Jay Belknap's E53 X5 4.6iS S3
Photography by Dan Wagener & Ryan Lee
Traditional love stories typically begin with "once upon a time" and end with "and they lived happily ever after." Most people would hope that held true for every relationship, but through past experience we all know it to be an unrealistic expectation. Some relationships can start out as planned, but take a turn for the worst. Others may start out rough, but were all worth it in the end. For Jay Belknap and his 2003 X5 it was the latter.
Ever since Jay had a daily driver it's been some sort of truck/utility vehicle. It was something cheap and paid off which allowed him to sink money into his 1994 Mitsubishi 3000GT VR4. Well, once he was satisfied with how the VR4 turned out, he figured he'd get the truck he had always wanted—a Range Rover Sport (Supercharged). So he went on the forums and asked the owners how they liked them… half said they were awesome, and the other half didn't know because they were always at the dealer for service. He then started researching the runner-up, the E53 X5 (keep in mind this is before the X5M had made its debut). Jay found that the 4.6iS could be supercharged through Dinan for a modest cost (much more affordable than what G-Power wanted to supercharge the 4.8iS for) so he decided to look for a clean one in black. Months of searching showed no luck and he eventually gave up.
One day about half a year later he randomly browsed for X5's on the market and found a one-owner 4.6iS (with 85k on the clock) for sale in Texas. It just so conveniently happened to be Black Sapphire, supercharged, and come with Brembo brakes and an E46 M3 wheel already installed. Skeptical that it had to be some sort of scam, additional photos proved it was in fact the real deal. He took a flight out to Houston a few days later with a check in hand.
As he walked out of Houston International the black X5 whistled down the arrival ramp. It was freshly detailed and ready for him to take on a road trip back to Virginia Beach. He got in, exchanged pleasantries, got the paperwork done, and proceeded to drive to drop the previous owner off at his work. But as soon as they left the airport, boom, check engine light. The previous owner said he had a guy who was an old BMW master that did all the previous work and that he would have it fixed, right then. So they headed over to the shop and found a boost leak from a clamp that wasn't tightened down all the way. Already 4 hours behind schedule, Jay was ready to head home. When he finally got onto I-10 East, he punched it and the supercharged M62B46 said let's do this. He was instantly hooked; forgetting that the Range Rover Sport even existed.
After about an hour into Louisiana though, the supercharger belt decided it was no longer going to be friends with the engine. It took out every other belt and the A/C tensioner on its way off the motor. Jay shut the truck down and got a tow back west to Texas. That tow truck broke down so another tow truck took him the remainder of the distance West on I-10 to a hotel in Beaumont, Texas, two blocks away from Beaumont BMW. He figured he'd be the first one into BMW the next day, get it fixed and be on his way. Well, he was the first one onto the lot, but the secretary arrived and informed him that their service shop is closed on Saturdays. She invited him inside to call yet another tow truck, to get him further West to Momentum BMW in Houston. It was at that time the service manager, who was coming in to do his end of month reports, had overheard Jay's situation and started calling his techs. One was awake and said he'd be right in. They got him back on the road with just a new main belt (no A/C belt/tensioner or S/C belt). The previous owner called back and paid BMW for the work. Jay thanked him and said if anything else happened on the way home that he'd take care of it from there (nothing more did happen though). He later found out that the blower bracket tensioner needed an alignment.
Needless to say it was not a desirable first 24 hours of ownership. On a good note though, Jay later established a relationship with Dinan's after-sales support team. They got him set up with the parts needed to fix the tensioner rod, belt, etc. Like any machine, it needed maintenance, even the supercharger stuff.
Now to the untrained eye Jay's X5 may appear as if it came this way from the factory, but the finer details tell all to this rare beast. If you're not familiar with the 4.6iS model, it had a very short 2002-2003 production run. BMW had injected the standard X5 model with steroids metaphorically speaking, just like they do with the ///M models. These factory enhancements included larger fenders flares, massive 20" wheels, larger/louder exhausts, a unique variant of the 5HP24 transmission, aggressive camshaft profiles, the high flow intake manifold from the older M62 cars, bored, stroked and compressed to a 10.5:1 ratio producing 342hp/354lb·ft. What makes Jay's X5 even more rare is that it's 1 of 27 Dinan supercharged X5's in the world. The Dinan Signature 3 package consists of a Vortech V-2 S-Trim Supercharger (5.5psi), MAF, throttle body, DME flash, EGS flash, Delphi 37lb injectors, and E39 M5 fuel pump.
One common goal of any true performance-oriented enthusiast is to put as much tire on the road as possible. With that in mind, the weight of the vehicle, the additional power and simply because he wanted the ability to rotate tires, Jay sourced another pair of 20x10.5" OEM Style 87 rear wheels. He then got a fresh set of four Bridgestone Dueller HP Sport 315/35/20's. The improvement in grip from the 12.4" wide tires up front was night and day. The concave design of the Style 87 rear wheels barely cleared the eight piston Brembo calipers but didn't require a spacer like previously needed with the 9.5" fronts. To accommodate the lower offsets, he also added the X5 LeMans edition front fender flares. The rear wheels were spaced out 25mm with H&R DRA style spacers to help balance the front-to-rear track width. A Dinan strut bar and camber plates were also added to help brace the seam welded chassis for the twisties. The Brembo GT brake system 380mm (15") front, 355mm (14") rear helps bring the tank to a halt on demand, without a hint of fade.
At around 107k miles the supercharger's high speed bearings on the impeller shaft got a little noisy. With help from friend & mentor, Tony Acker, they had sent the blower off to Vortech, and performed the M62 timing guide & valley pan job at the same time. Vortech returned the supercharger with a newer Si-Trim impeller which meant more mid-range power than before.
During the summer of 2011 Jay decided it was far too hot out and had lost trust in his OEM water temp gauge. He also wanted to be able to read and clear codes on the fly so he removed the cluster (fixed the infamous pixel problem while in there) and integrated a PLX Devices DM-100 into the cluster. In addition to OBD date, the DM-100 was installed with PLX Boost, EGT, dual WBO2, and oil pressure modules. Other installed electronics include a Tekonsha P3 trailer brake controller, and a hardwired K40 Dual front/rear RADAR detector and front LASER jamming system.
With the 107k refresh and monitoring equipment fitted, everything was working tip top. Then one day as he came up a steep on-ramp that had a sharp crest to it, the X5 got airborne for a split second. Unluckily for Jay, he was at the top of the engine's 6600 rpm range when it happened. Inertia took over and all the exhaust valves slightly mushroomed—two cylinders were bad enough to notice under load. Making matters worse, the intake cam gears spun about the cams slightly. With Tony's help, they did compression, piston height, and leakdown tests. They removed the heads and sent them off to VAC Motorsports for a Stage 1 upgrade including Stainless Steel Intake valves and Inconel Exhaust valves. While the truck was down, he got bored and looked for other parts. He happened to find a very rare, new 4.6iS Tubi Rumore catback exhaust with serial number 9 stamped on it. Tubi is mostly known for making exhausts for exotic cars so he was surprised to discover that they even made one for the X5. After receiving and installing the original heads, now blessed by VAC, a huge improvement in power and efficiency was found.
All told, this X5 produces around 475bhp. Although Jay's never taken it to the drag strip, he'd like to think it's possible to break 12's in the 1/4 mile. Not bad for a 10 year old German tank, which is the reasoning behind the name "Panzer".
Today, Jay’s 4.6iS S3 has 135k miles on it, and has been supercharged for 133k of those miles. He would like to thank Dinan Engineering for their outstanding after-sales customer support. Jay would also like to send a huge thanks to Tony Acker for his knowledge and time spent keeping this X5 running so strong. Stronger, in fact, than the day he first got it, many years and many miles ago. So does a bad start have to equal a bad finish to a relationship? In this case, it most definitely did not.
