- Post is under moderation’CHARGED Z3 M Track-focussed monster. Words: Elizabeth de Latour. Photos: Patrick Lauder. From bone stock to supercharged autocross monster, this Z3 M Coupé has spent 14 years becoming the best machine it can be.
Supercharged / #BMW-Z3M-Coupe / #BMW-Z3M-Coupé-E36/8 / #BMW-Z3M-E36/8 / #BMW-Z3-E36/8 / #BMW-E36/8 / #BMW-Z3M / #BMW-Z3M-Coupe-Supercharged / #BMW-Z3-Supercharged / #BMW-Z3M-Coupe-Supercharged-E36/8 / #BMW-Z3 / #BMW-Z-Series / #BMW-Z-Series-E36/8 / #BMW
In America they call it the clown shoe; in the UK we call it the bread van but whatever you choose to call it the Z3 Coupé remains an incredibly special and unique machine. #BMW attempted to recapture the magic of its quirky miniature shooting brake with the E86 Z4 Coupé and while it was arguably a better car, it was also a lot more conventional and lost a lot of the appeal of its quirky forebear. Being unconventional may have caused people to fall in and out of love with the Z3 Coupé throughout its life but standing out from the crowd has most definitely worked in favour of the eye-catching machine and that is exactly why Grant Gillum ended up buying this car.
“I wasn’t a BMW guy per se,” Grant begins, “but I knew they made a quality product. As college was ending I began researching nice used cars to purchase after graduation. I wanted a front engine, rear-wheel-drive car that could be modified and used for autocross and track days. It would also be my daily for a while. After considering several cars including Corvettes, Camaros, Porsche 944s and 928s, the Pontiac GTO (not a used car at the time), Datsuns and Nissans of many years and models, I decided on an E36 M3. I liked the styling, the daily sensibilities and the aftermarket availability. They were also uncommon and more exclusive. All that changed the day that I saw a Z3 Coupé in traffic,” he says. “I had seen a million Z3 Roadsters and wasn’t really interested in a convertible. But this was different and I wasn’t even sure what I was looking at. I certainly didn’t recognize it as a Z3. It had a BMW logo so I started researching all their models, eventually finding information on the M Coupé. All the engine of an M3 but lighter, with a factory wide body, staggered wheels and a look that was comparable to some exotics. Sold. I had to have one,” he smiles. “It took nine months of scouring the internet to find the right one.
I bought a 22k mile example, bone stock but for a Dinan CAI and a stage one tune and still under warranty. I bought it sight unseen except photos and had it shipped cross country. I realized right away too that the M Coupé was a limited production run vehicle and so would be a cheap way for a blue collar guy to own something special. I bought the car knowing it would be a lifelong project car. I’ve known plenty of grey haired dudes that sold the hot rod of their youth and regretted it the rest of their lives. Not me. Hopefully,” he adds.
Unlike other owners who buy their cars and start out with no plans for modifying, Grant knew he was going to mod the Z3 and knew exactly which direction he wanted to take it in. “I wanted to race it right away and joined an autocross club soon after buying it,” he says, and his passion for autocross is shared by his wife. “Six years ago she came with me for a day at the track. She rode along on a couple runs and decided to give it a try. Except when pregnant, she’s raced in nearly every autocross event that I have since then. Averaging our times to a 60 second run, she’s about a half second off me. She’s been as close as a tenth second off my time. I’m much more of a fundamental driver, she drives much more by the seat of her pants. As soon as she tightens up her fundamentals, she’ll beat me,” he says. While you can take any car to an autocross event, if you’re serious about this particular form of motorsport, as Grant is, then your car will need to be modified and in a focussed way that will enable you to get the most out of it, which is why virtually everything he’s done to his Z3 has been all about making it a more finely-honed, precision autocross instrument.
It’s also why the supercharger that you can see strapped to the side of the engine came last and everything else came first as the chassis, handling and dynamics were the priorities here.
Wheels and tyres were the first items on what would become quite an extensive shopping list and while aesthetics do obviously play a part, lightness was mostly the deciding factor as far as wheel choice was concerned. “I went online and found the lightest wheels I could for the car,” explains Grant. “I bought a set of OZ Alleggerita HLTs in 8x17” and 8.5”x17”. They were light at less than 17lbs (7.7kg) per corner and dropped considerable unsprung weight over the stock wheels and I converted to wheel studs too.
I ran those wheels for a couple of autocross seasons before switching the rears to the front and widening the fronts to 10” and putting them on the rear. Now they weigh 16.8lbs (7.6kg) and 17.9lbs (8.1kg) front and rear; they are light, strong and handsome,” and what more could anyone ask for from a wheel? “I also run a set of 8x18” and 9x18” ASA AR1 wheels with black centres and 2” and 3” polished lips front and rear on the street,” he adds. The 17s really suit the Z3, as you can see in the photos, especially with the fat sidewalls of the super-sticky BF Goodrich g-Force R1 tyres filling out the arches and those tyres let you know that this M Coupé means business.
With lightweight wheels and track tyres taken care of, the next item on Grant’s to-do list was the suspension, and while he started off small, things quickly escalated. “I started with H&R springs and kept them for a few years until they sagged,” he says, “then I switched to Ground Control coilovers and adjustable spring perches. But not before modding the anti-roll bars with reinforcements, adding differential reinforcements, rear shock mounts, sub frame reinforcements and rear camber and toe adjustments. Then I poly bushed it followed by aluminium control arms.
“Disaster struck at the autocross one day when the diff pulled away from the subfloor and the rear end went squishy,” says Grant. “I thought that one of the rear anti-roll bar end links had given way. That’s how I got a tube frame rear subfloor that is way stiffer than the stock car ever thought of being. I love the coilovers, of course, but the single greatest suspension mod was poly bushing the rear subframe. It really changed the way the car transitioned weight in-corner to being much more predictable,” he says. As is often the case when it comes to modding, when things go wrong, break or fail, rather than just replacing them you upgrade them so, as with his boot floor, when the clutch started to slip Grant fitted an F1 Racing stage two clutch and 14lbs chromoly flywheel as well as a stainless steel clutch line and then added a UUC short shift kit and double shear selector rod plus a Z3 2.3 steering rack. Further drivetrain upgrades include a poly differential bush, UUC aluminium engine and transmission mounts and a rebuilt diff with four clutch zero preload and 80/60 ramping, polished ring and pinion gears and a 3.64 final drive in place of the standard 3.23 item. “Before the supercharger, lowering the final drive was a really dramatic NA mod. It went a long way to help pull me out of slow second gear turns,” explains Grant.
With the suspension and drivetrain taken care the Z3 was a far sharper machine but now the car’s stopping abilities needed to be addressed. “When I started doing a lot of track days it was apparent that the stock brakes were not up to long days of abuse,” he says. “That’s when I did the brake conversion and ducting. What a difference and zero fade. I didn’t go too big on the disc diameter as I was concerned with reducing as much rotational weight as possible, as autocross is more of a low speed competition.” The Z3 now wears Wilwood six-pot Superlite front calipers with 330mm GT-48 floating discs and Wilwood Dynalite four-pot rear calipers with 312mm lightweight discs and Wilwood B pads allround, while the ducting ensures that the brakes receive plenty of cool air to deliver peak performance at all times.
Having carried out all the groundwork to make sure that all aspects of the chassis and drivetrain were at peak performance, Grant could now turn his attention to extracting more power from the engine.
Unlike our Euro-spec Z3 M models, the US cars were fitted with the S52B32 engine, based on the M52, which had to make do with 240hp and 236lb ft of torque so it’s no surprise that Grant wanted to up these numbers. “I started with keeping the engine NA and wanted to let it breathe better,” he says. “I upgraded the cooling system with a rad, water pump thermostat and cover immediately. I kept the CAI and did the M50 intake manifold exchange and I also did the BBTB at the same time. A cat-back exhaust followed and a year later came exhaust manifolds and a mid-pipe. In general I would wait until OE parts needed replacement and would upgrade at that time; that way the financial hit of modifying was lessened by taking the money I would be spending on OE parts and putting that towards upgrades.
I replaced all the water hoses throughout and the oil cooler followed when I started doing more track days, as I live a 40 minute drive from Thunderhill Raceway here in California. While on track there one day the bottom radiator hose slipped off and started spewing out coolant; I realised it had happened within seconds but even though I coasted into the pits the water temp gauge showed hot and that’s how I got the new head and I went to under-driven pulleys then as well.
“After the rest of the car was pretty modified I bought the supercharger kit. I had become a dad and my wife wanted me to do less high speed track driving and just drive autocross, so after close to two dozen track days at Thunderhill my focus changed with regard to driving. I needed just a little more low-end torque to pull me out of slow second gear turns when I didn’t want to shift to first gear at autocross,” and the supercharger kit has certainly given Grant the grunt he was after. It’s an Active Autowerke Stage 1 kit with a Rotrex C38-92 supercharger and is accompanied by numerous supporting mods. “I removed the air con, replaced the alternator, installed the power steering cooler, did the oil pan/pump upgrade and fitted an ATI Super Damper, crank pulley and carried out a CCV delete with the supercharger kit,” he says. “The baseline dyno when I bought the car was 205hp and 203lb ft of torque at the wheels; the NA mods took that up to 230whp and 222lb ft and it now makes 312whp and 262lb ft at the wheels on the same dyno. Active Autowerke claims that this kit makes 360hp on a stock car; I’ve done a lot of other work to the engine, so if they want to claim 360hp I want to claim somewhere in the 380hp range,” says Grant. “That seems excessive, though, and I usually just quote my dyno numbers,” and that’s still plenty to enjoy both on road an track, and a huge increase over stock.
While Grant has focussed mainly on the performance and dynamic elements of the car he has not forgotten about aesthetics, both inside and out. The exterior as been enhanced with Motion Motorsports front splitters and aluminium undertay, a one-off AC Schnitzer rear diffuser centre section, the roof spoiler has been raised by 8mm to enhance the roofline and Grant’s also fitted black kidney grilles, black lower mesh grilles and carbon-look roundels among other things. The interior, meanwhile, has been treated to a Momo Competition steering wheel on a quick release hub, chrome handbrake handle, E46 M3 short shift gearknob, black leather gaiter with tricolour stitching and M Tech pedals and dead pedal. There’s also a H3R black HalGuard fire extinguisher, but this was added as a necessity following a scary incident…
“While testing the car after installing the M50 manifold a fuel hose wasn’t secured completely and popped off and sprayed fuel over the exhaust manifold,” says Grant. “Thank god the car wasn’t warmed up all the way and only billowed white smoke. I pulled over immediately and ran. It continued to smoke for a long, heart-pounding five minutes. I fitted the fire extinguisher after that,” he says.
Grant’s Z3 is a focussed build that’s been taken in a specific direction and the results speak for themselves. While it looks great it’s the changes that you can’t see and that we can’t experience or appreciate that make this car. It’s the vast amount of chassis work, the brakes, the hundreds of seemingly minor secondary mods that are so important for the success of the whole and which all add up to make a such big difference. This Z3 has evolved hugely during the 14 years that Grant has owned it, from autocross machine to track monster and back to autocross beast but this time with the wick turned way, way up, becoming more and more focussed at each stage and it’s not reached its final form just yet…
“In the not-too-distant future this car will retire from competition after nearly 80,000 miles that saw it driving to almost monthly autocross events (10 months a year). I have a pile of class win trophies adding, in my small way, to BMW’s racing heritage. I’ll paint and mount the new bumper and splitters I have waiting. I’ll delete the fog lights and the antenna for a cleaner look. At that time I’d also like a nice set of multipiece step-lipped wheels,” he nods, painting an attractive picture. At that point it’ll become a different animal altogether but whether or not that will be its final stage of evolution will remain to be seen…
TECHNICAL DATA FILE #Supercharged E36/8 Z3 M Coupé / #Active-Autowerke-Stage-1 / #Active-Autowerke / #Rotrex / #VAC / #Dinan /
ENGINE 3.2-litre straight-six #S52B32 / #BMW-S52 / #S52 / #S52-Supercharged , #UUC engine mounts, Active Autowerke Stage 1 supercharger kit with #Rotrex-C38-92 supercharger, CAI, 3” MAF, High flow Bosch fuel injectors, supercharger oil cooler, AA stage 1 programming for BBTB and M50 intake with 7k redline, polished supercharger bracket, #ATI-Super-Damper , #VAC-lightweight crank pulley, #Dinan big bore throttle body, M50 intake manifold and fuel rail cover, intake runner heat shields, Dr. Vanos stage 2 kit with cam gears, timing chains and solenoid, Turner shorty ceramic coated exhaust manifolds, ARP header studs, fiberglass manifold and exhaust wrap, SAS Racing dual 2.5” mid-pipes with stock cats, dual 2.75” Supersprint stainless cat-back exhaust, #BMP design exhaust tips, #VAC oil pump upgrade, VAC oil pan baffle, #Behr S54 E46 triple row radiator, 80° thermostat, power steering cooler, Stewart high-flow water pump with steel impeller, polished aluminum thermostat housing, polished aluminum water pump nut, 80/88º fan switch, Spal 16” electric puller fan, clutch fan delete, new overflow tank, BMP brass water bleeder, VAC 5x7” oil cooler with polished Euro oil filter housing, stock head gasket, #ARP head studs, head polished and gasket matched, new valve guides, lashes, locks and retainers, valve job, resurfaced head, hydraulic belt tensioner, CCV delete, new Valeo 115 app alternator, AC delete, radiator baffle.
POWER and torque 312whp and 262lb ft wtq
TRANSMISSION #ZF-Type-C / #ZF five-speed manual gearbox, #F1-Racing 14lbs chromoly flywheel and stage 2 clutch, stainless clutch line, UUC short shifter and double shear selector rod, poly differential bush, UUC aluminium transmission mounts, rebuilt diff with four clutch zero pre-load and 80/60 ramping, 3.64:1 final drive, polished ring and pinion gears
CHASSIS 8.5”x17” (front) and 10x17” (rear) #OZ-Alleggerita-HLT / #OZ wheels with 255/45 (front and rear) BF Goodrich g-Force R1 tyres, #Ground-Control front coilovers with Koni adjustable shocks, Eibach 500lbs front springs and 600lbs rear springs, Ground Control adjustable rear spring perches, Ground Control front camber and caster plates, #Racing-Dynamics 21mm front and 19 mm rear anti-rolls bars and end links, SAS Racing rear anti-roll bar reinforcements, #SAS-Racing differential reinforcements, SAS Racing rear shock mount reinforcements, Turner Motorsport aluminium and poly rear upper shock mounts, Ireland poly control arm bushes, #Turner front subframe reinforcements, Ireland poly rear trailing arm bushes, Turner rear camber and toe adjustments, 90mm rear and 75mm front lug stud conversion, E30 M3 polished aluminum control arms, Turner front hub extenders, Ground-Control bump stops, SAS Racing tube frame rear sub-floor, Z3 2.3 steering rack, #Wilwood sixpiston Superlite calipers with 330mm GT-48 floating discs with aluminium hats (front), Wilwood four-piston Dynalite calipers with 312mm lightweight discs (rear), Wilwood B pads (front and rear), stainless brake lines, Turner front brake backing plates and duct work, SAS Racing vented rear brake backing plates, new master cylinder and reservoir
EXTERIOR Arctic silver, Motion Motorsports front splitters and aluminium undertay, #AC-Schnitzer one-off rear diffuser centre section, OEM fog light kit, rear roof spoiler adjusted up 8mm and colour-matched, polished wiring harness brackets, door jamb stickers removed, carbon-look roundels, passenger wiper delete, HID headlamps with side markers and corner lamps colour matched, stealth turn signal bulbs, tinted tail lights, colour-matched wiper nozzles and hatch latch, black kidney grilles, black mesh lower grilles, rear wiper delete, clear front corner markers, front plate holder delete, new windscreen and exterior mouldings
INTERIOR Black and grey two-tone leather interior, Momo 350mm Competition steering wheel with hub, 15 mm spacer and adaptor, carbon-look roundel, Snap-off Industries steering wheel quick release hub, chrome handbrake handle, E46 M3 short gear knob, M Tech pedals and dead pedal, front and rear M logo floor mats, E36 M3 window button surrounds, black leather gaiters with tricolour stitching, windscreen and window tints, sun visor stickers removed, glove box facelift, carbon horn pin adapter, H3R black HalGuard fire extinguisher, poly seat bushes, custom rear hatch parcel shelf
Thanks My wife, for her all patience and participation. Jerard Shaha at SAS Racing, my 30-year mechanic and friend. He rebuilt my El Camino in 1987! SAS Racing has done all the work on this car over the years. Their specialty is racecar setup but they perform all mechanical work and fabrication to an expert level as well as engine building and auto transmission rebuilds (firstname.lastname@example.org). Jason Shaha, my childhood best friend and Jerard’s brother. Thanks for planting that competitive seed from your family into me. See you at the next race? The long-standing crew at Trinity Touring Club. Thanks for your loyalty to our sport and dedication to our club. If I didn’t have to drive 90 minutes each way I’d be at all the club meetings (trinitytouringclub.com)Stream item published successfully. Item will now be visible on your stream.