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K20a vs k20a2 vs k20z heads

33K views 27 replies 20 participants last post by  6spd_EK 
#1 ·
Hi guys,

Ive been searching on the web for a while and cannot seem to find any information on the differences between the heads on these engines.

All I can find are compression ratios, bore, etc etc but nothing on head comparison.

Beside the differences on the valve train, cams etc. I want to know if the heads are the same or is the type R jdm K20a more superior? If so, then Valves should be different as well?

Thanks for you help guys.
 
#4 ·
Yes the K20A, A2, Z1 all use the same exact head casting, there is absolutely no differences at all. The bare head's have the same part#.
 
#9 ·
It really depends what year you are talking about... generally before 2006 and includind the american Civic Si 2006+ heads they flow the same. The 2006+ TSX flows better. The japanese type r heads from the latest years flow better but still conservative for full blown applications
 
#22 ·
I flowed tested at the same day a 04 TSX head, a 06 TSX head and a 04 K20A2 head.

At lower lifts the 04-06 TSX head show better flow rates, 4-6cfm higher than the K20a2
at .500" lift the 06 & 04 K20A2 had the same value give or take 1-2cfm,
at .550" lift the 04 K20A2 flowed 4-5cfm more
 
#20 ·
^ yes i have a 06 Z1 head and a 06 tsx head. I want to drop one of them on my shortblock tonight or tomorrow. i dont want to port anything anytime soon thats why im looking for the best head to use stock.
 
#21 ·
The TSX head flows less than a Z3 head does at higher lifts. Depending on the purpose of the engine build, and what IM and exhaust are used, I would rather take a Z3 head, add bigger intake valves and run that. But if you can get the TSX head for cheap it is still a very adequate head design.
 
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