I have been getting a lot of messages regarding on how I went about doing my A2 cam/rocker swap. Here is a thread to help guide anyone that may be interested in doing such a project that nets impressive gains for our K20A3's.
First you should understand how the K20A3 i-Vtec system works vs the K20A2 system.
Here is a demonstration of the K20A3:
K20A3 i-Vtec
Here is the K20A2:
K20A2 i-Vtec
As you can see, the A3 i-Vtec only operates two rockers. When you switch over to a 3 rocker system our heads still can only function the use of two rockers as we don't have a lost motion spring. To make the 3 rockers work a simple switch of the internal pins will make it functional.
The following pictures I got from a member on K20a.org named Jeremyinlinepro.
Here is how the pins are normally setup:
This is how they should look after switching the middle pin (longer one) with the shorter pin (spring-less) on the side.
Here you can see the big rocker is locked with the small rocker, this will always remained lock regardless of your Vtec engagement.
Therefore before vtec engages you will have half of your valves running on the "big cam" while the other half runs on the "small cam" similar to how the original A3 cam/rocker setup is. Once vtec engages the solenoid will engage all three pins together making all remaining valves operate on the "big cam".
If you wanted to go to an upfront cheaper route and not have Vtec at all, the well known "Vtec Killer" setup is even easier. All you need is 4 exhaust rockers like this one for example:
You would put these on the intake side making you always ride on the big cam. I chose to go with the A2 rockers as sure they are more expensive up front, but your MPG won't be affected as much for daily driving.
A common question that always arises is do you need Kpro or some sort of ECU management, the answer is simply yes. To operate smoothly and to get a good amount of power out of the cam, a tune is always a must. It has been proven over and over that a fully bolt-on tuned K20A3 averages 170-180 whp while a cam'd K20A3 can easily hit 200+ in the RSX.
I plan to add more potentially to this thread. If anyone has any questions don't hesitate to post. If you have done such an install please share your knowledge as well!
:beerchug:
First you should understand how the K20A3 i-Vtec system works vs the K20A2 system.
Here is a demonstration of the K20A3:
K20A3 i-Vtec
Here is the K20A2:
K20A2 i-Vtec
As you can see, the A3 i-Vtec only operates two rockers. When you switch over to a 3 rocker system our heads still can only function the use of two rockers as we don't have a lost motion spring. To make the 3 rockers work a simple switch of the internal pins will make it functional.
The following pictures I got from a member on K20a.org named Jeremyinlinepro.
Here is how the pins are normally setup:
This is how they should look after switching the middle pin (longer one) with the shorter pin (spring-less) on the side.
Here you can see the big rocker is locked with the small rocker, this will always remained lock regardless of your Vtec engagement.
Therefore before vtec engages you will have half of your valves running on the "big cam" while the other half runs on the "small cam" similar to how the original A3 cam/rocker setup is. Once vtec engages the solenoid will engage all three pins together making all remaining valves operate on the "big cam".
If you wanted to go to an upfront cheaper route and not have Vtec at all, the well known "Vtec Killer" setup is even easier. All you need is 4 exhaust rockers like this one for example:
You would put these on the intake side making you always ride on the big cam. I chose to go with the A2 rockers as sure they are more expensive up front, but your MPG won't be affected as much for daily driving.
A common question that always arises is do you need Kpro or some sort of ECU management, the answer is simply yes. To operate smoothly and to get a good amount of power out of the cam, a tune is always a must. It has been proven over and over that a fully bolt-on tuned K20A3 averages 170-180 whp while a cam'd K20A3 can easily hit 200+ in the RSX.
I plan to add more potentially to this thread. If anyone has any questions don't hesitate to post. If you have done such an install please share your knowledge as well!
:beerchug: