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blitz118

2019 Edge ST Update

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So you are saying the ST was tested at 5000 ft and the 2015 Sport was tested at sea level - the explanation why the 2015 Sport performed so well vs. the ST?

I wish all the new ST owners the best, but for me, I would wait until these performance bugs are worked out - that's what you are paying for. I may be a little bias, but I am glad I am holding on to my 2015 Sport, especially since it only has 14K miles on it.

My lease was up on 2015, so I had to move on, and I love the ST. I have no regrets about leaving the Sport. The ST is a better overall vehicle. As soon as I drove it off the lot I could feel the better ride quality and throw in all the new tech, SYNC 3 and B/O stereo. I don't miss the Sport.

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Edited by blitz118

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There is no way you can go to 5000 ft with the same engine tuning and boost levels and NOT see a reduction in power. Less oxygen = less power. FI engines do better than NA engines for sure but there is still a loss.

 

Turbo lag also makes sense. Yet another fail by Ford’s marketing dept choosing that location.

 

The air is thinner but the percentage of oxygen is the same. If the turbo manage to do the same psi the amount of air entering the engine would be the same as at see level. So your low rpm power would be reduced by the lag but your upper rpm would only be affected if you made less boost. Probably talkin semantics here but oh well. A dyno graph comparison would be interesting.

 

So you are saying the ST was tested at 5000 ft and the 2015 Sport was tested at sea level - the explanation why the 2015 Sport performed so well vs. the ST?

I wish all the new ST owners the best, but for me, I would wait until these performance bugs are worked out - that's what you are paying for. I may be a little bias, but I am glad I am holding on to my 2015 Sport, especially since it only has 14K miles on it.

 

Yes that's what I am saying.

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still less overall oxygen at the same boost level milehigh vs sea. Engine management can drive boost higher to achieve the same power but you will need more boost to achieve the same power at milehigh vs at sea. Then you run into mpg issues because you may be going outside the turbo's efficiency map to achieve that higher boost. Gets messy.

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There is less oxygen per cubic foot of air at 5000 ft. It seems to me that the turbo is going to compress the air by the same amount so if you start with a less dense air mixture you’ll end up with a less dense compressed mixture even though the turbo is providing the same amount of compression. You would have to turn up the boost to get the same end result when starting with less dense air.

 

In a very simple example, let’s say the turbo provides a 4:1 compression. At sea level there are 20 parts Oxygen per cubic foot and at 5000 ft there are only 17 parts oxygen per cubic foot. If you compress 4:1 at sea level you end up with 80 parts oxygen per cubic foot but at 5K feet you only get 64 parts oxygen.

 

You only get more oxygen if you increase the amount of compression.

 

At least that’s the only explanation that makes sense to me.

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Mine is AWD - I special ordered it with every option available which was a good thing b/c the build date was October, 2015

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Blitz118 - congrats on your new ST - its a beautiful car and have no doubt its a better car than my 2015 Sport. The reason I kept my 2015 Sport is that it had only 14k miles on it, in showroom condition and the buyout was reasonable (26K) - Plus I have every option on it that was available at the time as I special ordered it. What I did instead is lease a Escape Titanium for my wife - she was driving a 16 year old mini van and it was time to replace it even thou she wanted to keep it. I have to say the SYNC 3 is a major improvement over SYNC2, and I love the heated steering wheel ('15 Sports did not offer the cold weather package). Anyway enjoy your ST - hopefully I will own one some day but for now, I still love my '15 Sport and could not justify a current upgrade to 50K vehicle.

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The percentage of oxygen doesn't change, just the molecules of everything that make up air is less dense. So there is more empty space between the molecules. Psi is Psi so at higher altitudes it can take more "work" to make that psi. Something like an air compressor has to work harder and longer to get a tank to an internal pressure of 120 or so because it gets less air in a compression stroke. So any power loss in a turbo motor would be due to the turbo taking longer to produce boost and possibly not reaching it's max boost because the turbo has to spin faster to get more air and not to make up for lower percentage of oxygen in air.

 

You are right though that there is less oxygen per cubic foot but only because there is less air also. Your compression ratio of air will increase on its own though because your turbo has to spin faster to make 1 psi at 5000ft than at sea level. Inducing lag and possibly less max boost.

 

http://www.altitude.org/why_less_oxygen.php

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But there is no mechanism to make the turbo “spin faster”. Perhaps the turbo produces more boost than is needed all the time which is controlled by the blowoff valve, so it will eventually hit max boost either way - it will just take longer at altitude thus the turbo lag. But I didn’t think that the blowoff valve worked that way and that it only prevented damage when the throttle was shut suddenly.

 

Either way a vehicle is going to be slower off the line at altitude without some type of tuning compensation. No way around it.

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Finally got around to reading the instrument tested Motortrend review of the Edge ST. So its slower than the Sport to 60, slower over 400m and pulls less G's through the figure 8. Seems about right... The ST is stronger on the brakes though.

 

Also, with this not being a piece of road picked by ford engineers like all the initial reviews we got from the ford sponsored event, this was the feedback on the handling:

 

" The performance shocks ride very, very stiffly on bad pavement and allowed a bit of early Focus RS-type pogoing mid-corner when pushed hard."

 

Edit: If you didnt know, the Focus RS is renowned for being the most overly stiff hot hatch of all, even more so than the old Civic Type R and A45...

Edited by MaX83_ZA
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