Pengo

ok, i just wanna check on the major differences between the 4g and 5g ecu's to figure out what method would be best for my next project. here's what i plan to build for fun: 4G civic hatch with boosted sohc vtec.

here are my two options for the swap. both just use the sohc vtec block mated to the 4g tranny, but one uses the intake/fuel system from the 4g bolted to the 5g block so that the 4g ecu can still be used and a vtec controller would have to be made. the other option uses the 5g fuel/intake system and ecu and a crapload of wiring.

now i know the second option will definitely work with the turbo kit i plan to get (greddy) b/c the blue box is made to work with the 5g ecu. what i'm wondering is if i have the 4g ecu with the external vtec controller, will the fcu piggybacked off of the 4g ecu still supply enough fuel and function properly?

ok, cliff notes version: using 4g ecu makes for an easier engine swap but possibly complicates installing the turbo kit, while using 5g ecu makes turbo kit possible but makes the swap process a little longer. if the 4g ecu will work fine with the fcu, then i guess that would be the route i will take, but i just need confirmation on this. any info, suggestions, opinions? thanks

-alan

G2turbo_terror

I plan on doing this but I'm gonna use a 5G ECU. The 5G ECU puts out more fuel once vtec engages compared to a rpm activated switch which won't. So a lack of fuel to start with combined with boost isn't good. I don't think the bluebox is going to detect a lack of fuel in the upper rmp and add more. Now I bet you could ditch the blue box, use a 4G ECU and an apexi v-afc to tune the fuel curve and vtec, but look into it more before you decide to do it.

Pengo

yea i was thinking it mite be easier and better to use the 5g ecu. the more i think about it, the 4g ecu mite be easier during the engine swap, but then the wiring for the fcu to the 4g would be a bitch. the wiring for the 5g ecu will take awhile but at least i kno it has been done before and will work.

-alan

TheShocker

I'm currently in the middle of a boosted a6 project.