Jump to content
SAU Community

Does Anyone Know How Much Cfm The Standard Fan Flows

DJRIFT

By DJRIFT,
in Engines & Forced Induction

 Share

Recommended Posts

DJRIFT Veteran

DJRIFT

Posted
Posted

hi all

i am just wondering if anyone knows what sort of CFM the standard mechanical fan flows on an R32gtst?

i am about to fit a thermo fan and id like to know that its going to flow enough.

i have got a 16" fan which i know flows 1100CFM but is it enough?

thanks damo

Cubes Grand Master

Cubes

Posted
Posted

Whats important is the air the fan is sucking is sucked over the whole area of the radiator, not just a select little area near the fan.

You will have to rig up a shroud of sorts. Grab a little sheet metal and bend it up using a few pieces of wood/metal what ever you can get your hands on. Then cut a hole to suit the size of the fan and you have a bodgy home made shroud.

I ran 2 x 12" thermo's directly on the radiator that I remember flowed on paper more than a single 16".

It was fine in normal temps but in heavy traffic with the a/c on it sent the needle to the H. Dropped the std fan and shroud back on and its been as good as gold since.

mad082 Grand Master

mad082

Posted
Posted

i thought 1 16" fan pumped more air than 2 12's.

the advantage of thermos is that they run faster at idle than a clutch fan, but the clutch fan gets faster with revs.

i'm just waiting for my 12" thermo to turn up to run as an aircon fan (since it currently doesn't have one). this will be used with the stock clutch fan.

DJRIFT Veteran

DJRIFT

Posted
  • Author
Posted

i was pretty sure the 2 12" fans flowed slightly less but it was a while ago now.

i got 1 16" fan so it could sit in the standard spot. this will still force air through the radiator evenly.

ive gone for a thermo because a you get slightly more power as the engine isnt driving a dead weight. and b for my custom cooler piping as i dont want to cut down the standard fan blades to suit.

it will also be switched off a propper weld in theermatic switch whitch turns on at 84 degs.

but id still like to know the flow rate if anyone has it handy.

Cubes Grand Master

Cubes

Posted
Posted

My bad. It does appear the single 16" does out flow 2 x 12" fans, however the 1100cfm 16" thermo fan listed by the thread op flows less than 2 x 12" thermo's. If its a davis fan then they apparently flow up around 1600cfm. I can't find anything solid on it though. :laugh:

Mad082, I replaced my 12" std a/c thermofan with a single curved blade (more efficient) 14" ebay fan. Has worked well. Made a noticeable difference to the a/c when sitting in peak hour traffic on those 40+degree days.

From memory the single 14" that I picked up flowed ~1400cfm.

RB30-POWER Mentor

RB30-POWER

Posted
Posted

just keep the original viscous clutch fan, way more reliable, flows more air.

thermos are crap on these apps.

your not saving power, as the alternator will be working harder to produce the power to run the fan still, so not sure how it makes car go harder.

also the alternators arent big enough to run all these thermos on idle, your lights will dim at lights and the current from the alternator will be used to run the fans instead of charging the battery.

there is just no reason to change to unreliable thermo fans, you have wiring to get hot, relays to fail, temp sensors to fail. thermos can cause trouble down the track. (usually when you are in the middle of no where...)

DJRIFT Veteran

DJRIFT

Posted
  • Author
Posted
just keep the original viscous clutch fan, way more reliable, flows more air.

thermos are crap on these apps.

your not saving power, as the alternator will be working harder to produce the power to run the fan still, so not sure how it makes car go harder.

also the alternators arent big enough to run all these thermos on idle, your lights will dim at lights and the current from the alternator will be used to run the fans instead of charging the battery.

there is just no reason to change to unreliable thermo fans, you have wiring to get hot, relays to fail, temp sensors to fail. thermos can cause trouble down the track. (usually when you are in the middle of no where...)

i understand what you are trying to say but if you had read my post propperly you would have found that i am changing because of where i am running my cooler pipeing. i am running it on more of a diagonal between the radiator and the engine so i need the room and even if you run an off the shelf kit you have to trim the standard fan blades which i think is dodgy.

also the wiring side of things will not be a dodgy back yard job either. i have gone to grate lengths to make sure this wont fail unlike setups ive seen in the past.

all i realy want to know is the flow rate of these standard fans.

and the drain on the alternator would hardly be as much as some tossars subwoofers in the boot so i cant see it being a big deal.

also where i live i dont get stuck in trafic for hours on end and the daily temp rairly reaches 40deg so its realy not that bad.

please someone tell me the flow rate not how to mod my car!

rev210 Grand Master

rev210

Posted
Posted
just keep the original viscous clutch fan, way more reliable, flows more air.

thermos are crap on these apps.

your not saving power, as the alternator will be working harder to produce the power to run the fan still, so not sure how it makes car go harder.

also the alternators arent big enough to run all these thermos on idle, your lights will dim at lights and the current from the alternator will be used to run the fans instead of charging the battery.

there is just no reason to change to unreliable thermo fans, you have wiring to get hot, relays to fail, temp sensors to fail. thermos can cause trouble down the track. (usually when you are in the middle of no where...)

No.

There is only a crap install/ crap products not poor concept.

You save power because they are not 'on' when there is enough airflow being pushed through the radiator, usually this is when you want extra power.

The alternator is quite large on RB engines, unless you have a doof doof stereo its fine. If you have a doof doof stereo then you probably already have a bigger alternator.

The wiring doesn't get hot, the relays don't fail, neither do the temp sensors. Had plenty of thermo fans on various cars and none ever gave me the woops.

If you have had a bad experience I can only suggest that if you associate them (thermo fans) with being on all the time that meant whoever set it up did so incorrectly.

rev210 Grand Master

rev210

Posted
Posted

Just to add also that if your fluid clutch fan fails or cracks and falls appart you will find it harder to get a replacement in the middle of nowhere. If you have a generic thermo fan, you find every auto shop flogs them in every town.

DJRIFT Veteran

DJRIFT

Posted
  • Author
Posted
My 2 x 12" thermo's were just setup badly.. Mounted directly onto the radiator so air was only flowing past ~30% of the radiators surface area.

Its a must thermo's use a shroud.

its a must for any fans realy. helps them cover more area.

VLT025 Enthusiast

VLT025

Posted
Posted

So how much do the factory ones flow? ;P

I guess because it varies so greatly depending on revs, it would be difficult to compare them directly to a thermo, which for the most part is 0 cfm or (insert manufacturers claim here)cfm. you would think that 3000 + CFM would not be unlikely at peak revs though.....

DJRIFT Veteran

DJRIFT

Posted
  • Author
Posted

yes you would think that the cfm would increase at higher rpms but i think a some point it would then become ineficent to the design of the fan blades and alike. also high rpms usualy mean high speeds where the radiator should see sufcent air flow with out the need of a fan at all. but in some things like drifting and short corce racing than grater airflow is needed.

so still no answer to how much cfm just more questions.

Simon-S14 Grand Master

Simon-S14

Posted
Posted

not sure of actual CFM but the fan stops increasing in speed at approx 4000rpm as this is the max rated speed, and the clutch does it job from there on.

I have fitted my clutch fan back in, and because of the cooler pip[e i had to trim down the blades, Used a large file on the edges with the motor running, then the pipe did the rest, theres acctually quite a fair bit trimmed off the outer edge now... Im guessing as a result im going to be sacrificing some of the maximum rated airflow...Ive kept the thermo fan on the front of the rad... just in case i spose.

mad082 Grand Master

mad082

Posted
Posted

i put a 12" thermo on the front of my radiator (on the passenger side where the is a cut out in the shroud for one) and after i hooked it up i put my hand down behind the cut out (after first putting it into the fan.....) and i can feel a little bit of airflow, but not as much as i thought. it is still better than nothing. i have it hooked up to my aircon.

i'm going to put a new thormostat in on the weekend, cause i think my stock one is half dead. it takes ages to come up to temp (about twice as long as the missus SSS pulsar) and even on the highway on xmas day i could hear the clutch fan half working, and round town it was on all the time. i think the thermostat isn't fully opening or closing.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • sunsetR33
      Unpeeling the Orange

      By sunsetR33 · Posted

      Update 3: Hi all It's been a while. Quite a lot of things happened in the meantime, among other things the car is (almost) back together and ready to be started again. Things that I fixed or changed: Full turbo removal, fitting back the OEM turbo oil hardlines. Had to do quite a bit of research and parts shopping to get every last piece that I need and make it work with the GT2860 turbos, but it does work and is not hard to do. Proves that the previous owner(s) just did not want to. While I was there I set the preload for the wastegates to 0,9bar to hopefully make it easier for the tuner to hit the 370hp I need for the legal inspections that will follow later on. Boost can always go up if necessary. Fitted a AN10 line from the catch can to the intake hose to make the catchcan and hopefully the cam covers a slight vacuum to have less restrictive oil returns from the head and not have mud build up as harshly in the lines and catch can. Removed the entire front interior just shy of the dashboard itself to clean up some of the absolutely horrendous wiring, (hopefully) fix the bumpy tacho and put in LED bulbs while I was there. Also put in bulbs where there was none before, like the airbag one. I also used that chance to remove the LED rpm gauge on the steering column, which was also wired in absolute horror show fashion. Moved the 4in1 Prosport gauge from sitting in front of the OEM oil pressure gauge to the center console vents, I used a 3D printed vent piece to hold that gauge there. The HKB steering wheel boss was likely on incorrectly as I sometimes noticed the indicator reset being uneven for left vs. right. In the meantime also installed an airbag delete resistor, as one should. Installed Cube Speed premium short shifter. Feels pretty nice, hope it'll work great too when I actually get to drive. Also put on a fancy Dragon Ball shift knob, cause why not. My buddy was kind enough to weld the rust hole in the back, it was basically rusted through in the lowermost corner of the passenger side trunk area where the wheel arch, trunk panel and rear quarter all meet. Obviously there is still a lot of crustiness in various areas but as long as it's not rusted out I'll just treat and isolate the corrosion and pretend it's not there. Also had to put down a new ground wire for the rear subframe as the original one was BARELY there. Probably a bit controversial depending on who you ask about this... but I ended up just covering the crack in the side of the engine block, the one above the oil feed, with JB Weld. I used a generous amount and roughed up the whole area with a Dremel before, so I hope this will hold the coolant where it should be for the foreseeable future. Did a cam cover gasket job as the half moons were a bit leaky, and there too one could see the people who worked on this car before me were absolute tools. The same half moons were probably used like 3 times without even cleaning the old RTV off. Dremeled out the inside of the flange where the turbine housing mates onto the exhaust manifolds so the diameter matches, as the OEM exhaust manifolds are even narrower than the turbine housings as we all know. Even if this doesn't do much, I had them out anyways, so can't harm. Ideally one would port-match both the turbo and the manifold to the gasket size but I really didn't feel up to disassembling the turbine housings. Wrapped turbo outlet dumps in heat wrap band. Will do the frontpipe again as well as now the oil leak which promted me to tear apart half the engine in the first place is hopefully fixed. Fitted an ATI super damper to get rid of the worn old harmonic balancer. Surely one of the easiest and most worth to do mods. But torquing that ARP bolt to spec was a bitch without being able to lock the flywheel. Did some minor adjustments in the ECU tables to change some things I didn't like, like the launch control that was ALWAYS active. Treated rusty spots and surface corrosion on places I could get to and on many spots under the car, not pretty or ideal but good enough for now. Removed the N1 rear spats and the carbon surrounding for the tailpipe to put them back on with new adhesive as the old one was lifting in many spots, not pretty. Took out the passenger rear lamp housing... what do you know. Amateur work screwed me again here as they were glued in hard and removing it took a lot of force, so I broke one of the housing bolts off. And when removing the adhesive from the chassis the paint came right off too. Thankfully all the damaged area won't be visible later, but whoever did the very limited bodywork on this car needs to have their limbs chopped off piece by piece.   Quite a list if I do say so myself, but a lot of time was spent just discovering new shit that is wrong with the car and finding a solution or parts to fix it. My last problem that I now have the headache of dealing with is that the exhaust studs on the turbo outlets are M10x1.25 threaded, but the previous owner already put on regular M10 nuts so the threads are... weird. I only found this out the hard way. So now I will just try if I can in any way fit the front pipe regardless, if not I'll have to redo the studs with the turbos installed. Lesson learned for the future: Redo ALL studs you put your hands on, especially if they are old and the previous owners were inept maniacs. Thanks for reading if you did, will update when the engine runs again. Hope nothing breaks or leaks and I can do a test drive.
    • Kapr
      What brakes on R34 GTT(Europe)

      By Kapr · Posted

      No those pads are DBA too  but they have colors too. I look at the and imo the green "street" are the best.
    • wizlb
      Who has a Infiniti Q60, Q50 (V37)?

      By wizlb · Posted

      I’m not sure what happened I told them about sonic tunes free OTS tune and the next the I know .. I was booted..   To funny 
    • Kinkstaah
      Starting again

      By Kinkstaah · Posted

      Yea - I mean I've seen my fuel pump which is decades old and uh, while I'm not saying this with real knowledge... but I sure get the ick at using anything in the fuel system that produced the state of that pump. Many years ago I went through multiple pumps (and strainers) before I dropped the tank to clean it out with extreme violence. I'm talking the car would do maybe 50km before coming to a halt, which resulted in me cleaning out the filter with some brake cleaner and going on my way. None of my stuff ever looked like what came out of your fuel tank. I don't think I'd be happy with it unless every single component was replaced (or at least checked/cleaned/confirmed to be clean here).
    • GTSBoy
      What brakes on R34 GTT(Europe)

      By GTSBoy · Posted

      I'm not going to recommend an EBC pad. I don't like them. Just about anything else would suit me better. I've been using Intima pads for a while now.
×
×
  • Create New...