you shouldnt even need a fan while moving with a proper setup cooling system. If you decide to replace the radiator check into triple pass style You may have to modify mounts etc but what it does simply make the coolant pass across three times instead of the normal one drop.
SO many things to say here…
I agree that if I inject 60 mph wind into the grill and had no fan, I probably could burn a lot of fuel and stay under 210 engine temp.
The problem is that I don’t know if I am getting the equivalent of 60 mph air through the radiator due to pressure, turbulence and other effects.
Regarding a 3 row… Jeep changed from a 2 row back to a 1 row to improve cooling during the TJ years. How and why? The answer is because the more rows you have, the less air flow you get. They matched the static pressure needs of the updated fan to the radiator and determined 1 row was a more efficient capacity result.
You might be right that 3 rows have more surface area, but to double surface area and drop air flow by more than 50% is not an improvement from a physics perspective.
I spoke to griffin yesterday and they make a deeper core B-Tube radiator. This one is dual row, but the rows are not oval and promote better flow. This is a truly “high capacity” unit. adding a third row probably would add more back pressure to the e-fan and may not actually cool better.
I know you have experience and I am not saying you are wrong, but I wanted to share all the details because if I have learned anything in this project, it is that there is never a straight answer to this type of issue unless you are dead stock (which I am not). Once you start playing around with components and restrictions, you start to create very complicated failure modes which are challenging to diagnose.
Griffin makes a shroud that can help create a higher pressure difference between front and back of the radiator. This one has flaps that blow up once you rach high speed to blow speed air though the dead corners of my radiator. This combined with a potentially newer ( known good, un-plugged and high flow) radiator is all I can think to change without going one step more and adding some venting to promote radiator air though-flow.
Again, anyone who has experience with doing one of these mods and seeing real engine temp improvement would be a huge help to me with my choice of where to go next.
Literally, my next step is to change my rad cap to an 18# stant (known good)… right after I fix this OPDA issue.
could you fit a pusher fan on the front of the radiator?
running a pusher against a puller is not an improvement. From all I read, a puller is about 50% more efficient on it’s own. The only advantage to a pusher at all is that the motor does not see high temp air wash during operation. For high speed inlet applications like our jeep grilles, it is never a good idea to add a pusher because it blocks things up right where you want passive air to flow.
I heard a guy suggest to me to run an auxiliary radiator like an oil cooler to help drop temps. Thats a big job for what I think will be a small gain, but it was an interesting “outside the box” type suggestion.
No worries about the water pump keeping up with the extra volume in the bigger rad? I have a thermal camera at work I might be able to borrow if you think it would give you any extra info.
Another good question…
According to Griffin, the water pump should be stock even for a high-cap radiator. The pressure is adequate and the flow matches the cooling dynamics of the system. 195 T stat ensures efficient engine low temp for fueling and the flow through the high cap is designed to linger in the radiator to ensure max “delta T” or difference between fluid and radiator material (which is being convection cooled by the fan).
I thought a flow-kooler might be a better fit and was told it would not really help. Some high capacity WP’s simply turn faster due to a revised pulley. This then changes the low RPM to be a bit more efficient with cooling, but over pressurizes the system at highway. People who generally crawl and don’t cruise at 3000 rpm as I do may see the WP as an improvement. Since my overheat is at higher rpm, it is unlikely to be a positive effect for my situation. It is a popular way to band-aid an “overheat at idle” condition, but is not ever the true overheat answer for a mostly stock Jeep cooling system.
If I could magically read the heat rejection in BTU of my radiator installed and compare it to a new one, it would be obvious what to do… all that testing will involve “buy and try” and at $300, it’s a gamble i’m dragging my feet on.
Maybe it’s a defective thermostat. I have seen many in my life and seen water pump turn in to pizza cutters. Get it to the shop so we can figure it out.
Mark, you might see this Jeep before it’s all said and done…
I have 2 more things to get done and if those do not work, it’s getting a piggy-back ride on Ray’s flat bed to the shop for a deeper dive.
It sucks to not have this Jeep for so much of the season! I am hopeful that the oil cooler, radiator exterior clear and condenser clean-out will show some marked improvement. the exhaust muffle is going in and the connections for the OPDA will be checked and re-seated. If that doesn’t solve the OPDA, I am getting a crowne replacement OPDA installed to hopefully fix the P0016 code and avoid any horror with the know defect.
After that, I’m back to scratching my head if all is not well.
I’m having an issue with my electric fan too. Keeps blowing 30amp fuses. I have good connections,ground and proper gauge wire. Funny though, it mostly seems to blow the fuse when I hit higher speeds. I wonder if there is some turbulence behind the fan making it overwork?
Look for the static pressure draw and then double the amperage. That is the hit that comes through on “on” condition. The surge can overrate the fuse. I fixed this by running a 70 amp relay and fuse and upgrading to large wire direct to battery.
Most fans are 18-22 amps at static pressure .5-1, 30 amps may not be enough for constant cycling.
Thanks!
9/20/18 Update:
Progress, but nothing that is “smoking gun” conclusive.
OPDA was changed. That fixed my ecu codes and perhaps other oddities with “advance”. It is not known if that had any affect on the heat based on the way I tested, but I know it did not hurt.
All the prior stuff like flushing the system, force filling with vacuum, new thermostat, new WP and sacrificing goats to Hephaestus the god of fire and metal working did not seem to fix the overtemp condition completely.
Each of the following was performed and then tested. Each thing showed some positive effect in order of magnitude it was:
- remove and pressure wash radiator and oil cooler
- replace cap with known good 18#\
- add “water wetter”
- Replace temp sensor
- replace lower hose section
The last 88 degree day, the Jeep completed the test run (about 25 miles, various speeds) it got to about "2 needle widths above the “0” of the “210”, but did not go off to the races into the red on the dash. IR results seemed similar, although I didn’t personally do that test run and was told, it was a bit cooler, but not 35 degrees cooler on the head.
Since this test, I have completed the re-engineer of the exhaust to now run a Hushpower 6X12 coned muffler. Since the dynomax was flapping around, there was some theory that exhaust gasses were not being expelled correctly and that could heat the manifold to a “higher than normal” temp and screw up my cooling at high sustained throttle.
I will have the Jeep back today to drive it around a while and shake things down. I am hoping to wheel at the Pig roast (first time in a while…) and see how the rig does. I’ll be carrying some Distilled water in my tool kit for the foreseeable future just in case…
Last note on water wetter. There are 1000 opinions, 4 “tests” and 2 products on water-based coolant additives. I cannot recommend them carte-blanche, but I can say that did lower the sustained temp in my application around 8 degrees on the gauge. The science is that it eliminates the surface tension for bubbles to form on over-heated, localized section of the system and prevents those bubbles from reducing the effective surface area of the cooling system. It does not “fix” a broken system, but in the case where you have a 450 HP engine in a 200hp system design, I think it can be a help. It works best when your overheat is prominent. I estimate under driving condition, the product took me from 230 to 220-225, hence my 8 degree estimate. If you were at 220, I doubt this would bring you all the way down to 210 or better. My opinion is that it does work, but under normal operating inputs and close to stock fuel use and HP, it is not required unless you want to run all water and no glycol. This desire is not applicable to Jeeps… at least not the Northeast.
wow alot has gone into solving this and i hope everything works out for you. out of curiosity does your lower rad hose have a spring in it?
The old one did, the new one does too
Not dead yet
Update 1/5/2019
Louvers in… 8 degrees seen dropped on engine temp before and after at 41f ambient…
Will that translate when it’s 85f? Don’t know, but it did seem to help.
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Nice! Those look good. I like them better than the large centered ones.
JJ, Any updates to this? Still considering a supercharger to my TJ but I haven’t fired it up since the rebuild. What louvers did you end up going with? I like that look over the Poison Sypder of Hyline.
I went with Genright for louvers. If you want high speed cooling, use the design as I did. I placed the vents at the low pressure points of the hood. This can be validated using some Aero techniques of taping short lengths at yarn on the hood and driving at 25+ mph. The yarn that lays flat is high pressure air that would work against cooling. The yarn that stands up is low pressure zones where the aero of the hood would help pull engine air out of the hood. To save you the time I can say my results and the genright recommendation are almost the same. This is only if you use the 3 pc. kit as I did. The PS full hood is great for the trail, but I don’t know if it is particularly effective for a Jeep that does a lot of road miles at speed.
I kind of like the Genright 5 pc. kit. I opted not to use the center 2 vents because it would have put a hole over my S/C…
SO…
Vents helped a lot, but did not solve it. I still run over 220F in 20 deg F air temps at highway speed.
I broke down and decided to do the intake/exhaust as well as the head gasket to cross this off the list even though I passed the head gasket gas test a few months back. I know my intake gasket micro failed because it hisses at boost of 3+ psi…
This lead to discovering a leakdown on CYL #5 which lead to discovery of a cracked piston.
The plan now is boreover .030, dss forged pistons, new gaskets, upgrade rods and pray for a Powerball combo I can cash on.
The newest theory is that the head gasket was failed, but only as boost which would explain my highway overheat. I think the piston was a casualty of the overheat as well as being over matched by the forces of this blown application. Hyper eutectic pistons are great for stock, but a combo of a bad forgin batch and the increased heat and forces of my setup make them less than ideal. Just another example of $60K on SEMA parts thrown together without a real build plan in mind for longevity.
No news here. I have officially rebuilt the whole flipping Jeep save the brake rotors and suspension to this point. Good thing it is a labor of love I guess…
R. Johnson is doing the engine work. Ricky Barrette et. al. are doing the leg work and I continue to Captain this S.S. Minnow project. It would appear that if it goes back together and stays cool, all is sorted and we anticipate this is a real putcome.
Literally, my money is on “great improvement, but still some bugs” will be the result. I hope it’s gooder enough to wheel and cruise in. I can’t go a whole summer without a Jeep!
update 7/15/19
After some struggles, I decided to just to do the head gasket. That led to the discovery of a cracked piston and then a “less than ideal” result breaking in the new machine work to get it back in action.
I have decided I have 3 options:
-
re-re-machine and risk a bad break-in due to overheat…then fix the overheat with more stuff and another trip to the tuner. 30% chance of success, pricey and could take 6 months.
-
sell the Jeep and quit. Easy, cowardly, Lame, sad and admitting total defeat. 100% chance of success, 100% chance of total regret. costs no additional money.
-
double down by sinking the supercharger to the bottom of the sea, recover the 4.0 and sell it as a fully upgraded 4.1L with full forged pistons, rods and all new internals for a N/A application for someone else and just bite the bullet and go 5.3L GM V8. 95% success estimate, 99% chance of fixed cost, 100% percent chance of ye-haw pedal restoration. Not cheap, but known money versus surprises and break downs compared to other alternatives
I chose #3.
I have told many of you how much I love this Jeep, but it was 2 items short of my ideal. One item was flat fenders vs. a high line… I prefer the highline and it has a nice PS setup that has grown on me. The second thing was I really wanted 350 Lb-Ft TQ and 300HP from a 5.7 or 5.3 V8 and this had the supercharger and a $1500 competition head instead. It’s been an expensive and intense learning experience, but I can say that tuning a 97-06 Jeep is a hardship. I hope to find a home for this build 4.1L (4.0) with all the goodies (headers, head etc.) but I recommend it for a stock replacement, not for a S/C. A plain-jane 5.3 LM7 is what I needed all along to make the extra TQ and HP I need.
I hope this is the final chapter for both my heat and “tuning” struggles. Ill probably start an entirely new thread to capture the V8 swap. I hope it will be done by the end of August, but Good beats Fast in this case and I don’t want to be on the sidelines anymore!
This thread is dedicated to Kate who upon learning of the bad luck on the motor work said “OK, I know you ‘could’ figure it all out, but just put in a V8 and be done with it already!” She’s a keeper…