Touch My Ass

I think this debate is over.. Pat just needs to gather himself and CONFESS!!

zapco98

There is absolutely no way your car is anywhere near a low 12 second car in that altitude - I am telling you that right now - I doubt it'd be low 12 second car at sea level! If that were the case, you might want to give Slverbullet a run then, because you might be a high 11 second car at sea level! Of course, I don't buy this, especially on that APR code... must... stop... smoking... the... herb

A low 12 second car at that level, is a low 12 second car - I would dare say you wouldn't break into the high 12s at altitude - especially on that code... that code doesn't run anymore than 16psi(unless you've obtained APR final code, which is only 418hp)

I can see you losing ~10-15hp - not sure what the altitude compensation setup is with those turbos, but let me tell ya, on K03s - theres little, if any room for it since they're being spun near their limits if chipped...

Touch My Ass

In his altitude they should be doing low to mid 13's

zapco98

Oh in that case I believe it - anyways, who races in the mountains?! ;-)

zapco98

not impressive :-P

Pat-SoCal

No one who has contributed anything to this thread has put up an ounce (pardon the pun smokin' joe) of factual evidence to support a turbo car's immunity to altitude. Something which you so blindly ranted about in your previous thread.

Get back on the fence where you belong (your spot is still warm in the 14 second clan) and let the rest of us worry about going fast at altitude. My explanation is the only one in this whole thread which is holding any water.

I admit that my thoughts on the situation were more overkill than reality, but they are still dead nuts on compared to your haphazard argument.<ul><li><a href="https://forums.audiworld.com/s4/msgs/830627.phtml">you adding a tenth for 3k feet...</a></li></ul>

Pat-SoCal

you're going on the wrong nights.

I'll give you a ring next time there is a decent race worth going to see. Bad things happened last time though so be on your toes.

quickersilver

...if they've configured the system to generate enough boost for true altitude compensation, you shouldn't see any hp loss. Did they? Dunno, but in theory, you're correct. From the following page:

<i>Turbochargers may also be used to altitude compensate (normalise) a non-turbocharged engine. An engine and turbo are matched and/or controlled to maintain sea level atmospheric manifold pressure at attitude, whereas a natural aspirated engine will lose 3% horsepower per thousand feet of altitude climbed. </i><ul><li><a href="http://turbo.com.sg/Tbchar.htm">http://turbo.com.sg/Tbchar.htm</a</li></ul>

TRM

holding compression ratio and maximum boost and octane constant...both will see a decrease in performance as elevation rises...less O2 in the air for combustion means less power to the road.

just because a turbo compresses air doesn't mean there will be a greater concentration of O2 in that air when comparing elevations.

pretty simple really.

TRM

they would somehow need to be able to increase maximum boost to compensate for altitude.

for example, if you only ever get 10 psi maximum from the engine management system, then altitude will effect you just as it would a NA engine, no?

any ideas?

i guess the possible error in my theory is that i am under the impression that the concentration (or percentage of O2) at higher elevations decreases. therefore compressing to the same psi with less O2 means you will experience the same decrease in power.

of course if overall O2 percentage does not change with altitude then i would agree that little to no effect of altitiude will effect performance.

does anyone really know if overall O2 percentage decreases with altitude? it's about 22% at sea level i think.