Boost numbers!

trevorpschield · Mar 11, 2014

What boost numbers are you guys seeing cruising around 1800 rpm? And what's the max boost you are seeing?

My cruising boost at 1800 rpm at 70 mph is around 12-15 lbs and the max I've seen is 45 lbs. Does my crusing boost sound right to you guys, seems high to me.

dsberman94 · Mar 11, 2014

In my friends 6.4 we hit 60 psi going up a hill when the tc locked in under heavy throttle and the dieselsite boots slid off the piping.

RedRice589 · Mar 11, 2014

trevorpschield said:
What boost numbers are you guys seeing cruising around 1800 rpm? And what's the max boost you are seeing?

My cruising boost at 1800 rpm at 70 mph is around 12-15 lbs and the max I've seen is 45 lbs. Does my crusing boost sound right to you guys, seems high to me.

Seems normal. When towing I pushed 18-22 at all times and cruising was right around there closer to 10 on the flats not pushing. I saw 52-53. Stock turbo doesn't give much over 50. Well not usable boost lol

sootie · Mar 11, 2014

seems about right.

RSK · Mar 11, 2014

trevorpschield said:
What boost numbers are you guys seeing cruising around 1800 rpm? And what's the max boost you are seeing?

My cruising boost at 1800 rpm at 70 mph is around 12-15 lbs and the max I've seen is 45 lbs. Does my crusing boost sound right to you guys, seems high to me.

at 70 and 1800rpm flat highway its around 10psi, depends on what tune you run. But 2009-2010's have 3.55's that puts more load on the motor. Making more boost at cruising speeds, rpm creates more boost, because boost is a restriction.

Rmartin-97 · Mar 11, 2014

With the mods in my sig. I push 57-60 psi at wot and cruise at 8-10. On a stock turbo 45 was the max I seen with gearhead tunes.

trevorpschield · Mar 11, 2014

Since mine is a fx4 does that mean it came with 3.73 or did they all come with 3.55

SEABEE08FX4 · Mar 11, 2014

For stock turbos thats about right.

RSK · Mar 12, 2014

trevorpschield said:
Since mine is a fx4 does that mean it came with 3.73 or did they all come with 3.55

They all came with 3.55's 09-10. 08's all got 3.73's which in all honesty are probably better for everything. The 3.55's make the motor work harder, and make more boost, so they use more fuel. 70-80 might be the sweet spot for 3.55's i know its not 55-60 thats for sure, that got me 14mpg all highway over 300 miles

SEABEE08FX4 · Mar 12, 2014

3.55's were an option not standard. There are several 9-10 trucks that came with 3.73's.

sootie · Mar 12, 2014

you could not get 3:73's in 2010 year model

i get better hwy mileage with 3:55's than when i had 3:73's

RSK · Mar 12, 2014

sootie said:
you could not get 3:73's in 2010 year model

i get better hwy mileage with 3:55's than when i had 3:73's

What rpm? Maybe my stock intake is hurting me. It could use a new filter, but i know i doing a no limit intake fairly shortly.

sootie · Mar 12, 2014

75-80mph 1800-1950 rpm

bigrpowr · Mar 12, 2014

RSK said:
at 70 and 1800rpm flat highway its around 10psi, depends on what tune you run. But 2009-2010's have 3.55's that puts more load on the motor. Making more boost at cruising speeds, rpm creates more boost, because boost is a restriction.

Just about all of this is incorrect. The restriction has nothing to do with it nor does 3:55 put more loading the motor. It actually puts less. It makes more boost at rpm because the turbine is driven harder via rpm.

RSK · Mar 12, 2014

bigrpowr said:
Just about all of this is incorrect. The restriction has nothing to do with it nor does 3:55 put more loading the motor. It actually puts less. It makes more boost at rpm because the turbine is driven harder via rpm.

You learn something new everyday

SEABEE08FX4 · Mar 12, 2014

sootie said:
you could not get 3:73's in 2010 year model

You most certainly could.

http://assets.forddirect.fordvehicl.../pdf_8801EF28-E5B8-A617-E84C-10E8E84C10E8.pdf

trevorpschield · Mar 17, 2014

Well with what ever gears I have with 35 inch tires at 70 mph I turn 1800 rpm and my speedo is correct. That seems like 3.73s to me not 3.55s and mine is a 2010