Ecu comparability

paulsv8manta · Post by **paulsv8manta** » Mon Jun 09, 2014 11:35 pm

Hi guys, can some one just clarify something for me. I'm currently building a 3.5 vittesse EFI which came with a Lucas 14 cu ecu, can I use a land rover discovery 3.9 v8 engine ecu which is a lucas 14 cux unit?

ChrisJC · Post by **ChrisJC** » Tue Jun 10, 2014 5:21 pm

I am pretty sure you can't. One (the CU) is for the flapper type injection (AFM is a moving flap), as fitted to SD1's. The 3.9 Disco ECU is for the hotwire type injection (AFM is a hot wire in the airstream).

They are totally different.

Chris.

paulsv8manta · Post by **paulsv8manta** » Fri Jun 13, 2014 7:49 am

Hi Chris, so if I up grade to the hot wire AFM that is all I need to do to use the 3.9 14cux ecu?

Spongo · Post by **Spongo** » Fri Jun 13, 2014 8:05 am

I think the injectors are different as well they are high impedance on the hot wire system and low impedance on the flapper system, there are I am sure some other things that are not campatible as well, if you want to use a hot wire injection system then probably best to get a used system second hand and transpose the bits you need.

chodjinn · Post by **chodjinn** » Fri Jun 13, 2014 10:34 am

Spongo wrote:I think the injectors are different as well they are high impedance on the hot wire system and low impedance on the flapper system, there are I am sure some other things that are not campatible as well, if you want to use a hot wire injection system then probably best to get a used system second hand and transpose the bits you need.

This. Flapper and Hotwire are not compatible, well some bits are but it's generally a headache unless you know exactly what to change. Easiest option is complete swap.