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Discussion Starter · #61 · (Edited)
Put the harness back on the drivetrain. Re-worked various odds & ends. Put in new spark plugs (NGK 6994). Conflicting gaps posted online, these came gapped to .030", not .044" as posted online. I split the difference & gapped them to .036" torqued to 16ft/lb.



Re-routing the harness on this side above the water pipe, instead of below it as before. Makes it tidier, and gives me more length where they need to connect to the cabin harnesses. It does mean that the plenum neck has to tuck behind the harness loop up to the injectors, so I ground back all the excess flange elements on my extension for the smaller TB







don't think I ever took a throat pic

had to futz with the bracket & bolt I used to secure the heater pipe - the flange it mounts to has to be shaved down for my water pipe to sit as it needs to

in shaving it, I cut into the driver's side hose, so I had to replace that. I know, I should have removed it before grinding
 

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don't think I ever took a throat pic
Looks like port matched. Does the 87.5x99 need that much hole for the IACV to get idle controlled in your area?

I just saw it the first time with recognition. Dose the head-sided IM part runner stare to heaven in a more then 15° angle with an s-shaped runner (from side view perspective)?
 

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Discussion Starter · #63 · (Edited)
Looks like port matched. Does the 87.5x99 need that much hole for the IACV to get idle controlled in your area?

I just saw it the first time with recognition. Dose the head-sided IM part runner stare to heaven in a more then 15° angle with an s-shaped runner (from side view perspective)?
I did port match the runner and plenum. No, I'm sure it doesn't need that much intake cross section, I did that to match the 72mm K-tuned TB I'm using. I have very little room off the firewall.

first, I built it for the 80mm TB, but I could never get a consistent idle under 1200rpm, so I made the adaptor plate & went to the smaller TB above

It's the stock RBB 2-part intake, I just chopped the plenum side for packaging in my chassis. The "injector base" (as Honda calls it) RAA runners are only "S" in the sense that the mount flanges return to horizontal plane from whatever angle the runners travel at, I never measured the angle.
original format:



the RAA runners incorporate a elaborate reed plate for crankcase evacuation under vacuum
 

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The "injector base" (as Honda calls it) RAA runners are only "S" in the sense that the mount flanges return to horizontal plane from whatever angle the runners travel at, I never measured the angle.
Thanks for the picture. Looks like the runners are steeper as the intake head ports, which are around 13°-17°, depending where you measure on the bottom line of the port. The runners look like to be around 25°-30°, most likely to generate enough height to clearance the upside down showing plenum and length of the post injector base runners. Thanks for that term, always nice to know the OE part name.

the RAA runners incorporate a elaborate reed plate for crankcase evacuation under vacuum
Means, when the under pressure is high enough the reed valve would open the path the crank case ventilation and close and block it when MAP have increased over a threshold pressure, when the reed valve closes again. I see every runner has a connection to the valve room. The black rubber sealing in the middle acts like the reed valve? Get pulled down under vacuum against the tension of the two bracket arms?
 

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Discussion Starter · #65 ·
Means, when the under pressure is high enough the reed valve would open the path the crank case ventilation and close and block it when MAP have increased over a threshold pressure, when the reed valve closes again. I see every runner has a connection to the valve room. The black rubber sealing in the middle acts like the reed valve? Get pulled down under vacuum against the tension of the two bracket arms?
I never took a pic of the channels in the cover - that center location is just seal - there is a bolt passing through

 

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never took a pic of the channels in the cover - that center location is just seal - there is a bolt passing through
Ah, I see the bolt in the middle, the blowby hose connection and the body shape of the upper housing, but I can't see a reed valve function. If there is one, it must be implemented in the upper housing around the middle bolt, mentioned above. Did you see it in that upper housing?
 

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Discussion Starter · #67 ·
Ah, I see the bolt in the middle, the blowby hose connection and the body shape of the upper housing, but I can't see a reed valve function. If there is one, it must be implemented in the upper housing around the middle bolt, mentioned above. Did you see it in that upper housing?
I honestly can't recall the upper plate passage way design. I assumed the elaborate layout functioned as blow-by reed valves, similar to the setup on my Volvo T5 intake (below), however it is not obvious that the plate can deflect in any way due to pressure change, so perhaps it is only channels for the gases to be drawn through. Seems awfully complex if that's all it is though.


 

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I assumed the elaborate layout functioned as blow-by reed valves, similar to the setup on my Volvo T5 intake (below)
Oh yes, these are definitely reed valves those two of the Volvo T5 intake. Thanks for sharing, always good to know what other brands provide regarding simple solutions on essential tasks of an engine system (y).
 

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Finished up all the wiring, module & actuator install for the RSX cruise control, so back to putting the drivetrain in the chassis
Sounds good. I am looking forward to see that engine running on the dyno or at least the result for comparison with the previous header.
 

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Discussion Starter · #71 ·
Sounds good. I am looking forward to see that engine running on the dyno or at least the result for comparison with the previous header.
It's probably going to be a while before I can get a Dyno session. The motor definitely feels much more lively up top than before, in the limited upper revs I have run so far. I need to run in the engine for a few hundred miles at varied rpms before I get on it really hard.

wrapping up the bay side of the cruise control install, and fixing the engine cover mesh that melted from the heat of the new header










my small garage, just big enough for an X1/9
 

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the RAA runners incorporate a elaborate reed plate for crankcase evacuation under vacuum
Thank you for taking this picture! Absolutely not thread jacking, but a few questions:
I don't understand this concept and why it's only on the k24s. Doesn't this just create more surface area to get gunked up by blow by gases/oils?

Second question: why do the k24s have a different PCV valve than the k20s? They have that red washer looking thing? What is the difference to the plain bolt looking pcv and are they interchangeable?
 

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Just a thought. The chassis of the K24 are 200-400 kg heavier, that means allot to engine designers. Low end torque is the key to overcome customers thinking of an throttled engine. The 87x99 engine was a great decision, despite the fact the 99 mm stroke are one of the biggest that time in the market, but the easiest way of increasing the displacement on the K-series platform. Honda changed more often the bore pitch then e.g. VAG who has the same two since over 35 years and just added a few to that. That mean a lot of for the fabrication cost and reuse of design elements. But back to customer experience and low end torque. Once you have a lot of low end torque from a almost plus 100 ccm/cylinder the blowby flow increases quite allot as the bore also got increases (= more leaking area for blowby). This and the need to still achieve the emission cycle test passing my forced Honda to this upgraded low load blowby path to control it better. What at least is better the blowby is more evenly portioned to all four cylinders, which has much likely to do with the higher VE in low load low engine speed situations to be able to introduce a more advanced ignition timing for better fuel consumption. More blowby and more VE bite each other, as blowby can introduce knock. Just as a thought around the blowby design differences.
 

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my small garage, just big enough for an X1/9
Looks amazing. You did really really a good paint job to recover all the damage.

It's probably going to be a while before I can get a Dyno session.
Oh, I need to train my patience. I already consumed all for mine 😆.

The motor definitely feels much more lively up top than before, in the limited upper revs I have run so far. I need to run in the engine for a few hundred miles at varied rpms before I get on it really hard.
I am happy to read this. Midrange should definitely came out better after tuning as less interference of cylinders destroy the effect of scavenge there and lower the point of engine speed where it finally does interfere. Top end may profit too. I am curious if my resonance calculation comes out reasonable.
 

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Thank you for taking this picture! Absolutely not thread jacking, but a few questions:
I don't understand this concept and why it's only on the k24s. Doesn't this just create more surface area to get gunked up by blow by gases/oils?

Second question: why do the k24s have a different PCV valve than the k20s? They have that red washer looking thing? What is the difference to the plain bolt looking pcv and are they interchangeable?
I recently bought a k24 upper manifold to use the flange for my intake manifold project. While stripping it down, i noticed that the top cover plate is mainly a distribution block for the exhaust gas recirculation. There's a port cast in the manifold from egr port beside the coolant port that feeds the top plate cavity, from there, there's 4 small distribution holes. One to feed each runner. There are also another set of holes to feed a common pcv port. The gasket system is there to seal the separate egr and pcv systems.
 

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I recently bought a k24 upper manifold to use the flange for my intake manifold project. While stripping it down, i noticed that the top cover plate is mainly a distribution block for the exhaust gas recirculation. There's a port cast in the manifold from egr port beside the coolant port that feeds the top plate cavity, from there, there's 4 small distribution holes. One to feed each runner. There are also another set of holes to feed a common pcv port. The gasket system is there to seal the separate egr and pcv systems.
O wow, thanks for the reply!
 

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Discussion Starter · #77 ·
I recently bought a k24 upper manifold to use the flange for my intake manifold project. While stripping it down, i noticed that the top cover plate is mainly a distribution block for the exhaust gas recirculation. There's a port cast in the manifold from egr port beside the coolant port that feeds the top plate cavity, from there, there's 4 small distribution holes. One to feed each runner. There are also another set of holes to feed a common pcv port. The gasket system is there to seal the separate egr and pcv systems.
There's no EGR on the JDM one I have - there were water passages and a thermovalve for the idle assist . The top plate is connected directly to the PCV valve



 
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