|
|
|
02-21-2008, 08:46 PM | #1 |
Private First Class
16
Rep 186
Posts |
Overboost (from N54 Engine Tech Manual)
Sorry if this observation has been made previously; I haven't seen it. I just read the N54 Tech manual in the sticky. Interesting to note that the stock setup allows for overboost of up to .8 bar, or 11.2 psi. That's a nice premium over the standard boost of 8lbs, and probably accounts for the variability of horsepower numbers being measured and reported, as well as the growing sense that HP is "under-reported" by BMW.
__________________
135i built 2/14/08 SGM w/Black and AL, 6 forward gears
|
02-21-2008, 10:16 PM | #2 |
Acquiring the taste.
2
Rep 151
Posts |
|
Appreciate
0
|
02-21-2008, 10:46 PM | #3 | |
Private First Class
16
Rep 186
Posts |
Quote:
HP ratings on turbo engines are highly elastic anyhow; they are much more dependent for example on air temp, both because cold air is denser (hence you are compressing more 02 per unit of volume) but also because the intercooler is so much more efficient. My point was only that if the engine rating of 300hp is based on standard boost levels of 8psi, then seeing ~300 at the wheels as some are reporting isn't surprising if the ecu is allowing pressure spikes to 11psi. Assuming the mfr built in sizeable safety margins, It also makes me feel aftermarket tuners who tune to 15psi are operating well within safe levels: basically just 4 psi over stock...
__________________
135i built 2/14/08 SGM w/Black and AL, 6 forward gears
|
|
Appreciate
0
|
Post Reply |
Bookmarks |
Thread Tools | Search this Thread |
|
|