RockTracXJ
NAXJA Forum User
- Location
- Colorado Springs
My Jeep has always run hot even in conditions that aren’t that bad. It’s modified with all the heavy bumpers, winches, rockrails, etc. Its generally loaded down with stuff for mountain adventures. And I live at 6700’ and only go up from here. Definitely tough conditions for a cooling system. I’ll also admit the old 4.0 isn’t in the greatest shape either, it burns oil. I’ve been through the system replacing the fan clutch, radiator, flush, etc. I even ran a switch to the e fan so that I could turn it on whenever. It was driveable and functional, but the temp was known to creap, especially climbing mountain passes. For the most part I’ve come to live with it.
Then I saw the Dirtbound efan conversion kit and for the price I thought it sounded great. So I ordered one and dropped it in a couple of weeks ago. The install wasn’t the easiest, it was about like trying to fit an oval peg into a round hole, it took some work and shoehorning and ultimately I cut the upper radiator support to get it to fit. Finally it was all in and I got to drive it. I ordered it with the controller and that worked great, turned the fans on when it should. The first time I drove it I immediately noticed that the engine was peppier. For an old gutless engine like mine that’s a very good thing. That first time I drove it I didn’t subject it to much, the temps weren’t that warm and I was just running errands, but everything seemed fine.
The fit hit the shan the next week when I tried to take the fully loaded Jeep up a pass for some camping. I have never seen the temps shoot up that hard and fast in my Jeep before. Maybe the two fans didn’t come on as they should? I pull over and have a look and all the fans are humming away. I let the Jeep cool down and started out again and just watched the temps shoot up (which ultimately led to what I would describe as vapor lock). It was quite discouraging. We went back down the mountain and filled it up with a fresh tank of gas. This helped with the vapor lock issue and we were able to make it up into the mountains, but it ran hot all the way up (should I pull over and let it cool, kind of hot). That day wasn’t even hot, it was probably around 65*. Obviously, it was quite apparent that this system had to go and I needed to return it to stock.
Unfortunately, I couldn’t just pull the conversion kit and drop my stock system back in because of the cutting I did to the upper radiator support (I cut the ‘back’ lip off that has the holes where the stock efan/fan shroud mounts). So now I’m in a trip to the junkyard as well.
So in the week since I’ve done some thinking and reading. I’ll admit I don’t think I researched the product or the mod as much as I should have before I went all in on it. I think we (I) can sometimes fall into the trap of thinking that if it’s an aftermarket modification than it is implicitly better than stock. And (outside of obvious junk) I think this is generally true. So I thought that this conversion would be better than stock. So, in this case, how would we define ‘better’ than stock? Because it is a mod to the cooling system, specifically fans, I would say that ‘better’ in this case is better cooling. And better cooling through fans means higher airflow, higher CFM. And why wouldn’t I think that I’m getting higher airflow, this kit averages 4300 CFM after all!
When I was putting these fans in I remember thinking that they didn’t look particularly big or aggressive, especially next to the stock fans. Even more so as I am pulling them back out. Every time I looked at these fans after pulling them out, I generally thought, ‘man, those fans are cute’. Someday when these fans grow up, they want to be a stock xj e fan.
Now, let’s talk numbers, because that’s what we’re really after here – CFM. This can be tricky because often these discussions are based more on conjecture than on fact. Fortunately, Dirtbound provided us some good facts from which to build (but I’m still going to throw in some conjecture). These can be seen here:
http://www.naxja.org/forum/showthread.php?t=1057920&page=2
To summarize:
DB avg CFM/fan = 1445
DB kit avg CFM = 4335
99 xj e fan CFM = 2300
When I first read that, I was quite impressed with the 99 e fan. Regardless, what we’re basically seeing here in our quest for CFM (total system capability) is that the mechanical fan only needs to pull 2035 CFM to equal the DB kit. Unfortunately I’ve not seen any credible numbers on the m fan, so we’re going to get into the conjecture a bit. But, I think we’ve got some good info to work from. First, just look at that fan! Look at the blade size and blade pitch – it’s quite bitchin, the fan is just straight menacing. I roughly measured the diameter of the fan tip to tip at 14.5”. Another huge benefit of the mechanical fan is that it’s speed varies based on engine speed. When I’m trying to climb a pass this is important. When these e fans or on, they’re on, and that’s all you get.
Anyway, as I said earlier in all my driving and wheeling my Jeep, I’ve never seen the temps shoot up like that before as with the DB kit. This, along with what I’ve stated above leads me to believe that the mechanical fan by itself moves a comparable amount of air as to the DB kit as a whole. Yessir, I’m convinced of at least 4000-4500 CFM at driving level engine speeds.
So, to summarize, I think that when converting from the stock system to the DB e fan kit, one is effectively losing at least 2000 CFM system capability, most likely even more than that. Now, I have read all of the positive reviews and results people have gotten from the DB kit. I think that in stock, good working order, the XJ’s CFM capability is overkill, it has a lot more than it needs. The average, good working XJ can have the stock fan system swapped out for this e fan kit and it will still move enough air to properly cool the Jeep. And removing the mechanical fan load on the engine is a definite bonus.
Returning to my earlier question - Is this mod better than stock? Based on my definition of 'better' above - CFM - there is no way. Not even close. But as I just stated, for many XJs the DB kit CFM rating may be more than enough, so in that case perhaps the mod is still a good choice based on removing the m fan load from the engine.
My goal here is to provide more information and another view to those thinking about doing any fan conversion. I think when we’re deliberating on how to spend our precious resources it’s always good to have as much info as possible. Oh, and yes, the DB fans and shroud are for sale.
Git ‘er Done.
RTXJ
Then I saw the Dirtbound efan conversion kit and for the price I thought it sounded great. So I ordered one and dropped it in a couple of weeks ago. The install wasn’t the easiest, it was about like trying to fit an oval peg into a round hole, it took some work and shoehorning and ultimately I cut the upper radiator support to get it to fit. Finally it was all in and I got to drive it. I ordered it with the controller and that worked great, turned the fans on when it should. The first time I drove it I immediately noticed that the engine was peppier. For an old gutless engine like mine that’s a very good thing. That first time I drove it I didn’t subject it to much, the temps weren’t that warm and I was just running errands, but everything seemed fine.
The fit hit the shan the next week when I tried to take the fully loaded Jeep up a pass for some camping. I have never seen the temps shoot up that hard and fast in my Jeep before. Maybe the two fans didn’t come on as they should? I pull over and have a look and all the fans are humming away. I let the Jeep cool down and started out again and just watched the temps shoot up (which ultimately led to what I would describe as vapor lock). It was quite discouraging. We went back down the mountain and filled it up with a fresh tank of gas. This helped with the vapor lock issue and we were able to make it up into the mountains, but it ran hot all the way up (should I pull over and let it cool, kind of hot). That day wasn’t even hot, it was probably around 65*. Obviously, it was quite apparent that this system had to go and I needed to return it to stock.
Unfortunately, I couldn’t just pull the conversion kit and drop my stock system back in because of the cutting I did to the upper radiator support (I cut the ‘back’ lip off that has the holes where the stock efan/fan shroud mounts). So now I’m in a trip to the junkyard as well.
So in the week since I’ve done some thinking and reading. I’ll admit I don’t think I researched the product or the mod as much as I should have before I went all in on it. I think we (I) can sometimes fall into the trap of thinking that if it’s an aftermarket modification than it is implicitly better than stock. And (outside of obvious junk) I think this is generally true. So I thought that this conversion would be better than stock. So, in this case, how would we define ‘better’ than stock? Because it is a mod to the cooling system, specifically fans, I would say that ‘better’ in this case is better cooling. And better cooling through fans means higher airflow, higher CFM. And why wouldn’t I think that I’m getting higher airflow, this kit averages 4300 CFM after all!
When I was putting these fans in I remember thinking that they didn’t look particularly big or aggressive, especially next to the stock fans. Even more so as I am pulling them back out. Every time I looked at these fans after pulling them out, I generally thought, ‘man, those fans are cute’. Someday when these fans grow up, they want to be a stock xj e fan.
Now, let’s talk numbers, because that’s what we’re really after here – CFM. This can be tricky because often these discussions are based more on conjecture than on fact. Fortunately, Dirtbound provided us some good facts from which to build (but I’m still going to throw in some conjecture). These can be seen here:
http://www.naxja.org/forum/showthread.php?t=1057920&page=2
To summarize:
DB avg CFM/fan = 1445
DB kit avg CFM = 4335
99 xj e fan CFM = 2300
When I first read that, I was quite impressed with the 99 e fan. Regardless, what we’re basically seeing here in our quest for CFM (total system capability) is that the mechanical fan only needs to pull 2035 CFM to equal the DB kit. Unfortunately I’ve not seen any credible numbers on the m fan, so we’re going to get into the conjecture a bit. But, I think we’ve got some good info to work from. First, just look at that fan! Look at the blade size and blade pitch – it’s quite bitchin, the fan is just straight menacing. I roughly measured the diameter of the fan tip to tip at 14.5”. Another huge benefit of the mechanical fan is that it’s speed varies based on engine speed. When I’m trying to climb a pass this is important. When these e fans or on, they’re on, and that’s all you get.
Anyway, as I said earlier in all my driving and wheeling my Jeep, I’ve never seen the temps shoot up like that before as with the DB kit. This, along with what I’ve stated above leads me to believe that the mechanical fan by itself moves a comparable amount of air as to the DB kit as a whole. Yessir, I’m convinced of at least 4000-4500 CFM at driving level engine speeds.
So, to summarize, I think that when converting from the stock system to the DB e fan kit, one is effectively losing at least 2000 CFM system capability, most likely even more than that. Now, I have read all of the positive reviews and results people have gotten from the DB kit. I think that in stock, good working order, the XJ’s CFM capability is overkill, it has a lot more than it needs. The average, good working XJ can have the stock fan system swapped out for this e fan kit and it will still move enough air to properly cool the Jeep. And removing the mechanical fan load on the engine is a definite bonus.
Returning to my earlier question - Is this mod better than stock? Based on my definition of 'better' above - CFM - there is no way. Not even close. But as I just stated, for many XJs the DB kit CFM rating may be more than enough, so in that case perhaps the mod is still a good choice based on removing the m fan load from the engine.
My goal here is to provide more information and another view to those thinking about doing any fan conversion. I think when we’re deliberating on how to spend our precious resources it’s always good to have as much info as possible. Oh, and yes, the DB fans and shroud are for sale.
Git ‘er Done.
RTXJ
