500 rwhp group

[9t8z28]

For the most part, out computer controlled cars are supposed to correct for changing altitude and what not

[Dr.Crash]

Best DA I had all last year was just over 7900....

i love living at sea level

[Dr.Crash]

[Mr. Luos]

For the most part, out computer controlled cars are supposed to correct for changing altitude and what not

Boosted cars don't stand a chance running their altitude tunes at sea level.

Stock computer leaves plenty of room for altitude changes, aftermarket stuff tends to need tweaking.

[Firebirdjones]

For the most part, out computer controlled cars are supposed to correct for changing altitude and what not

When the MAF is still in place it has the ability to adjust as long as the car is in closed loop (part throttle)

Once at full throttle the computer effectively goes into commanded PE mode. What ever AFR you have programmed into PE is what comes out no matter what the altitude is,,,,so this needs to be taylored to racing conditions.

For instance as I have found with my wideband,,,,If you have had a dyno tune near sea level with an AFR of 12.9,,,,,,then go to a track that is 7,000 feet up,,,the car will be pig rich at full throttle, due to less air at 7,000 feet. You will probably wind up with an AFR of 12.3 or worse.

In my case I had a tune that yielded 13.6 WOT AFR near sea level,,,a tad lean. But when I plugged that same tune into the car up here at 5,200 feet,,,the wideband showed an AFR of 13.2-13.3 at WOT. Gives you an idea.

[Firebirdjones]

From what I understand...I would probably end up running fat down at sea level.

It's the other way around. If you have the car dialed in up there in the clouds With a nice AFR,,,,you'll find the car will go leaner as you come down to sea level. More air available at sea level,,,therefore more fuel needs to be added.

We even play this game while racing at sea level. When the temp and humidity/dew point rises,,,so does the density altitude.
Although we are technically racing near sea level,,,the weather conditions can actually raise the altitude when the temps climb,,,in which case we end up pulling fuel out of the car to make it go faster.
The problem with this is the DA changes by the hour,,,every hour,,,,and is never the same. It really plays games with your tune.
Some tracks accross the country closer to sea level can actually have negative DA readings. It's a rare accurance most anywhere in the country though.

Every wonder why they run most magazine cars from the big manufactures out at New Jersey or up in Michigan??? Usually in the colder months too???
They are already close to sea level and the cooler weather conditions give them negative DA readings most of the time.
You'll never see them testing a new car in Colorado

[Mr. Luos]

It's the other way around. If you have the car dialed in up there in the clouds With a nice AFR,,,,you'll find the car will go leaner as you come down to sea level. More air available at sea level,,,therefore more fuel needs to be added.

While I agree 100%...as it makes complete sense.
Most guys end up running rich when they drive off the mountain. No idea why.

[Firebirdjones]

While I agree 100%...as it makes complete sense.
Most guys end up running rich when they drive off the mountain. No idea why.

Thats interesting,,,wonder whats going on there???

[Mr. Luos]

Thats interesting,,,wonder whats going on there???

The only thing I can think of is the computer making up for the new found air by dumping fuel.