[Petik]

i have a 93 2liter with a j-spec cam in it. the cam improved the performance a little, but as everyone else, i want some more. At first i was thinking turbo = too expensive and very high maintenance. SC sounds like a better idea, but still way out of my budget. Then there are the j-spec pistons... from what i heard they give really good performance increase. The questions are: are there tuning problems with these (i will have a shop install them, i don't have as much experience as to go tear the whole engine apart)? Second, the engine already has about 70k on it and even though i know pretty much how engines work, i don't really know what am i looking as to what parts are mainly affected with wear and tear that i should consider replacing at the same time? i know its not safe to use sc or turbo w/pistons cause the compression ratio is high enough already, but would it be safe to use NOS? Will i have to upgrade the ecu at the same time (i'm planning on it sometime, i just dunno if i'll be able to put together all the cash at the same time)?
Thanks for all your input.

 

[Mike 94PGT]

i have a 93 2liter with a j-spec cam in it. the cam improved the performance a little, but as everyone else, i want some more. At first i was thinking turbo = too expensive and very high maintenance. SC sounds like a better idea, but still way out of my budget. Then there are the j-spec pistons... from what i heard they give really good performance increase. The questions are: are there tuning problems with these (i will have a shop install them, i don't have as much experience as to go tear the whole engine apart)? Second, the engine already has about 70k on it and even though i know pretty much how engines work, i don't really know what am i looking as to what parts are mainly affected with wear and tear that i should consider replacing at the same time?

Putting brand new pistons into an engine with 70,000 miles on it will probably lead to grief. Cylinder bores wear due to piston and ring friction and most likely, the new units won't properly fit the bores. You'll end up with piston-slap and/or knock and probably oil burning as well.

At the very least, the bores should be honed to provide a cross-hatch pattern for the rings to seat. Bore gauges should be used to ensure the clearances are within specs, in both axes. If there's even a hint of a ridge at the top of the bores, you're likely going to get a bore recommendation from the engine shop.

i know its not safe to use sc or turbo w/pistons cause the compression ratio is high enough already, but would it be safe to use NOS? Will i have to upgrade the ecu at the same time (i'm planning on it sometime, i just dunno if i'll be able to put together all the cash at the same time)?
Thanks for all your input.

The PCM shouldn't need re-programming with a bump in compression resulting from the ZE pistons.

As far as the use of NOS goes, increased static compression will always result in an increased propensity for detonation. NOS may be more forgiving of higher compression due to its inherent charge-cooling, but you'd be best to be careful; start with small shots to see how the motor takes it, building up slowly to the point you feel comfortable with.