Ej20 no afm?

Cam · Post by **Cam** » Sat Aug 16, 2008 5:48 pm

Just cleaning up the brumby's motor i just realised that there's no maf sensor on the intake or in the throttle body itself... Is there going to be any problem with pushing air into the motor (blower) without it running lean or too rich? if so any easy fix?

Gannon · Post by **Gannon** » Sat Aug 16, 2008 6:09 pm

A little more info on the engine wouldnt go a-stray

Aftermarket ECU or factory?

By blower i assume you mean supercharger?

If it is map sensed and has a factory ECU, you are gonna have issues with adding boost.

If it has an aftermarket ECU, the fuel maps can easily be modified to accommodate boost

gx_rex · Post by **gx_rex** » Sat Aug 16, 2008 6:20 pm

His engine is out of a 98 GX impreza. EJ20 N/A

Cam · Post by **Cam** » Sat Aug 16, 2008 9:44 pm

Yep late 98 impreza, factory ecu, supercharger.

What does map sensed mean?

AndrewT · Post by **AndrewT** » Sat Aug 16, 2008 11:26 pm

map based ECU's control the engine based on a pre-defined set of values for the tune, rather than paying attention to sensors like airflow and adjusting the tune etc to suit. This is why map based ECU's usually need to be dyno tuned to be tuned properly.
for example, Matt's old EA82 motor didn't have to have it's original air flow sensor anymore because it was running from a Microtech map based ECU - he had to get it dyno tuned when changing to a different turbo etc.

I didn't realise Subaru's used any map based ecu's, I thought they all used air flow sensors?

YouTube · Post by **El_Freddo** » Sun Aug 17, 2008 1:01 am

AndrewT wrote:map based ECU's control the engine based on a pre-defined set of values for the tune, rather than paying attention to sensors like airflow and adjusting the tune etc to suit. This is why map based ECU's usually need to be dyno tuned to be tuned properly.

I didn't realise Subaru's used any map based ecu's, I thought they all used air flow sensors?

Which is better? I'm guessing the MAF sensored ECU's are easier all round to use in every day driving for best performance.

I too did not know that subaru used map based ECUs, actually, before this post I didn't know there was any different systems used...

Cheers

Bennie

vincentvega · Post by **vincentvega** » Sun Aug 17, 2008 7:01 am

MAP - manifold absolute pressure

instead of measuring airflow you measure manifold pressure.

Gannon · Post by **Gannon** » Sun Aug 17, 2008 7:02 am

What i meant by map was Manifold Air Pressure.

Cars without an Airflow Meter usually have a Manifold Air Pressure sensor and calculate fuel input from a pre programmed table of MAP and RPM inputs. This is known as a 'fuel map' (what alex was refering to)

I too dont know of any soobs that dont have a MAF sensor

steve_rising_sun · Post by **steve_rising_sun** » Sun Aug 17, 2008 9:58 am

After about 2000 Subis use MAP sensors on at least the non turbos. I will have to wait Monday to look up which did or didnt.
Steve

Suparoo wrote:What i meant by map was Manifold Air Pressure.

Cars without an Airflow Meter usually have a Manifold Air Pressure sensor and calculate fuel input from a pre programmed table of MAP and RPM inputs. This is known as a 'fuel map' (what alex was refering to)

I too dont know of any soobs that dont have a MAF sensor