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I am thinking of purchasing an '07 S60R with MT and keeping it at an altitude of 8,000 ft. I know how much fun it will be going up and down the twisties, but should I expect to need special tuning for high altitude?
 

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Re: High Altitude Performance (dlchasen)

Quote, originally posted by dlchasen »
I am thinking of purchasing an '07 S60R with MT and keeping it at an altitude of 8,000 ft.

Wow. You must have a very tall garage lift.... or a really steep driveway....
 

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Re: High Altitude Performance (rgrove)

You'll find that a Turbo car tends to High Altitudes on it's own........ try it, you'll like it

The PSI is still the same, the Lambda system takes care of the AFR

Modified by JimLill at 10:09 AM 3-22-2009
 

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Re: High Altitude Performance (dlchasen)

Your ECU will automatically compensate for the lower oxygen content of the atmosphere at 8,000 feet, so there is nothing you need to do. And the turbo will allow you to realize less loss of power at altitude than you would from a normally aspirated motor. Even so, I've noticed the difference when high up in the Rockies; there's noticeably less punch in the higher end of the rev band.
 

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The turbo will have to work harder (spin faster) to deliver the desired pressure from the thinner air. This means the charge air will be considerably hotter. You will lose some performance up high, but no where near what a N/A or belt driven blower car will lose.
 

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Re: (SlowR)

Quote, originally posted by SlowR »
The turbo will have to work harder (spin faster) to deliver the desired pressure from the thinner air. This means the charge air will be considerably hotter. You will lose some performance up high, but no where near what a N/A or belt driven blower car will lose.

Keep in mind that most of the rise in temp of the air is from the heat of compression more than turbo RPM and speed.
 

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The car is worse at 8,000. I go to Mammoth all the time to work on the lodges and resorts. The town center is at 7,500 and the main lodges are at 9,000.

I don't know where anyone got the idea that the turbo or what ever compansates, but it's not the same car up at the altitude and the car never improves on it's own over time.
 

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Re: High Altitude Performance (KillerB)

Quote, originally posted by KillerB »

I don't know where anyone got the idea that the turbo or what ever compansates, but it's not the same car up at the altitude and the car never improves on it's own over time.

I don't think anyone said it's the same, it's just better than a N/A car. At altitude a turbo car will still have decent peak power and torque, but it definitely takes longer to spool up and runs out of top end earlier.

When people say it compensates, what they mean is that it still tries to boost to the same absolute pressure, so your gauge pressure will read higher, although I haven't heard that specifically confirmed by anyone with a boost gage. I do know that the IPD stage 1 tune in my C70 runs up to 18-19 psig here in Denver, when the advertised boost is 15 psi.
 

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The R will perform great at high altitude, but it really needs high octane fuel, especially on hot days. Here in Colorado, 91 octane is the highest that's typically available, and that's not enough to prevent knock during prolonged high-boost situations. Blending in race fuel really improves performance and drivablility.
 

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Sorry, I was running out to car rental agency because 1 of our 3 vehicles needed to be extended when I gave the short answer.

The better answer to this question:

Quote, originally posted by dlchasen »
I am thinking of purchasing an '07 S60R with MT and keeping it at an altitude of 8,000 ft. I know how much fun it will be going up and down the twisties, but should I expect to need special tuning for high altitude?

... would be a Performance TCV and adjusting the waste gate.

To say the psi is still the same... it's not

http://www.2-stroke-porting.com/altiden.htm

To say the turbo runs faster... well the turbo's speed is a direct result of the exiting gas from the engine. If the original input to the engine is much less... then the output will be less... resulting a much slower Turbo speed at the bottom of the rpm range. I believe the Turbo tries to combate that by closing the waste gate allowing a higher level of psi into the input of the engine, but the turbo should never run faster than a sea level car.

If he adjusts the wastegate... then at least he'll salvage the lag. It's horrible at that altitude. I've stayed months on end when I work up there... it never adjusts.

Quote, originally posted by LloydDobler »

I don't think anyone said it's the same.

Quote, originally posted by JimLill »

The PSI is still the same, the Lambda system takes care of the AFR

Quote, originally posted by LloydDobler »

I do know that the IPD stage 1 tune in my C70 runs up to 18-19 psig here in Denver, when the advertised boost is 15 psi.

Very conflictive

My guess is that the MAF takes a reading and gives a false setting to the TCV.
 

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Re: High Altitude Performance (02s60t5)

Quote, originally posted by JimLill »


Keep in mind that most of the rise in temp of the air is from the heat of compression more than turbo RPM and speed.

Correct.

Quote, originally posted by 02s60t5 »
The R will perform great at high altitude, but it really needs high octane fuel, especially on hot days. Here in Colorado, 91 octane is the highest that's typically available, and that's not enough to prevent knock during prolonged high-boost situations. Blending in race fuel really improves performance and drivablility.

IIRC, octane compensation is applied in markets at high altitude. So 91 octane in Denver is closer to 89 in Boston. This is because octane requirements aren't as stringent at high altitude, where air density is lower.

R&T wrote an interesting article on this a few years ago.

That said, higher octane fuel does prevent ping and the timing compensation that follows. So I would agree with 02s60t5 that (to a point) higher octane = more fun in an R.
 

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Re: High Altitude Performance (RearWheelPaul)

I had a site bookmarked (long since gone) that would tell you based on altitude (elevation) air temp and humidity etc what would happen to hp. One could compare turbo engines to non turboed. It was pretty niffty. All I remember is that HP from a boosted engine fell of more slowly than a non-boosted engine. I find that the R has plenty of power at 7200 ft (my house) and I even runs pretty darn strong up at 10,800 ft (about 30 miles west of my house). I have never noticed any pinging and I use 91 octane. This is what an R looks like standing still at 10,800 ft
 

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Re: High Altitude Performance (Hi Alt R)

The formula for altitude density is a 1% drop for every 330 feet, or 3% per 1000 ft.

Most turbocharged engines don't start to experience a power drop until a few (~2-4) thousand feet. But this varies according to the turbo's ability to deliver air mass at progressively higher rpm.

At a certain point, turbo efficiency drops off as the compressor's speed gets into less and less efficient areas of the map.
 

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Re: High Altitude Performance (RearWheelPaul)

Quote, originally posted by RearWheelPaul »
The formula for altitude density is a 1% drop for every 330 feet, or 3% per 1000 ft.
.

Agreed. The old rule of thumb was that a normal internal combustion engine (whether car or boat) would lose 3 to 4% of its horsepower for every 1000 feet of elevation gain. Lake Tahoe is just over 6,000 and we figured that a car or boat would have lost 20% of its horsepower up here. Boats that go 100 miles per hour at sea level only go in the high 70's up here.
oclv
 

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Re: High Altitude Performance (dlchasen)

Quote, originally posted by dlchasen »
I know how much fun it will be going up and down the twisties, but should I expect to need special tuning for high altitude?
Getting back to the original question. You won't have to do any special tuning for high altitude. The car will adjust on its own to the best that it can. If you don't want to experience any loss in power from stock, then just add a downpipe, exhaust, stage II software. An intercooler for summer would be nice also. oclv
 

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Re: High Altitude Performance (KillerB)

Quote, originally posted by KillerB »

Very conflictive

When I said "I don't think anyone said it's the same", that was in response to your statement about it being the same car. Not in reference to boost pressure.

I interpreted Jim's comment as saying the manifold absolute pressure is the same. My post was intended to corroborate that by pointing out that my car runs a higher gauge pressure (psig) which is consistent with the same absolute pressure (psia) that would be in the manifold at sea level. At sea level if my car were making the advertised 15 psig boost, the manifold pressure would be 29.7 psia. My car at altitude holds 18 psig, which in an atmospheric pressure of 12.1 psia, is 30.1 psia manifold pressure. This is consistent with the car trying to compensate for altitude.

The only test I haven't done is to take my car to sea level and see if the gauge pressure drops to 15, like I believe it should. Do you have a boost gauge?
 

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Re: High Altitude Performance (Hi Alt R)

Quote, originally posted by Hi Alt R »
I find that the R has plenty of power at 7200 ft (my house) and I even runs pretty darn strong up at 10,800 ft (about 30 miles west of my house). I have never noticed any pinging and I use 91 octane.

You won't notice any audible pinging, since the sensors retard timing and/or drop boost at the slightest hint of detonation to protect the engine. When I ran the R on 91 octane, I used to notice a 'stuttering' sensation under prolonged high boost situations, such as when passing, or when climbing a hill under full throttle. It was pretty obvious that the car wasn't pulling quite as hard as it was capable of. Once I started blending in a few gallons of 100-octane race fuel, the stuttering went away, lag was reduced, and the car performed much better. The extra few points of octane raised the threshold of pinging high enough that the timing/boost didn't need to be retarded.
 

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I'll just say this.

I've gone to Tahoe 3 times in the past month.

Never fails at about 2000+ feet, and climibing I cannot get past .5 bar boost.

I didn't get all my boost back untill I came back down.
 
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