Stock Boost?


JOETWINT

FORD GT OWNER
Mark IV Lifetime
Jan 22, 2008
431
Brooklyn N.Y.
What psi should I be seeing on the boost gauge in 3rd or 4th gear WOT?I am seeing 15lbs.I thought the car should only make around 12 stock........I added a Stainless Works exhaust and K+N filters.....and thought I would loose a psi or so from reducing back pressure .....any idea?
 

Empty Pockets

ex-GT Owner
Mark IV Lifetime
Le Mans 2010 Supporter
Oct 18, 2006
1,361
Washington State
What psi should I be seeing on the boost gauge in 3rd or 4th gear WOT?I am seeing 15lbs.I thought the car should only make around 12 stock........I added a Stainless Works exhaust and K+N filters.....and thought I would loose a psi or so from reducing back pressure .....any idea?


Boost is suppose to be around 14lbs max as I recall. But, I won't bet the farm on my memory. Your gauge could simply be off a tadd too... OR the Stainless has simply affected the intake manifold "absolute pressure" itself in the opposite way from expected...though logic wouldn't sure wouldn't see it that way.

You might wanna loose the K&N filters. 'Word is the oil in same will coat intake 'sensors and mess 'em up. There's a post or two on the Forum somewhere about this. Maybe the boost pressure sensor is also affected by the K&N's oil?:shrug
 
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SteveA

GT Owner/B.O.D
Mark IV Lifetime
Dec 13, 2005
3,694
Sandpoint Id
Both my cars made just under 12psi stock on the dyno. The gauge in one car read about 11psi and the other cars gauge read right at 12 1/2psi.
 

BlackICE

GT Owner
Nov 2, 2005
1,416
SF Bay Area in California
Mine read somewhere around 12 psi before the Whipple, now it is pinned at 15psi when on boost. The stock boost and vacuum readings are inferred numbers based RPM and input from the MAF while assuming a stock displacement of 5.4L
 

Ed Sims

GT Owner
Mark IV Lifetime
Apr 7, 2006
7,850
NorCal
stock boost

I thought Ford states 12.5 lb is the max stock boost. I always saw around 12 on the gauge before my Whipple.

Ed