Thread: EFI into a 3.5 LC carb engine

Originally Posted by StuRR80

Hi all,

Quite a while back I read a post (yep did a serach and gave up when 200 posts came up in the search parameters!) about which EFI system was best to use on a 3.5. From memory it was the 3.9 system, is that right?

Chances are I can get a system from an '87 3.5 for some beer but thought if the 3.9 is far superior, then I'll try to find one of them. I have gas in the girl but the carbs hate it (mind you, I haven't driven her much in the last year but hope to fix those issues soon) so thought I'd upgrade to EFI to run gas 99% of the time.

Any comments/ questions welcomed!!

TIA

Stu

You're right
3.9 0ff a 90 model onwards is better .... But it would make no difference to you as you just want the butterfly part of the whole thing to smooth out the gas ... and only want petrol once in a blue moon

Both EFI injectors are gonna muck up regardless from not being used ... so on that note .. if your sticking to gas ... go for the one costs a slab of beer

Unfortunately getting the EFI through a mate fell through.
Does anyone have something suitable they want to get rid of for a carton?!

Cheers

Stu

To do this conversion properly, what would I need in terms of parts and what catches would I need to be wary of?

Obviously I'd need the manifold, injectors/rails, wiring loom, aftermarket ECU, air cleaner box. What else would I need?

An realistically, how technical is it all?!

TIA

Originally Posted by StuRR80

To do this conversion properly, what would I need in terms of parts and what catches would I need to be wary of?

Obviously I'd need the manifold, injectors/rails, wiring loom, aftermarket ECU, air cleaner box. What else would I need?

An realistically, how technical is it all?!

TIA

How technical .....This depends how many $$$$$ you want to put into it.
On a 3.5 I would not go over the top. You will find a Dunny door lucas RRC set up cheap. Also a Rover SD1 will work and are usually free. I'd be surprised if any one gives away a good 14cux with Hot wire for a slab.
Haltech make a pigyback ECU (Interceptor) that work well on 14CUX. Buy the Time you dyno it is $$$. They seem to help 3.9s a bit. To get these 8s going well will need head work, a cam and exhast as well. So costly
I'm adapting Delco set up of a 5Ltr VN commy to mine with Commy Dizzy with Haltech ECU. Main reason is Repairable in out back and Tuneable by Lap top. Tony

Originally Posted by Rangier Rover

I'd be surprised if any one gives away a good 14cux with Hot wire for a slab.

Sorry, that was my stupid sense of humour coming out! I don't really expect anyone to give them away but meant if anyone has something for sale I'd be interested!

Although saying that, from the sounds of things it might be a bit more technical than I can handle - I'm just a dumbar*e "plug and play" accountant... but am slowly learning mechanical things (when I have time...)

Originally Posted by StuRR80

Sorry, that was my stupid sense of humour coming out! I don't really expect anyone to give them away but meant if anyone has something for sale I'd be interested!

Although saying that, from the sounds of things it might be a bit more technical than I can handle - I'm just a dumbar*e "plug and play" accountant... but am slowly learning mechanical things (when I have time...)

if you can purchase a 3.5 or 3.9 shagged engine with the complete EFI system it should be a "Plug and Play" install, with the EFI wiring loom and computer all you need to do is swap over the EFI manifold, plenum, MAF, injectors, temp. senders, dissy, coil and get an Auto Leccy to wire in the wiring loom, shouldn't cost too much, Regards Frank.

I thought LPG and the flapper EFI dont go well together as the flapper doesnt like backfires. But if you have sequential LPG injection I dont think it does back fire. If you have an old LPG system - I'd go down the hot wire EFI route.