Altitude Adjustments?

[maw1048]

Just moved from Dallas to Denver, Colorado, and I notice that in first gear, my 2000 Infiniti I30t doesn't pick up power until 3000 RPMs. Seems to have a big power surge at 3000 RPMs.

It only does this when I'm in Colorado, and not in Dallas. I've noticed this since I've done several trips back and forth between both cities.

Two differences, the octane of the premium gas in Dallas is 93 while it's 91 here. I know that they use lower octane gas in higher altitudes. Can this cause the low power / surge at 3000 RPMs in first gear?

Since I'm now a permanent resident in Colorado, is there an adjustment that has to be done for the higher altitude?

Any ideas on what I should do?

Thanks.

Car Info:

2000 Infiniti I30t112000 MilesRegular Oil Changes with Mobil 1 oilAlways used premium gasRecently change out spark plugsReplaced air filter about 1 month ago.Located in Denver, Colorado.

[maxhopper]

In my opinion, your car should begin to adjust within a week or two to the different altitude. Your car's computer has adaptive learning, so it should begin to take into account the difference in the air mixture. There really isn't any manual adjustment that I know of that can be made.

The lower octane, will cause your knock sensor to retard the timing somewhat, which could be causing the lack of power you are describing; since your computer has probably not had time to adapt.

[maw1048]

Thanks. I'll let everyone know how the car is doing in a couple of weeks.

[MinisterofDOOM]

Cars are supposed to make 5% less horsepower on average for every 1000 feet above sea level, if I remember correctly. Whenever I go to sea level places, I notice big improvements in my car's performance. However, as mentioned above, the car will adjust somewhat to the different conditions, both the thinner (and therefore less-oxygen-rich) air and the lower octane fuel.

[cullenj76]

The car might adapt a little at partial throttle, but timing, air/fuel will not change at wide-open-throttle due to the ECU defaulting to specific settings as it does at wide-open-throttle. Some newer cars have sensors that detect pressure and termperature of intake air and adapt to it, but not the I30.

Dynos have proven a 20hp loss with the use of anything other than 93 and it's a very significant loss of low-end torque.

[maw1048]

Here's an update.

Put a can of BG 44K in it. Seemed to help some.

Thought I would go through the process of cleaning the MAF.

Upon inspection of Air Filter Box, I noticed that the connection at the bottom of the Air Filter Box that brings the air in was not completely connected. Looks like it got shifted to the side a bit and wasn't flush. So, I figured the engine wasn't getting as much air which sure didn't help with the higher altitiude either.

Disassembled everything. Cleaned the MAF and reassembled everything. Seems to be running alot better now.

Just thought I would give everyone an update.

Thanks.

[maxhopper]

Good deal, glad to hear everything is going well.