[redlightning]

Anyone know if the M274 compensates for high altitude driving by increasing the available turbo boost? I haven't had the chance to drive over the mountains yet. My Audi A4 1.8T would only run 9 psi at sea level and raise that up to ~15 around 11,000 ft with factory programming.

 

[kosta15auto]

If the AUDI does I don't believe Mercedes will fall that much behind.

 

[redlightning]

I hope it does. I was assuming the VW software would be similar to my old Audi, but my 2.0 TDI is kind of a turd at high altitude compared to down in town.

 

[Greenmanedlion]

A turbo automatically compensates for altitude as a nature of its design. It doesn't increase boost, 9psi is 9psi, irrespective of altitude.

 

[KEM]

Anyone know if the M274 compensates for high altitude driving by increasing the available turbo boost? I haven't had the chance to drive over the mountains yet. My Audi A4 1.8T would only run 9 psi at sea level and raise that up to ~15 around 11,000 ft with factory programming.

This reply is more than 5 years late, but when I first bought my 2018 Metris cargo van I drove it from San Diego to Oakland to ship to Hawaii, and I decided to take the scenic route and drove over the Sierra mountains to above 9,000ft and felt zero loss of power. It climbed the mountain roads with ease.

 

[Rockster]

This reply is more than 5 years late, but when I first bought my 2018 Metris cargo van I drove it from San Diego to Oakland to ship to Hawaii, and I decided to take the scenic route and drove over the Sierra mountains to above 9,000ft and felt zero loss of power. It climbed the mountain roads with ease.

My 2020 Metric cargo van was just fine on a drive from AR to CA and back on I-40. I didn't monitor boost but the engine felt just fine even through Flagstaff at over 7K feet above sea level. It climbed the grades and managed to pass with ease other vehicles along the route.

My info is the engine controller will allow more boost to satisfy the torque demanded by the driver. I haven't bothered to observe my van's boost but with my Porsche Turbo while 0.7 bar was the max boost at lower altitudes at higher altitudes (8K and above) I saw 0.8 and even 0.9 bar and these were solid boost numbers not glitches.

Even before my Turbo my VW Golf TDi (90hp turbocharged diesel but with a variable vane turbo) was a beast in the mountains. I don't recall the numbers now but I used an OBD2 scan tool to monitor among other things manifold pressure and at altitude it was quite above what it was at sea level. The car topped out at 115mph at 6K feet and above with ease. I really didn't feel the engine suffered to any noticeable degree from the altitude. In fact it was the Golf's performance in the mountains that sold me on the idea of if I chose to live at a high elevation to just budget for a turbocharged/supercharged car.

So after I sold the the VW Golf some few years later I jumped on a nice used Porsche Turbo. Then after I sold the Turbo I bought a MINI Cooper S JCW (turbocharged) and then a Hellcat (supercharged). Sold the MINI before I left CA but as soon as I could after I arrived in AR I bought the Metris. My other car is currently a N/A Dodge Challenger Scat Pack, but I'm looking to buy either a M-B AMG C 43 (turbocharged straight 6) or a BMW 230i (turbocharged 4).

My excuse? Where i live now it is around 1200 feet above sea level. High enough to <ahem> justify a new turbocharged car...

 

[imacd]

As I understand, the boost pressure sensor measures the absolute pressure before the throttle valve. This is what is being controlled and other factors (atmospheric pressure, dirty air filter, etc.) are taken care of and shouldn't affect engine performance.

 

[Rockster]

Update of sorts. I ended up buying the 2022 BMW 230i May 31. Now both my vehicles are turbocharged. Bring on the mountains!