hi iv just taking my 1.8 mreg si efi zetec engine out of my mk5 due to it blowing up iv got a 1.8 gti that iv put in that i have the correct wiring loom for wen i came to fit the engine i found my wireing loom was different wat shud i do change the loom or shud i use my efi inlet and old loom and go for dat i rele will i lose alot of power from the gti engine if i use the efi inlet andthotle body

 

If they're both zetecs, i'd take everything from the old engine and bolt it onto the new one.. plug and pray..

 

wat take the efi unit off and use my old injection and old wiring loom then and do away with the gti injection system will it lose power off the gti if i do that or nt thanks

 

If they're both 1.8's, it'll be the same.. The Si is apparently 105PS and the GTI is 115PS.. I doubt you'd notice the difference..

 

my Si had 115ps, but I plugged and prayed with the 130ps efi manifold & 2L throttlebody... and I noticed a big difference, I just hope ECU makes a difference aswell!

I've been in a 105ps si and it seemed slow compared to even 115ps one