Hi All,

I have searched high and low and there does not seem to be a single person on this planet that can/will tune the factory Denso computer so I think that a piggyback may be my best option to get all of my mods to play nice with each other while still keeping the car a functioning Jag. Does anyone on the forum have any actual experience with a piggyback on their 4.0L engine? I have done stand alone systems and chips before but never a piggyback so not sure the best brands that will allow me to tweak fuel and timing without sacrificing the other 9 billion things the computer manages.

If anyone has experience (good or bad) with brands please chime in! If not I just wait for Swallows to make their plug in ECU available to the public.

 

I would probably wait for Swallows to have their plug and play ECU and wiring loom to be available.

 

I think Performance Vehicle Engineering in the UK is doing the tuning for the Swallows stand-alone ECU. If Swallows won’t sell it, maybe they can help you?

 

so good timing as the latest Drivetribe video dropped yesterday and it was about ECU tuning the XKR. I reached out to PVE and they do sell the Maxxecu systems. They are going to get back to me in a few days with the details. fingers crossed that I can go programmable ECU but still retain all the other can-bus systems.

I will update this post as I get more info for others that may be looking for options.

 

Here’s to hoping you can get it done. Please keep us posted. It would make tuning and manual swapping these cars much easier.

 

Agreed, I’ll be very interested to hear what they have to say!

 

Any update with this proposal?

 

no, but I was told they would be out of the office part of last week. I will give them a day and check back tomorrow.

...stay tuned...

 

Quick update, Steve from PV Engineering got back to me yesterday, good news is the system is pretty flushed out and as close to plug and play as you can get for our cars. Install time is less than a handful of hours, mostly swapping out O2 sensors. The bad news is that the kit was designed specifically around eliminating the factory automatic transmission and installing a manual. My plans do not involve going manual (though the more I think about it....). Long story short, If there was enough interest Steve could slot that development into the queue but at the moment interest is a bit low. The other option would be a stand alone transmission control unit but obviously PVE could not offer any support.

So where I am at is looking at available 722.6 controllers and deciding if that along with the MaxxECU is the way to go. I know this guy has been making really nice TCU's for this trans for a long time and the price is quite reasonable for what you are getting (https://ofgear.dk). He even has a MaxxEcu plug-in built in so I am sure they can be made to play nice with each other and the level of shift control this thing offers coupled with the fully programmable ECU could make this a really really fun car to play with and get all my mods (twin screw, Meth Injection, blah blah) to harmonize nicely. I just need to do a little more digging and see how deep I will go down this rabbit hole. My top down time in Chicago is pretty limited and sneaking up on me so I cannot have this car on jacks all summer long. If I can find a competent tuner that can get this dialed in with a few days on the dyno then my comfort level will be much higher.

If anyone has any feedback or ideas on a transmission control solution please let us know, I am sure I am not the only one that would pull the trigger on this next level mod.

 

Hi All,
So this is where i am also at! I did source a company from Poland called HTG and they now have developed 2nd generation smart transmission control unit already developed which is fully compatible with the 6HP-26 auto gearbox and also does not need to be tuned at all. It is self learning and just simply plug & play. This allows to retain the auto gearbox fully functional and also option for sequential shifter. This would be installed aling with the Pro race MaxxECU stand alone with plug & play harness. The entire set up does not come cheap either but would estimate it is no more expensive than the manual option considering all the labour, bell house, custom flywheel/ plate. In fact may well be cheaper. I have also been in discussions with local motorsport company with the knowledge and expertise to carry out all this work and also rempapping. The total cost proposal for the MaxxECU, and harness kit, TCU and all harness etc to date is approx €4k, but i am sure it would be cheaper if there were multiple production. I am happy to share the info obtained to date on this subject with whoever is interested. The workshop is based here in Ireland. The workshop in question builds mainly drift racing cars so is very comfortable with this type of work. They would do all the work in house themselves also. Any feedback or interest, let me know.
Regards,
Paddy.

 

Hi,
I had a quick look at the 722. Controller and seem to be only compatible with somenolder Mercedes models and would not be compatible with ZF-6HP26 gearbox in tje X100 XKR's .......unless i have missed something ?

 

my car is a 2000 model year XKR and they came with the Mercedes 722.6 transmission. Probably one of the few "lucky" breaks the early XKR's had, that trans is near bulletproof and well supported in the aftermarket community.

Looking at HTG, that unit may even control the 722.6. I will reach out to them and see how it works with my model. I certainly like the PnP aspect, even if it is a bit more $$

 

I've been following this guy for a while who has built a 722.6 TCU running on an ESP32. It's open source, so can be modified to talk to a different ECU:-

https://ultimate-nag52.net/

 

l don't know if this is relevant here and now, but one of the problems with the 722.6 TCU in the Jaguar sense was getting the ECU to accept anything other than the original EGS51 TCU.

 

No doubt 25 years ago they were very limited for RAM, processor power and input/output pins, making it harder to add code to interface with new hardware. It would be interesting to know the specs of the original ECU and TCU and see how that compares to an ESP32 that costs a few $$ today. I'm sure the info is on the forum somewhere.

 

Quite a few of the Jags of that era use SH7055 (sometimes twin) or other SH-2E in the PCM. Very robust, lots of I/O.

 

AJ27 ECU uses a pair of Motorola/Freescale/NXP 68HC16 CPUs clocked at 20 MHz, each with 160 kByte of Flash ROM and ~7 kByte of RAM

 

I thought they'd run out of pins on the transmission module on the XKR because you can only get the transmission temperature when in drive or reverse? Presumably the pin was used for another function the rest of the time.


Those were the days when every line of code had to be essential or you'd run out of space.

As a comparison, for those who aren't familiar with it, the ESP32 has a dual core running at 240Mhz and 448k of ROM and 520k of RAM (plus Bluetooth and WiFi built in amongst other things). All for a few $$.

 

bumping this thread back up. Do any of you CAN-savvy guys know what actual inputs the 722.6 TCU actually needs to function at least from an ECU standpoint? I am about to install a 15HU differential with the Chirpy CAN module to fool the ECU into allowing the taller gear. I am REALLY itching to go with the Max Ecu and the only roadblock is keeping the Mercedes TCU happy.

Looking at the wiring diagram and most of the TCU inputs come from the transmission itself, the gear selector, Dual Liner Switch or the CAN itself. I dont actually see where the TCU takes any input from the ECU?? Wondering what I am missing.

I am ultimately ok going with a fully stand alone programmable TCU but not at the same time as a new ECU, just too many variables to deal with.

Anyone smarter than me (and there are a LOT of you) chime in if you see any dependencies the TCU has on the ECU

 

The ECU and TCM exchange a bunch of data over the Canbus - any module can talk to any other module over this bus. For X100 the ECU, TCM, INST cluster and ABS module all chat to each other over this bus.

crbass decoded all the messages and captured them in a spreadsheet which you can download if you search for the thread

Looking at it quickly, ECU sends to TCM shift management engine torque, throttle position, pedal position, torque reduction acknowledge, engine speed, speed control status, engine coolant temp, barometric pressure
and tcm sends to ecu torque reduction request, transmission overload, trans input speed, torque converter slip, kickdown, gear position torque converter status, shift map, fluid temp
They also exchange error status messages...