Honda / Acura K20a K24a Engine Forum banner

1 - 7 of 7 Posts

·
Registered
Joined
·
2 Posts
Discussion Starter #1
I used to build K swapped Fiat X1/9s, but a lot of water has passed under the bridge since I did that job, and several varieties of K series engines have been manufactured since then.

We used A2 and Z1 dropouts to build the swap cars. We also normally used a KPro. Some customers didn't want to spring for the extra money.

Fast forward to today. A2 and Z1 dropouts have become rare, and are usually high mileage and still expensive. I don't mind cheap and high mileage. I wouldn't mind expensive and low mileage if I planned to use a complete stock engine and stay NA. But expensive and high mileage seems like a problem to me when I already intend to open up the engine and install turbo pistons and stronger rods.

I'm starting to lean toward a K20Z3, which seems to flow nearly as well as the A2 and Z1 but is much easier to find--and the cars have factory LSD.

So here are the questions:

1) Should I be considering a different K series engine other than the A2 and Z1 for a 400HP turbo build? I do want to retain the rev-happy character of the A2 and Z1.

2) Should I be considering a hybrid engine with one bottom end and another cylinder head as a cost effective alternative to a complete A2 or Z1? I do sometimes think of a K24/20 hybrid as long as it would still rev well.

3) Is it better these days to go for later engine management and a FlashPro instead of the A2 ECU and a KPro?
 

·
Registered
Joined
·
174 Posts
These days start with Kpro, it takes about a month turn around these days. Lowish boost on stock cams if perfect for 400HP

The I would get the K20a2 if you can. The 2002 has 2000 AP1 S2000 outer valvesprings and has a inner dual spring. In the 2002 models the exhaust inner spring is still available as a part number. The intake inner spring is discontinued through 02-04 years. The S2000 that year came with just that single spring and no inner. Most people change the springs anyhow but it is still cool to find the spring set up.

The Z1 05-06 have single valve spring set up that is a PRB part number.

The K24 bottom end is plentiful. They rev to 8000 rpm in stock form pretty well. I had a Roots SC on a brand new 2004 K24a2 engine for 45,000 miles. Still running today on those same stock piston rings and 340 HP as a track car 14 years later. I have to have a k20 engine. They just suit the way I drive like I am abusing it, the K24 didn't like the way I drive, 99mm is a big stroke for a four banger. More stroke than a 68 400ci V8
 

·
Registered
Joined
·
2 Posts
Discussion Starter #3
These days start with Kpro, it takes about a month turn around these days. Lowish boost on stock cams if perfect for 400HP
Is there a reason for not going with the more plentiful 2006-2011 ECU and FlashPro?

The I would get the K20a2 if you can. The 2002 has 2000 AP1 S2000 outer valvesprings and has a inner dual spring. In the 2002 models the exhaust inner spring is still available as a part number. The intake inner spring is discontinued through 02-04 years. The S2000 that year came with just that single spring and no inner. Most people change the springs anyhow but it is still cool to find the spring set up.
That's cool to know, but I'll be upgrading springs once I prove concept in a running driving car. Other than valve springs, is there a reason not to go with the more plentiful and less expensive K20Z3?

99mm is a big stroke for a four banger. More stroke than a 68 400ci V8
Actually, quite a bit more stroke than practically any V8!
 

·
Registered
Joined
·
463 Posts
Is there a reason for not going with the more plentiful 2006-2011 ECU and FlashPro?



That's cool to know, but I'll be upgrading springs once I prove concept in a running driving car. Other than valve springs, is there a reason not to go with the more plentiful and less expensive K20Z3?



Actually, quite a bit more stroke than practically any V8!
Z3 Motor with a type s oil pump and you’re ready for lots of rpm 👍 I’m putting a k24 in my car to drive around with, but my built motor will definitely be an 86.5x86 z1. The way they rev up is too much fun.
 

·
Registered
Joined
·
174 Posts
Z3 Motor with a type s oil pump and you’re ready for lots of rpm 👍 I’m putting a k24 in my car to drive around with, but my built motor will definitely be an 86.5x86 z1. The way they rev up is too much fun.
I am with you on the way the 86x86 revs. They also get traction down well in many different scenarios. My favorite for road course. With 11psi SC boost and R1-R6 compound tires they are ridiculously fast. I have a pic of a 01 ITR SC K20a2 with 11psi JRSC full road course car with a 4.3 FD pulling 5th gear to 155mph easily on the back straight at VIR. We went into 6th for a brief second or two before having to triple downshift for the roller coaster downhills. That is why I like the K20, triple downshifts like hot butter on a biscuit.
 

·
Registered
Joined
·
463 Posts
I am with you on the way the 86x86 revs. They also get traction down well in many different scenarios. My favorite for road course. With 11psi SC boost and R1-R6 compound tires they are ridiculously fast. I have a pic of a 01 ITR SC K20a2 with 11psi JRSC full road course car with a 4.3 FD pulling 5th gear to 155mph easily on the back straight at VIR. We went into 6th for a brief second or two before having to triple downshift for the roller coaster downhills. That is why I like the K20, triple downshifts like hot butter on a biscuit.
I originally was going to put the 06 type s motor in my car instead of the k24a, but on arrival the shortblock was spun on what looked like 3 rods lol.(luckily the head is mint ) So for now the block is on my stand bare until I can put some dollars into it 🙄 The torque from the 2.4 is definitely a lot of fun around town I will say.
 

·
Registered
Joined
·
174 Posts
The TQ from the K24 is amazing for DD. I had one with a JRSC and just tapping the throttle the car moved out. Downshifting is ridiculous power
 
1 - 7 of 7 Posts
Top