Jaguar XJC Broadspeed

[Splendid Cat]

PLLLLEEAAAASSSSSSEEEE, does anybody have any links to footage of this car?

[Al Weyman]

I know someone who is building one, he occassionally posts here and may chip in.

[David J Howard]

Hi Al (Hope you are well mate) and "Splendid Cat" .... How about I come on once every 7 months !!!!

My Broadspeed Coupe is coming on a treat .... 7.3 Litre Engine is now nearly complete ..built by Rob (Beere) and Carl ...We are trying to come to a final decision on Carburation .........I can't do all that fuel injection malarky...Perhaps my (power) loss eventually.

My feeling is that it's really down to whether we go IDF Downdraught or DCOE Sidedraught ..

Expert or well advised opinion welcome Al and Co .

The bodyshell is complete and is currently having its Roll Cage installed by Chris Bray at Finishline

There are a few websites that give background on the Broadspeed Cats ...Ole Martin Mobecks has plenty to look at and I keep in contact with him .


Regards David Howard

[Al Weyman]

Hi Dave, sounds good I would'nt know how to advise on induction unless you want to fit a nice big Holley, what did the factory effort use?

[grelley]

There was one of the original cars sold about 6 months back for I think 85k GBP. good luck with your replica. I would be looking at Electronic Fuel Injection if it was me and was allowable. By the time you buy all the required jets and chokes etc the EFI and engine management will probably work out as cheap and a lot better in driveability.
Somewhere I have an Autosport article on the originals written at about the time they first started developing them. They certainly had the potential. Pity BL pulled the plug on them.

[Tim Falce]

Originally Posted by David J Howard

My Broadspeed Coupe is coming on a treat .... 7.3 Litre Engine is now nearly complete ..built by Rob (Beere) and Carl ...We are trying to come to a final decision on Carburation .........I can't do all that fuel injection malarky...Perhaps my (power) loss eventually.

My feeling is that it's really down to whether we go IDF Downdraught or DCOE Sidedraught ..

I doubt you'll lose any top end power with carbs just drivablity and maybe torque if you can't set them up exactly right. With injection it's just a case of plugging a computer in and making the necessary adjustments throughout the rev range without the need to stop every time and change jets. Of course this all depends on you finding someone who knows what they are doing on either system on your engine.

[Peter Mallett]

Originally Posted by grelley

Somewhere I have an Autosport article on the originals written at about the time they first started developing them. They certainly had the potential. Pity BL pulled the plug on them.

IIRC it was the rims on the rear. Couldn't withstand the power.

[Al Weyman]

Dave will hopefully run this car in our Classic Thunder series which by all accounts the entry at the Oulton opener is looking particularly healthy, lets hope for a good season for this very potential series and I can't wait to see the big Cat perform as it was one of my all time favourite race cars. Personally I would have thought properly set up carbs would not loose much if anything over a modified standard injection set up and I would image could actually produce more if set up correctly. I know a mate of mine who has his SDi on multi down draughts has very impressive power and low down torque which I doubt he would better using a modified road fuel injection system. Slide throttle aftermarket injection would be a different scenario again and probably the ultimate set up for this car if your pockets were deep enough!

Talking about Peters post I have just seen above, I know Dave has experencied at least two rear drive shaft/hub failures on his Post Historic XJ12 to my knowledge so I can see that as an achilles heel still on this car especially running on proper race rubber not 225x15 Formular R Hardellies from Dunlop!

[grelley]

I think the magic words with carbs are getting them set up properly, and the associated costs. I think one of the problems with the XJC was either the rear hubs or halfshafts. The problems were brought about by the high grip levels of the tyres. This also caused oil surge problems in the engines as they had to run wet sump lubrication.
Grelley

[David J Howard]

Thank you for that Al and Grelley ... Originally they did run an early mechanical fuel injection .... Maybe now is the time to drag myself into the 21st Century !!!

Regards David ..

[David J Howard]

Hi Chaps ... I've only just seen the later posts ...Hi Tim and Pete ...


Still not decided about induction ....Halfshaft shearing at the Hub end can be a problem As Al points out I know about this first hand .. I also witnessed Brian(Stevens ) XJS give way at very high speed mid bend at Spa a few years back ..Very Dramatic!!! (Roger Bowman is punting that car now )

It happened to me at the Bomb Hole Snetterton in 2006 ..Luckily not as fast as Brians but still hairy ! The Halfshaft also acts as the top suspension joint so when it shears you have nothing and loose control . If the shaft digs into the tarmac they can flip over .

Engine wise I thought they were Dry sumped ..but could be wrong ...Rob told me that the main problem was that the power came in at quite high revs ..so they had to thrash the nuts off them .. My engine is a 7.3 litre rather than 5.3 ..and with our cams we are hoping to keep her nicely below 7000 rpm. In my saloon I run an Accusump with an anti surge sump... and am hoping to get away with this on my coupe .....


Regards to all David .

[NALUTZ]

Great to see there are still some serious V12 people out there. I love the Jaguar V12.
My Company produces both 6 and 7.5 litre kits for these here in Australia. We ran a 6 litre V12 in a Tunnel Hull Boat for about 15 years, the Chevys couldn't catch us.
There was a Jag V12 powered Hydroplane that ran in the USA back in the 80's I believe that they banned because the V8's couldn't beat it.
One of our first 6 litre kits was in a XJS that competed in the "Cannonball" run from Darwin to Alice Springs. It made a conservitive 500hp and cruised at 300kph.
Have a 7.5 litre in a XJS that kept tearing up transmissions until they put a Viper T56 in it. Then it proceeded to destroy diffs and halfshafts.
Am currently building a XJS street car with a 450hp 6 litre with a T5Z transmission.
Keep up the good work on the XJC. Don't waste your time an money with the Webers, go FI.
I'm suprised Rob (Beere) hasn't advised the FI route.

[NALUTZ]

Grelley, an associoate of mine purchased the ex Win Percy Spa car in the UK in 2008.
I believe it's last race was in NZ, where it crashed.
He uses it in Historic racing here in Australia. It's unbelievable the way it goes past the A9X Torana's up the back straight at Sandown.

[Al Weyman]

Don't worry Jagman David is doing fine in his XJ12 saloon on Strombergs as is and whopped my Camaro's ass at Brands at the weekend and also broke a lap record in our Pre - 93 race, really looking forward to seeing the Coupe when it debuts as it was my favourite touring car as well.