I've never heard a machined or milled flywheel, let alone an aftermarket piece vibrate. Have you experienced some bad installs?

I am working on extrude honing and porting the stock headers and manifolds on a 2002 Altima v6. I will post all gains we achieve when the project is done. We are almost done with the heads........

 

Why yes, we did.

http://photos.yahoo.com/bc/qball2161...iew=t&.hires=t

If Nissan is correct in it's flywheel horsepower rating, the 5 spd Altima lost 40 horsepower in the drivetrain! WOW, hope the Z isn't like this.

 

NiceGuy,

I assume you meant honing and porting the stock heads instead of "headers" but what are you doing to the manifolds?

 

Well, not exactly, we are doing both the heads AND the manifolds. Since there is no header made for the 3.5 Altima yet, we opted to port and hone the stock manifolds to match the exhaust ports on the ported heads. Honing the stock headers will give a little more throttle response and will probably be good for a couple of horsepower and some low end torque since it will still be quite restrictive. We port matched the ends of the headers so they matched perfectly to allow exhaust flow to exit without restriction.

But yes, we also did a mild port/polish on both heads/valve job/ etc......

I can't WAIT until I get ahold of the 3.5 in my Z, lol. Looks like we'll see BIG gains with headwork. Watch out all you guys that plan on boosting! J/K

 

It's WAY too expensive to polish EVERY head they put on a car, you wouldn't be or have a cost conscious company if you did that. And this company being Nissan, the parts bin kings, I highly doubt they would take the long time to polish the heads or make any other costly mod to the car. Money is everything!

Comparing the Z to the Altima, I would think there are a couple reasons the Z MIGHT put out more horsepower:

Better exhaust system ie: freer (is that a word) flowing headers and exhaust.

Maybe, and I mean MAYBE a higher compression ratio.

Probably slightly bigger runners in the heads which in turn require slightly bigger ports. I wouldn't doubt if the head is altered (a little bit).

Also, probably a bigger cam profile on the exhaust side and a longer lope on the intake side. The more air the better. Don't be surprised if we see a couple "heads and cam" Z's running around here. (Picture the sound of an old v8 powered car rumbling and sounds like it's almost going to stall when idling, I think this "truck engine" the Z has will produce a great lope and v8 sound when tuned with headwork and different cams paired with headers and an exhaust system.

These reasons are what I would do, Nissan is a very cost conscious company like I said before, and don't like to modify something that's already a good thing.

I will be opening up the engine when I get my Z, so until then, I won't make any assurances, but it looks like even the Altima engine will benefit from this. But I wouldn't hold your breath, car producers don't like changing the heads or stuff on cars which use the same engine. You'll probably find your horsepower in a timing advance, better breathing, better exhaust/headers, enhanced fuel curve, and definitely less loss of hp due to a rear wheel drivetrain.