Thunder Saloon/Car Audio?

I’m sure is the first thing on many a diehard blue oval/power hungry enthusiasts tongue, It’s not very often we get a customer requirement such as Gavin Diamond and his incredible Sierra RS Cosworth.
• 539.4BHP @32lb of boost
• Secret Spec SCS cams
• Peened and balanced low comp bottom end
• Super Clutch twin plate mated to a Tremec TKO box
• AP Racing 330mm 6 pots
• Dymag 5 spoke wheels 7.5 and 8.5 x 17 respectively
• Proflex fully adjustable remote reservoir shocks with 350lb front springs and 180lb rears.
This was going to have to be a special build to cope with the stresses and strains this car can produce.

So our brief was to get the stereo to the same level as the car, without compromise and to retain stock looks that could eventually be shown. We decided to go with JL Audio products on this build with a set of JL C5 650’s up front and a JL 10 W7 in the boot. All powered from the fantastic JL 600/4 HD amplifier. The power these little amps manage to supply from there foot print is surprising to say the least.

The front doors in the Cosworth didn’t present the right type of mount we required for the 6.5 mid bass drivers which presented us with our first problem, not wanting to either A, cut the door card, B, cut any metal away… Fast forward to the third attempt and we were finally happy with these bespoke pockets trimmed in a matching grey synthetic leather. The first 2 designs worked but we just weren’t happy that they tied in with the car enough. regardless of compromise the designs still have to not only cope with the ruggedness of the car and its power but also tie in with what has to be one of the most “simple yet difficult” interiors we’ve come across. The tweeters were placed in the standard speaker locations mounted to custom baffles to ensure a snug fit.

The boot was to be functional and able to been displayed yet not over the top. Gavin also wanted some pockets to store bits and bobs in. This wasn’t a problem and they were placed to either side of the boot, in a factory manor. A vented load cover was also built to make full use of the boot and not take away any of the systems capability.


We managed to get the right capacity from a section of the huge wheel well for the W7. This was then trimmed in charcoal grey alcantara to complement the factory look grey carpet.

With a massive strut brace between the rear turrets the integrating both the back board and amp rack was a challenge but we think you will agree the outcome looks awesome. It would have been rude not to utilize the cars brace in order to strap the amp rack down to make it as secure as everything else.

As with all of our systems it was then tuned to give the best sound possible. In what is one of the most impressive, yet understated cars we have had the pleasure of working on. We anticipated the cars arrival like a bunch of kids!
Here are some more pictures of the build. We hope you enjoy something a little different to our normal builds. Any questions or queries based on performance cars and weight/car audio/good sound then feel free to leave a post entry on the blog, one of us is always around to justify the benefits of good sound.






As always comments are welcome
Paul – SIC