Vacuum seems LOW

[carryon525]

ALL Vacuum lines have been changed within 2 months. My boost/vacuum gauge is only showing -8 at idle in park??? The car does have a little larger than stock cam and ported stock heads. Need to know if this is WAY low and if so what do I look for now??

 

[psycho6cyl]

I'm not 100% sure but that's fairly low. I would look for vac leaks. What was reading before switching lines? I've been contemplating putting a smoke machine on mine as well..

 

[carryon525]

I'm not 100% sure but that's fairly low. I would look for vac leaks. What was reading before switching lines? I've been contemplating putting a smoke machine on mine as well..

Can't remember but the old lines were all cracked and some were melted off. Should I cap the wastegate solenoid ones since its not being used?

 

[earlbrown]

If you're not using the solenoid, Run one single line from the turbo straight to the wasegate. (and don't throw away that Tee)

 

[carryon525]

If you're not using the solenoid, Run one single line from the turbo straight to the wasegate. (and don't throw away that Tee)

That's what I currently am doing. I was really curious to know if the two ports on the solenoid just remain open?

 

[626gn]

ALL Vacuum lines have been changed within 2 months. My boost/vacuum gauge is only showing -8 at idle in park??? The car does have a little larger than stock cam and ported stock heads. Need to know if this is WAY low and if so what do I look for now??

Its low. If you're using that nylon vacuum line that come with most gauges that's where I'd check first.

 

[626gn]

That's what I currently am doing. I was really curious to know if the two ports on the solenoid just remain open?

Leave them open.

 

[MAK507]

Mine always shows -8 to -10 as well. I heard that was okay?

What's a heathy #? I too don't use the solenoid... But vacuum line is being used from the boost solenoid line on right fender. Would we not use this?


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[carryon525]

Its low. If you're using that nylon vacuum line that come with most gauges that's where I'd check first.

ALL of the lines I replaced were from gbodyparts racing sylicon line. WHAT about the vacuum canister? Does that ever need replacing?

 

[earlbrown]

Mine always shows -8 to -10 as well. I heard that was okay?

What's a heathy #? I too don't use the solenoid... But vacuum line is being used from the boost solenoid line on right fender. Would we not use this?


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The solenoid is on the PS valve cover. Are you talking about the MAP sensor for the dash's boost lights?

 

[carryon525]

Speaking of vacuum hoses. Can someone give me exact sizes to use for RJC and or the Lorenz boost controller? It seems that my compressor nipple is much bigger that the controllers so which hoses? I only use the wastegate to compressor. Btw I may be selling my rjc boost controller if anyone is interested. I'll know by Friday

 

[earlbrown]

I think RJC still uses the .170" (or possible .153") nipples on their controllers. I'm not 100% positive as I quit using that size quite a while ago.

 

[MAK507]

The solenoid is on the PS valve cover. Are you talking about the MAP sensor for the dash's boost lights?

Ah yes. You're right sir. That's what I'm talking about


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[carryon525]

changed line sizes on my boost/wastgate to a little smaller and tighten everything up better with new zip ties and now I'm at a better -11 vaccum. Went from -7 to 11.

 

[EVIL]

Man. I'm getting -16 to -17 and I thought I was a bit low.

D

 

[MAK507]

Shit I'm low too [emoji23]

idle/Park


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[Fast4Ward]

-18[emoji41]

 

[S10xGN]

My 215°/210° HR pulls 13" @ 850 RPM. A lot depends on idle speed, too. Lower idle just about always yields lower vacuum...

 

[Chuck Leeper]

Fresh 109, 206/206.......18" at 850 idle.
Is that gauge mechanical? If elec, is it reading from a MAP sensor, or pressure transducer?

 

[MAK507]

Fresh 109, 206/206.......18" at 850 idle.
Is that gauge mechanical? If elec, is it reading from a MAP sensor, or pressure transducer?

My gauge? Mechanical... Off of a tap that was put into the intake manifold.

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