Hello Andy, I'm the guy who fit the AJ16SC into a 1984 Jaguar VDP and it is running rather nicely if I may say so myself. It is equipped with the original
2.88 limited slip rear diff. At our 70 mph speed limit it cruises at 1700 rpm.
I am enjoying the torque and the smoothness at around town speeds most of all. I would be interested in purchasing a set of chips if the modification would enhance the low speed smoothness and torque if you have such a set available. Also another question, There is a old tech bulletin on a adjustment of the cam timing of the AJ16NA, naturally aspirated to reduce the overlap of the cam timing. Would you suggest this change to the AJ16SC in my search for more torque? How about moving the cam position sensor with the cam timing?

Thank you.

Larry Louton

 

Andy may have other views but a 2.88 differential would be quite low for such a heavy car. The factory differential set-up for the AJ16 engines ranges from the SC of 3.27 to the non-SC of 4.08, (see Page 82 & 83 of the Car Care Booklet).






So one way of improving torque performance is to go for a taller differential, but there is a trade off in fuel economy. Nevertheless, going up from 2.88 to 3.27 would be quite mild and would be a better match for the SC engine.

My SC comes with a 3.27 differential but I heard some SC owners prefer to adopt a 3.54 differential from the 4.0 non-SC sibling for a snappier drive, so I bought a 3.54 differential as reserve. This happened before I had a chance of driving my converted manual SC with the 3.27. However, I am happy with the manual-***-3.27 combination which makes it possible for me to stay on high gear during city traffic.

 

Have you tried one of Andy's Brackets , easy to install and works wonders without remapping the ECU 27C512 EPROM chip ? It biases the crankshaft sensor position 5 dergees to the ECU for the spark point to get you more low end torque . There is a change over point on the 110 or 114 cam with respect to the engine serial number as they were manufactured that Andy would know more about

Thanks , Joe

 

Really the two things you can do to increase torque is buy one of Andy's brackets ( there is another thread on that) and then fit the lower pulley made by Powerhouse in the UK.

Doing both of those will max out the airflow meter at higher rpm's, so anything more will require reprogramming the ECU and a different AFM. Lots more money, the first two are relatively inexpensive.

 

Hi Larry,
congratulations on your conversion. Jagbio64 is right. I can remap the ECU, but my revised crank sensor bracket is more cost effective. The revised crank pulley is less cost effective than my bracket, but also provides a good benefit in absolute torque and power increase, particularly at low engine speeds. As Marcus suggests, having a numerically lower final drive ratio will also increased vehicle acceleration, but at the cost of fuel economy and cruising refinement.

 

Thank you Andy, For your prompt reply. I already purchased and installed Andy bracket when I swapped motors. next move sounds like bigger lower pulley. Marcus, Checked two different sources for comparison and it appears that a 1987 Jaguar VDP or XJ6 weighs about 75 lbs less then a 1995 Jaguar XJR. Not by much.

 

Hello XJRengineer

I am french and own a x300 XJ6 3.2 sport for 15 years.
I am also an electronic engineer and did some enhancement on the center console :
->

I am now on a new project : turn the car to flex fuel.
In France E85 is 0.5€/litre against 1.30€ for unleaded, there is a real interest.
As only 10 to 20% of the gaz stations supplies E85, I don't want to turn the car to E85 only.

The goal is to use a flex fuel E85 sensor and send the signal to the ECU and switch the maps depending of the ethanol level.
Using a eprom 8 time the size, convert the sensor into 3 bits and connect them to the 3 high address pins of the eprom.

Do you mean this could work ?

Vincent

 

I developed some flex fuel vehicles 20 years ago for Volvo, as part of my job working for an automotive engineering consultancy. It is a very complicated process, not something that I would suggest is a DIY project. The X300 fuel system was not designed to be compatible with E85. You may suffer serious material compatibility issues with E85, causing failure of the fuel system.

 

Andy , Can the engine ECU on the AJ16 shift point be bumped up by remapping to 5500 in sport mode and be OK with the engine mechanicals ? Pretty aggressive cam profile to follow . Is the shift point done in the transmission ECU ? Do you know were I can find a good dynometer power
curve graph for a post TBS 114/110 overlap cam for N/A and SC ? I searched . The design limits with respect to reasonable power to the ZF4HP24 transmission ? You can hit me with the hard stuff as a real engineer . My goal is to get to 6.0 on 0 - 60 N/A and my background is formally educated in Chemical Engineering working in my career as a Jet Doctor in the areas of mechanical and electrical engineering for the airlines .

Thanks , Parker

 

There is a separate transmission control unit (TCU) to control the shift points. The engine rev limiter is set to 5950rpm. A programmable aftermarket controller could be fitted to control the transmission. This could be used to increase the full throttle upshifts to a higher speed. I wouldn't recommend increasing the shift speed above 5,950rpm, otherwise the engine will hit the rev limiter before it changes gear.


I am not aware whether Jaguar changed the official published power and torque curves for the engine, after making any cam timing changes following a technical service bulletin. To be honest, this is the first time anyone has suggested there was a TSB to change the cam timing. The torque limit on the ZF4HP24 transmission is 466Nm. This limit will never be reached with a naturally aspirated 4.0L AJ16 engine.


I hope this answers your question.

 

Thank You Andy ,

Do you have a reasonable or cruise EGT limit as I build it out in steps ?

Bellow 5950 rpm engine electronic governor and 343.7 (lbf∙ft) on the transmission

AJ16SC engine itself is at 378 lbf·ft with smaller crankshaft moment arm lenths ?

Do you have the number on the Getrag 290 transmission ?

There is a longer TSB as they went back and forth on the cam installed Vs.engine serial # during production

http://www.jagrepair.com/images/TSB/...%20Changes.pdf

Working with someone ( as well as my own X300 ) considering putting your engine into a Datson 280Z to double the power from 140 with your 5 degree bracket , the engine weight is the same from the information I have as the original is cast iron . Measured the dimensions today .

 

Included is factory tech bulletin for valve timing mod.

 

Included is factory tech bulletin for valve timing mod.

 

Let's try this again.

 

Andy ,

There is a TSB on SC valves , your work for Jaguar my have been completed before it came out .

http://www.jagrepair.com/images/TSB/...oor%20Idle.pdf

 

Lady Penelope,
If by EGT you mean Exhaust Gas Temperature limit, then from memory I mapped the engine to 950degC. I don't know what "number" you want for the Getrag transmission. Officially the gearbox is at its limit with the 512Nm output from the engine. However, my own XJR fitted with an Eaton M112 supercharger probably has a torque output of about 640Nm, and the gearbox has run for 20,000 miles since the engine torque was increased to this value.

 

Exhaust Gas Temperature limit as a long term running value other then a short term say one minute then valves ruined . I see the numbers on the Getrag for the future . Is the crankshaft different between the SC and NA ? off the top of my head I think I saw 2 different part numbers . Do you see any problems in a dry sump conversion with lower tension rings ?

4.09 rear end parts still available apparently at Jaguar Classic Parts as the 3.77 are gone .

Your big boy engine will fit in the Datson 280z and it weighs the same as the other project

Thanks , Parker

 

950degC is a reasonable long term running value for engine component durability.


I can't remember why the cranks are different between the 4.0L NA and SC engines. It maybe a difference in piston mass resulted in different machining of the balance weights on the crank.


There in no technical reason why an AJ16 engine couldn't be converted to a dry sump. The mounting of the oil filter would provide a convenient point to introduce the oil from an external pressure pump back into the main gallery. Ideally you would want to pair up the cranks bays 1 & 6 , 2 & 5 and 3 & 4 into three separate scavenge stages. Otherwise, you will introduce a lot of aeration into any scavenge manifold, if all the bays are connected together. However, it is a lot of work for minimal gain at standard engine speeds.

 

Thanks ,

950 c will be my alarm bell as I hope it will run a margin below that being I assume the valve and seat metallurgical limits is the limiting factor on long term sustainability . I understand the aeration issue but I thought as long as I scavage out of the bottom of the oil pan the separation into scavenge bays was never considered . I will run 2 separate electric pumps from 2 separate power buses for insurance not having looked into whether I could utilize the on board existing pump .

Check out Tcasmarcus's new pipes with video . Sounds like the spirit of your Jaguar engine.

https://www.jaguarforums.com/forum/x...-175912/page2/

 

Hi XKR Engineer,

I would like to swap a Jag XJR engine into an AC cobra replica. Is it possible to easily bypass the security? What kind of signal does the security use?

Thank You
Andrew