kevinrdz28

hello, i got a k24a2 block to drop in my rsx deciding on what head, either a k20a3 ported, k20a2 not ported or k24a2 ported head? whats going to get me the most power? i am going to be rebuilding these with cams, valves, etc.. any suggestions??

Deetz

If you have an k24a2 head already, use it. If you have to source out a head, either an k20A2 or Z3 head should work great. Personally, I wouldn't worry about porting too much....but valve stems are not a bad idea

kevinrdz28

if i swap the k24a2 and later turbo it can is still be putting down a descent number like 350 without blowing sht up?

Type-Spaz

I'm putting down 438 turbo K24A2

What year K24A2 do you have?

turbohatchBnuts

k20a2 has bigger ports and will yield higher peak power

k24a2 has smaller ports and has more mid range power and lower end power less peak power than the k20a2.

And yes you can still make 350whp after you swap it. Just make sure you have it tuned good.

kevinrdz28

i have an 06 k24a2 but if its worth putting the a2 head i will do it. money is not an issue i just want the best numbers i can get in this setup. spaz you said you were making 438 but your tranny is prolly built i dont plan on that i just plan on putting lsd and leaving it stock.

Type-Spaz

My trans is stock... kinda. Different final drive and 6th gear with LSD.

Type-Spaz

this is only true with the 05< years. 06-08 the K24A2 is better than the k20A2 in every way. Even the head. Before 06 the heads were very similar still even.

kevinrdz28

this is very good info thanks a lot.

turbohatchBnuts

Not sure on that one. For the 2006 model year, the K24A2 was updated to produce 205 hp (153 kW). The diameter of the throttle body and intake valves were slightly increased, along with the cam duration and valve lift. I believed the same thing until further researching. They never changed the casting of the tsx head until 2009. Just bigger valves. Heres some flow numbers from k20a.org. The rsx head can be ported more than a tsx for sure.


I did a lot of work on a flow bench last month to compare CRv head , Type s, and TSx head. I did a test on the TSX and the Type s with adapter and the CRV wihout adaptor. The result are:

Lift TSX CFM Type S CFM CRV (without adaptor)
.0500 50.2 43.9 61.5
.1000 105.07 96.9 111.7
.1500 139.00 107.9 155.1
.2000 176.00 134.4 192.8
,2500 204.5 175.2 222.7
.3000 229.1 207.00 245.0
.3500 247.5 233.1 259.2
.4000 260.00 253.00 269.3
.4500 268.4 257.4 275.8
.5000 273.6 269.5 281.8
.5500 274.1 281.2 286.2
.6000 276.2 287.6 289.5
.6500 275.4 292.5 291.2
.7000 276.4 296.6 293.4

You can see that the TSX is better below .5500 of lift and the Type S is better over .5500. This is normal because the Type s run higher RPM than the TSX and the TSX need more torque at low lift. For me the TSX head have more potential than the Type s have if you did a porting job. I will do this job next month and I will give you my result.

The surprise here is the CRV head. The shape with my eyes at the intake look the same that the Type s look. But the flow is really better than the Type S at low lift and equal over .6000 lift. But last year when I did this flow on the CRV head, I did that without adaptor. I will repeat this test with adaptor and give you the result. If this head is really better than the TSX and the Type s, without porting, it's going to be sad that this head didn't have the third spring holes.