[Blockay]

So I’m having hell figuring out what’s going on. A couple months ago i had to replace my turbo at 79k miles. 2017 2500 that was totally stock. I went with the bd screamer as a buddy of mine with basically the exact same rig as mine got one and loved it. He gets 33 psi of boost from his with an empty truck. I only got 26 psi right after install, which led me to believe i had a boost leak even tho i couldn’t hear anything and the truck doesn’t seem to be low on power or anything noticeable. Wound up replacing all my boost tubes and boots, went with the bigger banks tubes, but that got me to 27 psi. I just finished changing the map sensor and cleaning the intake horn and egr valve thinking that the egr might have been dirty and not sealing good. It wasn’t very dirty at all, and all of this seems to have changed nothing. The first time i floored it after the cleaning it hit 29 psi for just a second then dropped back to 27 and hasn’t gotten over it since. I’m at a loss and pretty disappointed honestly haha. I got 29 psi unloaded with the factory turbo even. At this point I’m wondering if i have something going on inside the turbo and am pretty well out of ideas. If anybody has any thoughts or suggestions, any help would be greatly appreciated!

 

[j98]

The real question is, was there a decrease/increase in performance after installing the turbo? Boost is just a number...

 

[Blockay]

The real question is, was there a decrease/increase in performance after installing the turbo? Boost is just a number...

i can’t tell any noticeable difference. What’s throwing me for a loop is my buddy that has an identical setup is getting 6 psi more than me and his feels a little peppier than mine

 

[j98]

In "theroy" the screamer should be a more efficient turbo, the real number to compare vs. stock is back pressure. A more efficient turbo may produce less boost due to a decrease in back/drive pressure.

If fueling and stock parameters havent changed I don't see why you should be getting any more boost then stock.

Both trucks have same gearing and tire sizes?

 

[Blockay]

In "theroy" the screamer should be a more efficient turbo, the real number to compare vs. stock is back pressure. A more efficient turbo may produce less boost due to a decrease in back/drive pressure.

If fueling and stock parameters havent changed I don't see why you should be getting any more boost then stock.

Both trucks have same gearing and tire sizes?

Yep, same gears and tire size on both rigs. That could be, this is my first delve into the world of turbos or diesels for that matter so i could be misunderstanding something. But from what i read on reviews of the turbo when i bought it, it seems like most people saw a 3-4 psi increase over stock with the bd. My main concern is that i have a leak somewhere and i don’t wanna end up trashing a $3200 turbo bc it’s over speeding and i don’t know it haha. I feel like I’ve pretty well ruled that out at this point tho, idk maybe I’m just overthinking it. The only other thing i can think of at this point is when i had the egr out to clean it, once i reassembled it i could blow through the inlet on it and could hear a very tiny amount of air squeezing by and i would think it should be airtight. But again, with my lack of knowledge about it all rn, I’m not sure if I’m thinking correctly in that the air could be squeezing by the egr and feeding back into the exhaust

 

[Mitchcook]

Do a boost leak test.
What tuning?

 

[j98]

"The larger Ballistic Billet compressor wheel and our new exclusive Low MOI QST turbine wheel results in reduced backpressure, quicker response, increased efficiency and increased turbine flow compared to the competition. This results in increased maximum potential power output, right up to 690 horsepower with performance modifications. No extra parts to install, just drop-in and enjoy the extra power potential."

Key word here : Potential. I don't see why you expect an increase in performance running stock calibration.

@Mitchcook

Unless I missed it he's not tuned.

 

[Blockay]

Do a boost leak test.
What tuning?

Yea that’s probably where I’m heading with it at this point. No tuning it’s all stock except the turbo and boost tubes/boots

 

[Blockay]

"The larger Ballistic Billet compressor wheel and our new exclusive Low MOI QST turbine wheel results in reduced backpressure, quicker response, increased efficiency and increased turbine flow compared to the competition. This results in increased maximum potential power output, right up to 690 horsepower with performance modifications. No extra parts to install, just drop-in and enjoy the extra power potential."

Key word here : Potential. I don't see why you expect an increase in performance running stock calibration.

@Mitchcook

Unless I missed it he's not tuned.

Simply from what i read on reviews from other users of it, and like i say my buddy’s truck that’s identical with him getting 6 pounds more than me from it, his is all stock as well

 

[BFD]

With all the egr, dpf etc garbage on these trucks, it wouldn’t surprise me if something else is making a difference.

 

[Blockay]

With all the egr, dpf etc garbage on these trucks, it wouldn’t surprise me if something else is making a difference.

Don’t i know it. It’s unmentionable but I’m saving up for “upgrades” to it all

 

[Proviron]

Have you compared actuator positions?

Did you calibrate your vgt actuator, my guess is under throttle your actuator position is off a hair preventing more flow to the turbo.

Stock turbo actuator position should be around 50-60% WOT, if your actuator position is above that then you're restricting the turbo.

For example when the exhaust brake is on and activates the actuator position hits 95-99% closing the vanes.

I would confirm your actuator is in the correct position and is properly calibrated.

If you've gone over everything for boost leaks then the actuator is most likely what is restricting the extra couple lbs of boost.

 

[Blockay]

Have you compared actuator positions?

Did you calibrate your vgt actuator, my guess is under throttle your actuator position is off a hair preventing more flow to the turbo.

Stock turbo actuator position should be around 50-60% WOT, if your actuator position is above that then you're restricting the turbo.

For example when the exhaust brake is on and activates the actuator position hits 95-99% closing the vanes.

I would confirm your actuator is in the correct position and is properly calibrated.

If you've gone over everything for boost leaks then the actuator is most likely what is restricting the extra couple lbs of boost.

No i never have bc it was supposed to have been already calibrated and could just bolt up. What you’re saying makes sense tho, it is possible they were off in their calibration of it i suppose

 

[Proviron]

No i never have bc it was supposed to have been already calibrated and could just bolt up. What you’re saying makes sense tho, it is possible they were off in their calibration of it i suppose

Same thing happened to my buddy's screamer, he had to get it calibrated even though his came pre calibrated.

It's a shot in the dark but seeing as you've looked over a fair amount of things non-turbo related so far it's something to consider since the only thing that's changed has been the turbo.

 

[Blockay]

Same thing happened to my buddy's screamer, he had to get it calibrated even though his came pre calibrated.

It's a shot in the dark but seeing as you've looked over a fair amount of things non-turbo related so far it's something to consider since the only thing that's changed has been the turbo.

Yea i think i will try that. Can’t hurt at this point haha. I actually have a brand new city diesel actuator sitting from when i was on the fence about doing that or the turbo. Just kept it bc my dads truck is acting up too so figured I’d sell it to him if all else fails. I think i may try throwing the city diesel one on and see what happens. Thank you, i hadn’t even thought of that possibility haha

 

[7492]

The real question is, was there a decrease/increase in performance after installing the turbo? Boost is just a number...

No, boost is horsepower.

 

[7492]

i can’t tell any noticeable difference. What’s throwing me for a loop is my buddy that has an identical setup is getting 6 psi more than me and his feels a little peppier than mine

It would with 6 more PSI.

 

[j98]

No, boost is horsepower.

To an extent. PSI does not correlate exactly with CFM.

 

[7492]

To an extent. PSI does not correlate exactly with CFM.

There are formulas for boost to HP, each engine has one.
Pittsburgh Power has them for many engines.

 

[Mitchcook]

No, boost is horsepower.

No