Jaguar X100 XKR Plug and Play ECU Project
This is a quick post about how the Manual XK conversion we sell in our webshop came about:
Some background on what we do with the AJV8, We’ve been often described as:
‘the most prolific AJV8 tuner’
Most of the Modern Jaguar tuners, for some reason don’t really mess around with the hardware. When I say hardware, I don’t mean supercharger pulleys and air filters. I get it, it’s all about sales for them. They will spend half a day talking online about a new air filter pipe they have developed. This goes along with a ‘Stage 5.32 flash’. Now, I’m not taking anything away from these guys, but it’s not for me. I like to spend lots of time developing, datalogging, ect and so on.
We are currently the only Jaguar tuner racing. We tune Jaguar race cars regularly. We have tuned various Jaguars with various Championship wins. We’ve developed (as far as I’m aware) with Swallows, the most powerful Normally Aspirated AJV8. We’ve developed, and tuned some of the most powerful V8 Supercharged AJV8.
Working heavily with Swallows Jaguar on various projects has allowed and we form very close ties. Swallows had taken on a project for a customer that was already fitted with a Manual gearbox, and a Kenne Bell Supercharger. The project had been put together in around 2012 by the owner. It was commonly known that the Jaguar S-Type Diesel gearbox fits onto the AJV8 bellhousing. The car had this gearbox fitted, and a clutch and flywheel from another Jaguar Specialist. The car would run, but not well. There was too much going on frankly to be dealt with in one hit with the OEM MB279700 ECU
Tom from Swallows Racing had mechanically converted an S-Type R to manual already, so we were able to use this car as a development car to an extent. We tried all sorts of external modules, and CAN replicators. We could get the car to run with no lights on, but the car didn’t drive well. The revs would hang massively between gear changes. The car was very ‘jumpy’ at low revs. All traits of an Automatic tune being expected. The ECU transmits torque over CAN to the TCM, among other things, and it was very hard to get anywhere near an OEM feel. It ‘worked’, but we gave up very quickly. It was never going to be a flexible solution honestly.
The customer decided the obvious thing to do would be to upgrade the engine management system with something more useable and tuneable. After various conversations we ended up building a new harness and fitting a MaxxECU Race to the vehicle. Swallows Racing went through the vehicle and upgraded lots of parts. It ended up with a fresh 4.2 being popped in, along with a relevant upgraded clutch, headers, exhaust methanol injection and so on!
We spent lots of time on the dyno, and ended up hitting over 700bhp (fly) on a Dyno-Dynamics!(No American crazy readings here!)
This opened our eyes honestly. The car drove well. What if we could sort this in a road car. Properly.
There have been other attempts at Manual conversions on these cars. Most of which have some problem or another. Aftermarket ECU’s being run in fuel implant mode, and various different converters to try and make the OEM CAN-BUS play nice. Generally though, we wanted to try and get everything working as it should. A seamless conversion. Running fully on a standalone ECU system. All the gauges, the traction control, the cruise control. A seamless OEM conversion. I was in, all in. Lets do this!
We’d already started the conversion on the S-Type R for Meguiars, another project we worked closely with Swallows on. Some of the CAN Protocol was the same. The ABS was different, but some of the addressing was the same as the late X100, so it was a good place to start. The adaptor harness and connectors were also similar.
We quickly began to realise that the ECU control all manner of other bits and pieces. Thing that seem mad. The handbrake switch is connected to the ECU directly. This sends a signal over CAN to the instrument cluster to bring the light on for arguments sakes. Lots of stuff, not just the tachometer!
Tom and the guys at Swallows started to build a nice pedal box. Most of the mechanical side of the Manual conversion is fairly straight forward being brutally honest. By this time, I’d built my own race XKR with a manual gearbox. Even an OEM propshaft will bolt up! I’d used a race pedal box for my car though. We needed something that we could bolt into a road car, and it not feel awkward, The pedal position, the bit point all had be spot on. Swallows got on this and made a few variations until they were happy.
One of the hardest things to do on the later version of the CAN Protocol (There are six!), was sorting the ABS communication. I spent some time getting this nailed I don’t mind telling you. There is a redundancy check on the CAN. I managed to replicate this along with the other messages in the end.
Finally after a few hundred hours, we had something that could be used! As it happens, an E-Mail came in from Drivetribe to Tom at Swallows Racing, asking if they would be interested in a Youtube series and build a Manual XKR! Tom triple checked with me, and we got involved!
If you’ve not followed the series and fancy having a watch, the link is here:
Following the Youtube series, Swallows were indundated with requests to manual convert customers cars! The phrase used by Richard Hammond when he drove it was
‘The Car Jaguar Should Have Built’
So we kept building harnesses for Swallows to use in their Manual swaps.
I’d decided then, that I’d quite like to have a bash at popping in the 8HP gearbox. This is the gearbox that is fitted to many cars. Many high performance cars, and widely considered one of the best gearboxs on the planet. A factory torque limit of 700NM, 8-Speed and lightening quick shift speeds.
I then 8HP Swapped my race car, which moved the whole project in a very interesting direction!
Once I'd proven that the 8HP (8HP70 in this instance) could be used on the AJV8 relatively easily it got me to thinking about providing a road going version. The X100 came fitted with the Mercedes based 5-Speed Automatic, or the later 6HP gearbox. Both considered very old hat nowadays. Both are very 'slushy' by modern day standards, and are now all old and are becoming troublesome. The 8HP is not just one step forward in drive and efficiency, it's 3 or 4!
The 8HP Project is moving forward. We have opted to use the newly released (27/07/26) MaxxECU Track.
It suits the project perfectly. It's designed specifically for a V8. It's twin LSU5.2 wideband Lambda sensors will make the car as efficient as it can possibly be. Coupled with a more modern gearbox, it'll be the perfect ULEZ car!
I'm currently on the 3rd revision of our adaptor box. I want the fitment to be as straightforward as possible for these cars. It's ultimately still going to need to be completed at a workshop. Swallows Racing will be converting the cars. Certainly in the beginning.
We have opted to remove the J-Gate in favour or the JLR stick looking shifter. They are leather bound, and suit the car far more than the BMW shifter ever will. It suits the interior perfectly, and has light up gear indication. I'm utterly convinced this is a good move.
We currently have a steering wheel being modified and retrimmed, so that we can introduce a decent paddle shift arrangement. We can utilise the system that is already prewired for the cruise control system for these paddles. Another great step forward with the project. This will be a great feature, and add I think another engagement level into the drive.
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