Altitude calibration?

we bought our 99 g20 in NY. the elevation there is about sea-level. we recently moved to denver, colorado, where the elevation is approx 5280 ft. when we brought it in to the Denver Infiniti dealer for its 15k miles checkup, he said that the sensors or whatever would need to be recalibrated because of the altitude change... or some shit. i dont remember if he charged or not, but he said he did it.

before i bother to dig up the invoice to see if he did in fact charge for this.... does any of it make any sense to you? or was he just taking me for a ride?

well...what I heard when I was learning about hondas is that the ECU can calibrate itself to the altitude...just need to reset ECU....I don't know if the same goes for the Nissan cars....This is what I heard...

Pure and total bullshit! If you were charged for anything related to that lie, you should notify the state Attourney General.

The SR20 engine uses a hotwire mass air flow sensor that will automatically adjust to differences in air density. There is absolutely nothing that needs to be changed when changing elevation.

Yeah, the only thing that changes is your HP :mad: I just moved from Phoenix to Tucson, Az. And it's about 1000 feet higher in Tucson (I havn't checked yet, but that's what I've heard). But I can feel it in my car. When I went back to Phoenix my car felt soooo much stronger. Oh well, I'll just have to get cams or something like that to make up the difference. Anyone know of a calculation to find the hp loss at any given altitude? Thanks

i found this

http://home.sprynet.com/~rshelq/calc_hp_dp.htm



OK so youre all saying there is no reason for the ECU to not compensate for a change in altitude. now, after a certain amount of miles, i can understand the ECU needing a recalibration. but would one need to be done after only 15,000 miles? this car would be over two and a half years old, though.

i still havent found the bill for the 15k miles checkup, but i do remember it coming out to over $400. this was all for routine stuff... nothing was breaking on the car or anything.

Originally posted by Brian P
i found this

http://home.sprynet.com/~rshelq/calc_hp_dp.htm


Indeed, higher altitude will hurt performance. You cannot do anything about that. The only thing that can counteract this is forced induction (turbo or supercharger).

Originally posted by Brian P
OK so youre all saying there is no reason for the ECU to not compensate for a change in altitude. now, after a certain amount of miles, i can understand the ECU needing a recalibration. but would one need to be done after only 15,000 miles? this car would be over two and a half years old, though.

i still havent found the bill for the 15k miles checkup, but i do remember it coming out to over $400. this was all for routine stuff... nothing was breaking on the car or anything.

The ECU requires no additional calibration. It reads the the amount of air entering the engine directly from the mass air flow meter. There is nothing to recalibrate.

There are some who think that resetting the ECU will help it to learn new conditions faster. Others believe it makes no difference. The reality is that it depends upon whether the base settings are closer to the idea settings than wherever it's currently at, and there is no way to tell.

The ECU has a self learning program to make minor adjustments based upon a variety of things. This is relatively minor however.

Ithink the ideal conditions are: Sea-level & 10 degres C° and dry.

Is that right?

the lower the altitude, the more oxygen for the engine. as for temperature... cold air is more dense, so i would think the colder it is, the better.




And as for the ECU adjusting... we'd had the car here for over 6 months. the ECU woulda finished adjusting by now, i would think, if ever. i truthfully didnt notice any difference in the engine. i'm gonna find that bill and oh boy if they charged...

Wait, wait let me guess Brian...

oh boy if they charged... you're gonna ask the owner if he's ever tried picking up teeth with broken fingers. ;)

i hear the WRX has some special sensor that will adjust its ecu to altitude changes so no matter where you go, it will continuously change the settings to get optimum performance.

does your G feel stronger than when you first arrived denver? if so, then they might've changed something in the car to make it perform better... from my honda buddies, I hear that the ecu on my honda cars will adjust to the new environment after about a week of driving around in the same atmosphere. could be only on my lude and not the civic. dont know.

i think its time you get a nos kit. hehehe. :D

Kenchan that is exactly what I said...Heard the same thing but I heard you just reset ECU and drive around for 30 minutes or something....don't know..

No special sensor and no ECU reset required.

i didnt really notice any difference in the performance of the engine... even if there was the tiniest of differences... it would probably be due to the other things they did like changing oil and such.

i'm still looking for that invoice.


and hey look what i found... a converter to figure out lost horsepower at altitude:

bhp loss = elevation in feet / 1000 x 0.03 x bhp at sea level

so my G woulda lost 22 bhp in Denver :(

fyi, that only works for N/A cars.

found the invoice. there was a long ass list of stuff that they did that was included in the 15k mile checkup.

at the top of the list was

Adj. Inj., Adj Fuel/Air ratio, A/F R


and the totals for the checkup were 4.2 hours, $315 labor.

that does not include the cost of replacement parts like air and oil filters. those totaled almost $100.


so did they charge me for labor hours? or what? if they didnt charge for labor hours, why would they even say anything about it at all?

Originally posted by Brian P
found the invoice. there was a long ass list of stuff that they did that was included in the 15k mile checkup.
<snip>
so did they charge me for labor hours? or what? if they didnt charge for labor hours, why would they even say anything about it at all?

Sounds like you bought a package. Case closed. You lost.

hmmm. yeah. i was asking the guy why it would need recalibration even though it had an airflow meter. he gave me an answer - i again asked why. i honestly wasnt expecting to get ripped off (i learned my lesson), so he caught me off gaurd. but next time ill keep this in the back (or front, rather) of my mind and demand detailed explanations of suspicious work that needs to be done. next time i hope to make it pretty clear to him that i'm not going to stand for being taken for a ride, even if it means changing all the filters myself from now on (since thats basically all they do).

:flipa: :finger:

well, now you are pshychologically 'tuned' to take on the roads of denver.... eehehehe. :D

the wrx claims that it has sensors that work immediately to changing environmental conditions. our sensors take some time, doesn't it? not sure, please explain... :confused: :confused: :confused:

welcome to denver brian . home of my broncos, buffs, and high altitude. my g was originally bought in chicago and brought here by the previous owner so i can't provide G20 info. but my mom used to have an older buick and my friend and i drove it out to california. obviously the buick is not the prime sports ride, but when we got to california it was moving pretty good. i was at a stop sign and slammed on the gas. it peeled out pretty good and we laughed all through the intersection. in denver it would never have been able to do this. so my conclusion is that altitude will affect your performance. btw, that's why i plan on buying my ferrari in denver instead of a lower altitude city. LOL i wish.