Boost Doesn't Make Horsepower
Posted: Wed Apr 17, 2002 1:27 am
This is just a random rant from a bitter old fat man.
Except for whatever increase one gets in dynamic compression, boost pressure does not make horsepower, air flow makes horsepower. Boost pressure is just the difference between what the turbo is producing and the engine is able to process and mix with fuel. A small turbo can easily hit high boost levels with an EJ22T, because its heads breathe so poorly that the boost stacks up. If our engines breathed as freely as say modern WRX heads, then the tiny turbos would not be able to produce as much boost pressure, because that air could go on through the engine and not stack up. To the best of my knowledge, the ECU on an EJ22T makes note of boost for the purpose of activating the overboost fuel cut and opening the wastegate, but its fuel and timing advance calculations are based on input from the mass air flow sensor, not from boost levels.
I don't care who ends up pissed as long as it isn't me
Bill Robinson
92 Legacy Turbo 5-speed with a few prudent street modifications.
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Except for whatever increase one gets in dynamic compression, boost pressure does not make horsepower, air flow makes horsepower. Boost pressure is just the difference between what the turbo is producing and the engine is able to process and mix with fuel. A small turbo can easily hit high boost levels with an EJ22T, because its heads breathe so poorly that the boost stacks up. If our engines breathed as freely as say modern WRX heads, then the tiny turbos would not be able to produce as much boost pressure, because that air could go on through the engine and not stack up. To the best of my knowledge, the ECU on an EJ22T makes note of boost for the purpose of activating the overboost fuel cut and opening the wastegate, but its fuel and timing advance calculations are based on input from the mass air flow sensor, not from boost levels.
I don't care who ends up pissed as long as it isn't me
Bill Robinson
92 Legacy Turbo 5-speed with a few prudent street modifications.
ADVERTISEMENT
<http://rd.yahoo.com/M=194081.1994012.34 ... ?code=3466> Click Here!
<http://us.adserver.yahoo.com/l?M=194081 ... =164094770>
To unsubscribe from this group, please send an email to:
BC-BFLegacyWorks-unsubscribe@egroups.com
zZz <http://docs.yahoo.com/info/terms/> .