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from what I have seen here, you're better off with a D or E depending on the application, expected life time of the engine and gearing.
 

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from what I have seen here, you're better off with a D or E depending on the application, expected life time of the engine and gearing.
I know there are better cams for drag, but I want to do it with Toda cams, my goal is to know if with good mods I can reach 300whp,
my build is
k24 / k20 88x99
cr 12.5
Mild port k20a2
crower rod
rbc ported
big tube header

I did not find anyone who has those 300whp numbers with aToda cams
 

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If you set yourself a sensible review limit, you won’t get 300whp.
rev it to 8100 rpm, yes. But it won’t last long exceeding formula1 and NASCAR piston speeds.
 

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If you set yourself a sensible review limit, you won’t get 300whp.
rev it to 8100 rpm, yes. But it won’t last long exceeding formula1 and NASCAR piston speeds.
yes i will only see 8500/8800 in 1/4 mile, track days only i got over 300whp with ultra 2 and dc4 but i want to know if i can achieve them with toda D or E
 

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Arouse the DAMPFHAMMER!
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yes i will only see 8500/8800 in 1/4 mile, track days only i got over 300whp with ultra 2 and dc4 but i want to know if i can achieve them with toda D or E
Not with TODA D, there duration is shorter and the S2 Ultra acceleration phase is a bit faster then the TODA one. That means the area under the lift profile is lower at the same duration (at same reference duration), which is also increased by the higher lift. This situation makes the S2 U2 a bit more efficient at higher engine speeds. Therefore your focus should TODA E. We had a user here who reached 310 flwhp with TODA D on his 12.5:1 CR 87.5x99 engine setup (modified RRC IM and data here (9) Skunk2 Street Manifold | Page 3 | Honda / Acura K20a K24a Engine Forum ). So this is far away from 300 whp. As the TODA E is using the same lift profile, just with more duration, you would shift the engine speed at peak power to the right by around 300-400 rpm (8700-8800 rpm).
 

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Not with TODA D, there duration is shorter and the S2 Ultra acceleration phase is a bit faster then the TODA one. That means the area under the lift profile is lower at the same duration (at same reference duration), which is also increased by the higher lift. This situation makes the S2 U2 a bit more efficient at higher engine speeds. Therefore your focus should TODA E. We had a user here who reached 310 flwhp with TODA D on his 12.5:1 CR 87.5x99 engine setup (modified RRC IM and data here (9) Skunk2 Street Manifold | Page 3 | Honda / Acura K20a K24a Engine Forum ). So this is far away from 300 whp. As the TODA E is using the same lift profile, just with more duration, you would shift the engine speed at peak power to the right by around 300-400 rpm (8700-8800 rpm).
ultra 2 is 270 @ 1mm
Toda E is 272 @ 1mm
correct me if I'm wrong.
perfect, that is, it would be very possible to reach 300whp with Toda E with the appropriate mods
 

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Arouse the DAMPFHAMMER!
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ultra 2 is 270 @ 1mm
Toda E is 272 @ 1mm
correct me if I'm wrong.
perfect, that is, it would be very possible to reach 300whp with Toda E with the appropriate mods
That's correct. For more info's I would need to simulate this engine setup. I would need the exact the exact details of it.
 

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Discussion Starter · #229 ·
Hello
I know it is an old thread, but i really want to experiment with TODA cams, do you think i can reach 300 whp in k24 88x99?? cr 12.5, which one do you recommend? Toda a3, spec D or spec E??
104651

Hi man.
I had k24/k20 12.5 CR 315hp(~280whp)
with toda A3 and pick of power 7.900-8000rpm.
310NM.
The best cams for daily car and the power is everywhere (idle , midrange,high)

Of course you can try bigger toda cams like spec E for better power top end.
You have to think where will set the revlimiter and then will chose the correct toda cams !!
 

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View attachment 104651
Hi man.
I had k24/k20 12.5 CR 315hp(~280whp)
with toda A3 and pick of power 7.900-8000rpm.
310NM.
The best cams for daily car and the power is everywhere (idle , midrange,high)

Of course you can try bigger toda cams like spec E for better power top end.
You have to think where will set the revlimiter and then will chose the correct toda cams !!
woww performs very well, very good power with toda a3, I think that with toda D or E I could achieve 300whp, it is not very far from your 280whp.
if I can produce the 300whp at 8000 or 9000 I would not care as long as I stay in that rpm range
 

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That's correct. For more info's I would need to simulate this engine setup. I would need the exact the exact details of it.
my build is 88x99
cr 12.5, I have to test a custom IM, a kind of modified ultra street, runner lenght 180mm and 56mm ID, 3.5L plenum with tb 80mm central.
Header is 4a1 17/8 - 2 - 21/8 27 "primaries, it is copy burns, head is mild port I have no cfm data
 

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Arouse the DAMPFHAMMER!
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my build is 88x99
cr 12.5, I have to test a custom IM, a kind of modified ultra street, runner lenght 180mm and 56mm ID, 3.5L plenum with tb 80mm central.
Header is 4a1 17/8 - 2 - 21/8 27 "primaries, it is copy burns, head is mild port I have no cfm data
I will give a trial when I find a free time window. Will take some days as I invest at least 1 h for a rough calculation.
 

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I will give a trial when I find a free time window. Will take some days as I invest at least 1 h for a rough calculation.
no problem, it would be quite an achievement to reach 300whp and achieve a decent time in 1/4 mile, I just want to achieve it with Toda cams, it is my goal
 

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Arouse the DAMPFHAMMER!
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my build is 88x99
cr 12.5, I have to test a custom IM, a kind of modified ultra street, runner lenght 180mm and 56mm ID, 3.5L plenum with tb 80mm central.
Header is 4a1 17/8 - 2 - 21/8 27 "primaries, it is copy burns, head is mild port I have no cfm data
Disclaimer: this is a 20 min engine setup simulation, which took me 1.5 h incl. the data output graph. Don't take this as a finalized results, as there are some compromises. The combustion is from a 87.5x99 engine dyno calibration, the intake and exhaust are roughly transferred into the setup as the input data you delivered is rough too. With more input date and fine tuning there would be more reliable results, with those I would be able to optimize this longblock.

Actually the setup shows some potential, but I see the CR could be higher for those cams, they love cam advance, so the piston valve relief need to have a proper depth. Of course: IM, H, CAI and E would be a nice playground for further optimizations :D.

Now to the results. Using a 370 [email protected]" flowing head gives me for both cams 343 flwhp (according curve characteristics) somewhere between 8500 and 9000 rpm (edit: 8800 rpm when using 100 rpm steps for TODA E). Both cams are within 2 Nm on par, with the advantage for the TODA E. If I do the math of the drivetrain losses, I would need to assume a 0.88 efficiency to reach 300 whp. Typically the drivetrain efficiencies are around 0.85 to 0.88 for the K-series gearboxes, depending on dyno'd gear ratio and torque. So I would say, the simulation for the 300 whp setup with the S2 U2 is roughly in the target, the one with the TODA E was surprising to me.

Just to validate the results further, did you clay the S2 U2 setup. I have seen best results on both cams when intake valve-piston clearance is at 6 mm lift at TDC. I can't translate it into VTC as I don't know the centerline to VTC reference to 0° VTC. So if you have that correlation we could compare it.

104658


Calculated points are every 500 rpm from 7000 rpm on. To get to know where the peak power point comes down I would need to run a higher resolution like 200 rpm steps from 8500-9500 rpm. My assumption is it lays around 8500 and 9000 rpm.
 

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I will give a trial when I find a free time window. Will take some days as I invest at least 1 h for a rough calculation.
Disclaimer: this is a 20 min engine setup simulation, which took me 1.5 h incl. the data output graph. Don't take this as a finalized results, as there are some compromises. The combustion is from a 87.5x99 engine dyno calibration, the intake and exhaust are roughly transferred into the setup as the input data you delivered is rough too. With more input date and fine tuning there would be more reliable results, with those I would be able to optimize this longblock.

Actually the setup shows some potential, but I see the CR could be higher for those cams, they love cam advance, so the piston valve relief need to have a proper depth. Of course: IM, H, CAI and E would be a nice playground for further optimizations :D.

Now to the results. Using a 370 [email protected]" flowing head gives me for both cams 343 flwhp (according curve characteristics) somewhere between 8500 and 9000 rpm (edit: 8800 rpm when using 100 rpm steps for TODA E). Both cams are within 2 Nm on par, with the advantage for the TODA E. If I do the math of the drivetrain losses, I would need to assume a 0.88 efficiency to reach 300 whp. Typically the drivetrain efficiencies are around 0.85 to 0.88 for the K-series gearboxes, depending on dyno'd gear ratio and torque. So I would say, the simulation for the 300 whp setup with the S2 U2 is roughly in the target, the one with the TODA E was surprising to me.

Just to validate the results further, did you clay the S2 U2 setup. I have seen best results on both cams when intake valve-piston clearance is at 6 mm lift at TDC. I can't translate it into VTC as I don't know the centerline to VTC reference to 0° VTC. So if you have that correlation we could compare it.

View attachment 104658

Calculated points are every 500 rpm from 7000 rpm on. To get to know where the peak power point comes down I would need to run a higher resolution like 200 rpm steps from 8500-9500 rpm. My assumption is it lays around 8500 and 9000 rpm.
Wooow great, i don't remember now the data i got from the ultra 2 (I'll look it up), i'm currently finishing another with dc 1.5, on high can at 45 vtc i have v2v 0.08 at 0 lash.
If l increase my cr, it will ask me for more vtc from 7000 up (danger) my limitation to cr 12.5 is that i want to achieve this at pump gas 93 and Toda E
 

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Arouse the DAMPFHAMMER!
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I'll look it up
I am looking forward to see your claying results.

it will ask me for more vtc from 7000 up (danger) my limitation to cr 12.5 is that i want to achieve this at pump gas 93 and Toda E
That's something which is always a compromise between application and torque curve related cam choice. As you run just in the upper engine speed range, it is questionable if you need the VTC. A cam fixed cam gear would do the job on a save VtP clearance. My simulation has shown that 6 [email protected] is optimal for 7000-9000 rpm. For this you need very deep valve pockets. The CR plays a 2nd role in the VTC topic, as the valve relief depth is in a limited range for fabrication and weight independent from that, especially on a bigger stroke as less dome volume is needed to get the same CR compared to a 86 mm stroke.
 

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I am looking forward to see your claying results.

That's something which is always a compromise between application and torque curve related cam choice. As you run just in the upper engine speed range, it is questionable if you need the VTC. A cam fixed cam gear would do the job on a save VtP clearance. My simulation has shown that 6 [email protected] is optimal for 7000-9000 rpm. For this you need very deep valve pockets. The CR plays a 2nd role in the VTC topic, as the valve relief depth is in a limited range for fabrication and weight independent from that, especially on a bigger stroke as less dome volume is needed to get the same CR compared to a 86 mm stroke.
Ultra 2 open 6mm at 41° vtc
At 41° vtc v2p 2mm (0 lash) v2v 1.5mm
Exh cam at -1° v2p 2.5mm (0 lash)
Centerline that provides skunk2 of 111° i get it by retarding my exh cam 1.5°

In my old build i think he did not like more than 35° vtc in high cam with cr 12.5
 

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Arouse the DAMPFHAMMER!
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Ultra 2 open 6mm at 41° vtc
At 41° vtc v2p 2mm (0 lash) v2v 1.5mm
Exh cam at -1° v2p 2.5mm (0 lash)
Centerline that provides skunk2 of 111° i get it by retarding my exh cam 1.5°
Many thanks, looks like you did your job well 🆙. The overlapping period of the valves is quite retarded. I see why, the V2V situation is already getting tight. In my simulation I've run 4 [email protected], which would likely lead to crash the valves. I will check it out at 2.5 [email protected] on EX cam and 6 [email protected] on IN cam. In the result it lost about 15 [email protected] and 4 [email protected] rpm. If I retard the intake camshaft. I assume it to be the same for the S2 U2, as there is no hidden behavior we didn't see before.

Did you use different valves (brand and size) on that engine?

In my old build i think he did not like more than 35° vtc in high cam with cr 12.5
Maybe the pressure drop over the engine wasn't as good as mine used in the simulation, as my intake port performs 372 [email protected]", which is not a slight modification. What I would assume then is, that the combustion efficiency of your engine is better then mine. Would be curious what ign. timings it saw? I setup mine at 28° and with a slower burn through, which is most what I see on 87-88 12.5:1 engines.
 

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Many thanks, looks like you did your job well 🆙. The overlapping period of the valves is quite retarded. I see why, the V2V situation is already getting tight. In my simulation I've run 4 [email protected], which would likely lead to crash the valves. I will check it out at 2.5 [email protected] on EX cam and 6 [email protected] on IN cam. In the result it lost about 15 [email protected] and 4 [email protected] rpm. If I retard the intake camshaft. I assume it to be the same for the S2 U2, as there is no hidden behavior we didn't see before.

Did you use different valves (brand and size) on that engine?

Maybe the pressure drop over the engine wasn't as good as mine used in the simulation, as my intake port performs 372 [email protected]", which is not a slight modification. What I would assume then is, that the combustion efficiency of your engine is better then mine. Would be curious what ign. timings it saw? I setup mine at 28° and with a slower burn through, which is most what I see on 87-88 12.5:1 engines.
I always use supertech piston, it has enough valve relief, I always use stock valve.
it was around 30 ° of ignition.
never experiment with more cr 12.5, I don't know how it would behave with pum gas, if you have data I would appreciate it, I know that several factors come into play, but anything above 26 ° is fine for my taste
 

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Many thanks, looks like you did your job well 🆙. The overlapping period of the valves is quite retarded. I see why, the V2V situation is already getting tight. In my simulation I've run 4 [email protected], which would likely lead to crash the valves. I will check it out at 2.5 [email protected] on EX cam and 6 [email protected] on IN cam. In the result it lost about 15 [email protected] and 4 [email protected] rpm. If I retard the intake camshaft. I assume it to be the same for the S2 U2, as there is no hidden behavior we didn't see before.

Did you use different valves (brand and size) on that engine?

Maybe the pressure drop over the engine wasn't as good as mine used in the simulation, as my intake port performs 372 [email protected]", which is not a slight modification. What I would assume then is, that the combustion efficiency of your engine is better then mine. Would be curious what ign. timings it saw? I setup mine at 28° and with a slower burn through, which is most what I see on 87-88 12.5:1 engines.
has enough v2v at 0 lash, never crashed, even retarding my exh cam 1.5 ° has enough v2v, v2p at exh aprox 2mm
 
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