My main reasoning for using a turbo is because of efficiency (prochargers are pretty efficient, though, as well as less heat), but if I keep my foot out of it and the turbo spooled down, I still get respectable gas mileage.

 

thanks Cambo I knew it couldn't be that bad

And sorry for interrupting the flow on turbocharged engines guys

 

Just thought I'd get in here with a few questions. From my experience with turbo engines (I also own a Toyota Supra) the most tedious part of turbocharging a previously non turbo engine is the electronics. What I would like to know is the AJ16 ECU and sensors able to cope with the addition of boost? and if not can one simply use XJR6 MAF, injectors, fuel pump etc as a direct plug n play swap.

Basically I'd like to know if existing or XJR electronics could be utilized as opposed to a aftermarket ECU. Besides that I think the only other tricky thing would be fabricating an exhaust manifold.

 

Hey Adam good luck with installing an aftermarket ECU the only guy in the world that can remap the existing ECU is XJRengineer on this forum he has done my car
I was thinking of going to an aftermarket ECU but the cost was astronomical it would have cost more that the cars worth LOL

 

If you are a DIYer, there is a cheap ecu called Megasquirt. You can buy a kit and assemble it yourself (solder components to the board as well as all the connections), or I've seen already assembled kits available here and there on the web. You would just need to put the right plugs on the harness to plug into the Megasquirt ecu and from there, you can either map your own fuel/spark curve, etc... or in some applications, people have uploaded their own maps to the Megasquirt website for others to use. I have considered this as an option for my own car.

 

Well there was a turbo charged XJ40 Chasseur Stealth (4.0 straight six pot twin turbo's).

As rare as hens teeth and like an idiot I turned one down a few years ago.....

Here is a link to an old different forum thread to give you an idea.

Chasseur Stealth.

 

Well I was thinking that XJR6 ECU could be used as it must be capable of dealing with boost. In effect you'd end up with a XJR6 AJ16 running a turbo (or two) as opposed to the supercharger. Im not at all familiar with the parameters of Jaguar ECU's but it shouldn't matter to the ECU where the boost is coming from (turbo or sc).

With a 4 Litre capacity you could make crazy amounts of power or somewhat more importantly make an immensely driveable performance car both on and off boost. Im thinking along the lines of a single GT35 on a 4 litre and a GT30 on a 3.2.

 

I'm pretty sure you are right. The ecu will account for boost wherever it comes from as long as its just boost and not many other mods. I think I read elsewhere in this forum that the stock fuel system for the xjr can handle around 400, so if you get the ecu/injectors/fuel pump too, you might be able to reach that number. Just to be safe, my plan was to swap over all the sensors as well.

 

The first couple of minutes of this got me thinking about a turbo x300:


Personally I don't see any point in using twin turbos unless you want 600+hp, a well matched single turbo would reduce complexity and still provide a lot of power. Plus both the 3.2 and 4.0 have sufficient capacity to make lag minimal with a modern, ball bearing turbo without having to go to a tiny exhaust housing.

 

If you want to turbocharge a naturally aspirated AJ16 engine then I would recommend that yo fit the MAF, injectors and ECU from a supercharged AJ16 engine. You would also need to uprate the fuel system since the XJR6 has twin pumps in order to supply sufficient fuel. The second pump turns on above 4000rpm. You may just be able to replace the pump assembly and add the control module for the second pump. I don't know if the harnes for the naturally aspirated cars has all the wiring in it for the twin pumps.

However, this this would still leave you with an turbocharged engine with a 10.0:1 compression ratio. This would be very higher for a port injected engine turbo engine. I would very strongly recommend that you used a supercharged base engine so that you had a 8.5:1 compression ratio.

 

Does anybody know if the Maf, injectors and ecu will fit straight in?, the fuel pump could be swapped to a single high flow one like a Walbro or similar with an adjustable regulator. Either way something needs to be done to lower the compression although you may not need to have a compression ratio as low as the XJR6's. I wonder how low you could get it with a swap to a thicker head gasket.

 

You could and get down to the compression you would want, but the more head gaskets you use, the more likely one would blow at high boost.

I personally think a single, high flow fuel pump with an aftermarket regulator would work, as long as doing so doesn't make the ecu throw a code.

 

Hi All, Thread revival. I am looking at buying my first XJR and being in Australia there XJR6s are relatively good value now, with the 99 onwards 4.0 litre V8s about $10k AUD more. From what I have been reading in my lurking here, and whilst I haven't found a specific and detailed overview of it yet, the ECU seems to self learn and has a fair amount of excess capability built into it, up to 500hp on the twinscrew modifications. Is there any reason with either the XJR6 or later 4.0 v8 that you couldn't twin charge the system (ie add 1 single turbo, eg a gt35 or precision 6266) and v feed the pipework to the throttle bottle with one way valves on the turbo and supercharger outlets? If so, how much extra capacity is there in the fuel system? Given the efficiency, I would have thought conceptually this would be easy without the need for fuel/ecu mods?

 

The XJR V8 is covered in a different forum. I won't comment further than to say that the EMS on the XJR V8is much more complicated than the XJR6 as it has electronic throttle control.

The air meter of the XJR6 is sized for the std performance. If the engine is modified in any way to increase the airflow, this will not be measured by the airmeter as it will become saturated. The fuel injected with therefore not increase in proportion to the airflow. This will cause the engiento run less rich than intended. If you only increase the air flow by up to 10% thjis is probably still OK.

IF you increase the airflow by more than 10% I can reporgramme the engine ECU to get around this problem.

If you are thinking of combining a turbocharger with a supercharger, then I would suggest that you mount the turbocharger upstream of the supercharger in a serial configuration. Anything involving valves will be too complicated.

The std XJR6 injectors have about enough capacity for 400bhp andthe twin fuel pumps can flow enough fuel for 500bhp.

This would be a major project so don't under-estimate what would be involved.

 

Ok I see. Thankyou, and sorry about the v8 question, I realised too late it was the wrong section. Upstream? Do you mean in a compound type arrangement? Ie factory Eaton (?) blows pressurised air into the inlet of the turbo, with the charge air taking a single route to the throttle body from the turbine outlet via the charge/inter cooler?

 

No, the other way round. The air enters the car and passes through the following sequence of components
bespoke dirty air intake
large aftermarket air filter mounted on RH side of engine bay (viewed from driver's seat)
air meter - this will become saturated at whaever point the engine flows more than 1018kg/hr
turbocharger
air-air intercooler
std throttle body
Eaton M90 supercharger
air-water intercooler

 

Kompressed,
if you are in Australia, why don't you buy a Ford F6 310 and have it modified?
For those non-Australasians on the Forums, the F6 is a Ford Performance Vehicle (FPV) with 4.) DOHC IL6, turbo'ed, 310 kW (conservative factory number) which can do 0-100km/h in 5 secs or less, and retails for about 40,000 pounds new. It is heavily tunable up to 600bhp if not more.

 

Hi Al,

I wouldn't be surprised if there isn't a lot of the Jag 4.0 straight six in the Ford 4.0 straight six. I am after a Jaguar, and do like to tinker. It would be torque vs hp. Otherwise the Merc in my signature would be kept. .

 

it had occurred to me too. I asked XJREngineer Andy this question recently - he said no.
But on paper - Ford owned Jaguar at the time, and could have borrowed from Jaguar experience - IL6, DOHC, 4 litres, forced induction (turbo for Ford Australia, supercharger for Jag)... the similarities are there.
Countering this however if the long tradition of the FordOz IL6 from the 1960s on. Then late 80s Ford Oz came out with the 3.9 IL6 EA SOHC, which became the 4.0 SOHC in the later AU cars, then the DOHC 'Barra' engine of the 2002 BA Falcon - clear stepwise development of the Aussie IL6.

I love to tinker, but when it comes to a full-blown Jag, they do it so well now with the XFR and new-shape XJ ... if the budget stretches that far!

 

I see this question a lot from newcomers who I'm fairly certain don't know that there was a supercharged version of their car built by the factory and that they can get it for just a few thousand dollars more than a NA car.

I also think that the world "on he street" out there thinks, maybe correctly for some cars, that the quickest way to better performance is to "slap a turbo on that thing!"

That is also why we seldom hear back from the "I wanna put put a turbo on my Jag" newbies.
Vector