I'm working on a 16CU with an Ostrich 2 emulator and TunerPro, the Ostrich is $175 and allows real time tuning. The factory test port is adequate for datalogging but I will probably make a few code changes to improve it.

 

Please keep us up to date on progress.

 

I wish you luck and I hope you’ll come back on here and tell us what you did.
I’ve received several Jag cars because their owners couldn’t sort out the stock systems. The cost of trained technicians often exceeds the value of the car.
Attempts to get the mega squirt systems up also supplied me with parts cars. In fact I have a complete new Mega squirt system still in the box waiting for someone to walk me through the process. Actually as a racer I need more than plug and play sort of knowledge. Too bad someone with Tuner knowledge can’t do like the guy on U tube and walk us through the steps.

Those with the knowledge understand the value of that knowledge. Forcing me and many to go retro in order to modify our cars beyond stock.

 

I have been playing with the idea of Megasquirt, driving 12 COP's and EFI, getting feedback from wideband O2 sensors for real time autotune. Last time I checked Megasquirt needed an additional board to drive 12 COP's. And the whole autotune thing is under a big question mark.
It is doable, ThunderMax on my Harley works exactly like this. It totally changed the character of my bike. More power and amazingly enough it goes over 60 MPG when cruising. Never got better than 52 with stock ECM.

 

Well said!
Everybody gets all hinky about every detail on EFI. Like if they don’t time all 12 cylinders exactly they fail. Forgetting the factory batch fired for decades. Sure it’s possible and with limitless time doable. Fuel mileage will go up by . 00012 per mile. Horsepower gain? Maybe one?

 

Forget COP, either EDIS or GM DIS coil packs is the way to go even MS2 will run this native. The room in the V is limited and COP may not fit. The other issue ask anyone with COP and most have had at least 1 failure, my mate keeps a COP in his boot for his BMW 545.

 

In all fairness, my fuel mileage did increase considerably. I saw a road test in The Motor magazine in 1963 where they drove an S Type from London to Geneva and averaged 16 mpg. I drove mine from Calgary to Vancouver, Canada across the Rockies and averaged 29 mpg.

I have a Road Dyno box that can calculate power from an acceleration run and my last test was 165 hp and 236 ft lbs, and I know it was going lean on me during the run, which cost power. The seat of the pants meter says that both the power and torque are considerably increased from when it was on carbs and a distributor; however as I didn't have the Road Dyno before doing the conversion I can't give before and after figures.

I have a friend who has used Megasquirt on a 1967 Chrysler with a 440 and it now basically behaves like a modern car - turn the key and it starts, goes to fast idle and then drops down to slow idle. I think a big problem with mine is I used a carb adapter to mount an injector on top of an SU to use the carb body as a throttle body and I think quite a bit of fuel puddles behind the bridge of the carb - it's metered in, but isn't used by the engine in a predictable way. My winter project is a new manifold and better injector placement.

Perhaps the lesson of Megasquirt is that all the basics have to be good before going to injection - it's a not a bandaid that fixes things that are intrinsically poor.

 

Why not just use the EFI manifold made for the XJ6?

 

That manifold fits a straight port head and the S Type has a B type head - all the intake ports and studs are in different locations, and I had spent a considerable sum getting the head rebuilt before I made a decision to try EFI.

The second reason is the manifold does not fit into the engine bay unless a fair bit of sheet metal is cut away and it impinges into the footwell space - again something I wasn't prepared to do as it involved quite a bit of welding and repainting.

 

If someone has a DAC6338 it would be helpful to know what firmware it has, there is a sticker on the EPROM, and a picture of the area around the processor would be good. The DAC 6337 has a couple of configuration resistors that affect what areas of code the processor runs, I suspect that they select lambda control or open loop control.

 

As I believe, this was removed from XJ 5.3L 1992. This ECU does not work. I don't know why is the different numbers on the covers

 

Thank you for that. The firmware that I have is also 9009 so that confirms that it is the same although I have a lot fewer components populated. What is wrong with the ECU? I could probably repair it or would you be willing to sell it?

 

The engine will not start with this ECU. It was the beginning, the engine worked well only 15 minutes, then it stopped. The NEC processor was very hot. Then everything stopped working. I haven’t come up with anything better than replacing this ECU with a new one. This unit has been on the shelf since 99 years. I am ready to give it ( as a gift), but delivery to Europe will be £30-40.

PM me if interested.

 

Not only was compression dropped but smog compliance began. The 350 horsepower Chevy 350 wound up at 160 horsepower when the Jaguar was at 242DIN. and three years later ( 1975) fuel injected 262DIN
EUROPEANS lagged on smog compliance and while American Jaguar V12’s were 262DIN. European V12’s were at 299DIN COMPARED TO 160 SAE NET ( 157.8 DIN )

to convert SAE NET TO DIN DIVIDE SAE Net BY 1.0139

 

262 rated DIN horsepower. If it was rated the old Gross horsepower way it would be called 450 horsepower.

Headers if actual true headers and not just tubular exhaust manifolds will add slightly slightly less than 5% more horsepower.
Cams can add more than 100 horsepower but will make the engine slower in a drag race. That’s because any cam will lose power at Low RPM to gain power at 7000 rpm. Ya gotta ask yourself how much time will you spend around 7000 rpm against coming off the line?
E85 will add 10% but your fuel mileage will go from high teens down to single didgets. Maybe 7-8-9?
Port work will have the same effect as cams.
Remove pollution equipment and increase timing to about 10 degrees at idle 40 degrees above 3500 ( you’ll need the early 1972-1979 distributor) you’ll pick up a solid 10%

In Theory a megasquirt will offer potential gains but in reality it’s a complex change defiantly not plug and play. And I’ve never seen a before and after Dyno sheet

Before you get discouraged though, Corvette engines from that era made do with only 160 horsepower.

 

Hello, what is the current state of this project? I Have done some mods to my xjs, as installing high compression pistons, some head porting job, converted tranny to bmw 420G 6spd manual, so now definitely need help to correct fueling.

 

My XJS isn't on the road at present so I haven't done any further work in analysing the tables. Its much easier to do that when its running because TunerPro RT can be used with the address tracing function to see what tables are being hit when and to make live changes to the tune.

 

A Chevy 454 SS pickup has 235 net horsepower so The Jaguar V12 making 262 is 10%more powerful*.

*that same engine in England or Europe etc makes 299 horsepower DIN net That’s through the stock mufflers (which really muffle it). and through the stock air cleaner ( which hurts to the tune of 28 horsepower

Would it help you to call it 495 gross horsepower? Because that’s a fair comparison.
plus the torque of a V12 is massive compared to a V8 that’s because at any one moment a V8 only has two cylinders on the power stroke while a V12 has 50% more!

As others have said there are things you can do to increase the Jaguars horsepower. They are plug and play sort of things but the real easy thing is to look at what is holding back the power. It’s timing! Total advance on that engine is something like 19 degrees. The reason it’s so weak is because with 92 octane fuel that’s all you can get before preignition starts happening. 11.5-1 compression will do that.

The Jaguar V12 made from 1971-1981 had a total advance of 38 degrees. Yes that distributor will fit in your engine.

But wait you still only get 92 octane at the pumps. Unless you want to buy race gas in 55 gallon drums which starts at $7.00 or so plus shipping.
wouldn’t it be nice to get 100 octane at a decent price? If only huh?

Ever hear of E85? It’s 85% alcohol which helps the engine run clean and cool. That will operate on more advance. And the more advance you run the more power you make. There is your 100+ octane.

Just by itself E85 will net you about a 10% power gain. Add the benefit of more timing and power gain can approach 20%. So now you are at 310 DIN net. Or the old gross or advertised horsepower north of 500 horsepower.

the Good news, The transmission behind that V12 is the GM Turbo 400 ( the case is different just like the case for a Buick Cadillac Chevy whatever is different).
Oh and put away the metric wrenches. The Jaguar is all SAE nuts and bolts.

That engine looks scary because of all the hoses and lines etc. you don’t need those.

Get rid of that big ambulance size alternator use a little GM , get rid of that stupid air conditioner Use a GM or one of those small Japanese ones. The power steering pump is a GM product. And if you want there are little versions of that with remote tanks which will fit and work. You can probably get rid of that messy looking air pump too ( except California )

What’s left is really good looking all aluminum. Polish it up if you really want eye candy.
it’s narrower than a V8 plus the spark plugs are right on top so it’s easy to work on.
Most V12’s are unbelievably nice inside. I’ve pulled them apart with over 100,000 miles and you can still see the original hone marks. No ridge! Most V8’s have as few as 10 bolts holding a head on. JaguarV12? 34 studs holding a head on. The quality of components is fantastic. To get a Chevy to that standard you’d spend near $20,000
The crankshaft on most Chevies is cast iron. A 350 Small block’s crankshaft is about 25 pounds plus or minus a few pounds. The Jaguar’s crankshaft is made of the finest grade forged steel EN 40 and then hardened. It weighs a massive 78 pounds. That’s because instead of little 2.10 rod journals it has 2.30 inch rods with 3.000 mains. On a little 326 cubic inch engine! Forged con rods 12 point nuts on the rods.

Bad Reputation? Yes and no. If you don’t know anything and lead with your wallet you will be told all sorts of horror stories. Hey mechanics have to pay bills too and you don’t know any better well they will gladly relieve you of any you’re willing to give them.

There is a 3 part series on U tube that will make the scary fuel injection simple. The distributor is right up on top. Change the oil on time ( not mileage) and the valves will likely never need adjusting. Keep it filled with coolant and none of the “ overheating issues” will happen. They even make it simple. If you can count to six and remember A side & B side you’re gold.

 

I’m sure you know what a Chevy SS454 pickup is?
would you be surprised that the big bad 454 makes 235 horsepower SAE net? compare that the the V12’s DIN net ( DIN is a little more powerful than SAE rating 1.0139 to be exact ) 262. DIN net or 299 in the rest of the world.

tSO

Many people think of the old Gross or advertised horsepower numbers but basically a 450 gross or advertised horsepower chevy engine makes 235. The old Chevy 350 horsepower 350 makes 160 horsepower. Later fuel injected versions made 190 hp.
Chevy 454 235 hp Jaguar V12 262 horsepower.

 

In the UK there is no E85, E95 is the norm, E90 is coming. We have 97 octane RON available almost everywhere and 98 or 100 octane is widely available. We don't get any fuel at 'a decent price'.