Not sure. But I know most of the aftermarket performance companies are ranging between 15lbs - 17.5lbs on their ecu re-flashes. So 13lbs stock seems about right (or pretty close anyway).

 

I'm curious also to know what the boost levels are on the new x3. Trying to figure out what is left in each motor setup

 

I know nothing about the X3 but I was told the XP motor will handle 20 PSI and 25 PSI if you do the HD head studs. The stock Turbo runs out of efficiency above 18 PSI though.

Kelly at KMS Performance got 160 HP to the rear wheels out of a 17 4 seater using Dynojet Power Vision and one of his custom tunes. Stock baseline was 125 if I remember correctly. The owner posted a pic of the dyno chart but you can't see it because the of the balloon knots at Photobucket.

 

It isn't just boost that is responsible for the additional horsepower in the 17 model. Cams injectors pistons valves and other components contributed to the increase of power . The level of boost between the two is very close

 

Do we know for certain?

I thought it was head gasket, cams and tune?Rest was the same as 16 Block.

 

Mine was right around 15 stock, I now run 17-18 on 92 octane with a splash of octane boost with zero issues.

 

17 has bigger injectors and a bigger fuel pump to iirc

 

Boost is calculated on a pressure combination of atmospheric air, plus the boost amount requested... it's one big number lumped together. The factor here is your baro pressure. Air temps and altitude have huge impacts on what your boost numbers are.

The 2017 models call for roughly 29psi over 8000rpm. So lets say you are at 1000ft with a baro pressure of 14. Subtract the 14 from 29 and your calculated boost pressure the turbo needs to make would be 15. Actual boost will read slightly lower... normally 14.5. Now take a hike up the mountain and your baro pressure is at 12psi. Your boost pressure will make up the difference for the lower baro pressure to try and reach 29 overall PSI, so you will see 16.5psi on the boost gauge.

Keep in mind the factory puts an altitude map in place to keep things a little more "in check" and actually cap boost numbers based on the baro readings.

The simple version... boost can vary!

2017 XPT Stock - 13-15psi
2016 XPT Stock - 10-12psi

 

Boost is relative to your elevation and barometric pressure. This is why tuners like to speak in absolute boost like mike is talking about. The air pressure from the weight of the atmosphere above us at sea level is about 14.7 psi. So if you go up in elevation to 18,000 feet the static pressure has now dropped to half of what it is at sea level now reading only 7.34 psi. This is why n/a engines lose power as elevation increases.

The ECU calls for Absolute boost-
2017 = 29-30.7 psi depending on RPM
2016 = 27.2-27.8 psi depending on RPM

so as elevation goes up your relative boost goes up even though your absolute boost hasn't changed

Keep in mind that there is an cfm efficiency limit for the turbocharger so as pre intercooler boost temp climbs past the safe limit the ECU decreases boost to save the turbo. The is one area where our Turbo Mod customers will notice their setups out driving their friends.

The stock turbo cfm efficiency limit is right around 32.2 absolute boost.
The Bikeman Turbo Mod cfm efficiency limit is about 35.5 absolute boost