Lets talk about "Boost Drop"

[ZavzTy547]

OK!
I'm aware that having no muffler or cat may cause OVER BOOST
BUT!
Can no muffler/cat cause BOOST DROP?

In other words, can having too much exhaust air flow, cause "BOOST DROP"

My truck does not over boost at all, but for some reason I loose 3-5psi after TC lockup or when it shifts, no matter how much I adjust the actuator/boost controllers/manual boost valves/vac hoses/blow off valve/innertube test/ etc etc-I've tried them all....

The boost drops, then slowly creeps back up to desired boost (by the time that happens, I'm already past the traps).

Could it be a worn actuator spring? (the spring seems to be very stiff-the way its supposed to be, correct)?
Stiffer springs only helps in the event of OVER BOOST not BOOST DROP, correct?

Thanks in advance for your suggestions/advise.

 

[BacDoc]

Re: Lets talk about "Boost Drop"

Having similar problem.

 

[turbodig]

Re: Lets talk about "Boost Drop"

OK!
I'm aware that having no muffler or cat may cause OVER BOOST
BUT!
Can no muffler/cat cause BOOST DROP?

In other words, can having too much exhaust air flow, cause "BOOST DROP"

My truck does not over boost at all, but for some reason I loose 3-5psi after TC lockup or when it shifts, no matter how much I adjust the actuator/boost controllers/manual boost valves/vac hoses/blow off valve/innertube test/ etc etc-I've tried them all....

The boost drops, then slowly creeps back up to desired boost (by the time that happens, I'm already past the traps).

Could it be a worn actuator spring? (the spring seems to be very stiff-the way its supposed to be, correct)?
Stiffer springs only helps in the event of OVER BOOST not BOOST DROP, correct?

Thanks in advance for your suggestions/advise.

Depends on how the chip is set up. Ultimates were notorious for the up-down-up boost thing.

Another thing that can make it happen is too much fuel. You can control boost with fuel to a surprising extent.

Both require chip modifications to fix. Sometimes different spring rates can slow the oscillations down, but the only true fix is in the chip.

What's your AFR at the shift points? How low are your RPMs at the low end of the shift?

 

[ZavzTy547]

Re: Lets talk about "Boost Drop"

Depends on how the chip is set up. Ultimates were notorious for the up-down-up boost thing.

Another thing that can make it happen is too much fuel. You can control boost with fuel to a surprising extent.

Both require chip modifications to fix. Sometimes different spring rates can slow the oscillations down, but the only true fix is in the chip.

What's your AFR at the shift points? How low are your RPMs at the low end of the shift?

I'm running the 36lb injectors with the Ultimate on a stock calibration, so I'm pretty sure I'm running rich, (sometimes it loads up at idle) My Ultimate no longer controls my boost (using the profec) but both controllers shared the same boost drop, so being too rich is definitely suspect. I need to hook up with You or Paul so I can get a few bins burned.

After doing a search, I realized that my FP is way too high (I'm runing 45psi w/vac On)
Should I be running 35-37psi w/vac ON and 43-45psi with vac OFF, correct?

My 2800 TC really lowers my RPM's when it locks up, which will break up real bad when my alky is turned on to only 3, so that would be another indication of being too rich.


Dig, I think you put me in the right direction. Thanks Bro.
Zav.

 

[JSM]

Re: Lets talk about "Boost Drop"

Rich condition will def. not build as much boost or atleast be slow to build.

 

[BacDoc]

Re: Lets talk about "Boost Drop"

I think I may have added too much FP last time I was tweaking. I need to gauge it again. Thanks.

 

[ZavzTy547]

Re: Lets talk about "Boost Drop"

I think I may have added too much FP last time I was tweaking. I need to gauge it again. Thanks.

Thanks Jeff (when are you comming to town. I need a tune).

Seems like I'm getting KR during upshifts also, so FP and KR are the issues that I'm going to focus on.

 

[JSM]

Re: Lets talk about "Boost Drop"

Thanks Jeff (when are you comming to town. I need a tune).

Seems like I'm getting KR during upshifts also, so FP and KR are the issues that I'm going to focus on.

Next summer I plan to spend atleast a couple weeks out there again.

Job will be ending, want to come "home" for a bit and just relax.

 

[ZavzTy547]

Re: Lets talk about "Boost Drop"

Next summer I plan to spend atleast a couple weeks out there again.

Job will be ending, want to come "home" for a bit and just relax.

Hey Boeing's hiring locally again and I know the recruiter their.

 

[JSM]

Re: Lets talk about "Boost Drop"

Hey Boeing's hiring locally again and I know the recruiter their.

Worked for boeing once, got laid off, specifically told them to make sure to remove me from any rehire lists.

Money was ok I guess being right out of college. Job blew goats dobrick style. Can't stand a job you sit and watch the clock all day. Won't go back to Boeing until the new ice age starts.

 

[2kwik4u]

Re: Lets talk about "Boost Drop"

..........Job blew goats dobrick style.............

Finally some recognition for my efforts......You bastage.

In other thoughts....

Jeff you think too much fuel is causing Hardmans Ty to drop boost? essentially cooling things TOO much?

 

[BacDoc]

Re: Lets talk about "Boost Drop"

WOT boost spikes at 14.5 drops down to 10 then builds back to 14.5 then drops to 10....and so on.

Help?

 

[cloneman315]

Re: Lets talk about "Boost Drop"

u need to get a wbo2 and data log first imho

 

[dirtdemon]

Re: Lets talk about "Boost Drop"

Seems like I'm getting KR during upshifts also, so FP and KR are the issues that I'm going to focus on.

... poor spark might be an option, also a vac-leak :2cents:

man, are you sure 43-45 psi for ultimate is rich ??? ( i thought 50psi is the base for ultimate to play) ... i'm 47psi w/ stock chip/inj. - and truck's doing not too bad

reg,pat.

 

[myclone]

Re: Lets talk about "Boost Drop"

man, are you sure 43-45 psi for ultimate is rich ??? ( i thought 50psi is the base for ultimate to play) ... i'm 47psi w/ stock chip/inj. - and truck's doing not too bad .

He's running 36lb injectors so he's prolly a couple lbs too high even at 43psi. Depends on if the ultimate he's running is set up for the 36lb'ers or stock injectors though.

I bet some leaning out and/or addition of timing would help out the boost sag issue. Then again whadda I know....I cant even find the motivation to hook up a WB on my truck :roll: .

 

[ZavzTy547]

Re: Lets talk about "Boost Drop"

He's running 36lb injectors so he's prolly a couple lbs too high even at 43psi. Depends on if the ultimate he's running is set up for the 36lb'ers or stock injectors though.

I bet some leaning out and/or addition of timing would help out the boost sag issue. Then again whadda I know....I cant even find the motivation to hook up a WB on my truck :roll: .

Good point. I'm sure timing/spark could cause BD also...

So I lowered the FB to 38psi with the Vac on and it definitely improved the throttle response and held the boost around 18.5-20psi which is an improvement over the 3-5psi fluctuation.

 

[dirtdemon]

Re: Lets talk about "Boost Drop"

He's running 36lb injectors so he's prolly a couple lbs too high even at 43psi. Depends on if the ultimate he's running is set up for the 36lb'ers or stock injectors though.

... my false !!