I’m considering the major headache of swapping a K series into an EF hatch. My plan would be to buy a donor vehicle now, I would sell my existing daily drover and purchase either a RSX-S for the K20A2 motor, or a TSX for the K24A2 motor. From my conversations with the CA BAR / Ref, they indicated that the easiest and safest way to guarantee you will pass the ref check and get the sticker is to use a complete known donor car and document the process. I figure, I can sell my daily driver, buy a TSX or RSX, then down the road is that as my donor platform. I would then just sell the car to somebody else who can just swap a Motor back in.

Questions:

-What motor is better if planning on NA power only? Goal will be to be 250-275HP to wheels. I understand I’ll probably need to do I/H/E/cams/tune, but that can come after BAR’D and then taken off for song every 2yrs.

-Can you still run A/C with Kseries in an EF?

-Which years are best and why? From my research so far it sounds like the 2002-2004 RSX-S is the best platform, but others say they are all the same.

Any other comments please feel free to chime in thanks!

 

AC is possible but how you get there depends on which ECU you come up with. That ECU choice will have to match the engine you pick to pass BAR. No Hondata/KTuner allowed to hide missing oxygen sensors and reprogram pins for AC input.

Might be interesting finding an OEM exhaust manifold and catalytic converters that will fit the EF chassis without modifications. CARB allows for engine swaps but the emissions devices must remain unmodified.

Probably will need to also swap the EVAP control parts to keep a stock ECU happy. Also the immobilizer as you won't be able to bypass it in stock form.

All of these issues can be worked around if you want to put in the effort.

 

Here is a K swap EF with AC. This is the level of quality to aim for.

https://honda-tech.com/forums/vehicl...le%5D-3356256/

 

Thanks!

What are your thoughts on K20a2 vs K24a2?

And yes, you need to retain 100% of all emissions and also the gas tank supposedly.

 

K24A2 is going to be drive by wire with the matching stock ECU. Which is totally workable but gets way better with a tune to eliminate the odd throttle lag. This is also going to be CAN bus data for gauges and AC.

K20 with the stock matching ECU is going to be slightly easier to integrate being it is digital pulses for the gauges but they are not the same signals as the EF cluster. AC input however is from the RSX MICU over a serial connection to the ECU. I don't yet know of anyone that has deciphered that signal. So no AC without Hondata to reassign a pin on the ECU.

Both options have their challenges. My preference is for the torque of the K24 but a lightweight EF the K20 is still going to scoot! K20 being 19mm shorter will also make your hood and ground clearance better.

 

Thanks! Yes the clearance is also a major consideration.. The more I think about the headache the more I’m inclined to stick with a GSR or LSVTEC.. I’ll have to think about it more. I wish there were a lot of these already swapped/BAR’D and I’d just buy one done.

 

Spoke to Hasport a couple times.

On an EF they’re saying you have to modify/cut the rear crossmember to have engine fit, definitely if you’re keeping oem header and catalytic converter.

Also for AC sounds like modifications to AC bracket area on block, as well as the engine bay near/on headlight area are required.

Anybody have any info on the specifics they are referring to?

Depending upon how much cutting and fab is required I may just stick with B series but I’d like to flush this out more before making that decision.

 

another issue would be the fuel tank pressure sensor located on the gas tank.

 

yeah that’s probably also a pain to deal with

 

FTP is part of the EVAP pack next to the fuel tank. Also has the purge and vent solenoids as well as the charcoal canister. Comes in a lot of flavors as each model had a different shape of packages for fitment.

Not sure how much cutting is required. I know the bigger engine bay of the CR-Z needed a little trimming for the AC clutch to clear. I have two builds here in the Insight/CR-Z sub.