I've been hunting down and collecting Aston Martin DB7 GT parts for a few years and recently reached a critical mass of assemblies that are ready to install.
The 3900 Lbs / 420HP DB7 GT was tested at the Nurembergring with a time of 8:23. That's right up with with the E46 M3, Porsche 911 Carrera, Porsche Boxster, Jaguar XKR and that time bests a few other very high performance cars.
https://en.wikipedia.org/wiki/List_o...eife_lap_times
It's amazing Aston was able to take this 40 year old suspension design to that level. So the Aston DB7 GT Suspension, Brakes, 100 more HP and 300 Lbs less weight are being fitted to The 2015 Coupe. Its becoming the XJC GT. All this for some track time at Lime Rock on June 2nd.
Some chassis ideas from the 2018 Coupe stiffening project will be implemented too.

Technical Details:

Brakes.
Front: 14inch 355mm Drilled Brembo with Alu hat
Rear: 13 inch 330mm rear rotors and Brembo caliper

Suspension:
Much stiffer springs. (800Lb/in est) Remarkably similar to XJ springs but with with Eibach logo. Same 4 active coils. I'm using normal DB7 springs as I have much less weight to manage up front.

Bilstein Shocks (Probably same as XKR). Much larger shock with increased capacity

Very different Suspension geometry. Lower Ball joint moved out for Much improved scrub radius and camber change ratio. Similiar geometry to XJR
Thicker front and rear sway bar.

Quicker ratio steering rack.

Engine:
Engine remains the same for now as it provides more power and less weight than the Astons Ford derived V12.
Aston 420 HP 13.6 1/4 mile time.
XJC GT 500HP est. based on 12.6 1/4 mile time

Observations
XKR derived shocks are large and noticeably softer than the yellow Bilstein shocks typically fitted to our cars for performance but also stiffer than the KYB shocks.

Lower control arms are larger, thicker and noticeably lighter than the OE lower control arms. Must be some sort of newer allow of light weight high strength steel.

Spindle assemble is 1 piece without separate steering arm. Much lighter that the OE setup but slightly heavier that my 12 inch Wilwood setup.

I haven't had it out on the road yet but soon. Very soon.

Bushing are of a higher quality but still rubber. Lower control arm used OE like bushings but with hard urethane washers to limit movement. Can be seen in pic. Aston's were RED but brittle so I made some new ones.




14 inch alu hat brakes.



Revised Suspension



LCA limiting washers.



Eibach Springs

 

Are the control arms just aluminum? Stick a magnet on them and see if they are ferrous.

Whats the minimum wheel size due to those bigger brakes?

 

Crazy that worked!

Rusty

 

super cool!

 

LCA's are Steel. The metallurgy is fascinating to me. Beefier than the Jag item, yet lighter. I havent got to fitting wheels yet. But I have a hunch the 18 inch AML DB7 wheels will fit just fine. Tom Walkenshaw engineered the DB7 so I suspect much of what he learned racing the XJS found it's way to the DB7 GT and now the XJC GT. Sadly for us... I know of nothing he learned from racing the XJS that made it to a production XJS.


Here's a better pict of the LCA arms difference in length. This moves the lower ball joint out and since the upper ball joint is in the same place you have an improved scrub radius.



AML LCA on the Left. JAG LCA on the Right.

 

It would be worth contacting th current walkinshaw xjs owner for some pictures of shell strengthening, apart from the cage. I believe one was in Australia for years and recently returned to the UK

https://www.autoclassics.com/posts/r...ed-jaguar-mind

 

I've think ive seen it... it has a full tube frame no?. Engine is set very far back too. Perhaps that's a diffrent car. The details are not well documented as far as I can tell. Not much Jag left in Tube frame. That said XJS are much stiffer than an XJC, there are a few key production differences in how the frame rails mate to the firewall section and floor.

 

Mike Roddy would be a good guy to talk to - he restored and raced the Walkinshaw XJS

 

You should have a Lot of fun with that!
(';')

 

 

The use of taper bearing necessities a rather long and large stub. Jag didnt switch to the use of modern cartridge bearings until the XJ8/XK8.

You will need to late DB7 spindles and DB7 LCA
or...
Use XJ8 spindles and a custom steel tube LCA.

I was planning the later a few years ago but found the DB7 stuff. Making LCA's requires great welding proficiency, a tubing bender, tubing notcher, a jig table and others skills, knowledge and time I dont have so I choose the DB7 route.

 

After a few days of driving I can say... it's a proper sports car now yet still maintains all it's manners but with an edge.

Been driving the XJ6C GT for few days on the 265/35/R18 wheels /tires and the harshness is up noticeably but handling and road holding has been increased exponentially. The Dampers and 1100Lb/in springs are no where near as stiff as I expected but handling and feel is much improved. Aston really got it right.

The Brakes are too much for the weight of the car. They lock easily and quickly activate the ABS. I'm going to see how it goes with some fresh rubber.

Those 35 series low profile high performance tires have exposed some chassis flex so.... send in the welder.




Lower brace triangulates torque box




Completed ladder brace trangulated the relationship of the inner frame rail to the outer re-inforced sill.




After some testing and driving... additional bracing was added to link the inner frame rails to the tube reinforced outers sills. It made a significant difference in solidity over broken pavement. There less cowl shake with the performance tires even when pumped up to 45 PSI over broken pavement. I plan on continuing the idea with some more bracing a bit further back.

Spot welds for the frame rail were carefully located so the ladder brace would be working against solid and boxed metal.

 

What no Pictures!

 

There's 3 pics. Something is wrong with the forum.

 

 

DB7 wheel 18 X 9, sits a bit high with the 2 spring spacers. One or both of the spacers will likely come out once I finalize what size wheel I'm running. Silly to have left them in.





265 35 R18



New suspension geometry allows fat 265 tires with no rubbing lock-to-lock.



Tires easily clear new ladder brace.

 

series 1 bumper? looks good!

 

Looks good! Is that welded into a steel tube running inside the sill?

Makes good sense

 

That's way more room than I thought! I too gambled on washers and spring spacers> Going to be awhile before I know though!.

I am going with the asteroids i just love them! I Have 5 of them all restored and powder coated. I'm just not sure tire size yet.

Where is Blue?

Rusty

 

Very nice work !! Should be tons of fun !


I can only add:


1. Circa 1953, I paid to lap at Nurembergring Alas, limited HP in my bran new 53 MGTD!!


2. Herschell McGriff got back into a NASCAR racer and completed a 100 miler in a borrowed car. OH, and did the Anthem on his trombone. He is 90 years old!!!


Carl