#3 · (Edited)
Yes, I have some data points. Before installing the Cyc4 cooling mod, the temperature differential between my oil temp and water temp is about 20 degree F when the car is up to normal running temp. That is, if my oil temp is 190, my water temp will usually read 210 (not in the pic below). Don't pay too much attention to the absolute temp values because it depends on where you have the sensors installed, only the amount of temperature differential between oil and water matter in this discussion.
After installing the Cyc4 cooling mod, the temperature differential between my oil and water has reduced. That is, if my oil temp read 190, my water temp now reads 202. I am typically seeing a 8 degree F reduction in my water temp reading under most driving condition after installing this mod. Hope this helps.
#5 · (Edited)
Explain that!
If coolant comes out cooler, it is taking less from the engine. If everything were equal, There would be no way to bring a hot cylinder down to be equal to the others temp and not have hotter coolant
Personally Ill believe this uncontrolled experiment is meaningless.
Added: Everything is not equal raising the rate of flow will lower the coolant temperature assuming the thermostat and radiator are doing their job so that the coolant entering is ay a constant temperature
mheyman said:
Explain that!
......There would be no way to bring a hot cylinder down to be equal to the others temp and not have hotter coolant.....
Well.... if the Cyc4 mod increases the coolant circulation so good that it help to keep the engine cooler from start up then it will never get as hot as before.
#8 · May 30, 2021
So here's my opinion on it:
I dont think the cylinder 4 cooling mod is all that great. So it brings the temps of cylinder 4 down a couple of degrees, ok and. Technicnally it may make cyl 4 less prone to detonation under extrememe high temps but that would be under extreme conditions. This mod doesnt make the it so cyl 4 wont have a problem. It wasnt designed for that. It was simply just designed to help reduce a some cylinder temps under normal conditions. I think having a good tune on the car will be a better preventative thing than this mod.
I think the cyl 4 cooliong mod would be ok to do if you already have the coolant out already or are planning on a higher hp set up. Other than that, i dont think its really worth all the hassle. I also dont like how you are now adding an extra possible coolant leak to the car.
Just my 2cents.
I think to further substaniate this mod as being usefull, we would need to see it in action on cylinder 4 in multiple kinds of coniditions and power ranges. Also seeing how it effect the cylinder as whole over a long term.
So yeah, we need ALOT more data.
#10 · May 31, 2021
So here's my opinion on it:
I dont think the cylinder 4 cooling mod is all that great. So it brings the temps of cylinder 4 down a couple of degrees, ok and. Technicnally it may make cyl 4 less prone to detonation under extrememe high temps but that would be under extreme conditions. This mod doesnt make the it so cyl 4 wont have a problem. It wasnt designed for that. It was simply just designed to help reduce a some cylinder temps under normal conditions. I think having a good tune on the car will be a better preventative thing than this mod.I think the cyl 4 cooliong mod would be ok to do if you already have the coolant out already or are planning on a higher hp set up. Other than that, i dont think its really worth all the hassle. I also dont like how you are now adding an extra possible coolant leak to the car.
Just my 2cents.
I think to further substaniate this mod as being usefull, we would need to see it in action on cylinder 4 in multiple kinds of coniditions and power ranges. Also seeing how it effect the cylinder as whole over a long term.
So yeah, we need ALOT more data.
Yea I'm defintely more in this camp when it comes to this mod. Introducing an additional point of failure with a mod that doesn't conclusively solve the perceived problem with cylinder 4 is just counter intuitive in my mind.
I agree that it will take time and more data to prove the effectiveness of the part (in regards to temps). But in terms of just coolant flow, I believe it is pretty well documented that the coolant is known to just sit and potentially get hot (around cylinder 4). The cooling mod provides another exit point and hence generates flow and keeps coolant moving around the cylinder head. For me, that made sense and was one of the big factors to make the purchase. Will it make the EJ bulletproof? Hell no...but it does give me some peace of mind.
For whatever it’s worth, there have been a number of companies copying Dom’s original design since he released it a couple years ago. I guess it can’t be completely useless if others are releasing their own versions of it.
I wouldnt say its completley useless but certainly not worth it in my opinion. It seems like its relatively easy/simple to make and im sure cost effective on a mass production side. Im not surprised the aftermarket world jumped on. The subaru community is pretty large considering this engine is still in production 17 years later. Think about how many people own, have owned, will own, an EJ powered subaru. People will buy anything now a days for these cars under the guise of "preventative".
I have a simpler thought on this...the knock sensor for the whole engine is on cylinder 4 - right?
If that is the case and you decrease knock on cylinder 4, does that make the rest of the engine more likely to see knock?
Anyway, just a thought. I am far from expert on things but the Subaru engineers put the sensor there for a reason.
.@Leemanfor butted two rings on his motor... Cylinder 2 rings were warped and cylinder 4 rings were broke. I'm willing to be that if he had the coolant passing through the head, like it really should, he would not have had the rings butt.
For safety, I'd personally place the cylinder 4 cooling over the ELH.
I won't say that the cylinder 4 cooling mods don't work and If the EJ weren't going away we'd eventually learn the whole real story. But, I am pretty sure that Doms' documented few degrees of coolant temperature drop alone can not be a significant benefit. It may well be that under some circumstances, coolant boils there locally. If this were to occur, then it would be the equivalent of overheating in a very small area, and it would be short lived and fairly difficult to observe. Increased coolant flow would certainly be of benefit if this were the case. To my knowledge, No one has documented this.
#30 · (Edited)
Well no... It's not a saving grace or savior, because you're still stuck with a crappy Subaru EJ25.
To reference fueling an timing. Subaru does cylinder timing comps. Some years, they add timing to #4, other years, they reduce timing. That said, what's the common failed piston on an EJ? The cooling absolutely does affect timing, especially if you can keep the coolant and equalization consistent. THE designed goal is to reduce failures due to knock events that occur due to that side running hotter. THAT IS why it was created.
Subaru hasn't done this ground breaking discovery of a modd yet in any production sti or wrx. Why?
Why would they... They are selling cars, then short blocks. And, a lot of people seem to buy $40k Subaru's and throw another $20-40k into them, which is insane... But that is their customer.
