Hi, this is Andrew from Jaguar Specialties. I thought you might get a kick out of seeing some pics of our recent GM LS engine conversions into XJ8 models. To give a little background, we developed the conversion kits (mechanical and electrical interface) to make the install of GM LSx powetrains into these cars possible and practical. The kits work with any GM LS engine (the 5.7-6.0-7.0 all aluminum car versions or the alum-iron 4.8-5.3-6.0 truck units) and the 4L60E or 4L65E (4 speed auto overdrive) transmissions. Our electrical interface speaks directly to the Jag chassis (or CAN) without retaining the original Jag engine or trans ECU's. This is the key to the conversion, and we are the only company able to do this. Without this unit, no conversion is possible- the dash gauges wouldn't work (and the cluster itself would be lit up like a Christmas tree with warning lights), the HVAC system would be non-functional, among other issues.

Using our conversion kits, the cars run, drive and operate as original, but of course with much greater power and torque, infinitely improved reliability, and greatly reduced maintenance costs.

So now GM power is a practical, realistic, and reliable option for an XJ8 (or XJR as well). The parts cost of a conversion like this is less than a rebuilt XJ8 engine or major trans rebuild, and the increased reliability (and reduced maintenance costs) of the new drivetrain will easily pay for itself in years to come. And of course, with 325+hp and gobs of low rpm torque, these converted cars a lot of fun to drive as well....

Here are few pics of our prototype car (white 98 XJ8 with 98 Camaro 5.7L LS1) and one of our recent customers (gray 01 XJ8 with 99 GM 4.8L LS truck engine). As you can see the engines are a great fit.

PS- I also included some pics at the bottom of our 98 XK8 prototype that runs a 2004 GTO LS1 eng/trans (345hp). It's quite the ride. We offer kits for the XK8/XKR models too......

 

This is really cool and your work is impeccable, looks like it came from the factory with those engines.

Is there really a performance gain moving from a s/c 4.0 euro engine to an American 5.7? Even with an LS1, US engines are usually not typically as efficient as Euro-power; for example, Cadillac's 4.6 Northstar put out 20-less hp than the 4.2 engine Audi used in the same-time-period S4. Plus the XJR 4.0 s/c is 370hp, seems like a downgrade to move up to a 5.7 natural-aspiration that does 325hp and likely drinks more gas, am I just not getting it?

 

The purpose of this reply is not to convince you or anyone to do a conversion but to instead explain why some of our customers have done this. It is not an affront to the Jag drivetrain, just a comparison.

I think there are 3 ideas here really that make a conversion worthwhile:

1) Power- the LS engines (I believe) are intentionally under rated by GM as far power and torque, probably done for insurance reasons among others. Also, they have HUGE additional performance potential beyond stock with cams, head work, tuning, etc.,. that would easily push that ridiculous 325hp stock claim well over the 400 hp mark. And that would also boost the torque numbers well over the "stock" 350 ft-lb level. And here we are talking only about the LS1; the later LS2 and LS3's go far beyond that level to start with. And in general, the LS engines torque numbers come in at a noticeably lower rpm level than the Jag V8's- that's what moves the car around.

One other note- nearly all of the customers we have worked with so far have converted non-supercharged Jags to GM power, so the instant performance improvement of the LS1 is there from the onset....

2) Cost of running/repair- the overall cost to keep a package like this running in a Jag is perhaps 25-30% of what the Jag powertrain costs. Parts are less expensive, but so are major rebuilds (a transmission rebuild, if needed, would likely run well under $2k, including labor). And as far as mileage, we're getting greater than 25mpg, and if with some discipline, could approach

3) Up front costs- most of the cars that get converted already have major mechanical issues (engine or transmission blown, etc.,.) so the owner has the prospect of using replacement stock drivetrain pieces and live with the issues of #2 above, or go a different route, now, and put that all aside. Many do it for the performance potential which is hard to argue with. Does the converted car have the same level of refinement etc.,. of the original? Probably not, but that minute difference in feel (assuming you could even detect it if not told in advance) is a small price to pay.

Conversions aren't for everyone, but for those who like the cars but perhaps with a different twist, this is an interesting option.

Thanks

Andrew
Jaguar Specialties

 

How do those cars pass, especially in Cali, the smog test?

 

Here in California, believe it or not, engine conversions can be legal. There are some very basic rules to follow:

1) The new engine/transmission has to be as new as the car or newer

2) Only car engines go into cars- no truck engines, etc.,.

3) All emissions items on the new engine need to remain and be fully functional

4) All parts used on the engine (that can affect emissions) need to be either OE (originally as supplied by the manufacturer) or California approved aftermarket (provided with a CARB EO sticker, which means the part manufacturer has gone through an emissions testing process with the part and certified that it does no degrade emissions).

5) The new engine can only be used on the transmission type it originally came with- no Chevy engines on Toyota Landcruiser transmissions, etc., .

Following these guidelines, the car can be built and is then taken to a state run "referee" emissions inspection station. They inspect the conversion and make sure all of the correct parts are there, everything is functioning, and then they run the same sort of emissions test as all other California cars get. If all 3 sections of the inspection are good, they apply a special sticker to the car, and from there on, the car can be emissions inspected at any privately run station. In the case of our XK8, it would be inspected as a 2004 GTO.

Without the referee approval and the sticker, the car can't be registered or driven in California. Attached is a pic of the sticker on the XK8.

It can be a tough process, but if you know what you're doing and follow the rules, it's ok.

And if the conversion can be legal in California, the other 49 states are a snap.....

Andrew
Jaguar Specialties

 

Ahh, now I think I get it.

What does the conversion cost?

Regarding refinement, as a former Cadillac-man, the Jag engine does not really feel that refined to me, lol. The Jag is waaaaay more fun to drive than the Cady, but does not feel nearly as refined.

 

The conversion makes sense from a reliability standpoint with the tensioner, nikasil, water pump, and transmission problems the Jag drive train that fail like clockwork.


@vdpnyc, are you sure your engine is running properly? IMO the Jag V8 is one of the smoothest engines I have driven. It is even smoother IMO than the BMW 2.8L I6 in the 2000 E39 which I have a lot of experience with.

 

The cost a conversion varies widely depending on what eng/trans is used (new or used, LS1 LS2 etc.,.) and more importantly who is doing the work (your labor is free while a shop charges you to do it). But generally, the parts cost is typically the same as a major trans rebuild on one of these cars, and probably half what a dealer might charge for a rebuilt engine install.

Our kits are $995 for the mechanical components (engine mounts, trans mount, shifter pieces, cooling system parts, power steering hookup, driveshaft adaptors and more, and the detailed conversion manual) and $395 for the electronic interface (that key piece that allows the new engine computer to talk to the car). You provide the new eng/trans, some misc small parts, and the labor comes from somewhere....

So overall, very reasonable, and a great option for someone looking at major expenses on a stock drivetrain...

 

I think so?? In any case, it is a smooth running engine with excellent throttle response, but it certain aspects are not as refined feeling as the Cadillac, in particularly on deceleration where you feel noticeable engine braking (or perhaps it is pumping-loss?) and also the electronic throttle sensor does not "feel" as predictable as the old-skool mechanical linkage in the Caddy.

What it does do really well is drama-free acceleration, having minimal "angry-engine sounds" but yet noticeable acceleration G-Force is quite unique. The 5-speed Jag/BMW transmission is the smoothest that I have ever driven.

In your case with the 2.8 in a E39, the relatively-small inline-6 pushing a big heavy BMW 5-series is unlikely to feel very refined as it would be struggling whenever pushed hard. My Caddy was similar in weight with a 3.0liter and was tuned for Autobaughn speeds, so it was fairly slow off the line but after about 45+mph opening her up was a real thrill that would hold 3rd-gear well into 3-digit speeds.

 

Think of all you could really do with the ls package stroked to 454cid, turbos, blowers etc and all kinds of relativly cheap performance parts. Theres more for the ls series than probobly the entire history of jaguar as far as performance parts for jaguars. You cant argue with numbers...
A na ls with a few boltons can easily break 500hp and for cheap. Try that with a jaguar. To bad we really dont have more avail, but again, its all numbers
if my straight 6 would ever blow up, ide probobly do this swap in a heartbeat. Then i would have reason to swap in my jag diff with a locker cause ide have something to light up the tires

 

Straight 6? do you have an xj6 or xj6r?

 

96 XJ6 VDP long wheel base
with 01 XKR double 5 wheels, Stype HID projectors etc...

 

Very interesting stuff!

The question I have is aside from a LS engine, trans, wire harness and GM PCM what other stuff needs to be chased down over and above the "kit" you offer?

 

This is very cool and the kit sounds very affordable. If my engine ever takes a crap this is the route I'm going. You can get 5.3l truck engines, among others, very cheap.

 

That reminds me of another question...

Will the truck intake fit under the hood or is the car intake required?

 

The total cost of the swap would be less than buying just the parts to rebuild the Jag engine let alone the cost to get the cylinders re nic'd or sleeved.

I've done LS Swaps in a 92 Jeep Wrangler, 67 Camaro, 39 Chevrolet, and am currently working on a 1976 Corvette. In every case the outcome was/will be worth every penny spent on the swap.

 

lol now I have a response for all the people who are like "did they already convert that one to a 350 yet?" If I go with an LS1 I can say "Yes, the good 5.7l, not the crappy one "

I would wager that the truck intake would not clear the hood, but there is only one way to find out. You can just use firebird/camaro intakes among others.

What PCM do you use for the swap? Are there any limitations on transmissions?

EDIT: just noticed 4l60e, 65. Lots of good aftermarket for these transmissions as well. Probably beats the ZF trans by a mile!

 

Yup, you're right, the truck intake is wayyyy too tall.

We use the 4L60E or 4L65E trans (and the 4L70E would also work)- they're pretty tough and have no trouble hauling these tanks around....

We do also have one customer putting a car together with a 2010 Camaro LS3 and 6L80E trans- I'll have more info on that in a bit......

Andrew
Jaguar Specialties

 

To answer a question from yesterday, the additional cost to finish the conversion, besides our kits and the engine/transmission package is generally about $1000. I quote that number to include all of the extra little bits and outside services needed to finish. That would be driveline modifications, exhaust hookup, AC recharging, misc hoses and hardware, etc.,. Most of my customers report back that the number is pretty close, +/-.

So overall, the cost is pretty reasonable...

Andrew
Jaguar Specialties

 

If someone uses the truck engine and ends up cutting their hood and adds a hood scoop to an X308, they are officially banned from this forum, lol... that would so massacre the cars design, haha