Change in elevation for sd tune..

Reply Subscribe

Thread Tools

Search this Thread

Nov 2, 2015 | 08:21 AM

98Zheadsncam

Thread Starter

Launching!

iTrader: (26)

Joined: Jun 2011

Posts: 273

Likes: 2

From: Colorado

Change in elevation for sd tune..

Ok, please excuse my lack of tuning knowledge. The turbo car I bought recently is being shipped today, and will be going from under 500 ft of elevation to around 3300 ft at it's final destination here in Texas. The car has a decent OLSD tune on it as it sits. My question is, since the oxygen content is different by a percentage vs. the elevation change, couldn't I just apply a set percentage globally to the ve table and get the fueling back to what it needs to be?

I know the motor will be running rich...any input will be appreciated.

Thanks!

Nov 2, 2015 | 09:45 AM

eaglegoat

TECH Regular

Joined: Jun 2012

Posts: 414

Likes: 5

From: SV, AZ

If the setup/tune is done correctly it should be just fine. It will only have problems if it's hacked. The myth of needing to "retune for altitude" comes from hacked tunes on cars with cheap parts.

Nov 2, 2015 | 11:13 AM

98Zheadsncam

Thread Starter

Launching!

iTrader: (26)

Joined: Jun 2011

Posts: 273

Likes: 2

From: Colorado

Quote:

Originally Posted by eaglegoat

If the setup/tune is done correctly it should be just fine. It will only have problems if it's hacked. The myth of needing to "retune for altitude" comes from hacked tunes on cars with cheap parts.

So, because this is a speed density tune and the ecm is relying heavily on the map sensor, the tune won't change that much because air density is relative to pressure?

Nov 2, 2015 | 11:42 AM

MontecarloDrag

10 Second Club

iTrader: (3)

Joined: Aug 2005

Posts: 889

Likes: 6

Oxygen content does not change by elevation. Atmospheric pressure is what changes, so the air is less dense but contains the same oxygen content %
If the tune was done correctly it will reference the new MAP reading and adjust fueling and timing accordingly.

Nov 2, 2015 | 11:47 AM

98Zheadsncam

Thread Starter

Launching!

iTrader: (26)

Joined: Jun 2011

Posts: 273

Likes: 2

From: Colorado

Quote:

Originally Posted by MontecarloDrag

Cool. He spent a good amount of time on the V.E. table street tuning the car, so I'm crossing my fingers.

Thanks for the input.

Nov 2, 2015 | 12:57 PM

redtan

TECH Junkie

iTrader: (5)

Joined: May 2008

Posts: 3,764

Likes: 17

From: Belmont, MA

Quote:

So, because this is a speed density tune and the ecm is relying heavily on the map sensor, the tune won't change that much because air density is relative to pressure?

Well because it's relying so much on the MAP sensor is why it's going to be ok going to different elevations as others have mentioned. Your engine will see less manifold pressure at higher elevations for the same type of driving, and the PCM will see that and with a proper tune should be just fine.