LS cooling

I know most of us with the LS motors are probably having some challenges with cooling due to the restricted size of the radiator.

In recent months at autocrosses i started getting some high temps. Basically the car wouldn't cool in between runs.
I have a stock LS1 with the dual honda radiator.
This week i bought a stronger, better fan. A maradyne m142k. I kept it as a pusher and it is a really tight fit to the nose.
This weekends autocross i got great cooling between runs and feel a lot better about the situation. I did have to upgrade the fan fuse from 20amp to 30amp, but it seems to be working much better now.
I think the density of the two radiators was just too thick for the older fan to blow through. Especially with the hot side being the back side of the radiator stack it just wasn't moving enough air.

I had the same problem and had my mechanic install a toggle switch to run the fan when the car was shut off. Now after a run I let it idle for a couple of minutes then shut it off and run the fan. Seems to work, not as good as your solution though. I have AXR #1 with a LS3 and will keep your solution in mind if this doesn't work. Keep up all your info on the car, I really appreciate it.

jtmineha wrote:...I did have to upgrade the fan fuse from 20amp to 30amp...

Side question: Did you confirm that the gauge of wire in your fan circuit can handle a continuous 30A load?  

You might also check the relay's rating for its max continuous load limit.  The fan relay used in my engine harness is an Omron G8JN-1C7T-R-DC12, which has a max continuous load capability of 35A on the normally open contacts.

I'll have to check with Scott. I know they just went to a 30amp fuse as well with their two fan setup. They experimented with adding a 9 or 10" puller fan to the back side and kept the original fan on the front and it seems to be working.

After this weekend I ordered the same fan from Summit. i hope it is a simple swap. Did you have to make brackets for the wider fan? Anything else?

It was a pretty direct swap. I did have to flip the blades over. It came shipped in the puller orientation. My old connector was kind of melted together so i had to do a little bit of wiring, but if yours is in good shape should be plug and play. I did have a little bit of clearance ìssue at the bottom off the fan and had to grind down some of the plastic mounts that were hitting the flange of the hood/nose, but nothing too bad. I just used zip ties to mount to holes in the top and bottom edges of the radiator.

I think i found the problem with the stock fan. After the mech installed the on switch he must of reversed the wires when i checked it today it was pulling instead of pushing so I reversed the wires and it is working properly now. What about sealing the gap between the radiators so no air can escaped out between them forcing all the air through both of them? I was going to try duct tape this weekend and then more permanent with silicone caulk?

I believe it should be the blue wire as ground and the black wire as the positive. Sealing the two might be a good idea. Did you get the new fan yet? I know my original one was working correctly, but i think it just wasn't strong enough. The new fan definitely works better.

I actually looked at the fan just before it stopped and it was rotating the wrong way. The new fan isn't here yet so I needed to try something for this weekend. It was working better earlier this year so i am pretty sure the wires were crossed under the dash when he installed a constant run switch even with the key off.

jtmineha wrote:I believe it should be the blue wire as ground and the black wire as the positive. Sealing the two might be a good idea. Did you get the new fan yet? I know my original one was working correctly, but i think it just wasn't strong enough. The new fan definitely works better.

I wired mine with Black = Ground and Blue = 12V.  In this configuration, the motor spins clockwise (as marked on the fan body) as viewed from the front of the car.  Just to be certain it was correct, with the fan running, I held a piece of paper in front of the fan and let go; it sucked it against the guard indicating it's operating as a pusher.

Ultimately, I think what matters is that the direction of the rotation matches the orientation of the fan blades.  For example, my fan blade is installed such that, for a blade at the 6 o'clock position, the right edge of the blade is close to the radiator and the left edge is further away.  So, in order to have it push air, it needs to rotate clockwise.

If your fan is flipped over and the left edge is closer to the radiator and the right edge is further away, then you'd have to reverse the polarity to get the fan to rotate counterclockwise to operate as a pusher.

--
Regarding sealing, if you're seeing cooling issues at idle, then sealing the radiator to the hood won't really make a difference.

"Regarding sealing, if you're seeing cooling issues at idle, then sealing the radiator to the hood won't really make a difference."

The sealing refers to the gap between the two radiators forcing all the air out both cores not some that can pass out between the two radiators.

dgoetz wrote:"Regarding sealing, if you're seeing cooling issues at idle, then sealing the radiator to the hood won't really make a difference."

The sealing refers to the gap between the two radiators forcing all the air out both cores not some that can pass out between the two radiators.

Gah, sorry about that. I have the Mark Scott radiator, which is just the single core.

Just to clear it all up, it really depends on the brand and type of fan. But you cannot just switch polarity to make a fan a pusher or puller. The blades of the fans are air foils, they work in one direction. It is important to have the fan in the right direction as well as the polarity. On a local customers car, he had switched the fan around to make it a pusher, but didn't do the polarity. It did feel like it was sucking a little bit, but in reality it was not moving hardley anything. The air was actually stalling out, so even when driving the car at speed it would over heat because the fan was not allowing air through the radiator.
The double radiator seems to be working well, its Autocross in particular that is really hard on cooling systems. Lots of "stock" car are even overheating on hot autocross days between runs. It's hard to tell what is more efficent, it or the Mark Scott radiator. The MS radiator wasn't available for a period time so we had to get "creative".
It would be fun to take a pyrometer, and measure the temperature going in and out of the radiator at different engine temps to compare notes.

I have a Mark Scott radiator with an Ls7. I have the side panels on and a floor pan that only has an opening for the engine and trans. It is very closed up. It was 96 today. This thing stays cool in all situations but I have a 19" powerful pusher fan that is sealed on the front. It will idle all day or run hard with out over heating. It took a 23 lb radiator cap to make it work.
This radiator is great and it fits perfectly. Love it
Gale

I had the same issue with the little puller. Added a Spal pusher and still reached 240 deg after 5 130-142mph runs. Not crazy temps for an LS, but still high.

I have a sealed radiator in the nose. I added a 160 degree thermostat and 24lb cap. Now only issue is the steam tube. To fix this I had to re-locate steam tube from upper driver's side radiator to the expansion tank. If I had more $ I would opt for a much larger expansion tank behind radiator, then mount the little cat tank/filler higher on firewall/scuttle.

I found that the better Spal 11.9" fan placed in a puller config (might need to sand some of the plastic to fit chassis) is much better, esp when you have your tuner program the fans to come on full at 190. Better than both fans trickling at 180 then not going full blast until 220. Car seems to set in at 203 deg and peaks now at 230, which is about right for an LS.

I just ordered the Maradyne M142k.  The other two I was looking at were the Zirgo ZFU14S and SPAL 30102055.  I suspect SPAL & Meradyne will be close in terms of performance & reliability; as for the Zirgo, I wasn't quite sold on their claim that a 150W motor to churn out more CFM than either the M142K's 225W motor or the SPAL 30102055's 230W motor (think 'magic happens here'), and Zirgo's quality & customer service seems like it might be questionable.  I considered buying the Zirgo just to test it and return it later, but decided not to bother.

Interestingly, it appears that Sherco is no longer carrying any fans.

I also bought a little $12 anemometer off ebay to compare the CFM between the Sherco & Maradyne, because I'm weird like that.  I'm predicting that the Sherco CFM is going to be closer to 1000 CFM rather than the 2300 CFM that they claim.  However, I'm less concerned with the *actual* CFM numbers I get from my anemometer (+math) and more concerned with the relative difference between the Sherco & Maradyne.  The Maradyne M142k has a whopping 225W motor vs the puny 80W motor in the Sherco.

I'll update this thread with my findings, hopefully within a week or so.

To mount my Maradyne M142k fan, I decided to make some new brackets.

I used some 1/8" thick 2" aluminum angle, 2" flat aluminum, and drilled the top & bottom cross members of the radiator, using a drill stop to avoid hitting the coolant tubes.  The 2" angle brackets are attached to the radiator with both JB weld & 2 rivets each.  I tapped the flat aluminum with #10-32, and used both locknuts & threadlocker on all the screws.  The fan is supposed to be installed with a 1/4" gap to the radiator, and I closed this gap with some spare bulb weatherstripping that was left over after the windshield install.

In terms of the air speed between the Sherco & M142k, I measured 1019 linear ft/min for Sherco and 1569 linear ft/min for the M142k.  Keep in mind that is linear feet per minute, not cubic feet per minute.

To improve high speed cooling, like others, I also used some pipe insulation foam from the local HW store to seal up the area between the hood & radiator.  2" OD worked on the top, 1" on the sides, and 1" on the bottom with some relief cuts for the hinge nuts.

Initial performance indications are good: street driving seems to level out at 198F.  On track, after (2) 20 minute sessions in 80F ambient, coolant was around 212F and never triggered my alarm between 225-230F.  Unfortunately, future testing will have to wait a bit until the next track day, or maybe next summer when it gets hot again.




Here's a picture of the weatherstripping:



Mostly installed (I re-did the pipe foam later):

I don't have a stalker but depending on how much room you have/size of your radiator if you can use a Ford Taurus Fan, it'll most likely solve all of your cooling issues, along with some basic shrouding.

They're many times more powerful than even the most expensive electric fans I've seen, and can be had easily for less than 50$
I have one on my ls1 RX7 and the car never had an overheating problem again.
Here's a thread with some dimentsions. You could also cut down the factory shroud a bit if you needed to:
http://ls1tech.com/forums/conversions-hybrids/1489142-tarus-fan-size.html

Mark 8 fans are even better but bulky.


EDIT: Thunderbird fan might be a better fit, see this thread http://www.jalopyjournal.com/forum/threads/ford-taurus-cooling-fan-wow.486504/

I'm still quite happy with the Maradyne fan: Spent some time on track in 90F ambient and coolant didn't get above ~212F.

However, since my oil temp did end up in the 270F-280F range, I'm investigating some A/O coolers.

Slight correction:  After looking at the ECT logs from Torque, the highest temp it saw was 224.6F.  

It's worth noting that I'm pulling ECT from two places on the engine:
1. The stock sender location near the front of the driver's side cylinder head (highest measured was 224.6F, via OBDII
2. A second sender mounted on the rear of the passenger side cylinder head.  Highest (estimated, based off my bar graph) was around 212F.

Based on the flow of coolant in the LS3, it is normal to have such a difference between the temperature readings at these two locations.

225 doesn't worry me too much, but still I'm hopeful that adding an oil cooler will help reduce the burden on the coolant.

EDIT:Here's a quick graph showing ECT & RPM vs time during that session.  Looks like ECT more or less plateaus around 220F-ish:

Great information.

For what it's worth, I got stuck in traffic, in a tunnel with no air for 40 minutes traveling at 5-15 mph, and peaked at 232 water and 260 wish oil, with oil cooler. As soon as traffic broke a quick run to 85 brought temps to 185 and 220.

I found that the added capacity for both has helped a great deal, since moving my expansion tank to the scuttle wall, and adding a 16row oil cooler. I think a lager tank, like corvette size would end cure it all. I run only water and a bottle of purple ice.

The other issue is the overflow tank. For some reason I can only get the radiator to suck the coolant back in with the bottom of the tank capped, and a hose running into it from a larger hole in top, with hose running to bottom inside the tank and about 1" of fluid in tank. With hose attached to bottom, all that happens is steam comes out top, and no water ever gets back to the radiator.