Radiator fans: Push or pull?

[mmdb]

It all started when my Koyo got cracked so I'm out for replacement. I'm looking towards a Griffin radiator. Here's the dilemma, I have 2 basic configurations I can fit with the length and width equal, less thickness:

1. 38mm thick radiator 1 row with 2 pull style fans.
2. 76mm thick radiator 2 row with 1 push style fan.

Due to the space behind the radiator I'm limited to those configurations. I was leaning more towards the 3" because of the added capacity and the additional room between the radiator and the motor. But I'm not sure if push style is the way to go.

The benefit of the 38mm radiator is basically a drop in, with ease of install, also with the pull style fans.

Any opinions would be appreciated.

[greenman100]

Back when I was into watercooling PCs, extensive research was done one push vs. pull configs. In short, the difference was insignificant. Not insignificant though, is the shroud. Make sure it seals well.

[CoupedUp]

Back when I was into watercooling PCs, extensive research was done one push vs. pull configs. In short, the difference was insignificant. Not insignificant though, is the shroud. Make sure it seals well.

The only thing I can think of that is more advantageous for a Pull type setup is because you have a column of air on the front of the radiator when the car is moving. With a fan on the push side the shroud and such can cause a restriction to flow and cause air to flow around the radiator into the spaces around the radiator. In a pull setup you wouldn't have this issue. I am sure it is negligible just something to keep in mind.

[Colorado S14]

Take a look at some SPAL fans, they can go pretty slim that may buy you some space on a pull setup.

[Def]

Pull setups are generally more efficient with axial flow fans, but it is not a huge difference.

I'd go with the 3" thick one if the cost was roughly similar.

[Tower240sx]

I'd tend to favor the 3" solution, too many people report cooling issues with the LS motor...
as far as fans, I'm not sure what you'd do to prevent the shroud from killing the flow at speed, I know alot have flow thru flaps of rubber but those don't seem like they'd be feasible on the front of the radiator...

[Def]

I'd tend to favor the 3" solution, too many people report cooling issues with the LS motor...
as far as fans, I'm not sure what you'd do to prevent the shroud from killing the flow at speed, I know alot have flow thru flaps of rubber but those don't seem like they'd be feasible on the front of the radiator...

You'd just want a fan area about 25-35% larger than the radiator face area, then duct it down to the radaitor face. This way the area blockage by the radiator at least has a chance to undergo some total pressure recovery(i.e. feel about the same as if the fan wasn't in the way).

Harder to do than say, but it's probably the ideal solution with our packaging constraints and a pusher fan.

[gawdzilla]

i recently switched from push fans to pull fans and it took quite a bit of work to do so. radiator support was cut back to clear my pulleys and shift the rad fwd about an inch. i can say that pull fans (assuming same radiator) work better than push fans. the way i see it is the push fans are fighting with the incoming fresh air when you are at speed. i've noticed my coolant temps drop much faster from moving. as expected, at a standstill there is not much difference. that said, i can't say whether pull vs. push will outweigh fat vs. slim radiator, which seems to be your issue. but given the same radiator size, pull fan is the way to go IMO.

i can take some pics of my radiator support if you'd like to get some ideas on shifting the radiator forward.

[mmdb]

Hey thanks for the replies. I think I'll take the dive and go with the 3" and push style fan. I'm looking into something like this...

Griffin Radiator specs:
26 1/4in x 16 1/2in x 3in
2Row 1 in tubing.
15-18lbs

Speaking to a Griffin rep, they said they can possibly develop it as a dual pass setup, which would be nice assuming it runs cooler. They also can add fittings to run external temperature sensors. I'll be having 2 NPT fittings for my water temp for the SPAL fan controller and one for the SPA technique gauge. I'm not sure what the price will be for the radiator and fan, but I'll post up the info later.

I did look for other manufacturers such as C&R (way expensive and it's not off the shelf ~$675 for OEM dimensions), Fluidyne (oem dimensions, negative reviews gave me a bad feeling and cost ~$400), PWR (I want one, but would have to wait 3 weeks, but oem dimensions and ~$400). I'm not going to mention others (koyo, mishimoto, cxrraing) brands as I feel they lack in quality or performance. Though I have read people have had great reviews about them. Griffin came in on top with flexibility of design vs cost. Here's some pictures taken from zilvia.net by "MA JasonG" from MA motorsports.

http://i79.photobucket.com/albums/j123/JDMFresh/DSC_0215.jpg

http://i79.photobucket.com/albums/j123/JDMFresh/DSC_0212.jpg

http://i79.photobucket.com/albums/j123/JDMFresh/DSC_0211.jpg


To add to the mess I have a ~11" x 7" x 1.75" oil cooler. Will it be effective to put that behind the radiator while using a push style? I guess the best is to mount the oil cooler somewhere else I assume that's in direct flow of the high pressure air hitting the bumper. Any thoughts?

[Def]

Mount radiator on the side of the shrouding leading to the fan/radiator. Use the high pressure air trapped up on the face of the radiator to flow air through it.

Take advantage of the fact that you don't have a FMIC by doing good shrouding up front - I know I would but a FMIC makes it a total PITA.

[Geno]

What about using something like the mishimoto slim fan shroud/fan setup? I think it sticks out maybe 1/2inch.

[Air]

i have a LS1 with a megan radiator (similar to koyo, mishimoto, ect in demsions/design). I have the dual "pull" altima fans, wired into the stock ECU. Both fans come on at the "low" setting in the f-body ecu, which is 185 degrees. I also have a 160 degree thermostat.

I do not have any cooling issues. I dont have a cooling plate, shrouding leading to the front, or any other tricks up my sleeve. I even have a stock hood in the stock position. I have a oil cooler mounted in the front bumper as well (in the "o" face of the s13).

Temps never got above 180 on track, and in traffic never above 185, and only then when i am sitting. Whenever i am moving my temps almost immediately settle in around 160. This is measured from the water pump itself ( i tapped it for my sending unit)

fan clearance with altima fans and shroud:

http://i69.photobucket.com/albums/i52/chrishobo4/ls13%20done/P1030037Medium.jpg

Fans
http://i69.photobucket.com/albums/i52/chrishobo4/ls1%20swap%20parts/DSC_5688.jpg

radiator (only have a crappy pic)
http://i69.photobucket.com/albums/i52/chrishobo4/ls1%20swap%20parts/DSC_5699.jpg

temp sender
http://i69.photobucket.com/albums/i52/chrishobo4/ls1%20swap%20parts/P1020762Medium.jpg

oil cooler: (not sure of my oil temps, my oil temp sender is f-ed up)
http://i69.photobucket.com/albums/i52/chrishobo4/ls1%20swap%20parts/P1080355Medium.jpg

I will try to get more pictures if you think it would help you.

I would say the longest i have been On-track is about 45 mins, come in for 5, then go back out for 45. It was probably ~50 outside temp. My car has never been fazed by heat (yet). Im sure you beat on yours harder than mine as this is my first "season" with the ls.

I would say that a hood with heat extractors and proper ducting to the radiator are my next steps.

[mmdb]

Dang nice! I tried using the altima fan, but I might've purchased the wrong year :( That's pretty good temps. I have about the same setup and a lil bigger oil cooler and a 180 degree thermostat. I hit 180 daily driving and it stays there. During a 20 minute run at the track last time I hit about 212degree f, but it was maybe 65 degrees.

What do you guys think about running the oil cooler -> fan -> radiator (direction of air flow from left to right)? I figure there'd be air resistance and what not, but since my oil cooler limits where I stick the damn thing I would have piece of mind knowing it's not near the wheel well where I could potentially crack it easier. I wouldn't mind losing a bit of efficiency in cooling...

[CodyAce]

With the Altima fans, you can use any 93-2000 car for the same fans. Also found on 95-99 Maximas, and B14 Sentras as well.



In regard to your oil cooler, why just put it right infront of the radiator using the plastic ziptie-ish things? Unsure how you're seeing such high temps with the setup, as even road race F bodies don't have these heat issue, and they have a MUCH worse front end in regard to air flow. Sure you don't have an air bubble or anything?

[CodyAce]

i have a LS1 with a megan radiator (similar to koyo, mishimoto, ect in demsions/design). I have the dual "pull" altima fans, wired into the stock ECU. Both fans come on at the "low" setting in the f-body ecu, which is 185 degrees. I also have a 160 degree thermostat.

I don't want to sound 'snobby', but IMO, that is really low for an LSx...those cars love to have some heat in them, as they make much better power the warmer they get. If it were mine, I'd put the stock t-stat back in, as it's obvious your fans/radiator keep it sustained/cool. I'm also almost certain that at 160, you're in an area of the ECU that is pulling timing to help warm it up too...loosing more power (not to say that there is much lost, but you know what i mean :) )

[Tower240sx]

I would agree with Cody on the thermostat for the LS needing to be stock

For the record GM has always had cooling problems with these engines, remember the little lip spoiler on early F-bodys??? remove one and watch the car overheat constantly, ever seen the lengths gone to in a corvette to get air through the radiator??? and they had the luxury of knowing the cooling requirements when they chose the location and sizes of air inlets...our cars only needed to keep ~1/3 the displacements heat in check.

Every LS swapped s chassis (except apparently air's) that I know of has had a temp control issue. I've seen mmdb's car I'd say he's gone to some pretty substantial lengths to try to keep his temps in check,


Maybe the real solution is to get an electric waterpump and remove the thermostat,

They're only $$$$

[Def]

I don't see why an S chassis would have a hard time keeping an LS1 cool. It's got WAY more duct area than any F-body/C5/C6/GTO that was equipped with one stock. The thing most S chassis owners completely ignore is some basic ducting for the radiator to make the air actually go THROUGH the radiator. A big ass radiator and big duct area does nothing if the air just spills over the sides of the radiator and does nothing to cool the motor.

[WorkInProgressK]

you think ducktape holds at high speeds?

[Air]

I don't want to sound 'snobby', but IMO, that is really low for an LSx...those cars love to have some heat in them, as they make much better power the warmer they get. If it were mine, I'd put the stock t-stat back in, as it's obvious your fans/radiator keep it sustained/cool. I'm also almost certain that at 160, you're in an area of the ECU that is pulling timing to help warm it up too...loosing more power (not to say that there is much lost, but you know what i mean :) )

Understood. I also had this same concern when building, but i followed the advice given by the local Lsx tuner (RPM in Garner, NC). Seeing their lsx builds(9 sec stock body full interior TBSS), I decided they probably know what they are talking about. When i am on track, it gets up to ~180ish, which is stock temp for cruising around. If i had stock t-stat, i imagine i would be ~200ish on track. They also tuned my car, so i am sure they told it not to pull timing until 150 degrees or lower or something.

The only thing i might change soon is the fan setup. I might go back to the stock 2 stage setup (one fan at 185, one at 195 or something). I would also like to wire it up so i can over-ride the ecu and leave the fans running after a session to cool the car down. When sitting, it fluctuates pretty rapidly between 160 and 185. i would say ~3 minute cycles.

The fans are not going to come on while the car is moving (since they are ecu controlled) The fans coming on at speed would only disrupt air-flow into the car.

I have a 98 f-body, and i have never had any over-heat issues with it. (it also has a 160 degree t-stat). It does not have a oil cooler, but it does have a oil temp gauge that works. Its oil temps usually peak around 275 after a hard track session. That is HOT in my book...


On the s13, I have no cooling panel or ducting, but i do have the proper shroud on my radiator and all of the factory air management stuff (foam between radiator and radiator support, front bumper is 100% intact, ect.)

I have not read very many over-heat issues on silviav8.com, so hearing of these overheating s-chassis lsx's is new stuff to me.

[Tower240sx]

I don't see why an S chassis would have a hard time keeping an LS1 cool. It's got WAY more duct area than any F-body/C5/C6/GTO that was equipped with one stock. The thing most S chassis owners completely ignore is some basic ducting for the radiator to make the air actually go THROUGH the radiator. A big ass radiator and big duct area does nothing if the air just spills over the sides of the radiator and does nothing to cool the motor.

mmdb has a very sufficient ducting setup on his car...far better than any GM car this side of the Vette.





On the s13, I have no cooling panel or ducting, but i do have the proper shroud on my radiator and all of the factory air management stuff (foam between radiator and radiator support, front bumper is 100% intact, ect.)

I have not read very many over-heat issues on silviav8.com, so hearing of these overheating s-chassis lsx's is new stuff to me.

That is strange...I have spoken with 3 people with ls powered s chassis and 1 fd3s that is ls powered they all spent time chasing cooling issues similar to mmdb's experience...maybe it is a bleeding issue? I'd hate to think it's that easy but???

I know a couple of C6 guys that complain that they have hot running issues aswell..., GM keeps the oil temps up on purpose but the coolant temps above 200 scare me silly...what PSI rad caps are we running here???

[Air]

stock megan rad cap - 1.1 bar

my f-body is still on the stock "gauge" but being a 98 it has a linear gauge, whereas the 99 up have a 3-position gauge. Cruising around town with the 160* t-stat it barely registers, but once on track it goes up to mid-way and sits there.

Im not sure what the GM rad cap is.


Do the people with the LSx swap you know have the steam tube hooked up?

[Def]

200 isn't very high for a track car, but above about 215 I get very nervous.

Ducting out of the hood does wonders for airflow through the radiator too. Maybe mmdb won't have problem after that vent he recently added.