Anyone running a turbo LS V8 in their XJS. I know y'all mostly don't take kindly to swaps (lumps) but for those that have a turbo LS in their XJS, chime in. I'd like to see your setup!

 

I dont think anyone who posts here often has a Turbo LS XJS. I do have more than one high HP Jag and I can tell you after 350 HP the rear IRS moves around a lot IF you've got wheel traction. Do search for cage twist and IRS bracing and have a look at how some of the TWR XJS race cars braced the IRS. Turbo XJS would be super cool though, lots of room to set the engine back in the chassis and put a big single on the passenger side or set of front mount twins. The exhaust pipe routing on the driver side is a pain becasue if motor mount and steering shaft issues. Lots of room on the driver side for a big single but a single 3 inch exhaust will be tough fit especially with a auto trans. m

 

suppose it could be done, turbo LS in an XJS, but ICSA, is right the car was made for comfort and ride, not for hard accelleration!
it was never built for DIGS,, but just may be OK for ROLL race like 50 and up, the cage could rip loose and it may not handle hi speeds well?
but anything can be modded , just time and money!
i love the LS series engines, and GM trans.

 

I'm for sure going to LS swap my XJS. Not sure if I'll go turbo though, I wanted to see some setups first. This car won't be for racing that's for sure lol. But, a fast cruiser that can be ridiculous when I want it to be, that's moreso the goal.

 

Do tell me more. At what times does the IRS likes to move around?
I am actually curious to see what people are doing with the rear suspension too. My buddy Terry made a coilover setup for his old XJS that I envied. Of course this was a one off with lots of custom fab going on. This happened to be Terry at Fortune Auto.

Here's his car before he sold it:

 

I love them too! Cost per horsepower and easy to work on with parts galore.

 

i don't know of anyone running a turbo ls in a xjs, as far as the rear cage yeah even with a stock ls your probably going to want to brace your cage, its not the cage mounts that are the issue its the trailing arm bushings don't last and if the trailing arm bushing fails the cage mounts defiantly wont hold. i still haven't braced mine yet its on my to do list defiantly needs to be done. i normally have to change my trailing arm bushings at least once a year, one thing about a turbo is though that the power will come on a little softer than my roots blower. will be a little easier on things. i would probably stick with a automatic as well if your going to make decent horsepower. i think you will have a lot more issues if you start shocking things with a manual gear box. bracing the cage wouldn't be that hard to do. iv just been lazy about it and trailing arm bushings arn't that hard to change.

as far as fitmit there is plenty of room to the front of a v8 in a xjs engine by to do front mount single or twin turbo's clearance is a bit tight around the back cyl's i was looking at a turbo ls swap in a rx7 the other day and he was running a hooker cast manifold that looked like it would work with the xjs. i would probably point a manifold to the front on the driver side run the cross over under the front up to a single turbo on the passenger side if i was going to do it. getting a large dia single exhaust out the back would be a challenge for sure.

 

Is there a writeup on bracing the XJS chassis?

 

this is my XJS roadster , 'm in Austin TX.
lot of mods , mostly V12 HI-performance updates!
brakes , shocks, springs , couple body and rear cage braces!
ron




engine complete performance rebuild \, pistons, Crane cams, balanced , custom cylinder heads, big valves,ported polished , thermal coated chamber surfaces, and exhaust ports,manifolds.

cage mounts , as torque tries to twist the cage , bars push up, car weight pushes tires down for traction! single piece Aluminum driveshaft.

just showin off.

 

I finally got around to doing mine today still need to clean it up and paint it but basically what I did was tied the bottom of the cage to the factory x brace. That is very similar to how it was done on the db7. Notched 2 prices of angle iron and bolted them threw existing bolt holes on the cage and welded them to the x brace. This will also give a good mounting point if I wish to add another brace to the trans tunnel in the future I will say the improvements in the way the car drives is very good. Doesn't squirm when your hazing the tires at speed any more and the wiggle when you come out of a hard corner without keeping the rear end loaded is gone too. I'd even say it would be worthwhile on a stock car. No undesirable effects noticed so far.



Basically the goal is to tie the cage to the body of the car

 

Hi, this is Andrew from Jaguar Specialties. We have a little bit of experience with LS and Jags, and have a few customers getting into reasonably high output engines into the cars. And with that come some tweaks here and there for axle control in the rear....

What exactly were you thinking to do as far as a drivetrain???

Andrew
Jaguar Specialties

 

Hey Andrew,

We spoke via email a few weeks ago. LQ9 and 6L80e is looking to be the choice. Undecided if I'll go boost or NA.

 

Hey Ronbros, we have should meet up soon! I'm in Austin this Saturday with my kids and they'd get a kick out of the car for sure.

 

Getting back to the question of XJS and LS........

This may not be the best pic but it does give you an idea how far back the LS sits in the car. Even with this position there is still plenty of room for AC and heater hoses in the back (on the firewall), but what is really obvious is how much space there is in front between the engine and the radiator. A side mount supercharger would be no problem and I suppose there would be room for turbo plumbing if that's the direction you chose.... NA of course is no issue at all- the only note there is we have not tested (for clearance) any of the aftermarket LS intakes, which may or may not be too tall. The lower hoods on the 76-91 cars don't have a huge amount of space above the throttle body....

I hope that helps give you a feel for the space involved....

Thanks

Andrew
www.JaguarSpeicalties.com

 

Here are some better pics, courtesy of one of our customers from Australia- 85 XJS with 2004 LS1/4L60E. Here you can better see the space in front of the engine- enough to almost step in.

 

Thanks Andrew!

I might actually keep it NA. Though there seems to be a lot of room for a turbo, piping, and a intercooler etc. I should be able to get over 400whp with a cam and intake.

 

@EZRider any pics of the bracing?

Thanks!
E

 

Ha never mind. For some reason your pics in that post took forever to load. Thanks!