Turbo 'flutter' during low rpm / high gear acceleration...

SHOdded · April 15, 2016, 12:28:14 PM

Vent to Atmosphere for the blowoff valves. HowTo video:
https://youtu.be/kF7ix_ZxcCM

Generally, only the front is done, as the rear BOV is harder to access.

John Miller · April 15, 2016, 12:29:34 PM

Gotcha.

If both are vented, and closing one helped but didn't solve, wouldn't that again point to it being a boost issue as the original cause of the flutter?

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SHOdded · April 15, 2016, 01:02:45 PM

Some type of issue related to boost, yes. But where exactly has been hard to locate, maybe in the feedback circuits, assuming boost is even built at all under the given conditions. And your SHO is not currently VTA'd anyway, right, John?

panther427 · April 15, 2016, 01:11:27 PM

From my experience it seems to be from a combination of sources. Trying to maintain speed up a climb the computer calls for more boost. Then the computer may begin to detect knock or low speed pre ignition. So it dumps boost and the process starts again. But if I dropped the trans down a gear the problem went away.

The car thinks it has enough power to meet the required load but then its just not working out. It needs to downshift but the programming doesn't call for it

John Miller · April 15, 2016, 01:23:15 PM

Not VTA'd. Stock now, though I did just order a tuner to datalog and will look to tune once comfortable with the idea.

In the end, if I can get comfortable that this is not a mechanical problem that will get worse, having the trans kick down to 5th sooner (via a tune) might be a viable fix.

I drive 120 miles round trip each day, over mountains, and this flutter deal really hurts my enjoyment of a car I otherwise love.

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ZSHO · April 15, 2016, 01:43:56 PM

Quote from: John Miller on April 15, 2016, 01:23:15 PM
Not VTA'd. Stock now, though I did just order a tuner to datalog and will look to tune once comfortable with the idea.

In the end, if I can get comfortable that this is not a mechanical problem that will get worse, having the trans kick down to 5th sooner (via a tune) might be a viable fix.

I drive 120 miles round trip each day, over mountains, and this flutter deal really hurts my enjoyment of a car I otherwise love.

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Whats your elevation? Z

John Miller · April 15, 2016, 02:00:04 PM

Depending on exact location, between 350 and 800 ft above sea level. Northern Virginia

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xkrexplorer · April 19, 2016, 02:08:04 PM

Hello all,

2014 explorer sport. Have the same issue as the OP. Present since day 1. I suspect all 3.5 ecoboosts do it. If anyone wants to find out, vent the bypass valves to atmosphere, find a long slight hill on a highway and keep the vehicle at 65mph without letting car downshift. You will here the bypass valves dump boost every second or so. It is not the wastegates.

For me, it was present at stock, worse with the addition of my downpipes, and worse with diablosport tune. Downshift with a little gas or the paddles and it all goes away. It's annoying and I still am trying to find out if any tuner can tune it out. I think its too much boost under partial throttle and little bit of load.

AJP turbo · April 19, 2016, 02:13:32 PM

If it was too much boost the wastegates would open more and wastegate duty cycle would decrese.....i think its something else

John Miller · April 19, 2016, 02:16:22 PM

Tori at unleashed tuning says that he can make the car gear down to fifth sooner. Seems to me that is the answer. In the next couple days, I am going to data log the event on the stock tune. It is my hope that I can send that to Tori, and he could see the event, and see where it occurs based on throttle position, boost, RPMs, etc. From there, I'm hoping that he could make it downshift immediately preceding the event.

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xkrexplorer · April 19, 2016, 02:45:19 PM

AJP turbo,

Some thoughts, what do you think?...

I do not think the wastegate is opening under such low throttle and load. I think Ford has set the wastegates to remain closed at lower load to keep the tiny turbo's spinning and avoid lag. I don't know what the wastegates are set to open at under such low loads, but maybe they are programmed to open at a higher throttle/load/pressure. For me this all occurs at 1/4 throttle or less. Maybe they are not opening and that is the problem. They are not opening by design, but there is too much boost in the intake for the engine to use at such a smaller load, and instead of the bypass valves being opened when throttle closes to dissipate boost, they are opening to dump too much boost for the engine to use. Is that possible?
Maybe a tuner can jump in?

John Miller · April 20, 2016, 06:40:07 AM

I data logged it and sent in the Unleashed. He is going to compensate by making the car gear down to 5th faster. I suspect they'll be some tweaking necessary to get that exactly right, but I'll let everyone know how it goes. He got the tune to me already, but it will be tomorrow (at least) before I can get the thermostat, plugs, and tune into the car.

In the meantime, the data log config I used (per Torrie) had 36 PIDs. For the tuner types out there, if there are specific ones you want to see, list them out. I'll single them out within Livelink during the time the flutter is occurring, take a screen shot, and post up for the group.

John Miller · April 20, 2016, 07:00:03 AM

Wastegate in maroon, boost in orange, actual throttle angle in purple, RPM in light green.

Stating the obvious: Boost and Wastegate Percentage keep dropping and bouncing back up.

xkrexplorer · April 20, 2016, 07:49:00 AM

Quote from: John Miller on April 20, 2016, 07:00:03 AM

Wastegate in maroon, boost in orange, actual throttle angle in purple, RPM in light green.

Stating the obvious: Boost and Wastegate Percentage keep dropping and bouncing back up.

That is great work. The wastegate is dumping. I know for sure that in my explorer, the bypass valves are dumping as well (very clear if you vent to atmosphere as a test), and I wonder if that is because in your logging, the throttle position seems to increase and then decrease as the waste gate dumps and this opens the bypass valves. Again, I wonder if this is all because of Ford trying to prevent turbo lag and they keeping the turboes spinning at such low rpm's and part throttles but its too much boost for the amount of load the engine is under. I have started using the paddles to downshift at any point where I have found this to occur.

AJP turbo · April 20, 2016, 09:31:37 AM

Did you log desired tip? Post the log if u can

And see if the bypass valve pid is in the config. I dont usually look at the pid but i think the bypass valve is on/off so see if it pulses with the wastegate

This is strange but i would lean to a hole in the tune rather than hardware..the stock tune can have holes also

Torque converter speed ratio pid will help you see if its going in and out of lock...but i. 6th gear it locks fairly early for fuel economy...around 1400 rpm i think but need to look

What rpm and load is it