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From all I've read on reviews on turbo 4 cars like ours, Veloster Turbo, Focus/Fiesta ST, etc. they all say the power curve dips off well before stock redline due to the inherent nature of a small displacement turbo engine. How does tuning overcome this? I'm a laymen so the more simpler the explanation the better.

My limited understanding is that manufacturers set parameters to meet safe goals of performance/fuel efficiency/reliability; when raising it beyond stock specs, how 'unsafe' is it for a daily driver? Are we talking years off its lifespan like smoking 2 packs a day or more benign like eating fried chicken once in a while?

Forgive the analogies. I did say I was a layman.
 

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i can't tell you but if you don't get a good answer here VT forums definitely will
 

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Boost fall off is directly related to the size of the turbo and the motor itself. I always think of boost as a measure of resistance. The more you open up the intake side of things the less boost you will have even though the air volume would be the same. The exhaust also plays a role as well as the size of both wheels on the turbo, exhaust piping size etc. It really is a complex formula.

Rev limit had many factors such as bore and stroke, valves springs, and others I can't think of off the top of my head.

How those things will continue to wear and tear I am not sure though.
 

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Before you dig deep, ask yourself a few questions.

Mainly this one - how often you hit rev limiter now?


I got tune, can-tune.
I will walk you through a few things here.

Initially, completely stock - I would hit 18 psi from time to time, most of the time it was 16, 17, when going above 5000 rpm it would start falling to about 15, upshift, boost jumps to 18 and holds 16-17.
It would have uneven power sometimes, fuel would not really treat this issue.
So...
Then, I put HKS 45XL spark plugs and pour 93 octane.
As a result, power is much more instant and car pulls a bit better (not much, but noticeably), YET boost does not reach even 15 psi. No matter what.
Adding intake, removing second cat - not much of any help.


Next step was tune.
And from what I see it defies what Scoobdude said.
Here is why.
Boost is now at about 22-23 psi, hitting max of about 25 psi (based on my boost gauge) and it holds boost all the way up. It does not seem to have any problem doing it.
Boost depends on the turbo size (right), but also on the exhaust gases flow. The latter one depends on the flow into the engine. So the more you allow, the more exhaust you produce, the more boost you can get.

Also, I believe wastegate is into play redirecting exhaust flow to not hit too much power in the high end.


Now, going back to the question.
Rev limiter.

I am not sure if mine was elevated, but I do not feel like I need it.
Now, regardless of tires, they spin in 1, 2, and 3 if I hit hard enough.

I barely ever would hit rev limiter before. Even less now. Just no need with more power.
I find myself going way too fast in places I was OK before. After a year of driving with stock, having tune makes to still learn how fast the car accelerates now.
 

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How exactly did you disapprove my post? I do not know the effeciency range of this turbo so 25 maybe perfectly acceptable. But I can guarantee you if you try that on the Elantra sport or the 2017 model with the smaller turbo you will start to lose power. It's a complex formula this while volumetric effeciency thing. Just some factors are, size of the turbo, exhaust, clinger, throttle body, intake, compressor and turbine wheel design, had flow rates and design, all piping and bends, intercooler effeciency and pressure drop, etc etc etc

So no body is not always a direct connection to power as sometimes to much boost is just got out and to big of a turbo will take forever to spool up

Ok my WRX, I put a stock tdo4 style turbo but with cushion wheels so it flows about 125cfm but also spools about 2-300 rpm quicker and holds more boost till redline (made by ion performance). My WRX has also been re geared to be more like our forte sx are. This combo gives quick acceleration but I to out looks maybe 120ish at redline. But the car is explosive when boost kicks in which is right after you pay the throttle. Still not as quick as our little twin scroll though. But the point is a car is much more than an on/off switch. And there is not a turbo that is a one size fits all
 

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I just messaged my buddy on it ,but I believe your thoughts are way off the mark. there is a torque command setting aka "gain" on the ECM . when you look at the stock boost map you have an efficiency range of operation . The first generation gamma turbos have a lot more efficiency adjustment than the current gamma turbos and or the ford fiesta st turbos . When you move the range to different parts of the rev band you create power where you want it . The factory sets it up to be what they feel as reliable and safe for grandma . When moving the rev limit to 7200 you can hit 60 in 2nd with more power instead of gear shift and power loss into 3rd . The fiesta falls flat on its face because it has a much smaller turbo than the Ko3 and even though a ko3 derivative the current 2017 turbo its basically really close to the fiesta turbo in performance. The forte 2014-2016 has a lot of tuning room . With the new flash tuning, you can work with your tuner to dial in the car to your liking .
 

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How exactly did you disapprove my post?
I did not.
I was not investigating different setups, or different turbos, or going into details.
I was only providing feedback how it works on my car with pretty much stock setup, but before and after tune, and that was somewhat against your statement of boost falling. That is the tune itself, not the turbo.

BTW, I think Hyundai/KIA decided to put smaller turbo in the newer versions to limit tuning abilities. Again, the stock keeps 22 psi all the way to the redline without hiccups. How 2017 would perform? No clue...
 

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I did not.
I was not investigating different setups, or different turbos, or going into details.
I was only providing feedback how it works on my car with pretty much stock setup, but before and after tune, and that was somewhat against your statement of boost falling. That is the tune itself, not the turbo.

BTW, I think Hyundai/KIA decided to put smaller turbo in the newer versions to limit tuning abilities. Again, the stock keeps 22 psi all the way to the redline without hiccups. How 2017 would perform? No clue...
The stock turbo maybe good till that range. I have not looked into the specs on the turbo yet. Pretty sure there are others that can answer that part better.

But the better models did not get a smaller turbo to limit tuning, but rather to lower the peak torque. It has moved from 1750 to 1350 on the new models. This is to make it feel like more of a naturally aspirated motor with it's throttle response.

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