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Discussion Starter · #1 ·
I’ve been around a lot of naturally aspirated engines, but this is my first turbo. Can someone explain how this new engine works and why it’s so special?

A few questions to start the conversation:

I understand the turbo is on the small side, is that why the torque curve peaks early then gradually fades? Is this related to boost pressure (which would follow the same curve)?

How is boost pressure regulated, and is it electronic or mechanical? Where is it measured?

Easy performance upgrades are about getting air into and out of a motor as efficiently as possible, and turbos have a lot more plumbing so there can be more room for to improve? But not if the boost is regulated at the intake manifold?

It seems this motor was designed for mpg, not performance and mpg is not measured at WOT or redline, so that would also mean more room for performance upgrades?

How does the variable cam timing work, and is it really needed for a turbo?

Thx.


 

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Most of what these cars do is the same as any turbo car built since the 2000's.

Almost all cars stock have "small" turbos that are designed to spool rather early and run out of steam in the upper rpm's. This is to create low end torque of a larger displacement with a smaller displacement and gain mileage. More or less boost and torque are directly related yes. As boost tapers torque tapers.

Boost is standard, pneumatic wastegate with electronic boost control solenoid to give the computer the ability to tune the boost curve, it is measured in the charged path which for sake of simplicity is all at the same level post intercooler.

Boosted motors are still air pumps so the standard mod logic still applies. More air or less restriction in, or less restriction out means more hp. With a few small twists. The turbo will flow a specific amount of air at a specific temp. At some point the temp gets high enough that you loose hp by flowing more air. Optimal exhaust design isnt really relevant as all the manditory back pressure to deal with not burning exhaust valves is achieved by the turbo. So more or less the most power is achieved by having no post turbo exhaust. Exhaust manifold design can be used to allow different turbo designs but in our case with the stock turbo, there is never much power to be had by changing the exhaust manifold design. It is nothing like putting long tubes on an LS motor.

its 2014 all motors are designed for mpg, look at a 460hp lt1 and the c7 in general. It is heavily burdened by mpg concerns. The thing to consider about the the 1.6 ecoboost is that it has forged rods, and i have heard rumors the redline is a function of the turbo and the motor is good for much more rpm. If that is the case, then the motor, though tuned for mpg, had some considerable cost added to acomidate power creation.

Variable cam timing is actualy more useful for a turbo car than nonturbo, as you can get hundreds of rpm of spool by tuning the cam timing on the low end and make more power on the top end.


The biggest thing that is special is Direct injection which allows much more boost/compression on any specific octane due to its ability to cool the cylinder more effectively. Someone else may be able to get more specific about it as i havent tuned or directly delt with DI yet.
 

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Most of what these cars do is the same as any turbo car built since the 2000's.

Almost all cars stock have "small" turbos that are designed to spool rather early and run out of steam in the upper rpm's. This is to create low end torque of a larger displacement with a smaller displacement and gain mileage. More or less boost and torque are directly related yes. As boost tapers torque tapers.

Boost is standard, pneumatic wastegate with electronic boost control solenoid to give the computer the ability to tune the boost curve, it is measured in the charged path which for sake of simplicity is all at the same level post intercooler.

Boosted motors are still air pumps so the standard mod logic still applies. More air or less restriction in, or less restriction out means more hp. With a few small twists. The turbo will flow a specific amount of air at a specific temp. At some point the temp gets high enough that you loose hp by flowing more air. Optimal exhaust design isnt really relevant as all the manditory back pressure to deal with not burning exhaust valves is achieved by the turbo. So more or less the most power is achieved by having no post turbo exhaust. Exhaust manifold design can be used to allow different turbo designs but in our case with the stock turbo, there is never much power to be had by changing the exhaust manifold design. It is nothing like putting long tubes on an LS motor.

its 2014 all motors are designed for mpg, look at a 460hp lt1 and the c7 in general. It is heavily burdened by mpg concerns. The thing to consider about the the 1.6 ecoboost is that it has forged rods, and i have heard rumors the redline is a function of the turbo and the motor is good for much more rpm. If that is the case, then the motor, though tuned for mpg, had some considerable cost added to acomidate power creation.

Variable cam timing is actualy more useful for a turbo car than nonturbo, as you can get hundreds of rpm of spool by tuning the cam timing on the low end and make more power on the top end.


The biggest thing that is special is Direct injection which allows much more boost/compression on any specific octane due to its ability to cool the cylinder more effectively. Someone else may be able to get more specific about it as i havent tuned or directly delt with DI yet.
Approved by a Ford Technician;)
 

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Most of what these cars do is the same as any turbo car built since the 2000's.

Almost all cars stock have "small" turbos that are designed to spool rather early and run out of steam in the upper rpm's. This is to create low end torque of a larger displacement with a smaller displacement and gain mileage. More or less boost and torque are directly related yes. As boost tapers torque tapers.

Boost is standard, pneumatic wastegate with electronic boost control solenoid to give the computer the ability to tune the boost curve, it is measured in the charged path which for sake of simplicity is all at the same level post intercooler.

Boosted motors are still air pumps so the standard mod logic still applies. More air or less restriction in, or less restriction out means more hp. With a few small twists. The turbo will flow a specific amount of air at a specific temp. At some point the temp gets high enough that you loose hp by flowing more air. Optimal exhaust design isnt really relevant as all the manditory back pressure to deal with not burning exhaust valves is achieved by the turbo. So more or less the most power is achieved by having no post turbo exhaust. Exhaust manifold design can be used to allow different turbo designs but in our case with the stock turbo, there is never much power to be had by changing the exhaust manifold design. It is nothing like putting long tubes on an LS motor.

its 2014 all motors are designed for mpg, look at a 460hp lt1 and the c7 in general. It is heavily burdened by mpg concerns. The thing to consider about the the 1.6 ecoboost is that it has forged rods, and i have heard rumors the redline is a function of the turbo and the motor is good for much more rpm. If that is the case, then the motor, though tuned for mpg, had some considerable cost added to acomidate power creation.

Variable cam timing is actualy more useful for a turbo car than nonturbo, as you can get hundreds of rpm of spool by tuning the cam timing on the low end and make more power on the top end.


The biggest thing that is special is Direct injection which allows much more boost/compression on any specific octane due to its ability to cool the cylinder more effectively. Someone else may be able to get more specific about it as i havent tuned or directly delt with DI yet.
So in laymans terms, a wizzard blows your turbo to get everything going and the car gets good mileage because of Peyton Manning. I like this car :)
 

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Discussion Starter · #6 ·
Thanks, that's just what I was looking for. How/when does the computer alter the boost, and what is overboost?

Is it also safe to assume that at peak HP the turbo is giving all it has so any improvements would have to be in airflow? So that's what all the plumbing fixes are about? It's not like you can raise the boost at that point, right?
 

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Thanks, that's just what I was looking for. How/when does the computer alter the boost, and what is overboost?

Is it also safe to assume that at peak HP the turbo is giving all it has so any improvements would have to be in airflow? So that's what all the plumbing fixes are about? It's not like you can raise the boost at that point, right?
It is constantly altering boost and timing. If you are flat vs 50% throttle, different things happen. Some crude tunes are difficult to drive and are what gave the "turbo" the macho idea that it has now. On a crude tune, if you are 50% throttle, it will want to go 100% and boost will be punchy but not civilized. A well sorted tune will allow for a progressive throttle which makes it easier and more predictable.

Overboost is something that Ford makes sound like its a bigger deal than it is. The car in Europe has 170ish horsepower because they cannot count the overboost power, where here in North America, the 197hp includes the overboost. The overboost only comes on when the pedal is WOT and it gives you 20 seconds of 21psi boost where otherwise you would be limited to 18psi (I do not know the actual number). The principal behind this is to save the engine from extra strain, but all you have to do is lift your foot and get back into it and the 20 seconds of overboost starts over again. To be honest, it is highly unlikely that you will ever find a chance to be WOT in 1 gear for 20 seconds. If you do, you could be facing certain jail time and perhaps a crushed car (in Canada at least).

As far as the turbo giving all it has is concerned, it has yet to be proven. 21psi on a little turbo such as this is A LOT. Any more and you may run into inefficiencies. On other cars, the turbo may be at only 75% like on an Evo. Evo X are known to make well over 350whp on a stock turbo. The biggest issue is that a bigger turbo gives less low down power that we use on a day to day basis. A small turbo allows for the car to feel faster on a day to day basis even though it may not be up top where you drive 5% of the time, if that.

If/when a better intake/intercooler/downpipe set up is made, we may be able to run 19/20psi and make much more power because the efficiency of the turbo has been optimized. PSI isn't everything with a turbo even though a lot of people think it is. I have a feeling that this 1.6L Ecoboost will be a little monster when modded because it has forged rods and can already handle 21psi....I am excited to see what the aftermarket has in store!
 

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Discussion Starter · #8 ·
This is where I get confused, if boost roughly equals torque and the turbo is small it can’t push 21 psi at 6K (the engine sucks air faster than the turbo can put out at max psi). So if the only time there is 21 psi boost is at lower RPMs where is it over boosted for more than 20 seconds? By that time you’d be well into the upper rev range where the turbo can’t put out 21 psi.

I thought overboost was really over rev for the 20 seconds? That additional RPM will mean a few more HP, but that’s not related to boost (torque)? Am I missing something?


Sorry for all the Q's just trying to understand how this works. I know how to make a NA motor faster but this is a different beast. Very cool, but a totally different driving experience!



 

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overboost and overrev are 2 different things with different timer.

overboost is a momentary, 20 second, increase in requested torque in the ecu. Which means its adds boost across the rpm range not just at peak boost. I think the cars taper to like 13-14 psi by 6500. If you go to the google machine and read about modern ecu tuning there is massive ammounts of info out there. Only way you will be able to learn it is to invest a ton of time and then liekly buying an access port and atr, so you can actually see and feel how it all ties together. If its not worth the effort, let the black box stay a black box imo. In reality I think most people would be better off having no idea how tuning works. It is learnable for sure, but plan to invest hours in the hundreds just to get started. I don't think this community will ever be large enough to have enough of a skill base to get it all written down in our forums. Romraider forums are a great place to read for hours upon hours.

over rev is only a few seconds, 3 or 5. More than enough to go from 6150 to 6500 in 1st or second. stock tune is tapped out up there anyways so may as well shift in higher gears. There isn't really more hp up there, i think its just there to give you more usable gear. Probably also to allow for the exceptionally long 1-2 shift. They should have made it long enough to get to 60 in second imo, would have looked a bunch better for magazines.

It is likely the turbo is tuned stock near effeciency. I haven't been able to find compressor maps for it but its a good assumption. Which means there should be a few more pounds of useful boost in the turbo across the rpm range. The motor does run 10:1 compression, I get that DI is sort of magic but still, lots of boost on lots of compression. If you start moving out of effenciecy and pushing up charge temp, DI cant hold det off forever.
 

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Discussion Starter · #10 ·
Thanks, I appreciate the information. I like to (have to, it’s a disease) tinker with everything I own. I put cams, header, intake, and FS tunes into my ZX-3 which was fun (and it all works perfect), and I’ve built plenty of motorcycles. I like to get a baseline on how everything works before I start adding parts. I don’t want to go as deep as I did with my Focus but if there are any “easy and cheap” room for improvement I’m all over it. I understand airflow but not turbo, and I’ll look Cobb et al for tuning but if I understand it better I might be able to find a few bits on my own? Or avoid mods that don’t make any difference. ;)

I’d like to see boost vs RPM data as that will answer a lot of questions. It appears overboost is always on when you initially hit WOT? The 20 second limit would only seem to apply when topping out in 6[SUP]th[/SUP]. That won’t be a problem for me.
 

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I’d like to see boost vs RPM data as that will answer a lot of questions.
Cobb used to have an online dyno library of all the cars they tuned that you could see afr/boost/torque/hp. If they still have it the data would be there.

Then again go to any evo or impreza forum and look at their maps, you will see the same thing.
 

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Cobb used to have an online dyno library of all the cars they tuned that you could see afr/boost/torque/hp. If they still have it the data would be there.

Then again go to any evo or impreza forum and look at their maps, you will see the same thing.
Dyno database hasn't gone anywhere


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Read the book called "Maximum Boost" by Corky Bell.
Link to Book
 

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Discussion Starter · #15 ·
Unrestricting the intake and exhaust won't do anything if the ECU controls the max boost (if measured at the intake manifold). This is not the same as a NA car, the ECU controls to amount of air entering the engine. That was the reason for asking this question, I thought the ECU controlled max boost so you can't increase it w/o a tune?
 

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Unrestricting the intake and exhaust won't do anything if the ECU controls the max boost (if measured at the intake manifold). This is not the same as a NA car, the ECU controls to amount of air entering the engine. That was the reason for asking this question, I thought the ECU controlled max boost so you can't increase it w/o a tune?
Not exactly correct, if the turbo works less hard to make the same boost cause it doesn't have to "suck" as hard due to intake restriction reduction or have as much exhaust restriction allowing the turbine to spin faster at a specific exhaust gas output. Either of these things can free up hp without the boost peak changing by spooling the turbo sooner or recuding its work load thus producing less heat and making a more dense air charge.
 
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