It looks like torque is dropping of early on.

 

At a dyno day. Had some suspicion but this just confirms it its down on power.

 

At a dyno day.

What engine is it? What is the setup?

 

Would agree as you have basically what I do, mine is a custom 3” exhaust with KTuned swap header, and I made 220hp and 200ftlbs.

 

Someone mentioned HTS here.

One option of many.

I have no idea what that means though I don't speak header design.

It's only about the diameters. But as it is about wave management, length plays the also a role in that game.

 

One option of many.

It's only about the diameters. But as it is about wave management, length plays the also a role in that game.

Unfortunately the site doesn't mention the length of the header. I could ask them but if they actually have measurements on hand I'm unsure

 

looks more stepped bore primaries to me.

 

Long time lurker downunder and used this forum as a great resource for deciding the mild all motor build for my track focused Accord Euro CL9 that came with the K24A3 from factory in Australia.

As a result the build is as follows and wanted to share the results and take on any feedback:

Motor: K24A3 - Stock bottom end and stock head with upgraded Toda valve springs and other necessary valvetrain items

Header: Sege Bo to 2.5" test pipe

Cams: Toda Spec D with Toda 35 degree VTC

Intake: RBC to J35 to short ram 3.5" with Blox Velocity Stack pod filter

Exhaust: 3" from 2.5" test pipe, single exit

Tranny: Stock 6 speed with 5.3 FD

Misc Mods: K20 oil pump, 1000cc injectors, 255lph fuel pump, E85 Fuel

Track info: Bridgestone RE71RS tyres

Final tune by BYP Racing and car was on sticky RE71RS on the roller dyno:

Car has run very reliably for circuit use and set quick times, quite happy with the direction of the build.

Plan to stick with NA for now but feels like the setup can be optimised and many point out the common 4-2-1 PLM type (Tri-Y) header will yield more power, happy on any feedback on that.

Additionally, VTEC engagement set at 5500rpm as different points between 4200-4800 discussed by several members in old posts did not yield anymore power.

 

Long time lurker downunder and used this forum as a great resource for deciding the mild all motor build for my track focused Accord Euro CL9 that came with the K24A3 from factory in Australia.

As a result the build is as follows and wanted to share the results and take on any feedback:

Motor: K24A3 - Stock bottom end and stock head with upgraded Toda valve springs and other necessary valvetrain items

Header: Sege Bo to 2.5" test pipe

Cams: Toda Spec D with Toda 35 degree VTC

Intake: RBC to J35 to short ram 3.5" with Blox Velocity Stack pod filter

Exhaust: 3" from 2.5" test pipe, single exit

Tranny: Stock 6 speed with 5.3 FD

Misc Mods: K20 oil pump, 1000cc injectors, 255lph fuel pump, E85 Fuel

Track info: Bridgestone RE71RS tyres

Final tune by BYP Racing and car was on sticky RE71RS on the roller dyno:

View attachment 122252

Car has run very reliably for circuit use and set quick times, quite happy with the direction of the build.

Plan to stick with NA for now but feels like the setup can be optimised and many point out the common 4-2-1 PLM type (Tri-Y) header will yield more power, happy on any feedback on that.

Additionally, VTEC engagement set at 5500rpm as different points between 4200-4800 discussed by several members in old posts did not yield anymore power.

Stock cr?

 

Do we see a wheel based measurement or a flywheel-based one?

 

The dyno sheet is on a roller dyno and measured at the wheels

 

In Germany all roller dyno measure the wheel and flywheel curves, the later by calculating the drivetrain losses from the roll out in neutral gear. Anyway thanks, the numbers look fine to me for your setup.

 

Do you think there is room for improvement on the header/exhaust? Would a 3" collector/flange/test pipe or switching to a PLM 4-2-1 header yield more/better power over my current Serge Bo (WeaponR copy) with 2.5" flange/test pipe?

 

Sorry I thought you said you wanted more top end power instead of lots of midrange. A change in cam could do this without needing to extend the max rpm, just make it more peaky.

As a circuit car it would probably be slower but it should get the characteristics you are looking for?

 

I want this! With the k24 i get mid range in excess for my tight roads.
Is more difficult to dial the throttle as with the k20, that have way less low-mid range, with the closer 5.1FD and more revs, i was able to decelerate better and not loosing so much traccion in corners (even with half throttle in the k24, ~260nm in mid range vs ~220nm of the k20..)

 

you might just need more tire, better suspension and a better limited slip diff

 

Moving my power band up top will be enough

 

Α3 better than C low and midrange curves/performance.
6-7 hp of C top end will never feeling on the road...

 

Α3 better than C low and midrange curves/performance.
6-7 hp of C top end will never feeling on the road...

so, when to use C’s? You said that D’s are for high comp

 

Toda C works 12.5cr k22 k23 k24 high compression engines and depending the fuel,peripheral accessories ..
More compression more rpm more air from intake and ex mods more displacement D E F..

 

Accord CL7 (EUDM) K24A swapped.

Motor : K24A JDM stock bottom end, K20 RSP head fn2 type r

Headers : Bullboost 4-1 megaphone headers had to cut and lengthen them to fit about 1 inch added

Cams : FN2 intake and TSX exhaust, running 40 degrees of VTC max

Intake : stock airbox K&N filter and 80mm piping and a funnel to the airduct at the front bumper

Exhaust : 2.75 inch (70mm) 2 mufflers and sports catalyst

Transmission : AST5 6 speed, 4.4 FD

Misc Mods : RRC oil pump, RSP oil sump, stock injectors

The car has 235/40/18 eagle f1 asymmetric 6

Made 251 Whp and 27 Nm on Dynapack dyno Vtec set at 4750 rpm

Comparison with my old setup stock K24 RBB head and oil pump. Looking to remove power steering pump and upgrade to a full 3 inch exhaust and perhaps an adjustable exhaust cam gear. I believe there is more power to be made.

 

the cams will likely limit power. a k24 wants loads of lift and duration.

 

Wouldn’t the 3 inch exhaust have less back pressure or would it only be beneficial if I upgraded the cams as well ? Also I have heard of people gaining a few horsepower with the exhaust cam gear although that really depends on the setup. What should my next upgrade be anyways in your opinion

 

3“ will help a little bit, but more suitable cams will have a larger impact. Although it is already petty strong as is
given 15% assumed losses, this corresponds to more than 280 crank HP. This is very good.

 

Well that puts a smile on my face coming from you 😁. I was originally thinking of bigger cams but the increased fuel economy and the expense to get valve springs a new tune bigger injectors is what’s holding me back. The exhaust gear could potentially improve the midrange but that is also kinda limited by the 4-1 header and might be a waste of money. For now I am looking to buy an electric power steering pump and modify it to fit my accord and remove the hydraulic one, hopefully I will gain 5-6 horsepower this way, I’ll update in the future.

 

I feel like the trade offs from using the K20 intake cams in a K24 aren't well understood. The K24 by virtue of it's displacement is tolerant of more duration, that's why the factory low cam is more aggressive. Swapping in K20 cams gives a more aggressive high cam, but a less aggressive low cam. The K20 likely gets a small improvement with more intake VCT authority, but when you put the K20 cam into the K24 it will reduce mid-range performance.

A thorough evaluation of VCT angles for high and low cams, and an earlier VTEC engagement could improve your mid-range delivery.
I struggle with aftermarket camshaft manufacturers because they primarily focus only on high cam design and don't advertise what (if anything) they've done with the low cam design, which IMO is just as important for a smooth torque curve.

 

I feel like the trade offs from using the K20 intake cams in a K24 aren't well understood. The K24 by virtue of it's displacement is tolerant of more duration, that's why the factory low cam is more aggressive. Swapping in K20 cams gives a more aggressive high cam, but a less aggressive low cam. The K20 likely gets a small improvement with more intake VCT authority, but when you put the K20 cam into the K24 it will reduce mid-range performance.
View attachment 123505

A thorough evaluation of VCT angles for high and low cams, and an earlier VTEC engagement could improve your mid-range delivery.
I struggle with aftermarket camshaft manufacturers because they primarily focus only on high cam design and don't advertise what (if anything) they've done with the low cam design, which IMO is just as important for a smooth torque curve.

The Truth is, there is a difference in the low cams and not only that, I am using two differently designed cams and I guess it is expected to not perform as great in the midrange where they differ more. I am utilizing as much vtc as possible in the midrange, originally I used my stock cl7 ecu during the tuning but it was really hard to get it to work and I swapped a euro r one that is much more easy to tune. When we changed the values for the vtc (which we originally tried doing to no avail with the stock ecu) I gained around 20 horsepower in the midrange and that made the driving experience completely different the car was more responsive and faster. I was thinking of getting the exhaust cam gear to maybe give it some degrees of retard and let even more scavenging take place but I am not sure if it will be worth the effort anyways. Maybe I should go right to getting some other cams like toda a3 but then I will lose the most important gain of all with the stock cams reliability and fuel economy I get around 7L/100km which is crazy considering my car weight around 1.5 tons and has 250 hp. Maybe it is worth getting the TSX 06-08 intake cam which has a more aggressive low cam and a little better high cam and is still stock but it is too damn expensive to import right now in Greece.

 

Toda A3 are a reliable cam with no particularly high stress on TCT and chain.
Are your dyno numbers to the wheels or crank HP?

 

It is power to the hubs