Hello all, this is Andrew from Jaguar Specialties. I wanted to pass along a little update on a project we’ve had going here for a while (actually it was 2 projects- more on that in a bit). The purpose of this post is to share technical info for those interested to know and understand it. It is absolutely not here to convince anyone to do anything. This is a technical forum and this should be viewed only as a technical post.

Some of you may already know that we offer conversion kits to put GM LS engines and matching transmissions in 1997-2002 XK8 (and now XKR as well) cars. The XK8 kit has been available since approx 2012 and we upgraded our software within the last year to also cover the XKR models. All of the LS conversions done on these cars initially were with the LS Gen 3 engines, the first generation of the LS that debuted in 1997 in the Corvette, 1998 in the Camaro/Firebird, and 1999 in the Chevy/GMC light trucks (same engine architecture but with an iron block….). All of those installs were with either 4 speed automatic transmissions, or a 6-speed manual. GM kept developing the LS family and around 2008 or so they introduced the Gen4 versions that had many upgrades and new features, all coupled to more advanced transmissions as well. And we were itching to try one of the newer packages in a Jag.

So we located a wrecked 2009 Pontiac G8 GT with some 56,000 original miles. The drivetrain in this model is a 6.0L LS Gen4 (361hp, 385 ft-lbs torque) coupled to a 6L80E (6-speed automatic) transmission. There are many advanced features on this engine such as Displacement on Demand (DOD, which disables up to 4 cylinders under light loads; also known as Active Fuel Management, AFM). The transmission is advanced too having close ratios as well as 2 overdrives (5th being .85 and 6th being .67). Interestingly, the transmissions now have their dedicated controller inside the main case with the only major communication with the car/engine controller through the 2 wire CANBUS system. That greatly reduces the size of the engine ECM compared to earlier engine and transmission combo controllers (LS Gen 3 packages)

Anyway we pulled all of this together into an XK8 and it was a cupcake of a project- no real headaches and a good fit all around. The package was first put in a 97 convertible and finished down to the running stage when suddenly we came across a great deal on a 97 coupe, so everything from the convertible was transferred to the coupe. You can see the full buildup of this package into the convert here on our website:

Jaguar Specialties

The coupe is now up and running/driving and is just FABULOUS. Here are a few observations after some initial test miles.

1) Power- Even though this engine is only about 5% bigger in displacement than the earlier LS engines we’ve used (6.0L vs 5.7L) the difference in power is amazing. I have a feeling GM was very conservative with that 361 hp rating and it feels like it’s actually closer to 400hp based on how much my seat frame has been creaking under hard acceleration….And this is coming while still using the relatively sedate 3.08 open diff. We have a 3.27 posi unit here as well maybe waiting for this car…… or maybe not….

2) Transmission- the additional gears in the trans make for a very well matching unit to the engine. As you would expect, the extra gear sets make for very small drops in engine rpm through the shifts. That keeps the engine in the same powerband area from gear to gear and the power on and pushing you back in the seat. One feature that will absolutely need to be incorporated is the tap up/tap down shift feature originally on the G8. That allows the driver to put the trans in a basic “manual mode” and via a rocker switch on the steering wheel, or by moving the shifter itself forward or back, holding the shifts to where he wants them. In automatic mode, and less that 50% throttle, the transmission controller goes up through the gears quickly which may not be how a performance-oriented driver would like it… The TU/TD feature deals with that and is part of the standard G8 programming- it is purely a hardware install to enable it. Note- as it is, the stock XK8 shifter works perfectly with the GM trans giving you most basic control- P-R-N-6 (on the left side) and then 5-4 on the right side. One very helpful addition that is on the way is a digital gear indicator readout, very similar to what the original G8 dash cluster had. That would be very helpful, especially with the TU/TD feature enabled- we need to know what gear we’re in….

3) Drive by wire- believe it or not, this was our first LS-jag with drive by wire throttle and it is as smooth as silk and instantaneous. I was very interested to see how that all would work in the Jag and it seems perfect. You can see how we dealt with the relatively large GM DBW pedal and integrated it into the XK8 in one of the buildup pages from the link above.

4) Exhaust- on this build, we followed the same basic formula as the earlier cars:

a. Standard GM high flow, 2 ½” outlet cast iron exhaust manifolds

b. Standard GM catalytic converters (in this case the original G8 pieces; this is required for California emissions reasons).

c. Dual 2 ½” pipe from front 2 back

d. Central X-pipe crossover (approximately mid way back)

e. High flow tubular type rear resonators


This approach has been used on perhaps 5 LS powered Jags here and in each case the exhaust note was not loud, but growly. My feeling was that the combination of the factory cats, large pipe, and the crossover together do a lot for sound management. That’s why I figured the relatively light rear resonators, as used before, were all that would be required. Well in the car here, that same formula yielded a much louder exhaust note, and all I can figure is that advances have been made in cat converter flow efficiencies, as compared to the older units we've used, and we’re just getting more flow, or freeer flow, through the cats. To deal with that, the car will go back into the shop to replace the resonators with a pair of high flow turbo mufflers in the rearmost locations.

Attached are a few pics of the car and engine compartment. Cosmetically, the car is no gem but does suit the purposes of the project perfectly. The air intake is a modification of an earlier K&N high flow kit for the 2004-2006 GTO’s and seems to fit the space well. One last piece needed there is a heat shield between the filter and the rest of the engine compartment to ensure we are pulling in cooler air. In the engine compartment pic you can also see the engine controller just below and in front of the air filter (finned alum box- it is a hardened package suited for this duty). In the lower left of the pic you can see the finished wiring installation including our CANBUS interface (black rectangular box). Note- the factory Jaguar ECM enclosure covers will fit completely over this area and seal it to the engine compartment and outside moisture/weather. When buttoned up, this area will look just like a standard XK8.

I hope you enjoyed this little update. Building this car has been great fun and we’re been more than rewarded with the drive quality afterwards…..

All the best

Andrew

Jaguar Specialties

 

I LOVE IT and can't wait to do it to my xk8... I found a guy here locally who puts LS motors in everything (but primarily drift cars)... he seems very knowledgeable and I want to have you and him talk before I commit to him. I have eyes on an 38K mile 400HP LS1 (with LS6 heads) that was previously in a Jag (he pulled it and put in a 550+ HP LS3) - you know Keith... I am very excited and hope to get all started in the next month or two!!

The MAIN reason for the swap is because my previous low mileage jag decided to blow a connecting rod bearing, so rather than rebuild the jag and then have to deal with the A-Drum timebomb on the ZF 5HP24 transmission I figured I might as well swap it out for some good old GM reliability.

 

What is the weight difference between the original 4.0 and the LS?

 

curious as to the MPG for this setup.

 

Considering Andrew had a donor engine and transmission, I'm curious at the hours/cost of labour and parts for this LS4 conversion.

 

I don't believe there is any difference in weight between the 4.0 and the all aluminum LS engines. My guess is the 6 speed automatic may be 50lbs heavier as it's a heavy duty unit (a version of which is used in the GM trucks). Note- there are probably a dozen of these cars running around with LS truck engines (iron block) and that series of engine weighs in some 75-85 lbs heavier than the all alum LS.

A GM qualified tech could do a swap like this in 70 hrs or so- assuming he gets familiar (reads the book) ahead of time and accumulates the other small bits ahead as well.

MPG, if you can keep your foot out of it- a tall order- should be in the mid-20's. Now this LS with DOD could probably touch 30 with the slippery LS body, the coupe especially..... Again, if you can keep your foot out of it....

 

Andrew, it is great that you have been able to do this. But there is more to the story regarding the engine you put in the car. 2008 and 2009 Pontiac G8s and G8 GXPs are a coveted car and not too many lower mileage LS2 / L76 engine dropouts show up for sale. Production numbers for the G8 were very low. (See below) The G8 GXP had the lowest production numbers and these days this LS3 with the needed GXP harnesses is even more rare.

• G8 Sedan LY7 V6, model number 2ER69 – 8,080.
• G8 GT L76 V8, model number 2EC69 – 16,464.
• G8 GXP LS3 V8, model number 2EP69 – 1,824.
• Total=26,368.
• Two year total=38,404.

As has been discussed in the past, the Pontiac G8 was built by Holden and in only 08 and 09, GM produced this car with an E38 ECM that did not have GM Global A security. You just can't take a L76 out of another car and use the E38 ECM that comes with it. The G8 engine harness connector pinouts are about 30% different than their GM/Chevrolet versions. A regular GM E38 ECM can be reprogrammed to work with the G8 engines. (Unless you want an engine harness rewire job, you have to use the G8 or G8 GXP harnesses.) I haven't seen a separate G8 or G8 /GXP harness for sale on Ebay for over 2 years. I look for these harness on a regular basis.
Presently on Ebay, there is one L76 G8 dropout with 88K miles on it with an asking price of $6K + shipping, and 4 other engines with well over 100K miles in the $4K+ price range.

I have a couple of questions.
1. Are you using the stock G8 engine harness or a GM hot rod harness? (As I recall, an E38 series ECM is dependent on using the BCM, so you must be reprogramming the ECM to break these CAN links?)
2, Is this a new Jag-GM CANBUS interface you have created? Or have you modified your existing one?
3, Is the conversion car's instrument console and other interfaces fully functional?

Joe

 

Just to clarify

1) We had a complete G8 donor car and used the original wiring harness in the Jag (with some simplifications to make it standalone)
2) The comment about not being able to use the E38 that came with the L76 is not correct- it can indeed be done, and without reprogramming, if that's what an end user wants.
3) The LS- Jag CANBUS interface we developed for this conversion (and as provided with all of our XJ8 and XK8 kits) is GM input to Jag CAN output. Due to pending US Patent proceedings, I can't get into more detail than that.
4) The instrument cluster and nearly all other original functions in the XK8 are fully operational, as before. That includes full gauge function, in dash control of check engine light and parking brake warning light, speed sensitive steering, automatic AC function, etc.,.

Your questions are interesting- are you in the process of doing something similar to this in another Jag or another car???

Also interesting is the comment about the pinouts between the G8 ECMS and other E38 applications being 30% different. I'm not sure what you're comparing to but the 2009 G8 GT ECM pinouts are very very close to those of a 2010 Camaro L99 pinouts,and they should be. Besides the displacement (G8 6.0L, Camaro 6.2L) the engines are virtually identical. I'm sure there may be differences to other E38 applications (and there are many of them) but that may be an apples and oranges thing. For like applications, the wiring is very very similar.

 

[The comment about not being able to use the E38 that came with the L76 is not correct- it can indeed be done, and without reprogramming, if that's what an end user wants.]

- I need to clarify, perhaps I didn't write this clear enough: L76 engines out of the Silverado and Sierra trucks in the same time frame had their E38 ECM programmed differently than the Pontiac G8s and have a different engine wiring harness. The E38 ECMs are the same, but Pontiac did make changes in the G8 ECM programming between the 08 and 09 ECMs such that you can't use a later 09 G8 ECM in an 08 G8
E38 (2006) - Service Number 12603892
E38 (2007) - Service Number 12597121
E38 (2008) - Service Number 12612384 (was carried over into the 2009 model year with the G8 GT)
E38 (2009) - Service Number 12625455
E38 (2010+) - Service Number 12633238

[The LS- Jag CANBUS interface we developed for this conversion (and as provided with all of our XJ8 and XK8 kits) is GM input to Jag CAN output. Due to pending US Patent proceedings, I can't get into more detail than that.]
- I wonder if your updated Canbus interface could close some of the gaps I had in my LS3 6 speed GXP conversion I put in one of my S-types back in 2012. I gave up because I didn't have time to rewire the car to an 09 GXP. and the car has been sitting for 6+ years now.

- Regarding the harness pinouts: The E38 ECM pinouts are the same between the G8/G8-GXP/Camaro in the different harnesses. The 30% differences are in the wiring of the connectors that go to the engine bay harness, and dashboard/BCM harness.

Note too, that back when I did the mechanical portion of my conversion, using an Camaro LS3, HP Tuners hadn't hacked the Canbus and I had to use a core set of CAN-modules to get the car to run. BCM, Instrument cluster, Fuel pump module, and the ignition system module. I wanted to use GMs traction control system, so I also needed to tie in GM cruise control, ABS module, and things like the steering wheel angle sensor, yaw module and wheel speed sensor.

Correct me if I am wrong, but aren't your conversion for XK8s between 97 and 02? If I recall, these electrical systems are different than S-types. It has been too many years since I worked on the early S-type systems.
Do both the 97-2002 XK8 and 2000-2002.5 S-types use Ford's Standard Corporate Protocol (SCP) SAE J1850 specifications?

 

Have you started looking at any conversions on cars after 2002?

 

Stypes are completely different than XK8/XJ8 models so nothing that we offer there will be of help. The XK8/XJ8's use SCP but only for non-critical systems like body control, security, etc.,. The ECM, TCM, ABS module, the cluster, and even the shifter surround are on a high speed CAN all by themselves (the cluster is the only piece that talks to both systems...)

I don't want to get into the depths of LS programming and ECM options as there are too many different options and it's not really that relevant to this thread. As a general recommendation to customers and shops doing conversions with any of the fully electronic and injected GM packages, I suggest they use a matched package of engine/trans/wiring/computer so as to minimize issues with compatibilty.

And to answer another question that popped up, there is very little call for conversions on the 03 and later XK8 and XK models. It seems Jaguar sorted out their engine and transmission issues with the 4.2 and 6 speed trans, so no market there. I get maybe 3 or 4 calls a year on those. There's a message in there.....

 

Andrew. This as an exciting progression and the next step forward. Keep up the fantastic progress!

I have my 98 XK8 that I purchased with a swap in mind.
I'll hold out until you figure out how to put in a LS3 or even better, a LZ1.

I think there will be more interest in newer XK8s and XKR swaps as that generation car sees higher and higher mileage.
Since the 4.2 engines have around 300hp and the XKRs have either 390 or 420 HP. Owners who want more power can't get much more out the the engine unless they spend big dollars on the engines similar to what AVOS has done.
From this perspective, you need to put in an engine with over 500hp to make it worth while. A LS series engine will get you get higher HP for less money.
Unfortunately, dealing with Later model Ford/Jaguar CAN systems and GM CAN system makes the swap even more complicated.

It seems to me that with all of the E38 hacks and tunes, one should be able to put a LS3 into an XK8 without that much more effort.

 

Hey, just to clarify, you can put an LS3, or pretty much any LS engine into your XK8 now. There is no need to wait- nothing more than what we offer now is needed.......

I hope there is no confusion in that our CANBUS interface is very flexible and will work with all LS control systems. We did not develop anything new to make this Gen4 swap possible. And attached are some pics of a customer's 97 XK8 with 430hp LS3 and T56 manual trans.... This car has been up and running for a while.....

Not sure what an LZ1 is....






Tijoe (I'll hold out until you figure out how to put in a LS3 or even better, a LZ1.)

 

Sorry Typo: Meant gen V "LT1".or LT4 But I think these engines uses a different ECM in 2017. (So many GM engine variations these days for all the various versions of the LS engines.)

- 6.2L LT4 Supercharged V-8, VVT with Direct Injection
- Valvetrain: Overhead-valve, two valves per cylinder
- Fuel delivery: Direct, high-pressure fuel injection
- Horsepower (hp / kW @ rpm): 650 / 485 @ 6400 (SAE certified)
- Torque (lb.-ft. / Nm @ rpm): 650 / 868 @ 3600 (SAE certified)

 

If it is LT you're looking for, you'll probably want to get started on your own- we'll never do it. The vast variety of LS displacements, outputs, and aftermarket support will last as a source for Jaguar conversions for us for many years. And there are still plenty of LS varieties we haven't even touched yet- variable valve timing, etc.,. There's no need, and certainly no demand, for changing to the new LT engine family. And couple that with the very very limited LT engine choices, the technical challenges, and lack of a wide variety of even OE GM parts to help and we're done. Different ECM's?? That's just the tip of the iceberg....

So sorry to say, the best we can do for you now is a 556hp LSA supercharged powerplant. I hope you'll be able to make do......

But don't let that inhibit you- take it on yourself. I know I for one will be very interested to follow along. But on a different thread

And on that note, let's keep this thread on the LS possibilities which are real and on the table today....

Andrew
Jaguar Specialties

 

Cool stuff, Andrew. Will there be any driving videos available?

 

I'll have to look into that.... I have a feeling the car (and the sounds) would make a good video..... You might even be able to see the tire smoke from the back seat where the camera(person) would be sitting....

 

An LS conversion on a '97-'99 Coupe is near the top of my Bucket List. I want it Fast & Loud....

 

Let's do it- coupes are out there......we could even find one for you if needed....

 

I just picked up a '99 convertible for $2K for that LS conversion. I was jonesing for a Coupe but this car was offered to me last week by a friend who just wants to unload it. I am well acquainted with the car and it's in good condition, has never been driven in winter and until recently has always been garaged. It has 100K miles on it and the motor recently had the timing chain work done on it so I hope to get a few bucks for the 4.0, and keep the tranny as a spare for my 97. I'm looking for an LS motor that I hope to build up to the 400 HP range. Probably an iron 5.3 but I'd love to score an aluminum block. I'm also building a new house and preparing to move so it may be a few months before I contact you about a kit.