measuring back pressure?
12-16-2011, 08:29 PM
#1
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measuring back pressure? so im trying to measure the back pressure on my car. and well at 15 psi boost the gauge reads 0 psi of back pressure. i just dont think that's right. i have to have some back pressure. right? 2.5" merge 50mm jgs gate
365ci
87mm turbine
t4 1.25 ar
80mm compressor
i run 25psi boost but i need race gas. so 15 psi on pump gas is all i could test tonight
365ci
87mm turbine
t4 1.25 ar
80mm compressor
i run 25psi boost but i need race gas. so 15 psi on pump gas is all i could test tonight
12-17-2011, 08:14 PM
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Its a 2" gauge 0-100 psi. Have not tested the gauge yet. The copper tubing is maybe 50". I took the gauge off the tubing and I could put my finger over it w/o a problem when its under boost
Yep!
12-18-2011, 03:26 PM
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ok i tried a new gauge and well this one works.
car is making around 13 psi +/- 2psi boost and about 15 psi back pressure. i was driving by my self and could not get a good long pull, an extra set of eyes would help too. so 13 lbs boost 15 psi back pressure whats it mean?
car is making around 13 psi +/- 2psi boost and about 15 psi back pressure. i was driving by my self and could not get a good long pull, an extra set of eyes would help too. so 13 lbs boost 15 psi back pressure whats it mean?
12-18-2011, 04:39 PM
#10
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Could mean many things.
Either it's wrong. It's very efficient, the turbine is far too big.
Depends why you are measuring, and if you feel there is a problem somewhere.
Either it's wrong. It's very efficient, the turbine is far too big.
Depends why you are measuring, and if you feel there is a problem somewhere.
12-18-2011, 05:58 PM
#12
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well i can run 15 lbs boost on pump gas but higer then 15 lbs i like to run some 100+ octane gas. tonight was just a test to see if the new gauge worked.
i am trying to figure out why my car is NOT as fast as i thought i should be.
its only gone 9.4s at 150 im a seccond too slow and 10+ mph down.
i run 25psi with race gas, so thats the next thing to do is measure back pressure at 25psi.
also need to measure the pressure drop threw the ebay a/a intercooler
i am trying to figure out why my car is NOT as fast as i thought i should be.
its only gone 9.4s at 150 im a seccond too slow and 10+ mph down.
i run 25psi with race gas, so thats the next thing to do is measure back pressure at 25psi.
also need to measure the pressure drop threw the ebay a/a intercooler
12-19-2011, 02:46 AM
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S480 80/87 T4? or 4508?
I ran it through BW's calculator and get around 33 psi BP at 23 psi.
And your on the edge of the compressor map based on a few assumptions.
Do you have a straight dump or piped to the back?
Did you measure at the compressor or the intake?
Probably your inter cooler has a big drop or your cold side is small.
I know of one guy going 9.4 at 142 w/ 20 psi at the compressor and 15 in the intake w/100f IAT. He has 30 psi BP with a slightly smaller flowing T6 1.1 87 turbine - and 1000lbs heavier!
Hook your gauge up to a street tire and check against a tire gauge. They should be close.
I ran it through BW's calculator and get around 33 psi BP at 23 psi.
And your on the edge of the compressor map based on a few assumptions.
Do you have a straight dump or piped to the back?
Did you measure at the compressor or the intake?
Probably your inter cooler has a big drop or your cold side is small.
I know of one guy going 9.4 at 142 w/ 20 psi at the compressor and 15 in the intake w/100f IAT. He has 30 psi BP with a slightly smaller flowing T6 1.1 87 turbine - and 1000lbs heavier!
Hook your gauge up to a street tire and check against a tire gauge. They should be close.
12-19-2011, 02:41 PM
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S480 80/87 T4? or 4508?
its a 80mm compressor with race cover, 87mm turbine 1.25 devided t4 its from forcedinductions they called it a sx80 or others call it a s380r
I ran it through BW's calculator and get around 33 psi BP at 23 psi.
And your on the edge of the compressor map based on a few assumptions.
link to the BW calculator
Do you have a straight dump or piped to the back?
i have a 4" downpipe that exits out the front fender
Did you measure at the compressor or the intake?
im reading boost from the back of teh intake manifold
Probably your inter cooler has a big drop or your cold side is small.
ic piping is all 3" intercooler is 31x12x4 with a 3" in/out
I know of one guy going 9.4 at 142 w/ 20 psi at the compressor and 15 in the intake w/100f IAT. He has 30 psi BP with a slightly smaller flowing T6 1.1 87 turbine - and 1000lbs heavier!
Hook your gauge up to a street tire and check against a tire gauge. They should be close.
its a 80mm compressor with race cover, 87mm turbine 1.25 devided t4 its from forcedinductions they called it a sx80 or others call it a s380r
I ran it through BW's calculator and get around 33 psi BP at 23 psi.
And your on the edge of the compressor map based on a few assumptions.
link to the BW calculator
Do you have a straight dump or piped to the back?
i have a 4" downpipe that exits out the front fender
Did you measure at the compressor or the intake?
im reading boost from the back of teh intake manifold
Probably your inter cooler has a big drop or your cold side is small.
ic piping is all 3" intercooler is 31x12x4 with a 3" in/out
I know of one guy going 9.4 at 142 w/ 20 psi at the compressor and 15 in the intake w/100f IAT. He has 30 psi BP with a slightly smaller flowing T6 1.1 87 turbine - and 1000lbs heavier!
Hook your gauge up to a street tire and check against a tire gauge. They should be close.
