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Discussion Starter · #1 ·
I have a 2015 eco and whenever I do a hard pull surpassing 115 mph or more my turbo starts fluttering and the car gets really slow . The boost/vacuum gauge only goes up to 7 psi . It rarely happens , just 3 times I’ve experienced this issue . What’s really weird is that it doesn’t throw any codes and the problem goes away with just turning the car off and on again . Any suggestions on what the problem is ? Is it really bad ?
 

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Not being a smart guy at all, but are you sure you are not hitting the speed limiter? It is set at 121, as far as I know, some say 124, whatever it's around 120 and with speedometer error etc you could be reading 115 when the limiter kicks in. IDK, but it's a thought. If you are not having any other issues except this one, that is near the top speed allowed by the computer, that would be my guess.
 

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Not being a smart guy at all, but are you sure you are not hitting the speed limiter? It is set at 121, as far as I know, some say 124, whatever it's around 120 and with speedometer error etc you could be reading 115 when the limiter kicks in. IDK, but it's a thought. If you are not having any other issues except this one, that is near the top speed allowed by the computer, that would be my guess.
Not being a smart guy at all, but are you sure you are not hitting the speed limiter? It is set at 121, as far as I know, some say 124, whatever it's around 120 and with speedometer error etc you could be reading 115 when the limiter kicks in. IDK, but it's a thought. If you are not having any other issues except this one, that is near the top speed allowed by the computer, that would be my guess.
My bad I forgot to say my eco can surpass 120 I don’t even know how that’s possible lol . It’s completely stock as I’m aware . One time I went on the freeway and hit 137 and I let off but I’m confident it could hit 140 .
 

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I thought the speed limit was based off the tire rating the car came with from the factory. My 2020 eco premium with the 201A package with 19 inch wheel and ZR rated tire should be good for 149 mph per speed rating of tires.

BD
 

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Not trying to be rude but I was asking about the turbo fluttering and loss of power lol . I bought the car with 88k miles . The car came with lots of problems that I did not know , yes I got bamboozled . Some of em were Spark plugs , a bad sway bar link , etc . The code that was the most worrying was “under boost “ . Turns out the cold side charge pipe was damage . Literally had a big crack like if it had been under too much air flow . I fixed it and the only issue left is the turbo fluttering which is not a big deal since it rarely happens but I just wanna know if it’s serious or not .
 

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I thought the speed limit was based off the tire rating the car came with from the factory. My 2020 eco premium with the 201A package with 19 inch wheel and ZR rated tire should be good for 149 mph per speed rating of tires.

BD
At least for the earlier models (pre-HPP, so 15-19?), regular models were limited to ~121, I believe, while performance package models were good for 145. I know the HPP reportedly goes to 155. I think Ford would determine the top speed first, and then equip them with appropriate tires.
 

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Not trying to be rude but I was asking about the turbo fluttering and loss of power lol . I bought the car with 88k miles . The car came with lots of problems that I did not know , yes I got bamboozled . Some of em were Spark plugs , a bad sway bar link , etc . The code that was the most worrying was “under boost “ . Turns out the cold side charge pipe was damage . Literally had a big crack like if it had been under too much air flow . I fixed it and the only issue left is the turbo fluttering which is not a big deal since it rarely happens but I just wanna know if it’s serious or not .
Be patient. People are trying to understand more about your car to help you get to the real problem. Rarely can anyone diagnose one symptom without additional details.
 

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Not trying to be rude but I was asking about the turbo fluttering and loss of power lol . I bought the car with 88k miles . The car came with lots of problems that I did not know , yes I got bamboozled . Some of em were Spark plugs , a bad sway bar link , etc . The code that was the most worrying was “under boost “ . Turns out the cold side charge pipe was damage . Literally had a big crack like if it had been under too much air flow . I fixed it and the only issue left is the turbo fluttering which is not a big deal since it rarely happens but I just wanna know if it’s serious or not .
The factory cold charge hose will with age become hardened and crack like you found out which will cause the loss of power due to low boost. It is advisable to replace both hot and cold side charge pipes with aftermarket aluminum pipes with silicone hoses to alleviate the issue in the future.

Its possible the turbo flutter could be a symptom of the damaged cold charge pipe or possibly a failing BPV valve that is sticking or leaking at times. Or even may have a loose clamp on hot side that is allowing some boost leak to occur, you should see max boost in the range of 18 to 20 psi under full throttle in the 4000 to 5000 rpm range and up to 5500.

BD
 

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At least for the earlier models (pre-HPP, so 15-19?), regular models were limited to ~121, I believe, while performance package models were good for 145. I know the HPP reportedly goes to 155. I think Ford would determine the top speed first, and then equip them with appropriate tires.
Pontiac had the same issue back in 93 when the new model Trans Ams were released. You could get them with or without the sport performance package which only consisted of either H rated tires and a chip limiting speed to 118 mph or with Z rated tires and a chip limiting speed to 155 mph. Even the salesmen did not know the difference, so we had customers buying a Trans Ams coming back complaining that their new car would only go 118 when it was advertised to do 150+. As a tech I would go look at the tires on the car and if they were only H rated had to inform the customer, they had to replace the tires with Z rated in order for me to legally install the 155 mph chip. Lots of unhappy customers needless to say. In 94 all Trans Ams came with the sport performance package and Z rated tires.

Good to know about the speed limits by years. I also checked my tires and they have a W speed rating even though the size numbering shows 255/40/19ZR, so are rated for 149 mph. I have not had it over 120 so far so cannot confirm if it is limited to 145 or 149 as of yet.

Not sure if Ford equips with tires based on speed capabilities or limits speed based on tires installed per trim levels.

BD
 

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Are you checking your oil temp gauge? I guarantee you if you are doing consecutive pulls that take you into the 100mph+ category, then your oil temp is probably nearing yellow. Once it goes to yellow, the Eco will go into "limp mode".
 

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Are you checking your oil temp gauge? I guarantee you if you are doing consecutive pulls that take you into the 100mph+ category, then your oil temp is probably nearing yellow. Once it goes to yellow, the Eco will go into "limp mode".
What temp is into the yellow and is that a selectable readout from the gauge selection in the cluster.

BD
 

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At least for the earlier models (pre-HPP, so 15-19?), regular models were limited to ~121, I believe, while performance package models were good for 145. I know the HPP reportedly goes to 155. I think Ford would determine the top speed first, and then equip them with appropriate tires.
Correct. It's not the tires, as you say, easy to change tires. The speed limiter is based by model. The base ecoboost is limited because of lack of brakes, oil cooler etc. I know from experience that the brakes are adequate but quickly lose their ability to bring the car down from speed much past 100 mph. Others have stated the differential will quickly get hot when tracking and car will go into limp mode. So, I don't have an exact parts list or anything but brakes, adequate cooling of various fluids etc are the reason the speed limiters vary by model but with the base, I'm sure is set to right around 120. I'm also sure my base with fbo will go over 150 mph and with the 6 piston brembos and larger rotors on the front, it will now won't make you pee your pants at that speed when you stand on the brakes.
 

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Yea just too much FED nannies involved in today's car manufacturing for my liking.

I remember my 64 goat that had 4-wheel drum brakes with a single cylinder master cylinder and no PB, no PS, no seatbelts but did have a 389 tri power with 4 speed and posi that ran 12.70s off the showroom. It would go way faster than it slowed down and had H60- 15s bia belted tires that had no speed rating and the car did 145 mph.

I survived driving that car way beyond it limits with an ear to ear grin all day long. :):Do_O:giggle::devilish:

BD
 

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What temp is into the yellow and is that a selectable readout from the gauge selection in the cluster.

BD
Yessir. It should be. The oil temp gauge, should give you a digital rendition of an analog display. Haven't looked at it in a while. But if its a hot day, and I'm out on the expressway doing WOT's that get me up to a hundred or more (which I pretty much usually dare not do, for reasons covered in this therad), I have seen the gauge butt up rights against the yellow/caution area.

ECU reaction to high oil temp?
 

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I will have to start paying more attention to the oil temps. I don't generally do back to back runs as a rule, but while on the Hot Rod power tour I am planning on doing some drag strip and autocross events so that's good info to know. It will be one of the gauges I have on display.

It should be one of the analog readouts that is in the standard display screen IMO.

Thanks for the heads up and related thread link.

BD
 

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Not trying to be rude but I was asking about the turbo fluttering and loss of power lol . I bought the car with 88k miles . The car came with lots of problems that I did not know , yes I got bamboozled . Some of em were Spark plugs , a bad sway bar link , etc . The code that was the most worrying was “under boost “ . Turns out the cold side charge pipe was damage . Literally had a big crack like if it had been under too much air flow . I fixed it and the only issue left is the turbo fluttering which is not a big deal since it rarely happens but I just wanna know if it’s serious or not .
I feel for ya! My 1st Mustang also had 88K on the odometer.
I've never experienced "turbo flutter", but to my understanding, it's caused by reversing air flow. This is where data logging, helps in troubleshooting. Do you have a data logging device, or access to one?
 

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My bad I forgot to say my eco can surpass 120 I don’t even know how that’s possible lol . It’s completely stock as I’m aware . One time I went on the freeway and hit 137 and I let off but I’m confident it could hit 140 .
Doesn't sound like a non modified Ecoboost... Your factory limitations or fail-safes may be altered. Can you post some pictures of your engine compartment, perhaps we can help you pinpoint anything that isn't factory stock or non OEM. What type of exhaust is on your Stang?
 
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