vac/boost gauge readings..
#1
vac/boost gauge readings..
Okay so I was test fitting all my gauges and running all my wiring and such.. anyhow, the boost gauge shows about 22-24 vac at idle which is good.. but when the A/C goes on and both radiator fans are on, the gauge reads 20vac but it kinda vibrates there.. it's a slight vibration on the needle.. visible, but not enough to get off of 20vac. Anyone else experience this?
I've never seen this on any other car (non-Scion) that I've worked on.. I just want to make sure there isn't any issue before I do the install this next weekend.
I've never seen this on any other car (non-Scion) that I've worked on.. I just want to make sure there isn't any issue before I do the install this next weekend.
#2
which boost gauge do you have.. i have a digital gauge that constantly changes from 18-21 on idle but the vibration on idle i usually notice when idle afr goes a lil lean usuall 15.1 and vibration gets stronger when it gets leaner than 15.5.. enriching idle might help the vibration but a constantly changing manifold pressure could cause that too, ac and fans causes change in manifold pressure too.. i bet it gets crazier if you have cams
#3
I have an Autometer Cobalt mechanical boost gauge. The idle vac reading is rock solid at 22 vac.. but it only "vibrates" when both fans are on. I don't know AFR cuz my w/b isn't installed - and I'm not even boosted yet.
The vibration isn't significant enough to change the reading.. it's just at 20vac but shakes there... until the fan turns off then it's okay again... when fan comes back on, it does it again.
The vibration isn't significant enough to change the reading.. it's just at 20vac but shakes there... until the fan turns off then it's okay again... when fan comes back on, it does it again.
#4
maybe the vacuum reading is constantly changing so it kinda vibrates.. but i do notice that vac reading is a lil more unstable when fans or ac is on.. i dont know but it prolly how our stock tune is.. just get you kit installed and you will worry on something else
#7
yeah most dont notice coz they dont install gauges when theyre stock.. i wish i did so i will know how stock numbers are and maybe tune it like stock at vacuum.. if you can put your WB on stock setup. drive it around that would be better
#8
I know! Trust me I wish I could... I don't have jack/jack-stands and not even allowed to do it in this complex.
I already have an extra bung welded for the w/b on the stock S-pipe.
I already have an extra bung welded for the w/b on the stock S-pipe.
#10
Originally Posted by B_Real45
I know! Trust me I wish I could... I don't have jack/jack-stands and not even allowed to do it in this complex.
I already have an extra bung welded for the w/b on the stock S-pipe.
I already have an extra bung welded for the w/b on the stock S-pipe.
#12
Originally Posted by aen
it's a normal thing, vacuum systems aren't always at one stable position, it's constantly changing. dont worry about it
if it goes lower than 20 then there might be a leak though.
if it goes lower than 20 then there might be a leak though.
#13
my idle vacuum is 17.5-22 but it varies on different conditions, i didnt find any vac leaks so far but its always around 18-19s most of the time.. you guys think i have a leak?
#14
The TC pulls a lot of vacuum and it can throw off the guages. I had a similar problem which was corrected by installing a restrictor in the nylon line going to the boost guage. You don't want to restrict it too much, just a bit to slow down the flutter.
#18
Originally Posted by Ace83
wouldnt vacuum reading affected by other factors too like air flow, temp, idle rpm and such.. im check again my vac setup for leaks lol