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USDM > *
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Ah, very nice, you still have that RRC which you modified with the angle grinder and some other tools. How do you like the lower neck filler pot of the coolant outlet? Is it big enough to give the coolant circuit enough play to work cold and heated?
I haven’t had a chance to really drive the car yet, but no issues with cooling between this and a Rywire tucked radiator.
 

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USDM > *
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So turns out some of the rockers were installed incorrectly. Got those fixed and after waiting on a new dyno appointment, was able to get some new numbers.

The car made 289 HP/ 204 TQ.
I’m happy with the power band as the plan was to set the rev limiter around 8000 RPM.

I’m not sure what else could be done to improve the powerband at this point. I feel like any after market intake manifold will just sacrifice mid range power for top end HP.

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96 civic HX K24a
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So turns out some of the rockers were installed incorrectly. Got those fixed and after waiting on a new dyno appointment, was able to get some new numbers.

The car made 289 HP/ 204 TQ.
I’m happy with the power band as the plan was to set the rev limiter around 8000 RPM.

I’m not sure what else could be done to improve the powerband at this point. I feel like any after market intake manifold will just sacrifice mid range power for top end HP.

View attachment 107174
That’s more like it. So only some of the valves were seeing the high cam before ? 200+ tq looking great ! That dip is I’m guessing right at vtec engagement or just before ?
 

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USDM > *
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That’s more like it. So only some of the valves were seeing the high cam before ? 200+ tq looking great ! That dip is I’m guessing right at vtec engagement or just before ?
The dip is right at VTEC cross over. It is typical for reverse cone headers like the ASP header I have. I think it’s related to resonance and back pressure. I’m sure LotusElise could explain it better.

Tool Wood Bicycle part Composite material Auto part
 

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The dip is right at VTEC cross over. It is typical for reverse cone headers like the ASP header I have. I think it’s related to resonance and back pressure. I’m sure LotusElise could explain it better.

View attachment 107175
That is a beautiful piece and yes I’m sure he could 😂
I can’t wait to find out! Too much salt and snow on the roads to enjoy it yet…

I’m wondering if switching the J35 TB to a J37 TB and porting the RRC is keeping from the mythical 300 hp?
Boss there is one way to find out. Lol. It has a 4P head right ? So anything that doesn’t flow as much as that is technically a “bottleneck” or restriction ? I know precisely diddly about the flow math and all that stuff so I’m just thinking and typing now 😆
 

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Arouse the DAMPFHAMMER!
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Its k24a3
Thanks for the clarification.

plm (i made a typo) is header make for k2x engines that people shouldn't buy. Serge pulling up to 10hp more than plm at 6000-6500 top end and Im pulling 20 hp on it with ram air.
Mods are serge header, cat removed and intake mod with drop in kn filter with ram air ducting.
Sorry, I am confused, which torque line corresponds to what you are stating here?

Ram Air is the trick here. When I close ram intake car is a bit over 1sec slower from 100-200kmh vs when its open. It makes bigger difference when going 160+. Dyno was made with open intake so its adding around 15hp when going at speed. Dont know what air speed is simulated on BaPro dyno, I hear its like driving at 150kmh.
You are claiming a cold air intake provides another 15 hp just by "ram air"? I am sorry, but this has nothing to do with physics. When your car sees air running around the chassis the static pressure before the CAI is reduced by the amount of kinetic pressure is increased. The so called ram air is regained kinetic pressure as static pressure, but this will not happen at just 140 km/h, as kinetic pressure is around 8 mbar, but you won't gain it as your CAI location already causes loss of static pressure.



You see here a simulation from science.org of a chassis at 50 mph (80 km/h). The potential kinetic pressure at the flat front here is 2.7 mbar, actually it is only 0.6 mbar because air can't stay there, it has to flow sideways, up- and down-ways to let the car getting further. Air has always to flow around, it is not like with snow which get moved by a car when you run in to a 2 m high snow wall. Air flows around the car, when it flows it has already a kinetic pressure, which is not available for the CAI. In the example above the regain of kinetic pressure is 22 % of the kinetic pressure. Translating it into your example it would be 2 mbar. This is something you should be able to prove, by comparing the WOT MAP in a 1st gear compared to a 4th gear run.

Would be great if we can see the around 2 mbar added MAP regained by your "ram air". When you close the inlet of the CAI, you cause a pressure drop in the induction. Why should this not cause less power and therefore a slower 100-200 km/h?

Cl9 vs fn2 on same dyno
What do we see there regarding engine setup differences. I can't read your mind, just what you post.
 

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Arouse the DAMPFHAMMER!
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I’m not sure what else could be done to improve the powerband at this point. I feel like any after market intake manifold will just sacrifice mid range power for top end HP.
The combination of small plenum volume, small throttle body and "small" cams with the 4P's 156V2 ports unfortunately doesn't help to support power.

The low speed torque tells interesting stories about these ports, seems they need much more air flow to produce a nice impulse. The port volume of 156 ccm is likely to big to create a nice VE. I had the 156V1 in hand and measured it, it flows well, but created far less velocity as a stock head. The engine VE need a nice punch from the air column to get the engine into healthy torque areas at any engine speed. Bench flow numbers should always be rated at which throat and port general angle it is achieved, otherwise it is more or less worthless number, just telling about a flow capacity but nothing about the port efficiency.

I would recommend you:
  1. a stock port, nice valves from the PPA head (they have already a 30° back cut). What would you see? Much more torque from low speed cam to around the middle of the high speed cam. You may loose up top a bit of torque. That 156V2 ports are to big for your application and engine, VE and combustion speed sucks with it on that small displacement and low redline.
  2. To overcome the top end torque disadvantage you can sacrifice some of the nice torque level with an more performant cam like the S2 U1, which gives you a better low speed and high speed efficiency compared to a same duration cam from Prayoonto's lobe design. Around 160 [email protected] rpm is the 2-Liter race engine level. My 2-Liter DAMPFHAMMER made around 180 [email protected] rpm on a MAHA roller dyno. I am not focused on numbers, but magnitudes. Your engine have almost 100 ccm more per cylinder, that means the VE level at low speed cam is not were it should or can be, that is what I am pointing at here. That is the cause of the huge port volume of the 156V2. Of course the port helps at top, but the cams, the IM, the TB are not made to support huge VE beyond 7500 rpm on a 2.4 liter engine. The IM squeezes that throat first, than the cams, than the TB and then the head port want to start working.
  3. The RRC is good IM in the bunch of OEM IM, but it misses runner length, diameter and plenum volume to get this engine easily to the 300 whp. If you port it, maybe it will support your engine there. But I am not sure if the J37 engine TB would compensate what your enigne need to get there. If I can have a look at your calibration and last WOT run I would be able to say if there is a potential.
About that dip, the falling edge tells me the tuner doesn't know to tune VTEC properly. VTEC switch point and VTC has to be arranged in a sort of compromise not let the torque dip just because the transition of VTC and lambda doesn't fit to the stationary tuning of those. The rising edge of the torque dip tells me - if measured in 4th gear - that transition takes some time and maybe is combined with an resonance of the header. But this I would also see in the calibration and last WOT run log, which I would check and discuss with you.
 

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USDM > *
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The combination of small plenum volume, small throttle body and "small" cams with the 4P's 156V2 ports unfortunately doesn't help to support power.

The low speed torque tells interesting stories about these ports, seems they need much more air flow to produce a nice impulse. The port volume of 156 ccm is likely to big to create a nice VE. I had the 156V1 in hand and measured it, it flows well, but created far less velocity as a stock head. The engine VE need a nice punch from the air column to get the engine into healthy torque areas at any engine speed. Bench flow numbers should always be rated at which throat and port general angle it is achieved, otherwise it is more or less worthless number, just telling about a flow capacity but nothing about the port efficiency.

I would recommend you:
  1. a stock port, nice valves from the PPA head (they have already a 30° back cut). What would you see? Much more torque from low speed cam to around the middle of the high speed cam. You may loose up top a bit of torque. That 156V2 ports are to big for your application and engine, VE and combustion speed sucks with it on that small displacement and low redline.
  2. To overcome the top end torque disadvantage you can sacrifice some of the nice torque level with an more performant cam like the S2 U1, which gives you a better low speed and high speed efficiency compared to a same duration cam from Prayoonto's lobe design. Around 160 [email protected] rpm is the 2-Liter race engine level. My 2-Liter DAMPFHAMMER made around 180 [email protected] rpm on a MAHA roller dyno. I am not focused on numbers, but magnitudes. Your engine have almost 100 ccm more per cylinder, that means the VE level at low speed cam is not were it should or can be, that is what I am pointing at here. That is the cause of the huge port volume of the 156V2. Of course the port helps at top, but the cams, the IM, the TB are not made to support huge VE beyond 7500 rpm on a 2.4 liter engine. The IM squeezes that throat first, than the cams, than the TB and then the head port want to start working.
  3. The RRC is good IM in the bunch of OEM IM, but it misses runner length, diameter and plenum volume to get this engine easily to the 300 whp. If you port it, maybe it will support your engine there. But I am not sure if the J37 engine TB would compensate what your enigne need to get there. If I can have a look at your calibration and last WOT run I would be able to say if there is a potential.
About that dip, the falling edge tells me the tuner doesn't know to tune VTEC properly. VTEC switch point and VTC has to be arranged in a sort of compromise not let the torque dip just because the transition of VTC and lambda doesn't fit to the stationary tuning of those. The rising edge of the torque dip tells me - if measured in 4th gear - that transition takes some time and maybe is combined with an resonance of the header. But this I would also see in the calibration and last WOT run log, which I would check and discuss with you.
Thanks for the thorough reply.
For starters, I didn’t feel the dyno result was so bad. 290 HP and 205 TQ is a great result for a motor reving to 8000 RPM. And the midrange torque looks very good to me!

I am sure the 156v2 head could be further optimized but it appears to be an improvement over a stock PRB.

Although not a perfect comparison, this is almost an identical K24 block on E85 with stock PRB head and PR3 cams (Blue line) vs my engine (red line) with 156v2 head and ASP header. My engine does not appear to lose any midrange compared to the blue line.

Rectangle Slope Plot Parallel Font
 

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Arouse the DAMPFHAMMER!
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8,202 Posts
Although not a perfect comparison, this is almost an identical K24 block on E85 with stock PRB head and PR3 cams (Blue line) vs my engine (red line) with 156v2 head and ASP header. My engine does not appear to lose any midrange compared to the blue line.
Thanks for the comparison @BlackNDecker. BTW nice comparison technique. Do you have a single picture of the PRB head dyno sheet where I can identify the number of the scaled lines?
 

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USDM > *
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4,888 Posts
Thanks for the comparison @BlackNDecker. BTW nice comparison technique. Do you have a single picture of the PRB head dyno sheet where I can identify the number of the scaled lines?
Ha! Obviously not ideal but I used powerpoint and tried to scale the graphs as close as possible without spending a ton of time.

here you go…
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Arouse the DAMPFHAMMER!
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Ha! Obviously not ideal but I used powerpoint and tried to scale the graphs as close as possible without spending a ton of time.
Thanks for your effort on that.

What IM and header as well as E does the stock head engine have? The resonance points are different, seems they are different.
 

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USDM > *
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Thanks for your effort on that.

What IM and header as well as E does the stock head engine have? The resonance points are different, seems they are different.
The header was a generic PLM aka Chinese design.
RBC intake manifold with 70mm TB.

I think the biggest differences between the 2 engines were ported head and ASP header on mine.

I appreciate your input, but I feel like you might be overly critical of the build. This engine seems to have a fairly flat TQ curve with nearly 200 TQ at 5000 RPMs. It doesn’t look to me like it is sacrificing anything down low.
 
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