Drop in the tsx engine and call it a day. Unless you're gonna build the head then I'd say go frank

 

Truly it depends on the price tag. If you can find a full long block for cheap compared to just a short block. But you already spent money on a head.

I only recommend doing a frank build if you are "building" so pistons/rods etc. If not, just do a k24a2 Longblock and be done with it. Reliable and enjoyable.

 

Even if you swapped in the a2 pump... the car still wont be able to wrap out like your K20a2 because the rods on the K24 arent made for as high of RPMs... If you are going to just keep it stock and put a K20 head on it, I would say its not worth it unless you're planning on getting some upgraded rods/pistons... I would say drop in the K24a2 and call it a day sir. I did the exact same thing with a greddy turbo kit believe it or not :rotfl:... But now I have a fully built K24 getting built again for the 2nd time and currently for just fun have a K20 in the car. Best advice to you is to just throw the swap in there and go...

 

The frank will out perform the K24 long block every single time, stock bottom end or not.

The RBB head flows so poorly in comparison to the PRB head, the head swap alone will liven the motor up.

For the sake of ease, and your sanity, it may be best to install the K24 without opening it up and messing around with a head and oil pump swap.

 

Hmmm...been talking to a couple of seasoned forum members here on this topic, not so sure about Frank out performing. Why will it out perform?

CAMS in the TSX are the best, from what I read the flow of the head is not that much different, almost negligible

I am asking as I am in the same situation
1) Build K20Z1 bottom end + rebuilt head
2) K20Z1 OEM bottom end + rebuilt head
3) K24A2 06TSX
4) Frank

Thanks
T

 

What ^^^ said

 

I'd consider myself a seasoned forum member along with the rest of them.

The ports on the head are vey much different. In stock form you're looking at least 10 CFM from the head swap alone, assuming you're using a PRB head. Take a look at this flow chart courtesy of 4Piston Racing.

Head work is extremely critical and there is a lot of power to be made on stock bottom ends. The whole "2006-2008 TSX head is the best flowing head" is a complete myth. The 36mm valves were just shoved into the same cast as the 2004-2005, and they really do absolutely nothing but add weight. I say this because I drank from the punch bowl and sourced a 2007 motor, granted you are correct about the camshafts being the best. It's been stated that the RBB head is better suited for the K20 because of its port shape.

Here's another dyno test where a RSP head was tested, which flows about 20 CFM more than the RBB:

back from the dead with another test on a different motor

2008 stock TSX (longblock) with:
RRC IM, Injen Intake, P2R TB spacer, Header & exhaust

before stock RBB head with stock valves (+1mm oem intake)

after RSP with Ferrea 6000 (std size) valves. Gained 19whp up top! fyi we were able to eliminate the tq dip from 5000-5700 with a stepped intake w/velocity stack. Getting that to fit is another story LOL

The list can go on, here's some threads with good information and discussion:

http://www.k20a.org/forum/showthread.php?t=107797

http://www.k20a.org/forum/showthread.php?t=54746

I have ran both the 2007 K24A2 long block, as well as the 2007 K24A2 short block with a K20Z1 head after my K20Z1 bit the dust. In my opinion:

The K24A2 completely changed the driving characteristics of the car. Shorter revs, a lot more low end grunt, and more torque.

I miss the K20Z1 a lot. The motor felt like it had more soul to it, because of the fact you can wind it out to 8500+ in factory form and it just screams.

So...bottom line:

1. Sure, the 2006-2008 K24A2 has very desireable camshafts. They produce power, but there is a lot more at play than just what camshafts you install into your motor. Like I stated earlier, there is a lot of power to be made in just the head alone, and a cost effective way of doing so is a simple PRB head swap. You can put the biggest cams you want into the RBB head, but the PRB head will outflow and outshine it any day of the week. If I had the money, I'd love to install a 4Piston Pro 156 on my stock bottom end and see what numbers it could produce.

2. All of this is dependent on what you do with your car. In my opinion, if it's your daily driver, and power isn't a high priority, swap in the K24 long block and call it a day. Anything beyond that, it's up to you to decide what your use and goal for the car is, research, and continue from there.

Hope this helps answer some of your questions.

 

I'd consider myself a seasoned forum member along with the rest of them.

The ports on the head are vey much different. In stock form you're looking at least 10 CFM from the head swap alone, assuming you're using a PRB head. Take a look at this flow chart courtesy of 4Piston Racing.

Head work is extremely critical and there is a lot of power to be made on stock bottom ends. The whole "2006-2008 TSX head is the best flowing head" is a complete myth. The 36mm valves were just shoved into the same cast as the 2004-2005, and they really do absolutely nothing but add weight. I say this because I drank from the punch bowl and sourced a 2007 motor, granted you are correct about the camshafts being the best. It's been stated that the RBB head is better suited for the K20 because of its port shape.

Here's another dyno test where a RSP head was tested, which flows about 20 CFM more than the RBB:

The list can go on, here's some threads with good information and discussion:

http://www.k20a.org/forum/showthread.php?t=107797

http://www.k20a.org/forum/showthread.php?t=54746

I have ran both the 2007 K24A2 long block, as well as the 2007 K24A2 short block with a K20Z1 head after my K20Z1 bit the dust. In my opinion:

The K24A2 completely changed the driving characteristics of the car. Shorter revs, a lot more low end grunt, and more torque.

I miss the K20Z1 a lot. The motor felt like it had more soul to it, because of the fact you can wind it out to 8500+ in factory form and it just screams.

So...bottom line:

1. Sure, the 2006-2008 K24A2 has very desireable camshafts. They produce power, but there is a lot more at play than just what camshafts you install into your motor. Like I stated earlier, there is a lot of power to be made in just the head alone, and a cost effective way of doing so is a simple PRB head swap. You can put the biggest cams you want into the RBB head, but the PRB head will outflow and outshine it any day of the week. If I had the money, I'd love to install a 4Piston Pro 156 on my stock bottom end and see what numbers it could produce.

2. All of this is dependent on what you do with your car. In my opinion, if it's your daily driver, and power isn't a high priority, swap in the K24 long block and call it a day. Anything beyond that, it's up to you to decide what your use and goal for the car is, research, and continue from there.

Hope this helps answer some of your questions.

Yes!!! these were the answers I was looking for as well. This is by far the most informative post I've found regarding these options...This response should be a sticky based on the links involved with the response.

 

I only suggest doing a great build as if you are "building" so pistons/rods etc. If not, just do a k24a2 Long block and be done with it. Efficient and pleasant. Best of luck with your ride.

 

k24a2

Go full long block.

I/H/E/ e85 kpro 50 degree vtc

229 whp/ 190 tq (Dyno jet - during the summer)

 

This begs the question, why hasn't someone put together the "ultimate" OEM 2.4L k series motor? One with the following specs:

- RSP head
- RRC intake manifold
- '06-'08 TSX cams (K20 Type R valve train)
- 50' VTC
- K24 block, stock except for:
- CU2 11:1 pistons (Accord Euro or TSX '09+)
- K20 oil pump

Sort out 3" air flow for the intake, throttle body and exhaust. Include a capable header obviously.

Is it because the price of some of these OEM parts opens you up to the aftermarket where "better" options may be found?

 

:iamwiths:

I Have a question regarding this (Havent checked the links in the earlier post yet so may be answered when I do BUT)... I am going to go k24a2 frank in the future, right now I plan to get some 08 TSX cams as I hear they are drop in and give decent gains... Would it be a better idea to keep my 04 RSX-S cams for when I go frank or do the TSX cams work better In the k20a2 head with the k24a2 short block? PRB head flow, k24a2 cam lift, k24a2 displacement... It seems obvious to me to keep the TSX cams but I dont know much about building yet and their is always more then whats infront of you so figured Id ask.

 

I'll post up my numbers when we are done with the build. Currently waiting on the head to come back from 4 piston, then the build starts.

- k24a2 block and crank
- Carrillo pro a rods
- CP 12.5:1 pistons
- 4 piston pro 163 head (prb)
- skunk 2 ultra race intake manifold
- skunk 2 90mm TB
- 1000 cc injectors
- drag cartel 3.2 cams