,
 |
The benefit of the small log manifold is evident here with the entire turbo setup being squeezed into a confined space. Also check out the sweet rear frame using box section aluminum. Notice the ribbing on the frame section attached to the bottom of the carbon fiber tub for additional stiffness. |
The other reasons are less sexy. Log manifolds package easily into tight confines because they are relatively small. Because they are relatively small, they use less material which also makes them lighter and cheaper. McLaren went to great effort to reduce weight anywhere they could and the result was a vehicle dry weight of 2945lbs. With a price tag of $229k, the McLaren isn’t exactly cheap, but saving a few grand on the manifolds knocks down the price tag a few more thousand. In the competitive supercar market, 10k saved here and there might be enough to sway a Ferrari or Lamborghini buyer.
The turbo setup viewed on the driver’s side. These are fairly basic turbos with hose connections in and out of the compressor housing, integrated compressor bypass valves in the compressor housing (simpler packaging and reduced costs again), pneumatic wastegate actuator, and a close coupled catalytic converter.
 |
The turbo setup viewed on the driver’s side. These are fairly basic turbos with hose connections in and out of the compressor housing, integrated compressor bypass valves in the compressor housing (simpler packaging and reduced costs again), pneumatic wastegate actuator, and a close coupled catalytic converter. |
The engine could be considered a pair of 1.9L 4-bangers rated at 296hp and 221.5 lb-ft of torque with that torque being flat from 3000 to 7000rpms and a maximum boost pressure of 17.4psi. This engine has a really high redline of 8500rpms though, so you can see that these turbos were sized for greater midrange torque over top end power. From looking at the exhaust system, the only way to gain some significant bolt-on power will be to go with high flow cats or eliminate two of the four catalytic converters (I like my clean air, test pipes should only be used for track-only cars). As for a turbo upgrade, I think a pair of GTX3071s would shift the torque curve to 4000-8500rpms with a nice 900-1000 crank horsepower. It’s just a thought.
