Lower MAP readings with FAST 102 intake .
Thread Starter
On The Tree
Joined: Jan 2010
Posts: 124
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From: San diego , CA
Lower MAP readings with FAST 102 intake . I just went from stock LS6 intake to FAST 102 with 90mm TB and while I was tuning it I noticed that the MAP reading was dropped by 1 kpa on high rpm comparing to the LS6, not sure if this is a good or bad indication, I checked the intake many times and retorqued it and everything seems fine, no leaks at all .
Correct me if I’m wrong but i think when the engine pulled more air from the intake the intake pressure decrease , i just figure this out so i won’t be frustrated
.
Thanks
Correct me if I’m wrong but i think when the engine pulled more air from the intake the intake pressure decrease , i just figure this out so i won’t be frustrated
.Thanks
First, look at your BARO or low-RPM, WOT MAP reading
and be sure this isn't just a change in the weather.
Then, have a look at whether your throttle blade angle
at WOT is really dead-parallel with the air stream (dead
center is right of the air is coming in dead straight; if
the tract has close-in curvature, the air may be coming
in off-axis and the blade then disturbs flow). Changing
pieces can change that, and some of the bigger TBs
seem to need some extra setup fiddling to get right at
idle, get enough cable draw to open fully, etc. Check
that with a cinderblock on the pedal, a ruler on the TB
for blade center @ WOT, and an eye to the ducting to
see whether straight open is indeed the right answer
as-plumbed.
and be sure this isn't just a change in the weather.
Then, have a look at whether your throttle blade angle
at WOT is really dead-parallel with the air stream (dead
center is right of the air is coming in dead straight; if
the tract has close-in curvature, the air may be coming
in off-axis and the blade then disturbs flow). Changing
pieces can change that, and some of the bigger TBs
seem to need some extra setup fiddling to get right at
idle, get enough cable draw to open fully, etc. Check
that with a cinderblock on the pedal, a ruler on the TB
for blade center @ WOT, and an eye to the ducting to
see whether straight open is indeed the right answer
as-plumbed.
The way I see it is the air restriction caused by the tb or intake opening is read in vaccum by kpa. The lower the kpa the less restriciton the tb and intake opening are making on the engine sucking air in, this is a good thing... I have been boosted so long I honestly cant remember so I might be wrong. Your elevation should be sealevel and the reading would be 101kpa with the engine not running. 1 kpa would be 0.145psi loss BTW...
