R33 Ecu Decision

[paulr33]

this is where you are confused, and i suspect why you think map sensor is better.

when you a driving along (at 3900rpm) and your boost guage reads 18psi, what does this mean? how much air is present?

the answer is a set amount of air, it doesnt matter how much, just a set amount, so you can use the map sensor guess theory to come up with say 400 units of air.

the airflow meter system will say 400 units of air also as its measured the air coming in.

anyway

so you keep the throttle nailed and still at 4700rpm your boost gauge still reads 18psi. how much air is in the system?

is it

a) 400 units still

b) an amount larger than 400 units

c) neither

the map sensor guess theory will lead you to answer a, as based off its mathetical guess mode it assumes for 18psi, 400 units of air is present.

this in fact is not the case as, with the engine increase in RPM speed more and more air is being taken into the inlet system, despite pressure being the same.

pressure does not equal volume.

as pressure remains fixed, volume does not.

[MR331307]

this is where you are confused, and i suspect why you think map sensor is better.

when you a driving along (at 3900rpm) and your boost guage reads 18psi, what does this mean? how much air is present?

the answer is a set amount of air, it doesnt matter how much, just a set amount, so you can use the map sensor guess theory to come up with say 400 units of air.

the airflow meter system will say 400 units of air also as its measured the air coming in.

anyway

so you keep the throttle nailed and still at 4700rpm your boost gauge still reads 18psi. how much air is in the system?

is it

a) 400 units still

b) an amount larger than 400 units

c) neither

the map sensor guess theory will lead you to answer a, as based off its mathetical guess mode it assumes for 18psi, 400 units of air is present.

this in fact is not the case as, with the engine increase in RPM speed more and more air is being taken into the inlet system, despite pressure being the same.

pressure does not equal volume.

as pressure remains fixed, volume does not.

sorry champ i understand what you are saying

With a map sensor you adjust the map via RPM VS VAC/BOOST

when you are talking about the increased air your saying while reving the vehicle at 18 psi will cause the car to increase air volume going into the motor the way to adjust this is setting it via the rpm as it increases.but while tuning it the maps are usually the same when your on boost

if im wrong in understanding what your saying correct me

but in simple terms

the more you rev the engine the more air volume is increased in the induction of the motor

Isnt though getting a measurement from a manifold better then getting it from in front of the turbo

Its more accurate this way as it measure the cyclinder pressures and adjustes this via the rpm as well

if there is some sought of restrications after the turbo it will cause the air flow meter to read a higher air volume then what the engine is recieveing cause it to run richer or learner.

i still find that the air flow meter isnt as accurate as an Map sensor.90 % of circuit cars and drag cars run MAP sensors such as V8 super cars and High tech imports.Due to the more accurate readings it gives.

Edited May 9, 2006 by MR331307

[paulr33]

v8s and super cars are not a suitable comparison against a turbocharged car. v8s have intake restrictions, hence the map sensors. turbocharged cars have restrictions after the turbocharger, not before so that rules out the airflow meter restriction. and if you need more "airflow meter" volume then add another one, or change to a larger item.

as engine RPM increase and boost pressure is fixed more and more air is coming into the system despite the pressure not changing.

a lot of people believe airflow meters are a restriction, so like yourselves they change to map sensor as they believe its a restriction and surely more power can be had from map sensors. 90% of circuit cars? what circuit cars?