420A How to install a gm3bar and AFC on a Turbo'd 2gnt

[welchie]

im sorry if this is a noob question but i promised my buddy that i would install these two items for him while he is on deployment.

his car is a 98 gs that has been built with lower compression pistons and alot of other jazz... and a custom turbo kit installed. i found a site to wire the afc (SAFC Install and Tuning) but have yet to find out how to wire the 3bar.

now i know on hondas they install a 3bar because of the lack of the factory maf sensor reading anything above 11psi of pressure. so this should be good upgrade for a 2gnt maf sensor that cannot read boost right? also, i know the afc reads boost and vacuum from the maf so with the 3bar installed this should be good right?

any info, advice, insight on this subject would be greatly appreciated. thx!

 

[VelocitàPaola]

now i know on hondas they install a 3bar because of the lack of the factory maf sensor reading anything above 11psi of pressure. so this should be good upgrade for a 2gnt maf sensor that cannot read boost right? also, i know the afc reads boost and vacuum from the maf so with the 3bar installed this should be good right?

That may be true for Honda's, but for 420A DSM's, the factory MAP sensor can't read anything higher than about 1psi. Furthermore, the ECU wouldn't even know what to do with such a signal. Honda's at least have a portion of their ECU's mapped to support pressures greater than 0psi, whereas 420A DSM's do not. If the ECU registers anything greater than 0psi, it will cut fuel and throw you into the dashboard.

A 3 bar MAP sensor won't do anything but throw off the scaling of the stock ECU's fuel map. Even with different injectors and an S-AFC, the results won't be good. There are other ways of adding fuel for forced induction, such as an FMU, S-FMU or Megasquirt.

 

[welchie]

That may be true for Honda's, but for 420A DSM's, the factory MAP sensor can't read anything higher than about 1psi. Furthermore, the ECU wouldn't even know what to do with such a signal. Honda's at least have a portion of their ECU's mapped to support pressures greater than 0psi, whereas 420A DSM's do not. If the ECU registers anything greater than 0psi, it will cut fuel and throw you into the dashboard.

A 3 bar MAP sensor won't do anything but throw off the scaling of the stock ECU's fuel map. Even with different injectors and an S-AFC, the results won't be good. There are other ways of adding fuel for forced induction, such as an FMU, S-FMU or Megasquirt.

hum... i didnt realize the stock ecu was so insufficient. ill tell my buddy to buy an ems. i would never recommend a fmu to anybody because i personally believe they are ticking time bombs. thanks for your help!

 

[VelocitàPaola]

i would never recommend a fmu to anybody because i personally believe they are ticking time bombs. thanks for your help!

Quite the contrary. We use FMU's with 420A DSM's quite reliably. I've personally had one on my car for more than four years.

 

[welchie]

Quite the contrary. We use FMU's with 420A DSM's quite reliably. I've personally had one on my car for more than four years.

what supporting mods do you have to supplement the fmu? i do belive my friend currently has an fmu installed but he also told me that was why his first motor detonated.

 

[VelocitàPaola]

what supporting mods do you have to supplement the fmu? i do belive my friend currently has an fmu installed but he also told me that was why his first motor detonated.

Just the 12:1 FMU and a Walbro 255lph HP fuel pump. The rest of the fuel system is stock. It's a fairly common configuration suitable for up to 8psi.

 

[welchie]

Just the 12:1 FMU and a Walbro 255lph HP fuel pump. The rest of the fuel system is stock. It's a fairly common configuration suitable for up to 8psi.

you sir are a big help! thank you so much! i will talk to my friend and see what he wants to do.