Ok I have a 2002 civic si hatch with the k20a3. Can anyone tell me why my motor produces 160 hp and the k20a type r puts out 220hp. I got a good deal on the car but im going to sell it if i cant make it perform more like a type-s. What is different about the head on my car that makes it produce only 160hp. What are the best mods i can do for the head to up the power or would it be easier and cheaper to just buy a new head. I know if i get a new head itd be too costly and id just sell the car. A type-s head is probably atleast around 1500 then install and i'd have to get hondata or a new ecu. I'm not that crazy about the 02 hatch body anyway so i'm thinking about just selling it and buying a 92-95 eg with a built b16 or mayb even spend a lil more and find a k20 hatch. Im just really curious whats different about my head that makes it a lil weakling and if its feasible or worth modding.

 

Not a K-expert, but I believe the vtec mechanism between the two is completely different. The a2 system still employs low/mid/high cam profiles (like B-series vtec systems), whereas the a3 uses two cam profiles, low/high, which seems like more of an adaptation of the older vx/hx systems (e-vtec?). I've looked inside both heads and they're cast differently. I don't think you can swap a2 components in to an a3 head.

Also, port sizes are totally different. May be you can increase port size to help breathing, and use more aggressive valve sizes/valve springs, but I don't see how you can utilize the a2 rockers/cams in an a3.

K-dudes will have much more to add, I'm sure.

 

The K20a3 was the weakest K motor they ever produced, the A2 got all the good stuff. The IVTEC's are different, in that it only works on the Intake cam in the A3 and on both the intake and exhaust cams on the A2. The A2 head is a much better head with better cams as well. The A2 blocks had better rods, pistons/compression.