Limited Boost

BMFB

BMFB

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I have been tuning a bit, and have recently rebuilt my motor. I have put a bit over 1000 miles on it before starting to build boost. My Goal is around 22 psi, but right now I can only seem to build 15, with a spike of 18. I am using a 20G with 14cm exhaust housing, and the shaft play seems good. No fins are bent, and it spins freely. It spools just about as well as my stock turbo did, so I don’t think the turbo itself is the issue. I do not seem to have any leaks, and it will hold the 15 very consistently through a gear, and when the truck shifts it will spike to about 18 and then descend back to 15 pretty quickly, and repeatedly. I am tuning with Code59 and have gotten to the point where I am sitting at 99.62% duty cycle on the solenoid, with no gains in boost.

I was reading a bit and saw that someone mentioned that a wastegate could at some point be defeated and the internal flapper forced open (I am indeed using the stock internal wastegate) and was wondering if anyone had seen this happen. I know that the actuator was supplied by jwaller to the original owner, and was wondering if they were 'set up' to do so.

That might sound strange, but I've never seen a boost leak that was so consistent, and I cannot find anything else going on, unless my hks bov was opening up on its own (possible, it’s old). I made sure that the gate was fully closed by the adjustment rod when the engine is off and that it could move freely (it’s got a blanket over it that I was afraid could be stopping its travel) I am just seeing if what I have going on is common before I start digging much deeper.

Thank you in advance
 
WyoSyclone

WyoSyclone

Active member
Re: Limited Boost

You can send me over a log and I can take a look at it. Sounds like you've got a mechanical issue. Did you adjust the wastegate rod, and check all your vacuum lines?
 
BMFB

BMFB

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Re: Limited Boost

I adjusted the wastegate rod so that it was pulled in fully when the truck was off (pulled in as in bottom of lever moving toward the front of the truck). I have not checked all of my vacuum lines, and come to think of it it may not show like it would normally as I have tuned the idle with code 59, and could have hidden any obvious vacuum problem. what is the best way of getting the excel file to you?

also, thank you for taking a look at it, I won't be able to post it until later tonight after I get home to school (hour or 2)
 
BMFB

BMFB

Not to scale
Re: Limited Boost

is there a way to test for that? only thing I can think of is to add a spring to it or wire it shut and do an experimenting run, dangerous though it is.
 
WyoSyclone

WyoSyclone

Active member
Re: Limited Boost

BMFB said:
I adjusted the wastegate rod so that it was pulled in fully when the truck was off (pulled in as in bottom of lever moving toward the front of the truck). I have not checked all of my vacuum lines, and come to think of it it may not show like it would normally as I have tuned the idle with code 59, and could have hidden any obvious vacuum problem. what is the best way of getting the excel file to you?

also, thank you for taking a look at it, I won't be able to post it until later tonight after I get home to school (hour or 2)
Click to expand...

Rod should be adjusted so that it is 1/2 hole short.. so you'd have to pull the rod out to get it over wastegate pin/arm. You can email me at rputman@bresnan.net.
 
It's just a six

It's just a six

Super Member
Re: Limited Boost

With the boost spike, you need to port open the wastegate hole.:2cents:

Be careful, you can go too big & wastegate will not seal & or port too much in a different area, the wastegate can get stuck open & not seal closed.
 
BMFB

BMFB

Not to scale
Re: Limited Boost

alright, did that wrong then, ill redo it tomorrow, its even with the hole as of now.
 
BMFB

BMFB

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Re: Limited Boost

didn't end up adjusting the rod yet, u-joint went out. The problem seems to be getting worse though, can only make 11 psi...I can hear the turbo spooling. how big of a leak would it take to drop a 20g14cm turbo from full gate closed boost to 11psi?
 
BMFB

BMFB

Not to scale
Re: Limited Boost

well, I believe I fixed the issue, I adjusted the wastegate rod in about a 1/8 of an inch. The actuator had a bit of slop in it, and I had to put it out a bit before it was actually pulling on the gate. I may have gone a thread or 2 past the halfway point of the 'hole', but not to far. I also noted that my turboside hotpipe coupler was coming apart at the point where the hotpipe goes into the coupler, so I replaced it. Then, the new one i bought did the same thing. I have never had a problem with the couplers I have used in the past but now with this other bov I am blowing these things apart. I adjusted the spring in it as much as I could, but its still giving me trouble when I let off the throttle its like it can't move the air out of the pipe fast enough, and it gets a pressure spike and blows a coupler apart. So, until I get a my bov back, I have the boost turned way down in hopes to stop it from coming apart again. the couplers are the home depot couplers that I see alot of people using (again, never had an issue until this other bov) and the bov is an older hks, it looks like an ssqv, but it has an adjustment spring in the back of it, that I might add I backed off as far as it would go.

but before it blew apart I was getting controlled pressures of 15 psi and 19 psi, and still had a base of 9 that was pretty steady, so I think my low pressure issue is fixed. Thanks for the suggestion of readjusting my gate!
 
BMFB

BMFB

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Re: Limited Boost

I got a new BOV yesterday and it seems to have fixed my other issues of couplers blowing apart. I ended up getting an HKS SSQV IV. Nice looking, nickel plated. I believe that its basically the same thing as the 3 series but its...more fancy to try an thwart counterfeiters. IT sounds about the same as the 3, perhaps a bit less noisy. Operation is very smooth though, cost me 245 from a local speed shop.
 
BMFB

BMFB

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Re: Limited Boost

Well, I replaced the couplers and although it does seem to spool faster, I still cannot achive over 15 psi without the assist of the surge that occures between gears (even then I see 17psi max). I am thinking it is my actuator, or perhaps a clogged solinoid. I guess the next step is to test the solinoid (not sure how to do that yet) and perhaps put a spring on the gate to assist the actuator. any input would be apprechiated on this one...

EDIT: after some additional searching I notice that many of the 20g's had an issue such as this. it looks like a 15 pound spring will help with my case. i will go home and try it tonight
 
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BMFB

BMFB

Not to scale
Re: Limited Boost

still an ongoing thing, i have replaced the 20G actuator with a much stiffer actuator from a PTE turbo. it is acting the EXACT same way. it will build to about 15-16 psi and sit there until it hits around third gear where it will push to about 22-25. It will sometimes stay at that level until I let off, or it will often come back down to 16 psi pretty rapidly. I realize that is a spike, but I am doing my best to force it to do that, and I can control it if I wish to. I have the gate basically closed for the whole run (at least through the tune).

I ran at the strip this weekend with results that somewhat show this,
60ft 2.12
1/8 8.38@90
1/4 12.7@113.

my best 60ft of the day was 1.9.

anyone in the detroit area wanna hunt down a boost leak?
 
0966Sy

0966Sy

Code what?
Re: Limited Boost

Diagnose one part at a time, elimanate the BOV, they will cause boost to bleed off if not adjusted or functioning properly. Another words you just made a 250 guess on a new BOV. Verify the gate is functioning properly before you start replacing suspected parts? Are you running the factory wastegate solinoid? Eliminate it from the system to verify it is not your chip program that is effecting your boost control.

You need to check to the wastegate with a mitty vac/pressure pump to see what PSI the gate begins to open.
Sounds to me like you have a poor wastegate spring that cant handle the backpressure of the exhuast. If i wanted to run 20+psi i could run the red spring in my forge gate.

Is this a Ty or Sy?
 
BMFB

BMFB

Not to scale
Re: Limited Boost

This is a typhoon,

the base spring pressure of this gate is rated at 18psi. I used a pressure regulator hosed into the gate to see where the spring actually started to open up. From what I could tell, it did not start to move until about 17 psi was applied to it. I then did the same test with the original gate and it started to open around 6 psi. (these 2 gates gave the same results on the boost level).

The stall of the converter is rated at 2800/3200 (brake/flash) (vigilante) but it is closer to 3400/4100. I use the clutch to pull it back down into the power curve.

the run of 12.9 I ran with 4* of KR, but after that It ran very clean, including the 12.7 run (was tuning on the track).

I can try to eliminate the BOV, as I still have the original pipe. The valve I am running is an hks SSQV IV.

I am using the stock wastegate controller and am controlling it with code 59. I have a friend with a nice gate controller I could prolly borrow.
 
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