18k Miles 2015 EB Power Drop Off?

[Boosty15]

SSSSOOOO I'm driving my EB like an idiot. Blasting by people on the freeway, while getting 27.4mpg's , and as I'm screwing around trying to learn my car still since ive only owned it for about a month. I'm noticing my power seems to "drop off" or at least reach a plateau around 5500-6000 rpms :shrug:....

I'm super curious as to how to change that and why it feels this way. I know that it redlines past peak HP like most anything but it just feels like its dieing off early? Maybe this is how turbo cars are, this is also my first turbocharged car, and I'm not used to it.

Car is stock as stock can be...for the moment...and im wondering if modifications will change up my power curve enough to slowly remove this "drop off" feeling.

Thanks!!!

:usa:

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[PRG3k]

I'm noticing my power seems to "drop off" or at least reach a plateau around 5500-6000 rpms :shrug:....

That is peak power for the turbo. Big turbo sounds like it will solve your issue.

 

[JStang15]

That power drop off is definitely normal for a stock EB. The small turbo, factory tune, and restrictive downpipe are all contributors to it.

Getting an intercooler, custom tune, and an aftermarket downpipe will make it much better, but it still won't be a monster up top with the stock turbo.

 

[Boosty15]

The only mod I have ready for the car is my homebrew cat-back exhaust. Nothing huge just y-piped and some welded muffs with 2.5" piping. So should I restrain from climbing much higher then 6k when fooling around with other cars? Or should I still shift just before redline?

 

[stevnoof]

Get used to it

 

[Jdenkevitz]

Need to short shift.

 

[Juben]

This is normal for the stock turbo and head. It's the head more than anything, but the small turbo doesn't help either. Just short shift around 5,500-5,700 rpms.

 

[Boosty15]

Awesome. Thanks guys.

 

[TheLion]

SSSSOOOO I'm driving my EB like an idiot. Blasting by people on the freeway, while getting 27.4mpg's , and as I'm screwing around trying to learn my car still since ive only owned it for about a month. I'm noticing my power seems to "drop off" or at least reach a plateau around 5500-6000 rpms :shrug:....

I'm super curious as to how to change that and why it feels this way. I know that it redlines past peak HP like most anything but it just feels like its dieing off early? Maybe this is how turbo cars are, this is also my first turbocharged car, and I'm not used to it.

Car is stock as stock can be...for the moment...and im wondering if modifications will change up my power curve enough to slowly remove this "drop off" feeling.

Thanks!!!

:usa:

I somewhat disagree with several of the above comments. I'm assuming your car is stock as I haven't seen anything listed to show otherwise?

The stock Turbo isn't the biggest issue until your pushing to or over 400 HP. Adam spoke to me extensively on that at one point.

The first issue is the stock IC. It is not only under sized for even the stock application, it is also designed to be as cheap to produce as possible, making it one of the worst inter coolers to roll out of a factory production car in the last decade.

Another issue is the stock Diverter Valve is leaky, your not getting all of the boost your turbo can make. In highly modified cars for example are getting another 50lbs of torque at the wheels on a car that has just a tune and intercooler upgrade after they swapped out the BOV (they used Turbo Smart BOV).

The down pipe was mentioned, I agree with this one 100% but only if your running a tune. The stock down pipe isn't horrid, but there's certainly room for improvement. If your running the stock PCM software or the Ford Racing Tune (if it ever comes out), there's no need to upgrade the down pipe. If your running something like the Cobb tune, Tune + or any others, you NEED to upgrade the down pipe not just to lift the top end, but because your over heat the stock catalyst...that's actually why the factory tune tapers at the top end, the PCM is protecting the cheap ceramic substrate catalyst from over heating. It's not a limitation of the factory turbo.

The IC is hands down the biggest issue and is a very significant issue. The car isn't going to even make it's rated power with the stock IC after just one or two gears. ATP, FFTec and many others have documented this with data longgers extensively. I was really shocked and disappointed when I first got my 2016 EB 6MT, it absolutely fell flat on it's face in 3rd gear unless the ambient was very cool (60~70F), but even then it just really struggled when hitting 3rd. This a big complaint in all of the reviews from Motor Trend, C&D etc. also.

Replace the stock IC, don't change anything else, then see what you think before you start changing other things. Replacing the stock IC is the first step in building a good foundation for future power adders / reliability upgrades. I'll bet the engine will really come alive, far more than you would have ever expected from just an IC upgrade, which normally shouldn't net any gains if its properly sized. Now it won't give you a "huge" top end, however it should remain reasonably strong up to about 5700~6000 RPM instead of falling on its face and it should no longer "pull power". It should remain strong and consistent pull after pull, gear after gear.

Once the inter cooler outlet temps exceed 150F the PCM starts to pull throttle and timing to protect the engine from knock. After just a single pull in 3rd gear on a dyno the stock IC was hitting 145F outlet temps. As second pull in 4th resulted in 185F outlet temps!!! It's no wonder the stock EB is "lazy" and gets more anemic because it's severely handicapped by one of the most critical components in a turbo charged engine, the Inter Cooler...but I think there's a fair amount of us who bought the EB knowing it was a tuner car.

It's not that great stock, but it has a vast swath of untapped potential for under $2k~$3k that you are hard pressed to find in any other car at it's price point and that's where the treasure lies in the EB stangs, what it can be, not what it is. Otherwise I would have bought a WRX if I wasn't going to modify it as it's fairly strong out of the box.

 

[Juben]

The subject of this thread is the power drop off after 5,500 rpms or so. While I agree that the factory intercooler, factory BPV, and factory downpipe hamper performance to an extent, they are not the reason for the power drop off.

The factory head flows VERY poorly. In fact, a fart could probably outflow it. As such, the flow isn't there on the top end to continue to produce power up there. This has been shown and proven time and time and time again over the last year and a half. If upgrading the intercooler, BPV, and downpipe would have truly been the problematic area for power drop off, we would have seen this problem resolved in upgrading those parts. However, this has not happened. Even big turbo cars with full bolt-ons (FBO) will still experience the power drop off up top because of the head.

Now, that's not to say that the power drop off cannot be ever so slightly improved by upgrading those items, but even with upgrades, you're still going to feel it fall off after about 5,700 rpms. It's just the nature of the beast.

Running an upgraded intercooler, BOV, and downpipe will drastically improve the consistency and reliability of the power being produced but it simply won't resolve the drop off issue due to the head.

Also, the turbo also contributes to this in a minor way because it's a small turbo. Yes, the turbo can produce 25-26 psi of boost, but it will begin to taper off on the top end due to nearing the limit of its efficiency range. It cannot hold out boost to redline like a larger turbo, and as such, you'll also be able to feel that reduction in boost pressure from 25 psi to 21-22 psi on the top end.

There are a variety of things that can contribute to the power drop off, but the two parts with a majority of the impact are the head (taking most of it) and the smaller turbo.

I've been playing with this car for over a year and a half and was one of the first people that tuned their cars on here. I've been around to see what works and what doesn't. I'm not just spewing mindless BS without proven reasoning to back up what I'm saying, and if I'm unsure of something, I won't speak on it until I feel comfortable enough that it's not incorrect information. Also, this isn't my first modified EcoBoost car either, so I've been around the platform as a whole to have a good feel for what works and what doesn't.

 

[TheLion]

The EB cannot make good power when the throttle and timing are pulled. It doesn't matter what turbo size, head flow you add. Now the stock turbo, head and dp as you mentioned limit the top end, I wasn't suggest they don't, but rather that turbo / head flow limitations are not what he is experiencing as the "plateau". Your right that your not going to get a climbing power band as you would with something like the Subaru STI, which uses a larger turbo. However, as the stock IC heatsoaks (which it does more so at higher RPMs under load), the upper power band drops of incredibly quick and just hits a wall. It's a combination of smaller turbo and head with the IC deficiency, however the IC is the much bigger offender in this instance. Not only that, but the more he pushes it, run after run it's going to get worse and worse, amplifying this "dead upper band".

You can do quite a bit with the stock turbo and have a strong pull to the end, it may not continue to "climb" all the way to redline, but it can be strong all the way to redline... http://www.atpturbo.com/platform/MustangEcoboost.html

The EB seems to get a lot of criticism for it's "small turbo" as if it's a big deficiency in the power ranges most people are running, yet with a few changes (not the turbo being one of them), you can get a torque band very similar to something like the tesla roadster or S coupe top tier model, with the S coup having a 0-60 in 2.8 seconds despite it 5,000lb curb weight. Take at the torque curve: http://www.mustang6g.com/forums/showthread.php?t=61200&goto=newpost

Small turbos provide a very electric motor like torque curve. Yes if you want big power (450~500+) you will need an upgraded turbo and head among other things, but your going to most likely out turbo the stock block as well at that point and need a built short like from MAP or others. I don't think upgrading the turbo and DP off the bat are going to help as the ECU will still pull timing and throttle to protect against knock. Solve that problem first, get a tune, better BOV to keep the boost your already making and the top end will be plenty strong for most. That's why I disagree, but I could be wrong...at any rate, either path has merits, the OP can decide which one he believes is the best approach to start with if he even cares enough to address it, he may have just been curious over anything else. And no, I'm not trying to start a fight or anything like that, I'm just looking at it from a different angle that the majority.

 

[Juben]

I agree that it cannot make good power when the throttle and timing are pulled, but that doesn't affect the "plateau" feeling as much as you're projecting that it does.

I wasn't suggesting that he replace the head and/or turbo, but rather I was providing an explanation as to why he felt the power flatten out after 5,500 rpms or so. I've driven the car stock and modded. I had the stock intercooler experience and have had an upgraded intercooler since I first purchased the car. I ordered my intercooler from Nik back in January of last year (2015) because I've had the experience to know that the stock intercoolers are crap.

However, even with being a bolt-on car tuned on E30, I still experience that plateau on the top end after 5,500 rpms. Why? Because bolt-ons aren't the solution to fixing the plateau. The solution is porting the head. Now, does everyone want or need to do that? No, but I was merely providing information as to what the solution would be was he to want to pursue having a strong pull that doesn't flatten out on the top end.

A bigger turbo will help mask that feeling somewhat just as an intercooler will, but again, I was directly addressing what caused the plateau feeling and how to remedy it.

The EcoBoost turbo isn't "small" when compared to some factory turbos, but when you come from cars with a history of much larger turbos, you tend to think of these as small. I've been wrenching and building on cars since I was 14 years old and that's been many moons ago. I've driven cars with all sorts of turbos and sizes, and to me, this is a smaller turbo. That's not to say it isn't capable or it's handicapped, but rather it's just not conducive to higher horsepower goals. Some people want to do simple bolt-ons and be done with it. For that, the stocker is more than adequate, especially for those that like a hard, low end punch. For myself, I prefer the spool of a larger turbo that comes in stronger albeit much more linear than a smaller unit like the factory turbo.

To get "strong pull" to the end as you've described it, you're going to have to do more than bolt-ons. That's what I'm saying. Maybe what you feel is strong pull is different from me? Let's say it like this though, if you want the hard pull feeling on the bottom and mid-range up in the top of the rpm band, you'll have to upgrade the turbo at minimum.

I have a modified EcoBoost that I've tried different setups and tuning with. I have friends with big turbo EcoBoost cars that I've driven more than around a parking lot too. I'm not saying that upgrading the intercooler won't help improve performance (that was lost from heat soak) and make it more consistent, but unless I'm reading it wrong, you seem to imply that upgrading the intercooler is going to fix the top end plateau. And the truth is, it won't. I have experience with this — not theory. Once you receive your intercooler from Nik, you'll see what I'm talking about.

Also, this wasn't a thread about upgrade paths. I always recommend an intercooler first then tuning and colder plugs. It's not about saying an intercooler won't help but rather it doesn't address what the OP was specifically referring to.

In any event, I'm going to bow out of this thread. It seems like every thread is turning into bantering back and forth for the last bit, and honestly, I'm growing weary of trying to prove everything that's been common knowledge about the platform for longer than most have been around. I'm not trying to be a dick by that statement, but rather, I'm just tired of the back and forth with people. When I discuss a topic, I add input that I have first hand knowledge and experience with. I don't just try to spew out stuff without rhyme or reason and it almost comes across as if that's what's being projected that a few of us OGs are doing. If that isn't the case, then forgive me, but that's what it seems like. It's good to question things. I, myself, don't take everything at face value until I do research and get hands on experience, but some of this stuff doesn't need to be debated time and time again.

Anyways, Boosty15. I hope you've gained something out of all of this, and congrats on your new Mustang! :cheers:

 

[TheLion]

I was trying to imply the "plateau" is the OP is referencing is actually the almost exponential taper of torque at the upper rpm range. The torque is falling at a faster rate than the RPM is increasing, thus we get an "exponential" like falling of the torque curve and declining power curve. As the turbo moves out of it's efficiency range torque should drop rather linearly, but it doesn't.

I think what the OP is describing as a plateau is actually the taper. It's not plateauing or table topping, but rather falling. The factory turbo can produce about 27 PSI boost in the peak efficiency range and starts to drop once you move out of that range. Even at 6500 RPM however it still produces about 23-24 PSI. The ECU will only allow 18 PSi to be regulated in the higher gears (it allows "overboost" in 1 and 2 only to my knowledge, which is 22 PSI).

I think I'm reading into his statement more than the statement makes at face valve where your looking at it directly at face value and very literally. There's also back pressure to consider, which is another culprit in the increasing magnitude of the decreasing slope of the torque curve (phew), however that can largely be relieved by an upgraded DP.

You can flatten out the top end power curve with just boltons in low and medium power ranges. But yes, your absolutely right that your NOT going to get a climbing power curve with the stock turbo in the upper range. Your not going to get a climbing power / torque band all the way to redline like big turbo engines or something like the flat plane crank 5.2L in the GT350. But, the OP should have plenty of info now to look into from everyone's contributions, even the dissenting ones...and I would agree that "strong pull" is subjective to the individual. I should probably do likewise and give it up, I digress.

 

[Boosty15]

Thank you both very much Juben and TheLion! I can tell you both are well informed on various subjects. I have learned enough from both of your comments to know where to start looking to get the power curve I desire . A little bit of "civil disagreement" helps newbies like me learn from multiple parties at once.

Again, thank you both and everyone else who has thrown in their .02!

 

[Boosty15]

I have read a couple articles, not all on this forum, about the "Overboost" function and how you can have it active during all gears as long as you go from WOT to 0% back to WOT within 3 sec. I cant promise that be true as I'm much more interested in watching where my car is pointed rather then my little digital boost gauge. *which I have a hard time believing as once I seen it read 15psi and stop there through 1-2-3 then it opened up and showed >20

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