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ECMlink holset airflow issue?

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Or measure at the rear o2 since its unused in my car. Looking for something simple to testing purpose.

The back pressure he is referring to is pre-turbine. You'd need to plumb a gauge/sensor into the exhaust manifold.
 
I'm not sure that can easily be done with my wrap and coating. But I am wondering if I can port my divided 12 housing big enough to match a 16? Or at least close to it?

I absolutely hate taking the manifold and or turbo off that car. The manifold makes it hard to get and tool in there that isnt so time consuming. Lol.
 

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Here is another log. With higher boost yet no airflow changes. So is the manifold and housing actually restricting this thing? The butt dyno says airflow is definitely above 45lb/min. My 20g showed 41lb/min. So that brings me up to maybe airflow calibration is messed up yet all other aspects of the log look good? Boostest and actual are also really close up until it starts falling off which I still dont know why.

Im going to look at the waste gates again but since im actually seeing high boost, that tells me the airflow issue isn't mechanical?
 

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I just dont see a way that this holset is only flowing 4lb more than my 20g. Im not racer, have no experience, have total of 5 passes ever. But for what its worth. My 20g I finished at 14.5 at 98mph. On my holset I finished 14.1 at 120mph spinning tire like crazy to the 1/8th. That tells me that there is more power here that just isnt showing in link.
 
Air flow is, where it should be , spin that engine to 8500 and it should move 57lbs/min

I have tried that before and never saw over 45lb. The log above I had boost spike to 42psi and saw 49lb. But as rpm goes up, boost falls off into the 28 range. So it will never see 57.
 
Either there is something mechanically wrong with the car or the turbo is seeing an incredible amount of back-pressure. Simple as that in my opinion.
 
Either there is something mechanically wrong with the car or the turbo is seeing an incredible amount of back-pressure. Simple as that in my opinion.

Would running a side exhaust or something much shorter than the length of the car verify anything? I dont really have a easy way of measing back pressure.
 
It’s highly unlikely. The back pressure you’re possibly seeing is a combination of your engine, turbine, turbine housing and exhaust system creating excess pressure in the turbine housing that fights the system. It’s what bdsm was referring to when he recommended changing your setup.
 
I totally understand changing the setup. But after a bunch of money for this, really disappointing. Currently I am looking for a bigger turbine housing for cheap. But changing the manifold isnt going to happen. I could rework the exhaust but not sure what needs to change with it? Backpressure can directly affect airflow?
 
So in the mean time, I ported the 12cm housing anyway and saw 2 more lb/min of airflow. I recently pickup up a 16cm housing but having issues. The divided 12 came with a 3 inch outlet for the downpipe. But my new 16 is 2.5. What are my options?

Cut the flange off the band new housing and weld my 3 inch vband? or change my downpipe to 2.5? I wish there was a adapter or something. I was unaware of this before purchase. Kind of a big issue.
 
Here are pics of the issue
 

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Sorry this is still being a issue but the tune is correct. Did you ever try playing with cam overlap?

No I didnt. I personally feel like thats not the issue based on reports of other peoples results. Also read many of bastarddsm posts reguarding housing selection. I came to the conclusion that upgradeing the housing to a divided 16cm housing would at least help flow up top and let me contol it better. I also hope boost come on more linear than the spike I saw very quickly in my logs. I still want a truly divided setup since I have the parts. I didnt know that the housing I purchased only had a 2.5 outlet, so I welded a 3inch vband on. Without porting the housing. But the gasket it came with matches the manifold but the divided section openings were much smaller than the gasket and manifold.

On my 12cm housing I ported it to match the gasket and I beleive I noticed a 2lb/min increase but it could be coincidence. I havent ran the car yet because I have to re work my downpipe for some reason but hopefully tomorow I can get this thing out. Also bought a pair of green tial springs to up my wastegate boost to I believe 20 compared to my 17. I was kinda thinking that is why boost falls off up top because boost is almost twice my spring pressure. Before you gave me a formula to find out base duty cycle while including the wastgate spring pressure to find base duty cycle. But currently my duty cycle is really high like 97. That tells me its almost all the way open which made me upgrade the gate springs. Not sure if this has effect on it. But I was working on the boost control to try and elimate the spike I would see prior to dropping off. Im getting closer but gotta wait till I make my downpipe work.
 
Did you ever try letting ecm link run the solenoid and try plumbing it with both top and bottom ports on gate? I do recall from the log it would spike like 38psi then drop bellow 30 redline witch it should not.
 
Did you ever try letting ecm link run the solenoid and try plumbing it with both top and bottom ports on gate? I do recall from the log it would spike like 38psi then drop bellow 30 redline witch it should not.

I have tried that and that's my normal operation. I been working with link to try and eliminate the spike and run a constant. It's getting better as far as spikes. But still falls off to 25-28 at redline. And that's at 97 or 100 duty cycle. Does that mean I need to upgrade springs? I didn't want to to avoid wheel spin in lower gears. My latest log I had a spike to 42 and that to high for my comfort.

Do you remember the formula to calculate wastegate, desired boost to find duty cycle.

Even with the 42 psi airflow was still 47. I do think porting the divided 12 added 2 to airflow. In excitited/curious how the 16cm will react.

Also I know I should measure back pressure. But what are symptoms of to high of back pressure? And is there a easy temporary way to measure without welding a bung?
 
What springs do you currently run? How much boost does it make on those springs?

One way to feel out turbine backpressure is to compare spring rating to actual boost. Excessive turbine backpressure works against the springs and opens the gate at a lower boost pressure than the spring rating.

On my hx40 setup with a 14cm2 housing I see 33psi from a 25 psi spring combo, which might suggest it is flowing quite well, and may actually be running lower turbine drive pressure than boost pressure. The springs are made with the standard assumption of 1:1 ratio turbine drive pressure-to-boost pressure, so any significant deviation from that MIGHT be an indicator of how turbine back pressure is affecting your setup. Super easy to check if u dont already know.

Have you "bench tested" your wastegates with shop air? I'll see if I can find the procedure..

Edit: try this out. just to get a feel for if the gates are working properly

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Are you running boost to top of the gate too? I run 18psi ish of spring plumbed that way. My car seeing rock solid 30psi at 40% duty. Granted I’m on a 62mm in .82 housing.
 
No that was with both top ports open, and the hose going from the compressor cover to a tee, then to each bottom port on my gates. Mine is a 7blade 60mm compressor and 10 blade turbine in the 14cm2 Holset non-gated housing.
 
What springs do you currently run? How much boost does it make on those springs?

One way to feel out turbine backpressure is to compare spring rating to actual boost. Excessive turbine backpressure works against the springs and opens the gate at a lower boost pressure than the spring rating.

On my hx40 setup with a 14cm2 housing I see 33psi from a 25 psi spring combo, which might suggest it is flowing quite well, and may actually be running lower turbine drive pressure than boost pressure. The springs are made with the standard assumption of 1:1 ratio turbine drive pressure-to-boost pressure, so any significant deviation from that MIGHT be an indicator of how turbine back pressure is affecting your setup. Super easy to check if u dont already know.

Have you "bench tested" your wastegates with shop air? I'll see if I can find the procedure..

Edit: try this out. just to get a feel for if the gates are

I have bench test both together and individually and all good there. My springs are the 16-18 psi springs. My boost control off only running gate pressure I'm seeing what boost gate pressure without lag or anything.

Are you running boost to top of the gate too? I run 18psi ish of spring plumbed that way. My car seeing rock solid 30psi at 40% duty. Granted I’m on a 62mm in .82 housing.

My lines are like the image. Short and equal lengths. But at 100 duty my theory is I should be making all the boost in the world. Saw spike of 41. I been playing with link to resolve the spike. But maybe I need more springs? But I dont want high boost at first and second gear. My 12cm was a gated housing welded shut. I have yet to drive with the new 16cm housing.
 

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