N/A engine work, need your opinions

[RexPokinghorn]

Hey everyone... I'm looking to do N/A engine work in the very near future and would like your opinions.

I'm planning on:
increasing the bore / stroke
forged / sleeved pistons
port and polish head / manifold
blueprint and balancing
cams

What would be a safe increase without comprimising the cylinder wall strength?

I know cams will give better performance for what I want, but will I run into any problems with a larger cam profile?

Also, with this engine work, would I need to retune my ECU?

Thanks in advance for your comments / suggestions.

[icyjaws]

asuming this is a GT-S
well cams will be out in the early spring (if i ever get off my ass and mail my head out).
Over-Bore not without custom sleaves being made cause ours have a thin lining don't remeber what kind that will be ruined.
Stoking it is possible maybe hard but something i'm looking into since i have a blown block in my basment.
P&P is a good idea along with other work but you will prob need to end up tuning the car somehow.
Balance/Blueprinting i don't think would be that much help unless your going to move the fuel cut to like 9k or something.

[chameleon]

RexPokinghorn, I don't think that boring out the cylindars or increasing the stroke would be a very good idea. The 1zz and 2zz ge engines are both 1.8 liters of displacement but they are internally different for good reasons. The 2zz GTS engine has a larger cylindar size and shorter stroke while the 1zz GT engine has smaller cylindar's and larger stroke. The reason that this was done is was to help the GTS engine cope with the extreamly high rpm's that it runs at. If you are running an engine at really high rpm's you want a short stroke because it decreases the amount of the momentum that the pistons get. If you increased the stroke you may run into valve clearance problems because during high engine speeds the momentum will actually cause some of the internal parts to "stretch" a little.

Since the 2zz has a larger boar already from the factory, further boaring and resleaving will probably yeild little or no gains in actual cylindar size because they are already almost as large as they can be. The cylindar walls have a chemical coating to prevent piston ring wear on them from the factory instead of sleeves. This thin coating was used in order to maximize the clearance between cylindars, as opposed to the sleeves that are conventionally used on aluminum engines. If you boared them out as much as was possable and put sleeves in them you very well may be right back were you started before you boared them out in the first place.

New cams, however, are an excellent idea. I think that there is a lot of room for improvement in the cam profile, especially the first cam. I would like the first cam to be more rev happy, and possably move the power band up a bit so it doesent even start making power untill around 2,500rpm.

You may run into some valvetran problems with the new cam profile, depending on how wild it is. You may want to look into upgrading the valves, installing stiffer springs, and possably replacing some of the valvetrain parts with light weight ones.

Also, you will probably want to retune the ecu. The extra air the the larger cam profile gives you won't do you any good if the stock fuel map doesnt add enough fuel to the mixture.;)