Dan Rose’s Z3 M Coupe was one of the first in the country to be fitted with a GM LS powerplant, and it’s one of a few in Time Trial competition.
The General Motors LS V8 architecture has been finding its way into cars from and on every continent. It tucks neatly into so many engine compartments, makes such ample power and is so abundant that there are prefabbed kits that will cross-fit an LS engine into nearly anything.
However, when NASA SoCal Time Trial driver Dan Rose was attempting to fit an LS2 6.0-liter into his Z3 M Coupe, to his knowledge, there was only one other car in the country that had the swap, and all of it was done the hard way, by trial and error, hand-selecting parts and troubleshooting problems as they developed.
Now, Rose had gone through two S52 engines in his current car before he resorted to LS power. It’s pretty interesting that Rose’s car was totaled by an insurance company due to a fire in the interior. Most of the reason it was totaled was because it was filled with dry-chemical fire extinguishing material. Rose bought it from the insurance company for $8,000 and $500 to the owner for his trouble, brought home, cleaned it up and sold most of the interior and other parts for enough money to pay for the whole car.
After he blew up the S52 the second time, he went out and found the LS2 out of a 2006 GTO. He took on the project in 2007.
“There was one guy who had done it, and I had been thinking about it for a while, but I knew it would fit because I had gotten the measuring tape and I thought, ‘Yeah, it’ll work,’” Rose said. “Then one guy actually did it, and I was like, well, if he can do it, I can do it.
“There were no swap parts at the time, so I couldn’t buy a kit for it or anything,” Rose said. “There was only one little company that was making a standalone harness for these things. There was nothing on the market yet to do any of this stuff, so it was a bit of a challenge. I don’t have a lift, so everything I did was on my back in the garage.”
Rose fabricated his own engine mounts, and they seemed to line up nicely, provided the right driveshaft angles and he had what he thought was enough room for the shift linkage inside the transmission tunnel. In one weekend, he had the LS engine and Jerico four-speed transmission mounted in the car.
On the first test day, he took it to Auto Club Speedway in Fontana, Calif., and the car kept popping out of fourth gear. He took it home, pulled the transmission, sent it back to Jerico, which couldn’t find anything wrong, but replaced the fourth gear dog ring anyway. When he got it back, it was doing the same thing. Turns out the external shift levers were coming into contact the with the transmission under full throttle and popping it out of gear.
“These cars are stiff and solid, but it’s amazing how much things move around,” Rose said. “You don’t realize it because all this stuff is figured out by the factory, so unless you’re doing something that’s completely unusual, you don’t run into stuff like this because it’s all been engineered already.”
But, of course, what Rose was doing at the time was completely unusual. He took a big hammer to the transmission tunnel and fixed the problem. The wiring was difficult, and he destroyed a differential and a few clutches. He spent the first 18 months dialing the car in, which was a slow trickle of trial and error because the only place he could drive it was on a racetrack.
He finally found a differential builder, Metric Mechanic, to build something that lasts. He tied the differential to the rear floor with a custom steel bracket, and ended up with a Tilton clutch setup. Combined with the Jerico gearbox, Rose finally found a pretty bulletproof setup.
He installed a remote oil filter, a small Setrab oil cooler and initially used a universal set of Hedman “block hugging” headers, though he had to rearrange the steering shaft to go around the exhaust. Once he got everything dialed in he found a set of headers designed specifically for LS swaps and picked up 15 horsepower.
He runs the car in NASA SoCal in TT1, and he regularly finds himself on the podium and occasionally in first place. Were he to run stickier tires, he might be able to do better, but he’s happy with the results he achieves with the equipment he has.
“Truthfully, I really shouldn’t be doing any of this. But it’s like a drug,” Rose said. “There are some drug addicts that can’t afford their drugs, but somehow they figure out a way to get it. I’m the same way. I can’t afford my racing, but somehow I figure out a way to get it.”
|Model:||Z3 M Coupe|
|Weight:||2,650 lbs. w/o driver|
|Engine/Horsepower:||6.0-liter GM LS2 /420 hp|
|Suspension Front:||T.C. Kline spring and shock setup|
|Suspension Rear:||T.C. Kline spring and shock setup|
|Tires Front:||Maxxis 275-35-17|
|Tires Rear:||Maxxis 275-35-17|
|Brakes Front:||OEM calipers with Carbotech XP20|
|Brakes Rear:||OEM calipers with Carbotech XP12|
|Sponsors:||Dan Rose’s wallet|
For more photos of the build process, click HERE.