1984 XJ6.0 Turbo

Hello all, here is the beginning of my journey of installing a turbo LS engine into my 1984 XJ6.

A quick bit of background about me - I’m a 30 something mechanical engineer with a young family working in the aerospace industry and wrenching in my spare time. I’ve done a couple of LS transplants into non-native cars and a few other “fun” cars as well (6.0 into BMW E39, 6.2 L92 into C5 Corvette, 6.0 into Crown Victoria police car).

After pulling the 6.0/80E out of my Crown Vic Police Interceptor for some winter maintenance and upgrades, I couldn’t bring myself to put it back in the car as the body was really starting to rot underneath. I vowed to myself that I would never buy any other rusty piles as I refuse to do bodywork and have no time for rust repair. Patina aside, it got old getting into a car with rusty fenders and rockers - just not my style I guess.

This one is a 1984 Jaguar XJ6 that was originally delivered with the 4.2 straight six and 3 speed auto. The PO owned the car for over a decade and babied it, never driving it in bad weather. He had a shop install new tires, brakes, go over the rear end, and even had it repainted. Ultimately as with all old cars the drivetrain started nickel and diming him to death, so once it got to the point where it wouldn’t start he decided it was time to move on. Perfectly convenient for me as I don’t need the old drivetrain and have no intention of getting it running.

Bringing it to my storage spot in November 2021:

Getting it on the dolly was a breeze with my DIY winch.

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Some more photos of the car…

It has a super weird twin (but separate) fuel tank setup with a filler cap on each side and a driver operated tank select switch. I plan on ditching the tanks and going with a fuel cell but I really want to keep the dual fillers as they’re unique and in my opinion give the car its character.

The 4.2 cranks but doesn’t run and has had many cases of “here, let me take a look at it”. It will get pulled and listed for some die hard Jag purist to pick up.

This build will have a couple unique features for me…

-Oldest car I have ever owned, and has the styling/smells/vintage feel I like from that era. No ABS, no airbags, we die like men…

-Being pre-1996 that means it will not require a state emissions inspection which has always been a hassle for my swapped cars. Furthermore, since I don’t need to run emissions, I don’t need to use the stock Express PCM, so that has been sold off and I will be running a Holley Terminator X Max. I never enjoyed the HPTuners learning curve and am looking forward to the self tuning feature. Anybody want to buy my MVPI Standard?

-Plan on running a flex fuel setup and enough fueling to support 700+whp. Never run E85 before so this should be fun. I will need recommendations on an ethanol friendly fuel cell, and need to decide whether to run a couple in tank pumps or one external. Never messed with fuel cells so that will be a learning experience.

-Still going to run the 6.0/80E that came out of the Crown Vic. Most everything is staying the same internally (SS2 and 1218s) but I’m going to need to revise the front accessories to be able to run the LS1 intake to clear the hood. The car will stay 100% stock looking, no cut up Draguar hood here.

The rear is most likely a 2.88 open so that will need attention, but being based on the Dana 44 with some minor differences a gear swap shouldn’t be hard. The entire IRS drops out as one assembly. Driveshaft is already disconnected from the diff from when I towed it on the dolly, too. I’m thinking a 3.54 or similar ratio to allow for easy highway cruising on the 26" tire.

I’m on the fence about AC since it doesn’t get that hot here in WNY, but the exhaust will definitely utilize a 3" cat that then feeds the stock Jaguar exhaust that I’m sure is whisper quiet. 3" boost activated cutout will dump post turbo, pre cat. I absolutely plan on keeping the cool s-shaped tail pipes.

Holiday update time - hope everyone had a Merry Christmas and enjoyed it despite how crazy the world is right now.

I finally made the room in my garage to be able to get the Jag home - so we loaded it up on my buddy’s trailer and hauled it home.

Rolled her big ass into the garage and got it up on the lift. Initial impressions are good - little to no rust on the unibody underneath, really just surface rust on some subframes and pinch welds. That’ll be easy to grind down and paint black - no body work needed.

I will admit that my time working in the garage has been extremely limited lately - preparing for my son’s arrival in February while watching my year and a half old daughter takes up the majority of my time. Anyhow, I was lucky enough to get out there for a whole day and remove the bonnet, and pull the stock boat anchor.

Looking like the rear sump Camaro pan will work, and the subframe has nice flat pedestals to work off of for mounts.

37 years of oil leaks, grease, grime, and filth. I powerwashed as much as I could - no photos of the after since I was pretty soaked.

Anyone want to buy the stock motor/trans? I’ve never pulled a motor this old (1984), that actually has roots dating back to the 50s. Everything is so massive and overbuilt…

Next up is removing lots of unnecessary junk from the engine bay, cleaning it up, and maybe shooting some paint onto the frame rails. Looks like someone spilled brake fluid at some point, nothing that can’t be fixed with a rattle can.

Today’s update - I brought home my freshly rebuilt 4L80E. I was kicking around the idea of rebuilding it myself but found a local builder who is experienced in the task and had it done in a week; for $600 this was far easier and faster than tackling it myself.

Part of the reason the price was so good was that I brought him 2 80Es. #1 had decent internals but a large piece of the case broken off, and #2 had a good case but fried internals.

The broken case was caused by a failed driveshaft u-joint that caused the yoke to whip around wildly and stress the case.

This is the inside of the pan of the fried 80E…not much was left.

When I was a kid, my Polish parents told me a joke about a Russian watchmaker that is brought 2 broken watches to be repaired. He not only repairs both, but has enough parts left over to keep as payment. :smile:

The broken case was mounted to a scrap aluminum 5.7 block I bought in 2014 to make a coffee table out of, but never got around to. Turns out the block is much more useful as a mockup device. Notice the massively worn thrust surfaces…this is after the block was glass bead blasted.

Just be aware that Jaguar went for the panier fuel tanks for a good reason, there’s not much room to fit a fuel cell in the boot/trunk if you want to carry anything else. Are you really set on a fuel cell?

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I’m not against using them but the fuel system requirements for this kind of power are significant. Also, by the time I refresh the various rubber hoses, valves, etc it may have been more economical to just run a cell. I was thinking about fitting one in the spare tire well, but we’ll see.

Ideally I would keep the tanks as they’re already installed, but that’s assuming they’re in good condition. Remember that I bought the car non running so who knows what could be going on with the fuel system. The stock tanks use an external pump which would be replaced with a high flow unit, but that relies on an uninterrupted flow from a single source, whereas the stock tanks have the switchover, etc.

Lots of decisions to make.

A bit to consider. Use an endoscope to see what condition the tanks are in in respect corrosion. Or, note the rubberoid plugs on the valance panels just aft of the rear wheels. They can be removed, although they are destroyed in the process. My car lives fine without them. There are drains there. A small one within a larger one. have new gaskets available. various sources for them. Much to be learned from what comes out, if anything. The pickup pipes have socks. good to renew them as well. If indicated, a good flush can resolve future fuel issues.

The factory Bosche pump can deliver a lot of fuel at a high PSI. Sorry to see that you are not going to use EFI. Far ahead of the best carb. I am now a believer.

Plumb out the selection valve. Mine works just fine. Others report issues Use two filters before the pump. And two one way valves, And a “T” to replace the selector valve. Filling two tanks is a bit of fun… I do a nice piroute when doing so.

The trans tunnel will need some percusssion adjustment to accomodate the 480 trans. Teh LS sump will need some cutting and welding.

Have another look at the Pumkin in the jaguar IRS. DANA!!!

Nothing “rare” about the dual tanks: they ALL came that way.

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Replies in BOLD below!

A bit to consider. Use an endoscope to see what condition the tanks are in in respect corrosion. Or, note the rubberoid plugs on the valance panels just aft of the rear wheels. They can be removed, although they are destroyed in the process. My car lives fine without them. There are drains there. A small one within a larger one. have new gaskets available. various sources for them. Much to be learned from what comes out, if anything. The pickup pipes have socks. good to renew them as well. If indicated, a good flush can resolve future fuel issues.

Interesting note about the sump plugs. Those might make for the perfect ports to Tee together and feed a large external pump and pre/post filters. It would have been nice to use a modern EFI basket with in-tank pumps, but I don’t think the architecture of each tank will support that.

The factory Bosche pump can deliver a lot of fuel at a high PSI. Sorry to see that you are not going to use EFI. Far ahead of the best carb. I am now a believer.

No way I’m going carb. Not only is it incompatible with my planned forced induction setup, it’s fussy and requires constant adjustment which I have zero intention of performing. The 6.0 will run a standard GM 58psi EFI system controlled by a Holley Terminator. If you have some time check out the system on Youtube. You can set your base timing and fuel now without getting of the car - don’t even need a laptop anymore.

Plumb out the selection valve. Mine works just fine. Others report issues Use two filters before the pump. And two one way valves, And a “T” to replace the selector valve. Filling two tanks is a bit of fun… I do a nice piroute when doing so.

Wonder if I can just eliminate the selection valve entirely and have both tanks feed one line. I’m not a fan of the complexity already present and want to simplify the system.

The trans tunnel will need some percusssion adjustment to accomodate the 480 trans. Teh LS sump will need some cutting and welding.

Should be easy to figure out the placement with my mockup drivetrain. Hoping to avoid chopping up the oil pan, although I did so on my front sump GTO pan on a 6.0 in my 2001 540i back in 2012 with no ill effects.

Have another look at the Pumkin in the jaguar IRS. DANA!!!

Yes, unfortunately I have the open 2.88. I have been doing some reading about upgrading to a Auburn limited slip and changing ratios, but am considering leaving it as is so I can enjoy the car this summer. Pulling the rear IRS might make for a nice project next winter. Finding a 3.31 or 3.54 Jag pumpkin is not looking good, let alone with the Power Lock.

Something to add to your “think about” list…

With this swap you might be reaching the point where the IRS mountings can’t cope with the available torque/power. The worry isn’t just that they might break, which is possible, but also that they can’t effectively keep the IRS properly located and thus effect driving/steering/handling characteristics.

Experienced lumpers can chime in here with advice. I’m not sure at what power level the mounts might become a serious issue…but they’re a weak link in the chain.

Cheers
DD

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You will be surprised when you remove S curved tail pipes, only 1 7/8 inches OD

I left mine in and enjoy the look but not the loss of HP

Hi Norbert,

For the E85 set up try E-Flex Fuel, very serious company and they have a unit that you can fully customize the fuelling and cold start.
I have it in my Range Rover V8.

As for the dual fuel tanks:
Yes, extra complexity, but a very cool feature once you get used to it and you save a ton of space in the boot.
The fuel tanks themselves have nothing inside that is non compatible with E85.
Use Barricade low permutation hoses and you will be fine.

As for the fuel pump, even though the trend Is in-tank pumps, the external pump setup has the huge advantage of being very easy to access and replace and you can leave the original tanks in place without any modifications (if they are in good shape of course).
Pretty sure there are plenty of high flow external pumps out there to choose from.

Just connecting the two tanks together is not recommended because if you park on a slope with full tanks the one on the lower side could overflow.

As for the tank switch-over solenoid:
The original is a piece of bad engineering and might cross leak or not work even if new.
See my solution bellow with a motorized bal valve. And it delivers an uninterrupted flow when switching.

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Aristides:

The park on slope issue can be solved. One way valves for each tank.

Carl

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Yes indeed Carl, but then you will have to always fill both tanks equally as they will never equalise, and if one is full and the other empty the pump might start sucking air.

Is not the same possibility with the tank selection valve in place?

One Sunday AM, dear departed and I were on the way to church. In the middle of a main intersection, the Jaguar faltered. A higher power must have intervened and I switched tanks. Power returned and we go to church on time!!!

My 85 Ford F150 enjoyed twin tanks. A selection valve as well. However, if one tank went dry, the pump continued to fuel from the other!!! Fortunately, I never had to investigate how that was done!

Carl

there’s a guy here in the Phoenix metro area attempting to do the same.
i haven’t talked to the guy for some time. i’ve no clue if he’s still plugging away at the project.
one of the biggest hurdles is header clearance around the steering shaft/linkage.
i suspect the next biggest hurdle would be traction.
i’m 400 at the wheels and it’s too much for the little 225 contact patch.
do you plan on tubbing the rear for more rubber?
i got a 3:54 powerlock xjs center section from a salvage yard in california for a decent price and put that in my lump

Good questions…

I planned on running forced induction from the start so long tube headers are totally unnecessary. My existing pipework has a truck header on the driver’s side exiting rearwards and crossing under the bellhousing to merge into the rear of a turbo log on the passenger’s side. That feeds a turbo at the front passenger side of the engine bay, with a 3" downpipe heading down the passenger framerail and out the back.

Unfortunately the steering shaft won’t allow me to go rearward on the driver’s side, so I think I’m going to exit fowards on that side with a truck manifold and go around the FEAD to join up with the turbo on the passenger side. That way I don’t have to modify the subframe, frame rails, or the steering rack/shaft.

For traction - I bolted up a set of BMW M-Parallel wheels from my previously owned Bimmers and they fit very well, although the rear fender lips will need to be rolled and the front end will need to be lowered. Tires are 255/35/18 square currently; if I need more I have some 275/35/18s that might fit out back. I really do not want to tub anything or modify the bodywork at all as the car has a fresh paint job and I despise bodywork.

Glad you found a 3.54; I’m going to try out the 2.88s for now and see how they work. The theory is that the long gears will take full advantage of the 3200 converter and help load up the turbo faster due to lack of mechanical advantage. Cruising RPMs will be nice and low too.

Lots of progress made over the past few weeks, I need to upload photos.

yes! pics please!
sounds like you’re on a path to success
the turbo should like the numerically lower gearset
wonder if those bimmer wheels would fit a series 1 xj6?

If you weren’t so damn far away, I take that whole lump right off of your hands!

I don’t see why not as long as the bolt pattern and centerbore are similar. These wheels are sized for an E39 5 Series, so 5x120 and 74.1 centerbore.