Stock Ty runs 12.60??

[TurboManiacal]

Is this an intelligent well mannered conversation? Naw can't be!

My thoughts would be that you would have the same amount of combustable gas at any altitude in a forced induction engine. But, I'd really like to see the physics on it.

 

[Stangfreek]

ooh ooh can i play?

the conversion factor is a viable scientific method of calculating the difference between an altitude run and a sea level run. but, the factors for a naturally aspirated motor is different from a FI motor. i think the simpelist way to put it is that the ratio of oxygen to atmosphere is the same at altitude as sea level, but the barometric pressure is not, to the tune of about 18% per 5000ft. So basically, for every measurement of air taken in by a motor, there is less oxygen at altitude then at sea level. Now, FI motors don't lose as much because they are forcing air in, or effectively increasing the barometric pressure according to the motor, and the losses aren't linear, as opposed to a N/A motor, which is only sucking air, not forcing it. Since thin air is more easily compressed than thicker air, the "gains" of an FI car at sea level are not as much as those of a N/A car.....

 

[Rick_From_Mi]

well this summer im gonna try to get my ty tuned and hopefully run faster than a 12.90 which i was told by good sources thats what it ran right before i got it, but we shall see..

lata

 

[Wes]

Yeah, there will still be some difference though. I'm not a fan of adjusted numbers myself.

I think it's acutally closer to 13.6 like Will's Ty here in CO, and 12.6 is the adjusted number for sea level, according to the NHRA guidelines.

I may be wrong, but isn't a turbo capable of sustaining the same boost whether at sea level or altitude? If that is the case the same psi at sea level and the same psi at altitude will make the same hp. Now, I know with blowers it's different because you depend on a fixed pulley so you are limited. For instance I run 6psi at 3300', but at sea level I would run 7.5 psi. But with a turbo, isn't your psi regulated by the wastegate which is dependently on psi?
Just a thought.

 

[RS25.com]

You guys are still talking about this? Okay, here's some jargon for you:

Altitude and Engine Performance

Atmospheric Pressure = 14.7 psi & 13 cubic feet of air = 1 pound

Power Loss due to Altitude
Air Density decreases at a rate of 2.9% - 3.0% for each 1000 ft. of elevation above Sea Level. See Standard Atmosphere below for background information.

Naturally Aspirated: Atmospheric Pressure 14.5 psi (It's hard to ride at sea level 14.7 psi)
Atmospheric Pressure @ 9000 feet = 10.5 psi
Pressure Loss = (14.5 - 10.5) = 4.5 (4.5/14.5) = 31 % @ 9,000 feet


Does a Turbo lose power with altitude? Yes!
Atmospheric Pressure = 14.5 psi, Boost = 10 psi, Total Pressure = 24.5
Atmospheric Pressure @ 9000 feet = 10.5 psi + Boost of 10 psi = Total 20.5 psi

Approximate Pressure Loss = (24.5 - 20.5) = 4.5 (4.5/24.5) = 18.36 % @ 9,000 feet

The power loss due to altitude is much less with the Turbo. The critical difference is that you can flip the switch on the Turbo to 15 lbs boost and get your sea level HP!!

Turbo considerations: As altitude is increased the turbo fan must increase rpm to maintain a constant boost pressure. With large displacement engines (read 800cc) the turbo fan may have to spin faster than is efficient. The result is slower acceleration. The cure is a larger turbo or lower elevation. Mountain sleds will challenge the best tuners ability to compensate for temperature, altitude, and changing snow conditions!

--------------------------------------------------------------------------------

Understanding Air Density
In simple terms, density is the mass of anything divided by the volume it occupies. Scientists usually measure air density in kilograms per cubic meter. At sea level, if the air is completely dry, and the temperature is 0 degrees Celsius, a cubic meter will have 1.275 kilograms of air in it. In other words, the density is 1.275 kilograms per cubic meter.

The air's density depends on its temperature, its pressure and how much water vapor is in the air. We'll talk about dry air first, which means we'll be concerned only with temperature and pressure.

The molecules of nitrogen, oxygen and other gases that make up air are moving around at incredible speeds, colliding with each other and all other objects. The higher the temperature, the faster the molecules are moving. As the air is heated, the molecules speed up, which means they push harder against their surroundings. If the air is in a balloon, heating it will expand the balloon, cooling it will cause the balloon to shrink as the molecules slow down. If the heated air is surrounded by nothing but air, it will push the surrounding air aside. As a result, the amount of air in a particular "box" decreases when the air is heated if the air is free to escape from the box. In the free atmosphere, the air's density decreases as the air is heated.

Pressure has the opposite effect on air. Increasing the pressure increases the density. Think of what happens when you press down the handle of a bicycle pump. The air is compressed. The density increases as pressure increases.

Altitude and weather systems can change the air's pressure. As you go higher, the air's pressure decreases from around 1,000 millibars at sea level to 500 millibars at around 18,000 feet. At 100,000 feet above sea level the air's pressure is only about 10 millibars. Weather systems that bring higher or lower air pressure also affect the air's density, but not nearly as much as altitude.

We see that the air's density is lowest at a high elevation on a hot day when the atmospheric pressure is low, say in Denver when a storm is moving in on a hot day. The air's density is highest at low elevations when the pressure is high and the temperature is low, such as on a sunny but extremely cold, winter's day in Alaska.

So yes, you could turn up boost to get power back, but you risk damage to the engine (pistons and rods may not handle the power) and the turbo may operate out of it's range of efficiency, causing a loss of power. And, of course, other factors are to be considered, like temperature, humidity, and engine timing/fuel/etc.

Shall I research more?

 

[RS25.com]

Oh, this is interesting:

With a naturally aspirated engine, horsepower drops off 3 percent per 1000 ft (300m) because of the 3 percent decrease in air density per 1000 ft (300 m). If fuel delivery is not reduced, smoke level and fuel dilution will increase with altitude.

With a turbocharged engine, an increase in altitude also increases the pressure drop across the turbine. Inlet turbine pressure remains the same, but the outlet pressure decreases as the altitude increases. Turbine speed also increases as the pressure differential increases. The compressor wheel turns faster, providing approximately the same inlet manifold pressure as at sea level, even though the incoming air is less dense.

However, there are limitations to the actual amount of altitude compensation a turbocharged engine has. This is primarily determined by the amount of turbocharger boost and the turbocharger-to-engine match.

 

[Ty1173]

If anybody watches football you might remember that when games played at Mile High in Denver the visitors wore o2 masks because they couldn't breath. Why? Less o2. Just like RS25 stated. More o2 more power.

 

[Xtreme 4pt3]

i agree on the boost at altitude bein same on a turbo.....what i dont see is that there arent any sy/ty's running 12.60's even at sea level. at an altitude say 4000' wont the sy/ty run slower, closer to 14's if they in fact do loose a second or so, which i know there is a loss, just how much isnt certain. even a correction on a 14.0 is gonna net around 13.0 which is still pretty fast for a srtock ty especially.

 

[Xtreme 4pt3]

i started thinking about this.....but a turbo vehicle never looses boost as said before. thin air or not the wastegate will not open till the set boost is achieved, so at an altitude a sy/ty would still run full boost. only thing i can find that would actually make the 12.60 correction legit is that a turbo car has different guidelines for altitude when correcting for altitude being that they will achieve same power at sea level. make sense to anyone?

 

[RS25.com]

Well yes, that goes back to what I originally said:

All of them make 14.7 PSI boost (stock truck here, remember?)

At sea level, there is more o2 in the air, hence better fuel burn characteristics, and more horsepower

At altitude, there is less o2 (as much as ... 20%... maybe?), hence worse fuel burn characteristics, and less horsepower. Less horsepower at the same boost level = less speed. 8/10 of a second is apparently the approximation of speed loss at altitude (maybe 1 full second, I dunno.)

Sure, turning up the boost will increase the amount of air going into the engine, because of the increase of 02 present. And, if I turn up the boost up here, I could probably (attempt) to run a real 12.6 second 1/4 mile. However, running 20 PSI on stock internals is probably risking damage. I'd have more detonation, more pressure on piston, rods, bearings, and the crank, as well as everything else involved. 5 PSI more than what the engine normally sees. Irregardless of the amount of o2 present, more PSI is *probably* going to damage something.

So, on a stock truck, if I make a run at sea level, and one at altitude, the one at sea level will be faster at the same boost level simply by virtue of better burn characteristics seen by more dense air.

Also, Will said this run was made with 110 or 118 octane gasoline, not pump gas, and ... I can't remember if there was anything else, but stock internals, turbo, and exhaust.

 

[Xtreme 4pt3]

but the air is no more dense at sea level on a turbo application. to make a long story short we will say it takes (this is just for a example and has nothing to do with reality) 300 square inches of air to fill your intake to bar at sea level. well you go to 5000' above sea level. it still takes the same 300 inches or air to reach bar. the air is not as dense at 5000' but then again the sy/ty reaches bar no matter what by means of a wastegate that will only let exhaust escape the turbo once the 300 inches or air is filled and bar is achieved. in turn the turbo spins a little faster and pushes the pressure to 14.7 (bar) and you retain the same air density as a sea level by spinning the turbo quicker and pulling (or pushing) in more air. im gonna do a little research on this and see what comes up. my theory here might be dead wrong....i dunno, but it makes sense in my head lol. later

 

[V8 Sonoma GT]

I think it's acutally closer to 13.6 like Will's Ty here in CO, and 12.6 is the adjusted number for sea level, according to the NHRA guidelines.

I may be wrong, but isn't a turbo capable of sustaining the same boost whether at sea level or altitude? If that is the case the same psi at sea level and the same psi at altitude will make the same hp. Now, I know with blowers it's different because you depend on a fixed pulley so you are limited. For instance I run 6psi at 3300', but at sea level I would run 7.5 psi. But with a turbo, isn't your psi regulated by the wastegate which is dependently on psi?
Just a thought.

The boost does remain the same, but do remember, the air is still less dence. Its not gravity, but the atmoshpreric pressure, which does not push as much oxygen down. There is less pressure, so there is less air. So you compress less dence air to 14 pounds, you still have 14 pounds of boost, but less power, do to the thiner air. And air is the key to combustion. Does that make sence?

 

[TurboManiacal]

you need to go back and replace a bunch of C's with S's

 

[smeagol]

ugh leave tech discussions to the tech forum

if air is compressed to the same pressure, with the same temperature... and all else is equal...there is the same *amount* of air (or number of molecules, whatever you want to say)

Why do turbos still not create as much power in high altitudes? (though they do better than the NA cars)

The atmospheric pressure pushing air into the turbo inlet is lower, so the turbo has to work harder to create that same manifold pressure. Turbo works harder = air is heated up more, turbo isn't in peak efficiency, and so forth......

Create a ram air setup, and you will minimize this problem at higher speeds, but that goes for any buildup.

 

[UNIsackV6]

ugh leave tech discussions to the tech forum

if air is compressed to the same pressure, with the same temperature... and all else is equal...there is the same *amount* of air (or number of molecules, whatever you want to say)

Why do turbos still not create as much power in high altitudes? (though they do better than the NA cars)

The atmospheric pressure pushing air into the turbo inlet is lower, so the turbo has to work harder to create that same manifold pressure. Turbo works harder = air is heated up more, turbo isn't in peak efficiency, and so forth......

Create a ram air setup, and you will minimize this problem at higher speeds, but that goes for any buildup.

HEHE you don't know what you're talking about...leave the tough stuff to Bob and Guy they really know their shit...don't be a rookie tool...Bob, Guy please tell us the truth we know you are guru's...

 

[92BlkTy]

damn, i need to get my ass on tuning up my Ty! 13.6 would fawkin rock for a stocker at bandimere. it feels strong now, but it dosent feel 13.6 strong. sure would shut my friend (mustang owner) up. his 67 only runs 14.8 off the bottle. its 13.4 on. thats very motivating.

 

[turbotyphoon69]

I BELIVE IT, THAT WAS HOW I WAS TURNED ON TO SYTY'Z I WAS ONLY ABOUT 13YRS AND I SAW A LITTLE BLAZER WITH GROUND EFFECTS RUN 12.9 AT BANDIMERE SPEEDWAY IN CO, IT WAS TRUCKFEST OF COURSE, AND WHEN I COUGHT THE GUY ON THE SHOW GROUND I LEARNED ABOUT SYTYZ AND BEING A HARD CORE CHEVY FAN, I FIGURE OUT HOW TO BE MY HIGH SCHOOLS ENVEY! :agrue:


EXTEMELY HARD EARNED 93 TY #566-MUSTANG MURDERA

 

[msheller]

Re: Stock Ty runs 12.60??

old thread/new reply

I work at Arapahoe Basin w/ 11,000 feet elev. base area. Practically speaking ...My friends Honda has alot less power up there than usual ...ALOT less...like there's none left! feels like 50% less. My Ty has SLIGHTLY less power than usual...significant, but not too bad ...feels like 10-20% less

Matt

 

[gkrcr882]

Re: Stock Ty runs 12.60??

N/A engines depend on atmospheric pressure to fill the cylinders with air. Less pressure, less air. Less air, less O2 to support combustion, less power. Boosted engines have an auxiliary means of forcing air into the cylinders so they don't suffer as great of a power loss. WOT on a N/A engine @ sea level is 14.7psi in the manifold, whereas in Denver its 12.? I think. Things get fuzzy when turbo pressure (true boost) and manifold pressure begin to get involved .

 

[sytyguy]

Re: Stock Ty runs 12.60??