Google Group 44 Jaguar XJS. You’ll see what my car will look like when finished. It’s a serious race car. Weight will be down around 2700 pounds. Horsepower around 550-600.
If you don’t like those flairs, but are willing to do some work TWR raced with 17x 11 inch in front and 17x13 inch in the rear. Looking at the cars it’s hard to see how he did that. But it’s doable. If you want you could probably get away with 16x8 and a 30 series tire. With very little work on the fenders.
Purists will hate it though.

 

All depends on the wheel offsets/ back spacing. I'm putting on 15x9s with 275/60. 4.5inch back spacing (0 offset)

The group 44 were custom 3 peice wheels iirc

 

I'm kind of bring this thread back from the dead a bit.

This question could be for anyone, but based on an earlier photo maybe it's mostly for @Mguar since they posted some interesting pics of their rear fender work.

While I'm thinking about ways to buy myself some wheel well space, lighten the car, and replace body panels....
How structural is the rear outer fender? Is it possible to remove and adhesive on a new composite panel without creating other issues?
What does it look like structurally? Is it similar to the front outer fender where we have the metal then a liner and that's basically it and most of the integrity of the rear end comes from elsewhere?

It seemed like that's what was implied earlier in this chain... but I want to make sure. If the answer to that was yes...
Then is that crease in the body line below the roof pillars (I have a coupe) the right place to stop with a composite mold? And then use something like Bondo to fill the gap between the composite and metal parts to restore the smooth line?

Pictures of what others have done, especially related to how to handle these rear fenders would be greatly appreciated.
It sort of seems like if I need a little more wheel well space and can make composites, that might be a decent way to do it.
Even if I don't go out of my way to add extra flare, using a stiff composite changes how the fenders can be braced/lined/protected from road debris within the wheel well area which could buy me some space.

If that perception is wrong, I'm sure someone will let me know, but I want to actively encourage it correcting me this time haha. I don't want to walk into cutting up a fender, rusted or not, without having a decent understanding of the consequences.

 

For full metal modifications, you might want to see these threads:

https://www.jaguarforums.com/forum/x...rilege-153935/
&
https://www.jaguarforums.com/forum/x...-243283/page2/

Paul Hands made probably the loveliest looking widebody XJS in the form of the XJS Hypersport III (first done in metal), and may have some thoughts about the structure.
https://www.historics.co.uk/buying/a...rt-jaguar-xjs/

Personally, money no object, I'd be going for the EASY weight removals first (panel wise) Hood, Fenders, Trunk Doors get harder as you have to consider crash structures. Same for the roof and rear quarters. If it's going to be full race, it hardly matters as you'd be putting in a roll cage anyway, and at that point most glass could be replaced with Optic Armor Windows.

~Paul K.

 

All custom work involves personal taste and judgement.

To answer your specific question, the rear panel serves only to cover the fender. So it’s not structural any more than the trunk lid is. The chassis strength goes from the front sub frame to the inner engine bay panels. Up through the roof and down through the rocker panels. To the rear sub frame.
Fiberglass will not afford the same crash protection as the factory designed steel panels. To retain that strength would require the use of carbon fiber and Kevlar.
Attachment can be either adhesive, fasteners, or a combination of both.
The street panels use body lines as joining points but will require careful filling to eliminate any potential for visible cracking.
As a racer I will not worry about that as much as someone intending to use it on the street should. With different materials affected by sun and heat the potential exists for paint and even bondo cracking over time. ( years)
Group 44 raced 3 different cars. The first weighed 3150 pounds and was all steel. Those original flairs were done by cutting out the required clearance and then welding in steel panel to connect the outer pieces. That requires exact measuring and real metal working skills. Plus a lot of time.
The second one weighed 2740 pounds and had all fiberglass fenders, hood, and trunk. ( in carbon fiber/Kevlar a few hundred more pounds could be removed.
The third one was tube framed and all fiberglass except the roof and aluminum floor. It weighed 2350 pounds So that is the difference between steel and fiberglass

I will be using 15x10 wheels because that is the largest allowed in vintage racing. Your wheels with 4&1/2 back spacing should be fine.
TWR used 17x 9 in the front and 17x13 in the rear without fender flairs. But I’m very sure some real artisans worked on those fenders to afford that clearance. Not to mention that the spring rate was almost tripled and basically the car appeared to ride like a rigid go-cart
Racing, the forces are smoother and less likely to cause cracking than the pot holes and bumps on the street. In Vintage racing far less likely to be in accidents than on the street. Contact in Vintage racing is taboo and seriously dealt with. In more than 40 years I had one trivial accident that took less than 15 minutes to completely make invisible.

 

Thank you for the information both of you! It's interesting, and less expensive, seeing what other people have done before trying myself

I wonder if in the TWR car, they didn't have the bump stop in the wheel well in the rear and instead had bump stops in/on the coil overs like I've seen on other cars?
Based on what I see in my rear wheel well, being able to grind all of that off would buy me in the neighborhood of 1/2" to 3/4" of extra backspacing.

That's 4&1/2 backspacing for which sizes? I made a different post about 245mm on 8.5" in the front and 285mm on 10" in the rear and that backspacing I don't think would cut it in the rear?
That said, I don't know if I'll really go through with that. I'm not sure if my car is modified or not, but when I used my mock ups I noticed I had more room than I was expecting.

The front seems like it'll fit fine. The rear bump stop will stop the suspension travel about 3/4" too late to keep a really wide wheel from rubbing on the fender lip.
It looks like in the rear I have a spray in liner (similar to Rhino Liner for a truck bed) which I can't believe I never noticed? But that means I don't have a real liner in my way, really just a fender lip.
Which again, I wasn't expecting based on other posts I've seen around. I thought it would be much worse.

As far as crash safety, that is a pretty good point to remember. Not necessarily for me, I'm volunteering for whatever hunk of mostly British engineering I end up in, but any passengers are worth thinking about.

 

You could roll the fender lip under rather than cut it off. It’s simple and straight forward. The tire cushions everything and folds the lip under without need for paint work.
You can gain an invisible inch or so using a hydraulic Jack and a sand bag with a 2x4 behind it.
if you do it gradually it’s not at all noticeable. It looks factory original.
The easy way is with a old wooden baseball bat. I’ve enough experience doing body work that I’d hammer and dolly it.