Drive Accord Honda Forums banner

1 - 16 of 16 Posts

·
Registered
Joined
·
21 Posts
Discussion Starter #1
Question for all you gearheads. Is there an actual difference in these engines, or is it just that when they test them in the factory the Z3 is stable at higher RPMs, so they set it to a higher redline than the Z2, and the additional power over the Z2 is only produced at these higher RPMs? If you look at the horsepower and torque curves of these 2 engines, would they be identical other than the fact that the Z2 stops at 6800 RPM?

I work with computers for a living and this is EXACTLY how many different speeds/price levels of processors are created. For a given "family" of processors they are all manufactured in the same way, and then tested to see how fast they can run and labeled appropriately after that.

No ideas from anyone or did I just post this in the wrong section of the forum? The K24Z3 is the engine found in the non-V6 EX and EX-L and it's rated to have 190hp and redlines at 7100 rpm. The K24Z2 is the engine in the LX and LX-P and it's rated to have 177hp and redlines at 6800 rpm. I left all that information out of my first post because I assumed that anyone replying would already know all that.
 

·
6th Gear
Joined
·
966 Posts
Honestly I don't know and I have not researched this, but I am going to pull an answer out of thin air and say the z3 w/ 190hp is faster than the z2 with 177hp.

I don't know what the difference is between these two engines as far as design goes, or tuning. My best guess is the z3 is more performance-oriented, and from what I have read online on other websites it is the faster of the two engines.

the z2 is still a good engine, being Honda and all, but probably not as performance-oriented. Overall they are most likely the exact same engines, just tuned to operate differently.
 

·
Registered
Joined
·
15 Posts
The reason the EX motor has a higher output is exhaust and ECU tuning. Mechanically I do not think there is a difference in the motor. Meaning they have the same cams, valve sizes, head, block, pistons, compression ratios. The ECU allows the motor to spin to a higher RPM and the slightly larger exhaust diameter allows the motor to take advantage of that higher RPM. I am sure there is more than just a higher redline than invloved in the ECU programming, you will have to wait until someone cracks the ECUs to knoww that.
 

·
Registered
Joined
·
21 Posts
Discussion Starter #4
Thanks for the explanation. Now it makes perfect sense to me that the only difference between these 2 engines is some money. With the EX you're paying for the tuning and exhaust system, and I still suspect that these engines might be cherry picked from the production line that makes both the Z2 and Z3 in a similar fashion to how computer processors are picked.
 

·
Car so nice, bought twice
Joined
·
4,708 Posts
so if it is just programming can one simply change out the ECU?
Tried it, and no. K24Z3 ECU freaked out in my K24Z2 car because the K24Z2 has different tranny gear ratios than the K24Z3. Shaft speed sensor values weren't what the ecu was expecting => limp mode.
 

·
Wisdom Born of Age
Joined
·
2,375 Posts
It's a sales gimmick. The extra HP after 6800 isn't really usable in the real world. As drowned12 pointed out, you can't just swap out the ECU and the different gearing is due to increased weight of EX. Even if you used the exhaust from the EX you wouldn't gain the revs over 6800 as the ECU controls that. It's not a chip that you can overclock, it's an engine. Different sensors, different exhaust, different ECU and more $$$, but alas, no real useable power.
 
  • Like
Reactions: turtleh

·
Registered
Joined
·
1 Posts
orientacion

¿ Le queda un motor de 4 cilindros con número K24A1 a un honda accord 2009, el cual tiene un motor 4 cilindros con número K24Z2 ?
 

·
Car so nice, bought twice
Joined
·
4,708 Posts
¿ Le queda un motor de 4 cilindros con número K24A1 a un honda accord 2009, el cual tiene un motor 4 cilindros con número K24Z2 ?
Solo el 7th Generation Accords tienen un K24A* (2003?-2007).
 

·
2010 Honda Accord EX
Joined
·
712 Posts
Thanks for answering megustahonda's question, drowned12.

Back on topic, I cannot think of a single instance I ever had my EX up to 6,800 RPM, so it is all academic to me (the difference in the engine, power, pipes, etc.).

As someone else with loads of computer experience I appreciated the CPU analogy, but as said, this is an entirely different can of worms. Truthfully, it's more appropriate to compare the ECU to a BIOS rather than a CPU).

Scott C.
 

·
Registered
Joined
·
19 Posts
ÑHow does the 4 cylinder in an 08 LX-S differ from the LX 4 cylinder? Is it simple or major to get that 13 HP? The LX-S is listed at 190 hp and the LX at 177 HP.
 

·
↑ ↑ ↓ ↓ ← → ← → B A
Joined
·
12,590 Posts

The Other Economy I-VTEC

With their integrated exhaust manifolds and non-existent performance-oriented VTEC, the case for choosing any of the following engines instead of Honda's performance i-VTEC or more conventional economy i-VTEC engines isn't a good one. In an effort to further improve catalytic converter efficiency, Honda eliminated its standard exhaust manifold and instead integrated it into the cylinder head. The results are reduced emissions but a severely limited platform in terms of exhaust modifications. Honda also went on to eliminate all 2.0L configurations from its lineup, now exclusively relying on the larger, 2.4L platform, which isn't necessarily a bad thing.

K24Z2 / K24Z6
  • 2008-2012 Accord: 177 hp, 161 lb-ft torque
  • 2010-2011 CR-V: 180 hp, 161 lb-ft torque

The K24Z engine family (excluding the 2007-2009 CR-V's K24Z1) builds upon the already successful tenants of its predecessor's K24A yet now places even more emphasis on low emissions. These 2.4L i-VTEC engines produce more power and torque than earlier engines, but the K24Z engine family makes for a much more challenging engine to build upon thanks to their integrated exhaust manifolds. No longer is adapting a true header or exhaust manifold possible with these types of cylinders heads. Still, the K24Z engine family can make for a solid foundation. Aside from an all-new, downward-facing oil filter placement, bottom-end-wise, the new 2.4L family of K-series engines isn't much different than its predecessors.

K24Z3 / K24Z7
  • 2008-2012 Accord: 190 hp, 162 lb-ft torque
  • 2009-2013 TSX: 201 hp, 172 lb-ft torque
  • 2012-2013 Civic Si: 201 hp, 170 lb-ft torque
  • 2012-2013 CR-V: 185 hp, 163 lb-ft torque

Honda once again updated its K-series engine platform for the completely redesigned TSX and Civic Si. To better suit the second-generation TSX's and ninth-generation Civic's slightly larger size and heavier chassis, the all-new, larger-displacement K24Z3 and K24Z7 were selected. Similar to the older TSX's K24A2, both feature 2,354 cc of displacement by means of Honda's standard bore and stroke yet benefit from a higher 11.0:1 compression ratio. The results are slightly more power and a lot more torque. In a seeming effort to confuse everyone, Honda went on to develop another K24Z3, this time for the 2008-2012 Accord, and another K24Z3, now for the fourth-generation, 2012-2013 CR-V. Although a K24Z3 and K24Z7 by name, their compression ratios, horsepower, and torque figures all pale to the TSX's and Civic Si's. What's even more curious is that none of these engines benefit from performance i-VTEC or performance-orientated, aluminum intake manifolds, which TSX and Si enthusiasts have thus far come to expect. It isn't just the TSX and Civic Si that are being singled out, though; by the time the eighth-generation Si's final production run was completed in 2011, so was performance i-VTEC.
 

·
Registered
Joined
·
45 Posts
Z2 uses R44 intake and exhaust valve while Z3 uses R40 same as TSX Z3. Camshafts are identical between Z2 and Z3 in ACCORDS, but TSX Z3 has different camshafts on both sides as well as higher compression piston.
 

·
Turbo lag
Joined
·
996 Posts
Z2 uses R44 intake and exhaust valve while Z3 uses R40 same as TSX Z3. Camshafts are identical between Z2 and Z3 in ACCORDS, but TSX Z3 has different camshafts on both sides as well as higher compression piston.
Are R44 valves dimensionally different from the R40 valves?
 

·
port & polish everything
Joined
·
1,664 Posts
The part number for valves seems to just depend on model year or a trim batch or run. For 2008 I actually see both R44 and R40 on both LX and EX automatic, even for both emissions level (49 state and PZEV) which suggests they are interchangeable. This could be just that there is more than one supplier, the same thing happens with NGK vs Denso spark plugs.
 
  • Like
Reactions: Hudouc
1 - 16 of 16 Posts
Top