives the most accurate reading over placing it anywhere else.

 

[fyrlt67]

I agree front of intake is the best place