daveak05

You are completely ignoring the fact that ECM will not simply allow a car turbo to infinitely spin to its limits, and over work itself in the process, in order to move more but less dense air. In any event, it certainly would not be "same power level to 10,000 ft" as you claimed. That is simply not reality.

Also, while there may be addtl boost capacity, which is typical to virtually all car turbos, there is a reason that a certain level of boost is provided by the engine ECM in the first place. ECM allows for boost parameters which will not overheat the turbo and adversely affect its durability.

It's time to move from theory here and onto actual turbo equipped cars.

daveak05

Not necessairly. Reno average temp in summer is 95 degrees at 4500 ft. Where I lived in Tahoe it could easily get into low 90's at 6000 ft on occasion. So, it's not a given that a harder working, faster spinning turbo will be aided by cooler temps at altitude.

Yes, the car has abilty to read ambient temperature and monitor intercooler temp, and that is EXACTLY where ECM would enter in to dial back and avoid overheating of turbo.

I don't think an ECM is simply going to say run 13 psi from 8 psi to compensate. I don't think ECM would alow for that and risk turbo failure.

cpurick

These units have been dialed way back from what they're capable of, as the tuners have shown.

We're not talking about whether the engine will create chipped power levels at altitude; we're simply talking about whether the same reserve of boost used by the tuners can be applied by the factory program to compensate for altitude.

You have a problem: on one hand you've been swearing up and down that power loss due to altitude is negligible. And now you're saying that a thoroughly detuned and under-utilized turbo can't compensate for that negligible loss. Make up your mind.

Considering what others have wrung out of this turbo without exceeding the manufacturers' temperature limits, I'd say it's ridiculous to suggest that a couple more PSI -- to make merely stock power levels -- is going to push it out of the envelope. Not likely.

You sound a lot like when you said the A3 and the B7 don't have variable assist steering (which they actually do), and like when you said they have active steering systems (which they don't).

daveak05

Also, are not chipped cars advancing timing, modifying A/F, typically accompanied by aftermarket intakes/exhaust, and therefore not doing it all by excessively increasing boost?

I said(at least started) that NA engines suffering excessive power loss under normal driving conditions, as asked by the original post, was a non issue. Then the WOT crowd screamed in and laid claim with their own bad experiences against a buddies turbo car, no matter road conditions, driving ability. That seemed even to include any large 6's and V8's, no matter the car. That's when it got ugly, at least from my viewpoint.

A turbo with excess boost capacity(and which ones don't?!) cannot compensate totally and will not run at max levels for very long without suffering.

Look, it's one thing to jump on a chipped car at its higher boost(capability) now and then, but quite another to imply that a turbo will run at max boost indefinitely to maintain same power at high altitudes. It's not gonna happen if there's a functioning ECM in the car.

I believe both the A3 and B7 have servotronic steering. While that may still be a passive system, it is not the variable assist of prior years.

PD Performance

Stock my car ran more boost in the summer then it did in november before being chipped.

Why becuase with it being hotter it needed more boost to make the same power.

When I was doing some testing with chips in late summer and then got some final beta versions to try in late fall the same files ran less boost when it was colder.

I mentioned it and they went back and adjusted the amount of change for temperature out a little.

PD Performance

If you look at some they actually mimic the stock fuel curve exactly.

But just as they can modify boost timing and fuel with a performance chip the stock ECU is capable of doing all that also.


If a chipped car was to go to high altitude then it may not be able to match its power. However stock these cars are dialed back a GREAT deal from what the limits are.. timing is unimpressive. They run pig rich and they dip as low as 7psi by redline.


And no most cars do not have intakes and exhausts, some do but most modified cars do not.

daveak05

Where did I say a stock car's ECM couldn't or didn't?

And HOW does the chipped car get the extra HP?

In other words both stock and chipped ECU's are minotoring engine settings in the same manner, but to different levels.

Are you really saying that it's a simple matter of the turbo car at high altitude running those kinds of max boost levels, constantly, and no problem?

If that's the case, then why don't mfgrs deliver from factory turbo cars tuned to use the max boost a particular turbo can supply? Why would they detune in the first place? Well, aside from driveability concerns for their majority, non racing customers, I don't think they want to be replacing turbos every few thousand miles.

I don't think you'd disagree that a turbo's number 1 enemy is heat, right? The intercooler is design specific for that car's turbo, but it cannot prevent overheating a turbo under certain conditions or abuse.

The chipped cars that aren't also using diff injectors/intake/exhaust typically don't realize the advertised HP gains, though.

I think this is a silly argument at this point and not really proving anything.

cpurick

It's a matter of demand priority. The systems (both turbo AND normally aspirated) are designed to manage all parameters to produce the appropriate power for the pedal position.

Even in an NA car, the ECU could (in practice I don't know if this is really done) be programmed to produce sea-level throttle response regardless of altitude. It would be easy -- the only catch would be that you'd start running out of throttle at increasingly higher pedal positions as the car got higher.

When they do this in the turbo, they also have control over additional boost. So, in theory they could go much higher without running out of throttle. Now, you seem concerned that this couldn't be very effective because of added heat. Personally, I think that's a non-issue, but the real authority would be an Audi engineer. As you've pointed out, they're withholding boost at sea level. But, for some reason, they've decided it's okay to use that reserve boost at altitude. So even if you have a heat concern, it's obviously not enough to concern *them*.

Look up Audi's specifications for the A3: it says "variable assist steering." (Technically, I don't think it's a Servotronic system, either. Though the A3 steering feel is similar to the B7, it uses different technologies. And I haven't seen it called "Servotronic" in any of the A3 literature.)

daveak05

***The A3's premium-level technology even extends into the steering box, which is now electromagnetically adjusted in response to steering wheel angle and vehicle speed.***

If you are calling that simple variable power assist, as in past vehicles, then I don't know what to say.

I have to say that it's a bit of a reach for you to say that "they", Audi engineers have "decided it's okay to use that reserve boost for altitude" ...

...and that I have a heat concern but "it's obviously not enough of a concern for them"

Come on cpurick! Where are you coming up with this? I realize it's a long thread and and maybe word fatigue may be entering in here for you, but your entire argument, at least in this post, doesn't make a whole lot of sense.

cpurick

It's not me who's calling it that; those are Audi's words:
"Variable power assist rack and pinion steering; turning circle: 35.1 ft."
If you think it needs to be hyped up, talk to Audi. Or better yet, tell them it's not really variable assist.

You're the one who claims that altitude related losses are insignificant. Why then do you think it should be a big deal for a turbocharger to compensate for those insignificant losses?

You frame all your talk about NA performance in the context that nobody's running around with the engine WOT all day, but then you point out that a turbo might not be able to run WOT all day at altitude without getting hot?

Your positions are inconsistent, Dave.