Thread: 4.6 replacment for 3.9 thor or gems????

Originally Posted by PhilipA

based on your questions, I think some of the other responders have underestimated the difficulty.

1 The Bosch injection runs at a higher pressure than 14CUX, so you wwill need a special fuel pump and Fuel pressure regulator. These are expensive and not common, though I think there is a FPR used by some eurpoean turbo cars that will fit. the Bosch injection has no fuel return and the FPR in teh tank so is quite different to 14CUX. the injectors are shorter so you cannot fit a 14CUX with Bosch injectors.

2 EDIS stands roughly for Electronic Distributorless Ignition System, where the igniotion signals are generated by a sensor reading pulses ion the flywheel or aftermarket sensors on the front pulley. These are fed to the ECU which has a map and is also adjusted by knock sensors.

Look IMHO, it is in PRACTICAL terms not possible /feasible to rig up a Thor ECU into a 14CUX car. I have done a lot of research and never come across even one conversion. It would save you a lot of grief to set up the 14CUX onto the 4.6 and it will run it quite well. if you are really keen you can fit a Thor manifold , but even that is comnplex, and I have done it.

You can fit or have fitted an aftermarket ECU as suggested. I was quoted $3000 by an australian supplier for this for dyno tuning etc. Remember that car manufacturers spend MILLIONS developing starting strategies etc. A LR specialist told me some years ago that he hated selling even MOTEC as the man in the street customer was always unhappy as they never ran as seamlessly as a factory ECU.

So my recommendation is to run your 14CUX with a Tornado Chip which is designed to enable 14CUX to run a 4.6. If you want EDIS or electronic control of advance you can buy computers to do this such as Magajolt. If you then are unhappy fit a Thor manifold as these are what gives Thor its better low down torque.
Regards Philip A

looks like bang for buck just to stay away from the bosch side of things. 4.6 short with all my 3.9 ancillaries much easier and i can do it all in my garage!

Sounds like good advice from Phillip A. Changing to an aftermarket injection and ignition set up is not to be taken lightly. I only went down that path because I felt the 14CUX would not keep up with the 4.6 in terms of getting the full potential out of it. All up it cost about $1000 to do it all so not that cheap but it worked out really well, mind you I'm still learning how to tune it but that's an interesting process too. Good luck with your project
Nick

I had a Thor manifold, plenum, fuel rail and MAF, all just ready to put onto my 3.5 LC engine, and I was planning on running an after-market ECU with a crank position sensor (hall effect sensor and a crank shaft trigger disc).

MS and Spitronics are good options and offer batch, paired, and full sequential injection if you have cam sensors as well.

But I think PhilipA has it right: for a quick plug & play system simply use the 14CUX and the old inlet / injection system.

I agree with PhilipA on this, aftermarket ECUs sound like the answer to everything but they are seldom just plug 'n play devices. They are costly to buy, can be tricky to install yourself, and need expensive dyno time to set up properly.

My recommendation is go top hat high comp 4.6, retain the 14CUX and order one of Mark Adams Aussie spec Tornado chips which simply plugs into your exiting ECU (takes only a few minutes). Personally, I'd retain the simple distributor (I swapped the Lucas for a custom curved Scorcher) but if you must go distributorless there's plenty of aftermarket sytems around that will do the job.

well update on the new heart for my rover... i have found a neat 4.4 leyland engine which i will be using all i need to do i believe is modify my flywheel to fit the crank?

You will need to have the flywheel machined/redrilled to suit. The block is physically taller and wider, so your exhaust may rub on the chassis. Your engine mounts will have to be adapted. Your inlet manifold won't fit the P76 without spacer plates ($400+). Your front timing cover and water pump has to go on. It WILL easily overheat with the standard Rover water pump etc as this is smaller than the P76 one. You would be wise to remove the heads and ream out the water transfer passages at the back of the block/head interface as these are often poorly finished and restrictive to coolant flow.

Originally Posted by Nick S

Starky, have a look at ExtraEFI in the UK, they sell complete MS ECUs for Rover V8s. I used one for a 4.6 in my RRC. Its a fully programmable ECU. I got rid of my distributor, MAF and ran it with coil packs and a Ford EDIS system and has a wideband O2 sensor. Bit scary ripping out all the old 14CUX and associated wiring but even an electrical novice like me managed to get it all running. The thing I like is that you can adjust just about anything on it with your laptop. You can tune it for bit better economy when cruising etc + the coil packs a very good at resiting water unlike the dizzy. I just mounted the ECU under the dash.
Nick

Hi Nick,

I am just about to undertake an MS2 conversion on my Rangie. What coil packs did you use for yours?

Richard.

I too am looking at options to induct a 4.6. MegaSquirt would seem to be the way to go for injection/ignition and MegaJolt if only looking at ignition.

I haven't decided as yet if I will stay with the carbs off my old 3.5 tweeked to handle the 4.6, go with manifold injectors and plenum off a 3.9 and run my Megasquirt or go to a Thor manifold etc also run by Megasquirt. There are certainly maps for the Gems system available and most likely for the Thor but not sure of the later.

Initially I will most likely take the easy option and use the carbs but look at injection issues later. The carbs will make my system run OK and give me time to research further and locate bits I need for the right injection system.

Garry