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Discussion Starter · #1 ·
Hello all,

I don't know much about cars, but find myself in a situation needing help, badly. I live in very high altitude (11,000+ feet), and my 2018 Crosstrek had no power up here at all. I've been searching on different things I can do to get a bit more power, and one was to take out the catalytic converter. Will this make a difference? What could I expect to happen with the oxygen sensor(s), will they stay lit forever and drive me insane?
Another thing I was told to do was change the air/gas ratio and use higher octane gas, but that is not an option here as the gas is essentially garbage here.

Any help would be greatly appreciated, thanks.
 

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Prefers black cats
'18 and '19 Crosstrek Limiteds
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Sell it and get a faster car it will be cheaper than getting any significant hp gainsz
Yep! I had started a reply to the OP and deleted it. Who lives at 11K and buys a Crosstrek? Our '18 struggles over 7K in Big Bear and is a liability over 10K in the Sierras.

If this is a legitimate post then, yes, sell it and buy something with a turbo...
 

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2016 Crosstrek
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1,407 Posts
A naturally aspirated coke bottle is going to wheeze at 11k feet. It's not a question of exhaust, it's a matter of intake density. Opening up the exhaust won't help, plus it's illegal - at least most places - to remove catalytic convertors.
 

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2020 Crosstrek Premium
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1,412 Posts
Your warning light would always be on. The best gains in power you could get would be from a custom tune, which might be able to turn off the warning light. But it's 2 liters, even if you make it really easy to breathe, you'll never get past that limitation. I agree that you need a different vehicle to get more power.
A custom turbo or supercharger setup would help, but that's probably more than $10k and would kill reliability.
 

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2021 Crosstrek Limited, Pure Red
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OP is in Bolivia ... a perfect country for a Subaru other than the altitude. When I was there, most of the cars seemed to be struggling. Amazing place, though.

Anyway, you might get a theoretical, very marginal increase in power if you removed the cat converter, but if the converter is functioning properly I can't see it even being noticeable. Only way that might actually help is if you're getting additional back pressure because the converter is clogged.

It's possible that some other, older vehicles down there don't display engineering that's up to contemporary standards, and their exhaust systems are creating additional back pressure, but that's not going to be true with mainstream contemporary cars. Mostly, messing with a modern exhaust system just makes cars seem more powerful, because they're usually louder ...
 

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Discussion Starter · #9 ·
Thank you all for the help and information. Yes, unfortunately, it is a legit post. As I said, I'm not much of a car person and I didn't realize how much a car would be affected at high altitude. I live in La Paz, Bolivia, so taking out the catalytic converter wouldn't be an (illegal) issue here, but considering the overwhelming response of 'no, it won't help', it's pretty much a dead issue for me as this was essentially my last hope. Buying another car and selling this one is not an easy endeavor. I'll probably just keep it for my time here and sell it then.

Is the problem the CVT transmission? One thing I forgot to mention, my Crosstrek was purchased in the U.S. and shipped to La Paz, Bolivia.

I'll give the Crosstrek credit though, I've pushed to over 16,500 feet... it gets there, just slowly.
 

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2021 Crosstrek Limited, Pure Red
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Have you talked to the Subaru dealer there? I don't know that they would have any solutions, but at least you could confirm that there's not a mechanical issue with your car that's causing it to perform less well than other XVs down there, and that would be worth finding out.

It's not the CVT or any other one part of the overall vehicle package -- it's just that all internal-combustion engines inherently lose a lot of their power at that altitude. Modern fuel injection systems are actually able to better-handle altitude changes than cars built a couple generations ago were.

I don't remember the vehicle I was in, but I remember going to Chacaltaya when I was down there, and by the time we got up to about 15,000 feet the vehicle was barely able to move. We ended up walking the last couple of miles. :)
 

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A lot of people complain about lack of power (not talking about the OP) As I have said many many times. It just needs to be pedal to the metal and run in the 5000+ rpm.
In my opinion it won't hurt it but I personally don't worry about it bc I will be getting rid of it at 70K miles. So what I do is not for everyone.
 

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I live in La Paz, Bolivia, so taking out the catalytic converter wouldn't be an (illegal) issue here,
So as long as it is not illegal, hey no prob, yoink it. However, what is the purpose of the cat on the vehicle? Just to rob the engine of power so you can't go zoom zoom? So what's it matter that your vehicle will be fine little polluter sans cat as long as you can get that power, huh?
 

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Not a Canadian
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I'll give the Crosstrek credit though, I've pushed to over 16,500 feet... it gets there, just slowly.
DANG! Do you carry an oxygen bottle for yourself? But I suspect that your body is acclimated to that altitude. Years ago I went thru an altitude chamber and if I remember correctly, my consciousness started taking on a "dark" animated nature at that altitude. Weird. Not pleasant!
 

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2018 Orange Subaru Crosstrek Limited
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Weight is the enemy of overcoming inertia. If you need the performance and don't need the crap in back you could remove the rear seats and generally lighten the car. If you were really in a pickle and the car wouldn't keep going I guess that Nitrous might at least get you over a hill or mountain but that doesn't sound like your problem.
Some high altitude generators produce compressed air to fill auxillary air storage bottles besides electricity. The air storage bottle is used by the generator when it is under high load but doesn't have enough ambient air to handle it but I've never heard of such a thing on a car.
We once went on a hummingbird species hunt at altitudes above 14 K feet in Amazon headwaters (Ecuador.) Saw four species of hummingbirds furiously beating the air where it seemed impossible for us to breathe. My wife and I gasped at the sight of humingbirds at that height...well, we were gasping anyway...I mean started gasping at 10 K. Do you know how hard it is to use binoculars when you are crawling prone up a trail, gasping? I find it remarkable that cars can function there, hummingbirds more so. Safe travels in any case. I hope Bolivia is enjoying newly earned freedoms and stability.
 

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since you have a cvt are you manually shifting it though the fake gears? or just leaving it in drive?

if you manually shift it you can keep it in the power band which will help some. your motor is basically just a air compressor so by keeping the RPM higher your moving more air though the motor which in turn creates more power.
 

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3% of the atmosphere is lost per 1,000 feet, up to 20,000 feet. The MAF and upstream O2 sensor will have the ECU have
the injectors squirt less gas. You'll still have 1/3 less power than at sea level. Check with speed shops in your area for possible. NOx might help you climb hills.
 

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I'd do a couple things(not knowing the miles on the car):
1) Have both recalls(ECU software update for coil temps, updated pcv from plastic to steel version) done at a minimum if it has not.
2) If have garbage quality petrol as we do in the PNW, install a new set of plugs(NGK) and throw a bottle of chevron techon in the petrol tank before filling up with premium(this will help).
3) Make sure your air filter is relatively clean and of decent quality(IE reasonable flow rate).
I also changed out the garbage oil the dealer here uses as the car runs quite rough on it. Changed over to Castrol syntec 5w-30 and improved the running immediately afterwards(and installed the proper amount in it!). As others have mentioned, cat bypass pipes have their issues. I've installed a set of bypass pipes on one of our Boxster's, and it does make quite an improvement with no issues(cel lights or the like, passes emissions with flying colors). Having said that, the car has 4 cats, and your only getting rid of 2. There is definitely more power, less weight(very weighty). There is only 1 large cat on the Crosstrek. With a bypass pipe, you would probably need an O2 sensor spacer and a flash of the software to avoid CEL's. Would be interesting to see what a bypass pipe would do for the car.
You might consider some of the muffler delete options out there. I would not do a straight pipe, but there are some with much smaller, better flowing, and much lighter weight mufflers out there. The stock factory muffler is pretty heavy and restrictive.
Regards
 

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Might try a turbo charger. I have seen turbo kits for Crosstreks advertised, but probably the most cost effective solution is sell and replace the car.
 
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