Cam to big????
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From: jefferson city MO
Cam to big???? We just finished up and fired a 365" forged bottom end f1r procharger engine.
Cam specs are 239 252 623 624 114+4, (9.4:1)
I have changed map sensors re calibrated the map efficiency using hp tuners.
been tuning for a while and this thing is stumping me.. at 1000rpm it will only pull down to 100-102 kpa, touch the throttle nd rpm jumps to about 1300 and the map lowers to 80ish kpa... then slowly lowers rpm to 1k and kpa back to the 102 range...
we pulled the tube off the intake thinking the bov was not dumping enough air. went through the engine and check PR length to make sure we did not have a valve being held open.
pressure tested the intake (blow gun) through the hole drilled in the TB and can easily get boost to build with engine off key on.
can not hear or find any vacuum leaks any where...
any thoughts guys.. thanks
Cam specs are 239 252 623 624 114+4, (9.4:1)
I have changed map sensors re calibrated the map efficiency using hp tuners.
been tuning for a while and this thing is stumping me.. at 1000rpm it will only pull down to 100-102 kpa, touch the throttle nd rpm jumps to about 1300 and the map lowers to 80ish kpa... then slowly lowers rpm to 1k and kpa back to the 102 range...
we pulled the tube off the intake thinking the bov was not dumping enough air. went through the engine and check PR length to make sure we did not have a valve being held open.
pressure tested the intake (blow gun) through the hole drilled in the TB and can easily get boost to build with engine off key on.
can not hear or find any vacuum leaks any where...
any thoughts guys.. thanks
Last edited by 9sectruck; Mar 27, 2014 at 03:32 PM.
Maybe pull the sensor off, connect to a vacuum tool like a mighty vac and see if it's accurate? Do the same just sitting in atmosphere, and add some pressure maybe from an air hose.
See if it reads what you expect.
What sensor are you using?
See if it reads what you expect.
What sensor are you using?
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From: Norn Iron
When you log with engine running ( at least 10Hz ), is the map signal stable or all over the place ?
To have such low vacuum...ie none and the car idling at 1000rpm, it would indicate a major valve sealing issue, and it must be running pretty bad.
Compression test or leakdown test would do no harm.
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From: jefferson city MO
We will do a comp. Test tonight.
Preload on all the lifters are about 3/4 to 1 full turn pass zero lash.
The car runs damn near perfect (via map adjusted at the 100-105kpa for fueling) no obvious problem while its running.
Preload on all the lifters are about 3/4 to 1 full turn pass zero lash.
The car runs damn near perfect (via map adjusted at the 100-105kpa for fueling) no obvious problem while its running.
Last edited by 9sectruck; Mar 28, 2014 at 09:50 AM.
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From: jefferson city MO
guys.....it idles just fine no hunting or anything.. iac is around 35-40 sits a pers at 1000-1050 rpm at 100-102kpa.
we will get a vid 2maro with the kpa reading/idling
we will get a vid 2maro with the kpa reading/idling
