Boosting Characteristics After Downpipe Install
Jul 2, 2005, 07:42 PM
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Boosting Characteristics After Downpipe Install
First off, thanks to Jeff at 500whp.com who overnighted me the HFcat that i needed to complete this job. On to the ramblings...
I got my downpipe and highflow cat on today, rounding out my turbo-back exhuast. Currently i'm running the Apexi 3" downpipe (which isnt actually 3"), to a helix 3" highflow and a turboXS cat-back. on the inlet side, i have an AEM intake and a greddy type-s.
i noticed a slight boost drop after the exhaust install, but with some weird characteristics...
#1 from a stop if i get on it, the boost will spike to 19 psi and back off to about 17.5
this is relatively normal, and is holding higher boost than when i was running the stock BOV
#2 from a roll if i punch it i only spike to about 17.5 and back off to as low as 15psi sometimes. its largely dependent on the gear and RPM which i start at, and 15 is the lowest ive seen, but its fairly inconsistent and i dont think its making as much boost as stock.
i know i need some sort of boost controller and i think ill probably just go with a Dynoflash to hold stock-ish boost levels and tune for my mods. but is this a normal boosting pattern for running a 3" turbo-back without a boost controller?
things still needed include hard i/c piping, but id like to hear some other experiences on a similar setup. am i wrong to think that a free-er flowing exhaust should give me more boost at all rev ranges?
thanks.
I got my downpipe and highflow cat on today, rounding out my turbo-back exhuast. Currently i'm running the Apexi 3" downpipe (which isnt actually 3"), to a helix 3" highflow and a turboXS cat-back. on the inlet side, i have an AEM intake and a greddy type-s.
i noticed a slight boost drop after the exhaust install, but with some weird characteristics...
#1 from a stop if i get on it, the boost will spike to 19 psi and back off to about 17.5
this is relatively normal, and is holding higher boost than when i was running the stock BOV
#2 from a roll if i punch it i only spike to about 17.5 and back off to as low as 15psi sometimes. its largely dependent on the gear and RPM which i start at, and 15 is the lowest ive seen, but its fairly inconsistent and i dont think its making as much boost as stock.
i know i need some sort of boost controller and i think ill probably just go with a Dynoflash to hold stock-ish boost levels and tune for my mods. but is this a normal boosting pattern for running a 3" turbo-back without a boost controller?
things still needed include hard i/c piping, but id like to hear some other experiences on a similar setup. am i wrong to think that a free-er flowing exhaust should give me more boost at all rev ranges?
thanks.
Jul 2, 2005, 08:05 PM
#2
Originally Posted by avengerhed
i think ill probably just go with a Dynoflash to hold stock-ish boost levels and tune for my mods.
Originally Posted by avengerhed
but is this a normal boosting pattern for running a 3" turbo-back without a boost controller?
Jul 2, 2005, 08:33 PM
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thanks for the reply
with regards to the MBC, my buddy's hallman (older) locked up on him over the winter and he spiked to 26psi...he was later told that the valve had to be oiled.
does the "upgraded" hallman, with the ceramic check valve ball get rid of this?
thanks again
with regards to the MBC, my buddy's hallman (older) locked up on him over the winter and he spiked to 26psi...he was later told that the valve had to be oiled.
does the "upgraded" hallman, with the ceramic check valve ball get rid of this?
thanks again
