Not sure how to title this thread.
Before someone asks... I tried searching google and here, no luck tho.
Anyways, first of all:
I'm planning on boosting K20Z4 and swapping it into my car (there is a good reason why it's Z4 and not A2). Now I know Z4s dont hold power as well as A2, what is the reason tho? It seems like the only real difference internally between A & Z are pistons? If so, are A2 pistons interchangable with Z4? I'm wanting to open the block and do a rebuild, in mean time I could swap pistons out. Is there any other weaknesses when it comes to Z4?
Another question would be... maybe there are other OEM pistons that are lower compression and better for boost than A2s pistons. 11:1 seems rather high, and I imagine running a bar of boost on 97 or 99 octane would be a stuggle? I think 10:1 would be a nice balance for me. Is there eventual other ways to achive 10:1 without changing pistons? I know thicker head gaskets are a thing, but they dont lower compression that much.
Going back to pistons...
Yes, Im asking for OEM pistons, unless there are aftermarket hypereutectic or 4032 forged low comp /boost friendly pistons available (i found 4032 but they were high comp NA pistons, no good to me), i dont want cp or other race spec pistons (2618) is no go for me, the car will be driven too often, and it will see more chilled out driving than redline, plan is to get it tuned on 2 maps, low and high boost. Looking for 300hp at low boost to keep it fairly reliable and daily drivable and then have high boost for 400hp or more if i can, and even tho stock k20z4 can take it, i want to have a safety margin and have confidence that engine wont collapse, even if its gonna be only used occasionally at high boost.
I can't afford to rebuild engines every few weeks, because forged pistons arent being used in the way they were supposed to and now they slapping the hell out of the bores.
Any suggestions? Is it just better to run stock block? I will be running a Holset HY35 on it just for the reference.
Thanks
Before someone asks... I tried searching google and here, no luck tho.
Anyways, first of all:
I'm planning on boosting K20Z4 and swapping it into my car (there is a good reason why it's Z4 and not A2). Now I know Z4s dont hold power as well as A2, what is the reason tho? It seems like the only real difference internally between A & Z are pistons? If so, are A2 pistons interchangable with Z4? I'm wanting to open the block and do a rebuild, in mean time I could swap pistons out. Is there any other weaknesses when it comes to Z4?
Another question would be... maybe there are other OEM pistons that are lower compression and better for boost than A2s pistons. 11:1 seems rather high, and I imagine running a bar of boost on 97 or 99 octane would be a stuggle? I think 10:1 would be a nice balance for me. Is there eventual other ways to achive 10:1 without changing pistons? I know thicker head gaskets are a thing, but they dont lower compression that much.
Going back to pistons...
Yes, Im asking for OEM pistons, unless there are aftermarket hypereutectic or 4032 forged low comp /boost friendly pistons available (i found 4032 but they were high comp NA pistons, no good to me), i dont want cp or other race spec pistons (2618) is no go for me, the car will be driven too often, and it will see more chilled out driving than redline, plan is to get it tuned on 2 maps, low and high boost. Looking for 300hp at low boost to keep it fairly reliable and daily drivable and then have high boost for 400hp or more if i can, and even tho stock k20z4 can take it, i want to have a safety margin and have confidence that engine wont collapse, even if its gonna be only used occasionally at high boost.
I can't afford to rebuild engines every few weeks, because forged pistons arent being used in the way they were supposed to and now they slapping the hell out of the bores.
Any suggestions? Is it just better to run stock block? I will be running a Holset HY35 on it just for the reference.
Thanks