civicex

does anyone have dyno curves comparing the stock y7 versus the stock y8?

I'm trying to understand whether the y7 has more torque at low rpms (because of the stock intake manifold with long thin runners) than the y8, whereas the y8 is able to generate higher horsepower numbers at VTEC range rpm.

any insights would be greatly appreciated, as I am trying to plan modifications / turbo and I don't know whether mini-me just creates more problems for the +20hp at the flywheel than it is worth doing.

OR does the y8 head have better valves and springs that can better tolerate the high rpms?

OR are all the hp gains strictly due to valve timing via VTEC such that a y7=y8 until VTEC kicks in and unleashes +20hp in the high rpm range.


any insight would be greatly appreciated.

mel

civicex

bueller?

slow_dx

Mel,

the d16y7 and d16y8 heads are based on the same casting; they have the same 'swirl' intake port.

The differences are as follows:

1. The y8 has quench pads that are flush with the deck, vs. recessed quench pads on the y7. This will increase your compression ratio slightly when used with y7 pistons. Quench generally helps the motor to resist detonation (good for a turbo app!) but I don't know how this plays out between these two heads in real life.

2. The intake manifold on the y8 is better. A plenum is a nice feature for an intake manifold to have

3. The camshaft. VTEC does create some power, but I'm not sure how much

The other thing that makes a big difference in the ability of the motors to accelerate the car is the transmission. The y8 has a numerically greater final drive, which will give the car more snap everywhere. The tradeoff is that you turn higher rpm on the highway.

You could check the jackson racing website, and compare the stock graphs between the y8 and y7.