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Old 07-07-2017, 06:21 PM   #1
Imprezaspeed07
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Default Tune with an ewg

Hi everyone I've read a lot of posts about needing a tune for an ewg. But I just asked my tuner and he said I should just be able to adjust it my mbc and be fine. I have an mbc with an ebcs now. Does this make sense that I don't need one?

Edit: I have a hybrid boost control setup
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Last edited by Imprezaspeed07; 07-27-2017 at 12:38 AM.
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Old 07-09-2017, 11:29 PM   #2
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Bump please
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Old 07-10-2017, 09:57 AM   #3
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yes ewg needs a tune, and because you had to ask this question i am assuming you don't have tuning experience.. my advice, find a new tuner
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Old 07-10-2017, 10:02 AM   #4
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He said with an mbc you don't need a tune and the issue is that I don't have any other tuners in the area, and I have a warranty on my newly built engine if I use this tuner.
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Old 07-10-2017, 10:15 AM   #5
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You need a new tuner for sure... sounds like he doesn't have a clue
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Old 07-10-2017, 10:35 AM   #6
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i've had an ewg for the past 50k+ miles, i've had two different tuners, on the stock block and the the built block. Each tune ran the ewg vacume lines differently(not that there is only one way to run the lines, both worked properly). so yea running an ewg is a big deal and not something to run without a proper tune. the tuner will tune the ewg the way they prefer
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Old 07-21-2017, 10:12 PM   #7
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Default Tune with an ewg

But my tuner says I don't need a tune with an mbc... I am also on speed density

Last edited by Imprezaspeed07; 07-21-2017 at 10:18 PM.
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Old 07-21-2017, 10:32 PM   #8
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what he is tryng to say is that you can adjust your boost with the mbc if you want, but a EWG needs less wastegate duty to run the same boost, so yeah you can but be careful if you dont that you dont overboost cause that will cause your engine to go boom pretty quick
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Old 07-21-2017, 10:34 PM   #9
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My engine is also fully built and he said that any boost level that my td04 can put out is safe for the engine.
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Old 07-21-2017, 10:36 PM   #10
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Quote:
Originally Posted by Imprezaspeed07 View Post
My engine is also fully built and he said that any boost level that my td04 can put out is safe for the engine.
hmm yeah dont know about that, its not just boost level but its also how much air you are putting into the combustion chambers you can go lean.. there is more than just boost to worry about, I think I would honestly go get a new tuner
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Old 07-21-2017, 10:38 PM   #11
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Man everyone keeps telling me that... This guy is supposed to be one of the best in the southeast. And I have a warranty with my Engine builder if I use this tuner...
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Old 07-22-2017, 02:27 PM   #12
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Quote:
Originally Posted by subaru_gc8 View Post
what he is tryng to say is that you can adjust your boost with the mbc if you want, but a EWG needs less wastegate duty to run the same boost, so yeah you can but be careful if you dont that you dont overboost cause that will cause your engine to go boom pretty quick
When using a MBC, there is no closed loop solenoid control- the fact that you are talking about duty cycle in a MBC setup leads me to believe you don't have a clue here...

Quote:
Originally Posted by Imprezaspeed07 View Post
Man everyone keeps telling me that... This guy is supposed to be one of the best in the southeast. And I have a warranty with my Engine builder if I use this tuner...
So here's the deal- there is nothing boost control-related to tune because the electronic boost control has been disabled. The only thing the tuner would have done is adjust fueling, timing, and cam maps.

Now, speed density presents a problem:

With a MAF based tune, air coming into the motor is metered. Modifications that change airflow are more or less covered by the ECU simply 'seeing' a different amount of airflow.

With a SD based tune, air coming into the motor is ESTIMATED. If you perform any modifications that change the MASS of air entering a motor at a given load cell (which, for simplicity, is a 3D table of RPM vs. MAP, modified by IAT compensation), your tune will be 'off'.

The question here is whether or not an external wastegate will affect mass flow at a given load point. The answer *should be* no- mass flow should not be affected. Note the "should be" part again- this means that you need to log data and ensure your AFR and knock is within an acceptable range under OPEN LOOP fueling.

Your tuner is correct, but you may not be asking the right question. If you said "do I need a retune" then the answer is almost certainly 'no', but if you asked "will I benefit from an hour on the dyno or some street tuning", the answer is probably 'yes'. Your tuner will have set target open loop AFR values based on dyno tuning and what you should do now is log data and ensure you are still hitting those targets.
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Old 07-24-2017, 12:27 PM   #13
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Quote:
Originally Posted by mrsaturn7085 View Post
When using a MBC, there is no closed loop solenoid control- the fact that you are talking about duty cycle in a MBC setup leads me to believe you don't have a clue here...



So here's the deal- there is nothing boost control-related to tune because the electronic boost control has been disabled. The only thing the tuner would have done is adjust fueling, timing, and cam maps.

Now, speed density presents a problem:

With a MAF based tune, air coming into the motor is metered. Modifications that change airflow are more or less covered by the ECU simply 'seeing' a different amount of airflow.

With a SD based tune, air coming into the motor is ESTIMATED. If you perform any modifications that change the MASS of air entering a motor at a given load cell (which, for simplicity, is a 3D table of RPM vs. MAP, modified by IAT compensation), your tune will be 'off'.

The question here is whether or not an external wastegate will affect mass flow at a given load point. The answer *should be* no- mass flow should not be affected. Note the "should be" part again- this means that you need to log data and ensure your AFR and knock is within an acceptable range under OPEN LOOP fueling.

Your tuner is correct, but you may not be asking the right question. If you said "do I need a retune" then the answer is almost certainly 'no', but if you asked "will I benefit from an hour on the dyno or some street tuning", the answer is probably 'yes'. Your tuner will have set target open loop AFR values based on dyno tuning and what you should do now is log data and ensure you are still hitting those targets.
So just to be clear the mbc just controls the wastegate so if the Watergate lets say you are going from a 7 psi to a 14psi Watergate, you are going to over boost correct. So the tuner saying you don't need a tune is semi correct but more because you have to set it yourself right?
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Old 07-24-2017, 01:49 PM   #14
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Mbc control your max boost only and elimitate the flutter sound
Ebcs control your off boost
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Old 07-24-2017, 01:53 PM   #15
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Quote:
Originally Posted by subaru_gc8 View Post
So just to be clear the mbc just controls the wastegate so if the Watergate lets say you are going from a 7 psi to a 14psi Watergate, you are going to over boost correct. So the tuner saying you don't need a tune is semi correct but more because you have to set it yourself right?
A manual boost controller is literally a ball and spring valve. Turn the screw one way, boost goes up. Turn it the other way, boost goes down. The minimum boost you can run is the wastegate spring pressure.

Wastegate duty cycle is an abbreviated way of saying wastegate SOLENOID duty cycle. Since you aren't using the solenoid in a MBC setup, there is no duty cycle tuning to consider. Spool-up performance will likely suffer when compared to a tuned electronic system as the wastegate will gradually open when using a MBC.

The reason you do not need a re-tune with an EWG and MBC is that your fuel and timing tables should already be tuned in the relative load/RPM range. The mass flow of air entering the cylinders at a given boost pressure/RPM should not change much, at all. You also have no electronic boost control tables to mess with, so this is why you don't need a re-tune.
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Old 07-24-2017, 09:51 PM   #16
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Quote:
Originally Posted by mrsaturn7085 View Post
A manual boost controller is literally a ball and spring valve. Turn the screw one way, boost goes up. Turn it the other way, boost goes down. The minimum boost you can run is the wastegate spring pressure.

Wastegate duty cycle is an abbreviated way of saying wastegate SOLENOID duty cycle. Since you aren't using the solenoid in a MBC setup, there is no duty cycle tuning to consider. Spool-up performance will likely suffer when compared to a tuned electronic system as the wastegate will gradually open when using a MBC.

The reason you do not need a re-tune with an EWG and MBC is that your fuel and timing tables should already be tuned in the relative load/RPM range. The mass flow of air entering the cylinders at a given boost pressure/RPM should not change much, at all. You also have no electronic boost control tables to mess with, so this is why you don't need a re-tune.
So even if there is a discrepancy between spring pressures?
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Old 07-24-2017, 10:07 PM   #17
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Sounds like he has you on a hybrid setup. Iirc they run a higher (correction?) duty cycle so that the it can control part throttle boost. Then the mbc will still cap the pk boost. If both the iwg and ewg had same spring pressure then its likely fine without and adjustments
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Old 07-25-2017, 12:17 AM   #18
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Are we also forgetting the huge volumetric efficiency boost that comes also with an EWG? Generally when you increase the volumetric efficiency of an engine (using mechanical means) less timing is required. That may also be a consideration when it comes to tuning with an EWG.
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Old 07-25-2017, 02:52 PM   #19
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Quote:
Originally Posted by subaru_gc8 View Post
So even if there is a discrepancy between spring pressures?
Then you just turn the screw to fix it. This isn't tuning, this is turning.

Quote:
Originally Posted by no694terry View Post
Sounds like he has you on a hybrid setup.
You need to have OP confirm this before making assumptions. Based on the tuners recommendation that it doesn't need tuning, I HIGHLY doubt this is the case.

Quote:
Originally Posted by JSR84 View Post
Are we also forgetting the huge volumetric efficiency boost that comes also with an EWG? Generally when you increase the volumetric efficiency of an engine (using mechanical means) less timing is required. That may also be a consideration when it comes to tuning with an EWG.
I considered this, but you need to remember that for a given compressor with a fixed P/R, you've only got two variables left - compressor speed and mass flow. With a EWG, you will certainly be reducing the EGBP and I would expect this to have SOME effect on compressor speed (getting into theory that needs testing, here). I do not know how much it will affect compressor speed, but if you knew that, you'd know the exact change to expect in mass air flow.

This is where we come back to the point where I said it doesn't NEED a tune, but it may benefit from one. The best thing you can do at this point is to go do a few dyno (or street) pulls while logging relevant AFR, knock, and boost. While I never advocate for a permanent driver-viewable AFR gauge, this is a pull where you will want to have a fast reading wideband in full view of the driver (which is also why a dyno is a safer choice).

For the first pull, back the MBC out and let it run on spring pressure, then slowly creep back up to the target boost pressure. As long as your AFR matches the targets set by the tuner, you're good to go. You may still benefit from some fine tuning (you can ALWAYS improve a tune)... but unless the AFR or knock show any issues, you don't need it.
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Old 07-25-2017, 03:23 PM   #20
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OP, can we get a pic of the vacuum line routing at the boost controllers?
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Old 07-27-2017, 12:29 AM   #21
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Default Tune with an ewg

I don't have the car with me. Getting it back tomorrow. But it is a hybrid setup. So what it seems is that I just need to pull some logs and monitor afr. I could change it to a a purely mbc setup if need be.

Is there an issue running a hybrid setup without a tune?

I also am not as concerned about the power as much as reliability. I had boost issues running track days and we tried to tune it out and that didn't work so we tried a hybrid setup. Which also didn't work. So it pointed to an issue with the wastegate actuator. That couldn't be fixed and it just so happened that a wrx with a ewg was totaled so I got that uppipe with an ewg for $300.

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Old 07-27-2017, 01:22 AM   #22
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Yes, if you are still using the electronic boost control, it will be a problem and needs a tune. You can street tune it yourself... it's not difficult, just time consuming.
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Old 07-27-2017, 05:44 PM   #23
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Default Tune with an ewg

So I won't damage anything by pulling logs and then adjusting as needed right?

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Old 07-27-2017, 07:11 PM   #24
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Reduce duty to zero and start from there. Target boost, WGDC and WGDC max all need to be examined. Like I said - time consuming...
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Old 07-27-2017, 07:49 PM   #25
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Default Tune with an ewg

Ah okay my Engine builder drove it and said it drove fine. I didn't have the same result. Will post some logs later. I'll probably just remove the ebcs. Afr but 13 split second because the wastegate was oscillating... I stopped doing logs at that point. Knock never went above -2.8 tho.
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