Boost Pressure at 65mph
 

what kind of boost pressure are you guys seeing at 65-70 mph.

i get like 1 or 2 psi and that does not seem normal to me at all.

even know i have a cummins and a bigger turbo im at 12psi at 70 in 5th even with the stock turbo i was at 8 or 9 dont know why a duramax would be any different

yeah im a cummins man also and i see about 10-15 psi in 5th gear
my dads d max does the same low or no boost at highway speeds

i know it also depends weather your on flat land or a slight grade but 1 or 2 cant be corect:humm:

it all depends on the load on the motor.....I see as low as 3 lbs on flat ground doing 65-75 mph

Same here on flat ground just cruising no load no wind I see very little boost at 70. Slight grade will give some boost and a good hill I might see 10lbs.

i see low boost with no load on flat ground. on a hill with 5th wheel i might see 30. it depends on load on motor

even goin up a slight grade in the city itl go up to 2psi, but when its on flat land itl be at 1psi.

noticed im getting chit mileage too this tank :humm:

:humm: Think your turbo's going out? Could it be a waste gate issue or something?
How does your turbo respond otherwise?

im thinkin theres a leak somewhere, but can some one with a lb7 tell me what kind of boost they make at 65 mph cruising

am i like the only dmax with gauges out here :sos:

Yes.... :lol88:

But for fun I'm anywhere from 8-15 depending on conditions while not towing.

When I'm cruising at 70 mph unload. I see 3-5 psi on my boost gauge.

I dont think it matters what diesel ya drive in the end the boost gauge is basically a work gauge.....................the higher the boost the more fuel or harder the motor is being loaded :humm:


bottom line here is I dont think ya can pin a number on this

something is wrong because most 6.5s make 1-3 PSI of boost cruisin and we have smaller turbos and a lot lower top boost number. something is wrong with your turbo or something relalated to it

well i got 15mpg this tank... im suspecting a boost leak somewhere gonna have to look

boost looks too low for me, its only been 50 or so days since ive actually looked at them gauges

Are you seeing more smoke and higher egts? I would think that would also indicate a leak. I don't get to hung up on boost numbers unless they are dramatically different under the same conditions.

i was gettin almost 100* hotter at times.

i tightened all the clampes down some more and it seemed to help a bit. i really need to get to tuning this booger. never had good injectors with efi live before :D

Finnaly got a chance to go out and check for ya mine ran anywhere from 1.6 to 2.2 psi on flatish ground. So either that's normal or we both have somthing wrong

you got your truk back?

i'll check and see what i'm runnin here in a few minutes. i wanna say it's not much. but idk. I'm about to post a thread cause i'm havin some weird stuff happen with my boost.

i think i go tit fixed.

i got some tricks up my sleeve now...

well what's it runnin now? cause i ran 2.5-3 psi on my 220 tune and then like 3-4 on my 160 tune (doesn't make much sense to me. i might have read it wrong when i was on my 220 i was in a hurry to get to work and ended up racin with an srt-10:w2:)

Whats you top boost number again? Every thing seems A-Ok......I'm not understanding where theres somthing wrong with the turbo??? Gearing and tranny is the main consideration when looking at cruise boost numbers. Cruise boost really has no realativity to anything besides spool up and fuel economy. Now if we see an abnormal higher boost reading or sudden boost lost that would be cause for concern but 1-2 lbs is completely normal!

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PS...Please remember that you folks cant get an adequate representation of what a trucks supposed to run boost wise, Even if you both have the same setup same truck its still compairing apples to oranges. You've got elevation, the density of the air, Temp and so on. Just remember that just because someone 1500 miles away makes 5 lbs at cruise and you make 3 ...IT DOES NOT MEAN your have a boost leak or somthings not right!

i was experiencing some sluggish acceleration and slow building boost. figuerin that theres a boost leak somewhere.

i think i got it, boost comes in like how it used to and egts dont get past 1350 right now on the "big" tune i have.

Yep :c: glad to have yours up any running again?

oh hell yeah, i need to get to tuning it again, was lazy and threw something on there. maybe this weekend ill tune it an dyno it :pca1:

sweet! :pca1: let us know how it goes

My brothers 12v will run about 2 or 3 psi at 60 mph on flat ground. When it hits a hill it will just make a little more and climb right up.

mine with bd supermax runs around 5 on flat ground at 70, jumps to 7-10 on slight grade (running 215 hp tune)

My truck runs between 1-4psi at 70mph on flat. I have a fleece 68mm turbo with suncoast 4 and 1058 coverter. I got 18.5 mpg going up to minn and 13.2 coming back pulling 9k my turbo pushes 10-14psi on flat ground pulling 9k somtimes a little less. My stock turbo ran the same psi unloaded.