A few questions about engine stuff
 

Can you upgrade injectors to 460cc and not run rich at idle with everything else stock? It doesn't seem logical to me since the computer tells the injectors how long to stay open, not how much fuel to let go.

Does anyone know where I can get a set of oversized (86.5, 87mm) pistons? I've looked all over, and can't find any that don't have to be custom made. How about rods for less than $900?

How much of the EGR/stuff on the intake can be removed without causing adverse performance/idling? Emissions tests aren't a problem for me.

How much more power will a set of shot peened rods hold over stock rods? Does the rod itself usually fail first, or do the bolts fail first?

I'm rebuilding my turbo motor, and these are some questions I've come up with. Sorry to ask so many ;)

Well, I can't answer them all. But unless you "hot rod" your cpu for idle gas flow, you're stuck running a litle rich. On second thought, hmmm.....Let me think. Wouldn't the airflow meter allow more air into the mix if it sensed the car was running rich?

Anyway, if you do put bigger injectors in, your best bet would to install a 60mm throttle body as well.

You won't be able to run anything over 370cc's without having to change the computer. The computer can't compensate for an injector that's nearly double the size of the stock one. You can run 370's by adjusting the AFM, but even then it will still run a bit rich. If you plan to run 420 cc injectors or larger, you'll have to upgrade to either stand alone or the Z31 ECU/MAF swap and get the computer tweaked by JWT. If you're looking for aftermarket pistons, I think Wiseco, JG and Ross have pistons for the L28. Back in Japan I remember seeing Wiseco and Ross pistons on the shelves of some of the tuner shops so I'm certain they must have some available. I don't know about rods though, I do know they are usually one of the first things to fail on a stock high output Z motor.
John 82ZXT

The EFI on the '79 ZX didn't even use an oxygen sensor so it has no way to compensate for the additional fuel. I don't remember what year the O2 sensor was added - maybe '81.

I can't speak for all ZX years as they did make EFI changes between 79 and 83 and later model cars in general have integrated the EGR into the car's tuning and performance making removal of the EGR detrimental to engine. However, I ran my '79 a year or so with the EGR system removed without any problems. I noticed no performance difference - my car was stock and driven daily at the time.

although my car is a 79, it has the full compliment of the L28ET and therefore an O2 sensor and full EGR

you said you could adjust the AFM please tell me how i have a spare so i dont care if i screw 1 up please tell how to adjust it it allready has silicone around black cover so not sure if already done car had headers when i bought it from dealer he didnt know who had it before so stilll wondering what else if anything else has been done anyway please tell me how to adjust the AFM