KPower Industries K24 swap

[Four_wheel_drifts]

Originally Posted by Irace86.2.0

I asked Kpower if it is possible, and they said yes, but that it was easier to do the engine and transmission together, which is what I did. Clearance is probably an issue, even with dropping the sway bar.

Not sure why they had to drop the transmission, but the modifications they made now makes taking out the transmission without pulling the engine, too, an easy(ier) affair.

[RedReplicant]

Originally Posted by Four_wheel_drifts

Not sure why they had to drop the transmission, but the modifications they made now makes taking out the transmission without pulling the engine, too, an easy(ier) affair.

What did they change?

[Four_wheel_drifts]

Originally Posted by captain awesome

A simple band aid that could be done quick and easy is a 140 degree Mishimoto thermostat.

My concern from previously running a 140F thermostat on street driven cars, is the engine always running too cool. This made fuel efficiency terrible, amongst other issues.

[captain awesome]

Originally Posted by Four_wheel_drifts

My concern from previously running a 140F thermostat on street driven cars, is the engine always running too cool. This made fuel efficiency terrible, amongst other issues.

That's my worry as well. It really isn't the ideal solution but it also isn't getting warm enough when needed. If there was a thermostat that wasn't such a leap in temps, maybe somewhere in the middle of the two? I think the real solution is to send more hot coolant to the housing. It just sucks having to wait a day or two for welding if the tapping method isn't possible.

[captain awesome]

So it looks like they have updated the Mishimoto and other branded low temp thermostats to begin it's opening around 154.4 then fully open at 173.


Stock would be 172.4 opening and then fully at 194.



So roughly an 18-20 degree drop in opening.

[Irace86.2.0]

Originally Posted by captain awesome

I haven't modified the thermostat at all. It's a brand new Aisin unit and if not in any movement or airflow does open as it was intended. I haven't ever shown signs of overheating or of air bubbles being trapped in the system. The problem only arises when in motion where the radiator gets cool air. This starts the cycle of a fan always on to keep it just cool enough that it never opens but also can't really get it down enough to shut the fan off.

I already have the fans kicking on multiple degrees later and also both are staggered for a later response. I'll double check what I set it at but I believe it was north of 200 for both fans. Unfortunately the heat at the back of the head where the fans get their signal is considerably higher than when it finally reaches the thermostat housing. I can feel the thermostat housing is warm to the touch. Just not quite warm enough to open. I think a second heated circuit that hasn't been cooled by the heater core ever so slightly will get things like the Honda/Acura system was designed for.


A simple band aid that could be done quick and easy is a 140 degree Mishimoto thermostat.

One last thing would be setting when the fans shut off, but if I remember correctly it's already a fairly narrow window that I have set so that it wouldn't stay on too long.

How do you tell the fans are kicking on in motion? Can you hear them or something?

I checked tonight after I came home, and all my hoses were hot to the touch. My fan was cycling on and off while idling.

[captain awesome]

Originally Posted by Irace86.2.0

How do you tell the fans are kicking on in motion? Can you hear them or something?

I checked tonight after I came home, and all my hoses were hot to the touch. My fan was cycling on and off while idling.

The temp the sensor sees defines when the fans kick on. It's obvious when they kick on and off when watching my laptop based on temps rising or lowering.



So I tested some stuff when I got back to the house.


My previous settings for fan 1 to kick on was 198 and it should shut off at 190.


Fan 2 was set to kick on at 204 and should shut off at 195.


I started the car in the garage and let it idle. I revved it up a little to get the temp up and fans kicked on as intended. The thermostat housing got warm enough to start to warm the lower hose. Not much though, so it didn't seem to be fully open. Either way that's what I expected to happen.


So I adjusted the temp on fan 1 to kick on at 200 then shut off at 195. Then fan 2 was set at 202 and same shutoff at 195.


This allowed the lower hose to get warmer when idling in the garage.


I took the car out for a spin and under load with RPM above 3k I can keep the car below 200 easily. If I putter around at 2k however the temp started to climb. In fact it managed to get to 212 under light load. I quickly sped up RPM and it would drop pretty quick. When I pulled the car back in the garage it was hovering at 207 and couldn't drop enough with both fans on. The hose on the passenger side was hot but again now the lower hose is cold. Not ice cold but actually cool enough it's shocking.


I don't have a way to really check the temp on the thermostat housing but it's warm. Clearly still not enough to open the thermostat.


At this point I'm ordering a low temp thermostat to get a quick cheap fix and then when I can manage the downtime I will add a second coolant line to the thermostat housing.

[Irace86.2.0]

The hose leading to the thermostat is really hot, right? Like, it is hot enough that you can't hold it, right?

[captain awesome]

Originally Posted by Irace86.2.0

The hose leading to the thermostat is really hot, right? Like, it is hot enough that you can't hold it, right?

Correct. If I feel the thermostat housing it feeds into however I can hold my hand to it without needing to move my hand.


I also finally found a good diagram of the factory k24a2 coolant system. I think it confirms the secondary hose is needed or that it was designed with both hoses contributing to the flow. I wonder if I was able to have the current hose going into the blocked off port that it would activate the thermostat quicker at least until I could get the second added. It would dump directly onto the thermostat versus the other kinda being only closer to the tip of it and easily sucked into the water pump bypass.

[Irace86.2.0]

Originally Posted by captain awesome

Correct. If I feel the thermostat housing it feeds into however I can hold my hand to it without needing to move my hand.


I also finally found a good diagram of the factory k24a2 coolant system. I think it confirms the secondary hose is needed or that it was designed with both hoses contributing to the flow. I wonder if I was able to have the current hose going into the blocked off port that it would activate the thermostat quicker at least until I could get the second added. It would dump directly onto the thermostat versus the other kinda being only closer to the tip of it and easily sucked into the water pump bypass.

You have it backwards. The hard hose is closest to the water pump housing. The small hose feeds the backside and has to flow past the thermostat.

If the feed to the thermostat is hot enough, but you feel like it is moving too fast through the housing then you can simply bifurcate the single hose to feed both ports of the thermostat housing, which will slow the flow. The plastic is probably a thicker insulator than the hose, but I’m sure it is plenty hot in there.

Technically, the faster the flow, the more heat transfer should occur, if the water being delivered is the same temperature. The slower the speed, the incoming water has lost heat to the transferring medium, so the temperature differential is less. If there is a cooling stage in the system then the faster the flow the less heat is picked up off the transfer medium, but also less heat is removed in the cooling phase, so unless the cooling phase is more efficient at extracting heat than the warming phase, speed shouldn’t make a difference.

Now, you keep saying the cooling fans are cooling the water, yet your thermostat is closed. How is cool water returning to your engine to keep the engine cool? There is no flow, and the stagnant, cooled water in the radiator is not going to conduct/convect back along the passenger pipe to the rear of the engine to keep the engine cool. The engine should overheat if the thermostat never opens. The engine would need to be air cooling, or if you have an external oil cooler, staying cool enough being oil cooled like my Ducati Monster.

I have a JR radiator/oil cooler. My pipes still get hot, so I doubt your cool, radiator pipe is a result of efficient cooling with your radiator with an open thermostat unless you were living in a freezing/snowy climate or something—even then.

[captain awesome]

There is still flow or at least some with the water pump bypass. It must be just enough but it's hard to say? Either way I have read multiple threads where folks try to "simplify" their cooling system and end up having this same issue. I also have a thread on the GRM board that have had other Honda fans that have seen or read of the same issue. I am not 100 percent certain that's what's happening here with mine but it's completely plausible. I mean the factory has two lines going to that housing. Deleting one can easily reduce the functional flow of the system it was designed for.




As of right now my plan is to pull the stock thermostat this week when the new lower temp one shows up. I will boil both and monitor when they first open and then full for both. At least that way I can rule it out.



I think if there were any air trapped in the system it would just overheat. I'm not getting quite to that temp yet. I'll keep everyone posted on it. I'm certainly not trying to get everyone to freak out and think they need to redo the whole coolant system but if adding the second line helps I can't see the downside other than more effort.

[Mike_ZN6]

I am seeing multiple reports of this swap having serious NVH issues. Has anyone done this swap and not experienced the vibration problems?

[Irace86.2.0]

Originally Posted by Mike_ZN6

I am seeing multiple reports of this swap having serious NVH issues. Has anyone done this swap and not experienced the vibration problems?

Mine is feeling more manageable. I had some tuning improvements that is making the commute less harsh, but in general, it is still has a ton of NVH.

[captain awesome]

Mine is more manageable now as well but it's still there. Lurking.



After I pulled the poly Whiteline trans bushing and swapped in the shortened 2 piece it was considerably better. Then I added an STI trans mount since the stock one was touching the trans mount under high load left handers without the bushing. The vibes are back, maybe more muted but they are back. The stock mount is going back in soon. So I plan add clearance by pushing the trans bushing a little bit more to the driver side and see if that helps. Possibly cut/weld or hammer more space on the mount as well.


With that said it's really only there in a couple places that are noticeably annoying. My dash has some spots that I'm still trying to get to stop buzzing at idle. Some of that may be because I removed the whole dash to manual swap my automatic and things didn't get snug or are out of place rubbing something. The worst offender is my shifter buzzes from 3500-4500 which I think is the reverse lockout and my 1" shifter extension. The stock trans bushing without the poly bushing made a HUGE difference with this as well as the driveshaft. Barely there, and now it's back.



I still plan to use my shortened stock shifter assembly but the trans mounts welded to the tunnel make it impossible to install with the trans in the car. I'm rethinking what I can do to mitigate that other than tilting everything far enough to slide the pins in as there's not enough room where it sits.