Hello all,

I am wondering if anyone has ever attempted to...or has experience with...converting the Magneti Marelli/OBD1 V12 (1994 flavor) to the (1995-1996 flavor) Nippon Denso/OBD2 V12?

If so, what pointers and advice do you have?

In the alternative, I would also be open to exploring other ideas to update the engine management system to a fully OBD2 compliant system with a distributorless ignition system...possibly running it as 2 V6's, etc.

I'm just exploring different ideas at the present to figure out which direction I want to move in. This is for a resto-mod project I have for updating a '74 XJ12L to a more modern engine and electronics.

Thanks in advance!

 

Nothing is not doable.

We fitted a 6ltr to a MK2 a very long time ago.

The electronic support would be the key issue, but since its a S2 Body, there is zero there to start with.

Knowing what and how that Nippon system did what it did would be the challenge, as they are so rare anywhere, and parts are a problem for them.

Todays stand alone systems are hugely better/different to 20 years ago, so I reckon there would be a way.

 

Try talking to Emerald:
https://www.emeraldm3d.com/
I know that their system will work with a V12, but I know nothing else about them, apart from the fact that loads of UK special builders use them and they have a solid reputation. Also, their systems are not stupidly priced.

 

This is an old rusty memory, but I believe I saw a shop put a 6 litre in an E Type, using a distributor, ignition amp etc from the 5.3 system.
Might that be easier?
Rob

 

Hi- The Nippondenso system is very rare. It requires a different camshaft too. My 96 XJ12 has it. Unless you’re looking to blaze new trails, I think the three paths are:

1. Mobeck EFI kit... very expensive but very modern and it’s a kit https://mobeck.com/jaguar-v12-efi-kit/. If I had the cash I’d do it his way.
2. 80’s Lucas stuff from an XJS. Roger Bywater has a booklet on putting 80’s Lucas EFI in V12 e-types. Let me summarize it for you: just move everything from one car to your car. I plan to merge a rusty 83 XJS V12 with a 77 XJ6C next winter. I chose this method due to cost and my familiarity.
3. Mega squirt:.: it’s been done a few times but it is nowhere near as cheap as advertised when you add coils on plugs, injectors, etc. the two people that have done it that I know aren’t too good at explaining stuff to noobs like me.

 

the distributorless 93 and later is far more advance than the older Marelli system. The sole flaw is the ECU which lacks the ability to be modified. There are several more modern ECU’s one of which Advertised itself as a simple plug and play.
It’s naturally expensive. If you aren’t inclined to work things out yourself, spend the money.
On the other hand you can spend a few hundred dollars for a Megasquirt 3 pro and get connecting cables etc from D-I-Y auto works.
It gives you all sorts of options. Like flex fuel for example. Just by itself it allows you to use E85. The big advantage there is about a 15% boost in power. That gets you over 360 hp but it will also clean the backside of the intake valve which if you remove those deposits you’ll be much closer to the original 314 horsepower. Plus using E85 the engine runs cooler.
It doesn’t matter if you use premium or whatever gas like E15, E85. The sensor detects what’s going through the fuel line and adjusts automatically.
By the way. Once you’re hooked up properly the Megasquirt will self learn and start up without you going through endless programming to make it run.
But••••• You should buy a few hours on the chassis Dyno to completely sort out tuning issues.
Once you have the Megasquirt a turbo option is within reach. EBay turbo’s are getting really good lately. ( I’m putting a pair on my Jaguar race car )
The stone stock engine can easily deal with it without opening it up ( if it’s high mileage) and get you up to 600 hp relatively easily.
A pair of $135 turbo’s and a few more bucks for boost control and connecting the exhaust up. Cheapest horsepower and its so very civilized.