On top is the K20. Look close and you'll see four blue circles. They're from the #2 and #3 rod bolts. You're going to need to open clearance holes so the K20 assembly looks just like the K24 assembly.
This mutated mass is the stock Si intake system. The ironic thing is that it sounds pretty good.
Time to put some K20Z3 parts on your K24A2. On the right is the K20 oil pump assembly. Notice the deeper oil pickup snout. We have to use the K20 oil pan, which means we need the K20 pump. The snout is a press-fit piece.
The K20Z3 pan is on the floor and a K24A2 pan is on the engine. You can see how much deeper the K20 pan is. That's because it's also an engine mounting location this time. The K20Z3 oil pan has to go on the K24 because of this.
But this is the reason why it has to go-a mass-airflow sensor (MAF). A first for Honda, which has traditionally used a speed-density system (the '06 Si uses both). MAF sensors typically are a restriction in a manifold, so getting rid of them normally increases airflow. Besides, the K-Pro wouldn't know what to do with it.
Accord top, TSX bottom. Notice the TSX has a slightly bigger plenum, which makes for shorter runners, but they are no larger because the upper manifold (left) is the same for both. The TSX manifold has been dyno tested to give the best results on a TSX, even compared to the K20Z3 manifold, which is the same as the Euro Accord R. Leave the TSX manifold on.
The K20Z3 header is nearly identical to one from an RSX-S. Because of the '06 Si subframe, it has a slightly different turn to it and RSX headers won't fit on the Si. The header we used is a prototype '06 Si race header from DC Sports.
On the left is the TSX throttle body and the right is the Accord throttle body. They have the same diameter opening and bolt pattern. The TSX throttle body is almost identical to the '06 Si's. The only difference is the location of one of the water ports. Once Hondata comes up with a reflash for the '06 Si ECU, you should be able to use the TSX throttle body, since it is also drive-by-wire. Since we converted to cable operation we bolted on the Accord throttle body and throttle-cable bracket.
Drive by wire means there is no cable connecting the gaspedal and the engine. That function is controlled by the ECU, and with a K-Pro, we must switch back to a throttle cable. The original thought was to put in a conventional pedal instead of the Si pedal, which is on the right.
Instead of a different pedal, Hasport fashioned this very smart adaptor. A piece of bent sheet metal surrounds the pedal, while a couple of clamps attached to the original pedal arm pull on the RSX-S throttle cable. Difficult problem solved.
The wiring on this swap isn't as complex as you might think. The bottom plug is factory Si. Some of the wires in this plug were tapped to provide inputs for the K-Pro wires (three middle plugs). The top plug is a part of the RSX-S engine harness that's used instead of the Si's. See the wiring charts for the specific ins and outs.Caption25
Removal of the Si ECU means the majority of the instrument cluster won't work. That's because it uses the CAN bus system. The Hasport car has a Pi Xsport digital info center now. Shown here is the coolant-temp sensor mounted in a billet part Hasport sells for other K swaps. The sensor feeds directly to the Xsport cluster (it also needs to be grounded).
With some modification to its case, the Hondata K-Pro mounts in the stock computer's location. This is not a weatherproof solution and only temporary. Hopefully a Hondata reflash will be available for the stock ECU in the near future.
The K24A2 goes in just as easily as the K20Z3 came out, no tricks or special tips. Even though the K24 block is taller, it still fits under the extended cowl cover of the Si. Button it up and hide away your new red head.
By Tim Kelly
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