vq35de vs vq35hr?

[silverbullit05]

ok this is been something i need a tech that knows the engines because last weekend i went and watch 2 of my buddies race 1 owned a 08 350z and the other an 06. now the hr is stock no mods at all. and 06 plenum spacer, mrev2, stillen intake, ti exhaust, and a pro dyno tune. car made 279whp, and 241wtq on superflow dyno. and 282whp on a dynojet. and the hr motor i was told put like 260 to the wheels. but not sure if thats accurate. now both are 6mts. i want to know how or what makes the hr a faster car? they raced a total of 6 times and swapped cars and the result was the same so not driver error like i figgured. now i have been a mechanic for several yrs and this doesnt add up to me. the specs on both cars are hr 306hp 6800rpms and 268tq at 4800, and de 300hp at 6400 260tq at 4800. hr redlines 500 rpms higher but rev limiter is at 7400 on hr and 7200 de. the 06 is accually lighter do to its been gutted partially. i also think the hr compression ratio is slightly higher at 10.6to1 insted of 10.1to 1. other than that i think all is the same gear ratios tires and brakes. so what makes the hr so fast? im not saying that he won by a lot but half car is reason enough for me to be currious when racing a modded car and winning everytime by at least half a car. is something in the engine been lightened? does this engine have a lighter flywheel then the dual mass in the 06? the hr seems to rev like it has lightweight flywheel? does the twin tb's add that much bottom end and mid range? someone help im really i need of these answers? o one more thing i own an 05 g35 6mt with all the same mods as the 06 z but i have stillen td exhaust and a cobb accessport and the 06 takes me by a car to 2 car legths. so i know the 06 probly does 13.2 to 13.4 in the quarter. i ran it in 13.8.

[evildky]

the HR has dual intakes and a completely different intake, and I believe different cams and heads, I've driven a stock 03 and a stock 08 and the 03 feel torquier because it is but the 08 car is faster as it has more hp

[terrycs]

The HR heads flow much better than the DE heads. I don't have the exact numbers though. In short, the HR is said to make more power at the upper RPM range.

[C-Kwik]

The differences are likely fairly complicated as engines and the plumbing in and out of it are all desgned to work with each other to meet certain design goals. But, the primary reason there is more power in the HR is that it is designed to rev higher and breath well at the higher RPMs. Higher RPM operation at a given torque will provide more mechanical leverage (which is why the HP number is higher). But even aside from higher peak power, with the use of variable cam systems and careful engineering, they can actually broaden the HP/Torque curve and get a larger mean HP in the range of operation during high performance driving. The rev-up has a slightly boader curve than the original DE. I'd expect to see similar changes between the rev-up and HR.