RB25 swap over heating issue

[moonshinekouki]

hey guys finshed a series one rb25det swap into a 98 240sx. everting is great but it over heats in city traffic. i can go for abotu 30-45 mintues then ill have to pull over.
im running dual ten inch fans
a brand new rb25 thermostat
a hugee as fmic
eve9rythign is stock becsides the boost contolller set at 10 psi and a greddy intake manifold and a walbro fuel pump.


HELPP what do i doo to make it not overheat lol i know i sound liek a noob but i am lost since in toronto no one has really done the swap and no info.

thanks
mikey

[bardabe]

you are probably heat soaking the radiator, are you sitting in traffic for 30-45 minutes, or are you driving? make sure you have bleed the coolant system and it's free of air bubbles. what radiator are you using? the stock ECR33 or S14? how many CFM's do your fans flow?

[nlzmo400r]

even if he's running stock radiator, it shouldnt overheat just sitting in traffic. Try bleeding the system or make sure your thermo is opening.

[moonshinekouki]

im running a s14 kouo rad
and the fans im running are the flexi elite 10inch dual fans but no shroud

[moonshinekouki]

s14koyo*
and sitting in traffic at a stop and go

[nlzmo400r]

im running a s14 kouo rad
and the fans im running are the flexi elite 10inch dual fans but no shroud

again, have you bled thes system? Also, how old is your water pump? You probably should have just replaced that when you had your engine out of the car. Ducting/shrouding is EXTREMELY important in cooling. I can't stress that enough. Without ducting/shrouding the fans are just sucking air from outside of the radiator, not through it. Air will always take the path of least resistance, so by ducting/shrouding you made the easiest possibly way for the air to escape is to go right through the radiator.

[moonshinekouki]

i have a brand new water pump/ brand new thermo stat/ system was bleed multipleof times still the same. the fans i got were duplicates of flexilite fans but with out shrouds :(

damn it im so lost.

tahnks for the help guys

[moonshinekouki]

k i bleeded the system and its still over heating.....

[Yum-Yum]

i gottta a koyo s14 sr20 radiator. brand new never used. it will work with your rb25. let me know. my rb25 stays cool. im running a koyo radiator/dual fal fans running full-time.

[JDS Performance]

why dont you let us know your steps to bleeding your coolant system:coolugh:

[moonshinekouki]

what kind of fans are you using yum-yuum?

how should i be bleeding my coolent system?

[bardabe]

try swaping the gauge sensor, (happened to my friend once, sensor went bad ahd funny readings) and if it still overheats. then eh. post pics and I'll see what I can find wrong.

[moonshinekouki]

well i do feel alot of hot air comming out of the engine bay
ill post pics up

thanks

[moonshinekouki]

ok so its heat soke thats causing everythign to over heat.
im runnin two ten inch pusher fans
is ther anythign else i can do to get rid fo the heat /????

pics
http://i126.photobucket.com/albums/p114/mikeyboi88/Kouki/DSCN0236.jpg

http://i126.photobucket.com/albums/p114/mikeyboi88/Kouki/DSCN0235.jpg

http://i126.photobucket.com/albums/p114/mikeyboi88/Kouki/DSCN0234.jpg

[steve shadows]

put an additional puller fan on the back of the radiator and make sure the one that is pulling is a higher CFM than both 10inch fans.

Also get a lower thermostat and if you can afford 100 bucks pick up one of the coolant swirl tanks, it works great on my track car and a couple other cars Ive used it on.

we were having an issue like this ona friends car at the track recently.

1. get more air to the front of the car/ bigger mouth bumper, make sure the IC is not painted or rad etc.
2. vented hood helps in high temp track scenarios.
3. EMS? I know, but sometimes dpending on modification an improper tune or fuel map can cause the motor to run HOT.

If this is a reacurring issue, and poofs of white smoke start to appear out the tail i would suggest a leakdown/comp test when the car is ice cold.

[moonshinekouki]

will the coolent swirl tanks make a big differnce?
wat fan would u recemond?
thanks bro

[steve shadows]

will the coolent swirl tanks make a big differnce?
wat fan would u recemond?
thanks bro

coolant swirl tank constantly bleeds air out of your line. when PROPERLY installed they work great to keep hot air pockets out of the system.

Black Magic fan or something from FAl should do the trick, just find out how much air your 10 inch fans move, and get somethig better.

Summit should tell you what their fans pull in air mass, and so should the box or directions from the fan kit you already have.

[moonshinekouki]

ok thanks bro
its going to be hard for me cuz im in canada lol :(

[moonshinekouki]

my intercooler is painted wiht a logon on it. its not aht big thoo

liek me driving ont he highway is fine but once its stop and go traffic it gets hottttttt

[MELLO*SOS]

Are your fans on a thermostat?

Are your fans wired correctly (push instead of pull)

Are your fans right on the face of the radiator?

Try to do everything you can to direct airflow through the radiator instead of up and over it... Or around the sides of it.

[moonshinekouki]

theres only one setting on the fans and they are on all the time
and i have an oem hood.
alot of ppl are saying i need a vented hood is this true also?

[MELLO*SOS]

No you don't "need" anything like that. Sure it'll help a little with heat soak, but the majority of RB swaps are running just fine with a stock hood and some combo of e-fans and KA radiators. It seems most use the dual FALs on a Koyo with a stock hood and a huge FMIC and have no overheating problems.

Hey how is the radiator cap thats on your rad? If it's bad you won't be able to build pressure in your cooling system, and you'll overheat quickly. If it's not brand new you might want to think about picking up a new 1.3 bar cap off ebay or wherever.

Did you replace your water pump before you did the swap?

Just to confirm, the fans are blowing thru the radiator and not blowing towards the fmic right... GL

Also what brand/model/CFM are your 10" pushers?

[moonshinekouki]

i totally forget whawt brand the fansa dn waht cfm they are.
im pretty srue th fans are blowiing through the rad
its a brand new rad aslo
and the waterpump was replaced when i swapped the motor it

[steve shadows]

im pretty srue th fans are blowiing through the rad



thats like very very important

haha

[lucky7]

i gottta a koyo s14 sr20 radiator. brand new never used. it will work with your rb25. let me know. my rb25 stays cool. im running a koyo radiator/dual fal fans running full-time.

SR20 rad will NOT work with an RB. you need a KA rad. the inlets are backwards on an Sr.

[MELLO*SOS]

SR rad will sorta work but then you have to run the stupid crossover pipe which probably won't clear the FMIC piping or in his case the BOV

Hey moonshine depending on your climate you can try running like 85% water 15% coolant with water wetter and a higher pressure cap (assuming yours is <= .9 bar).

I think ultimately you're just not getting enough CFM from those 10" fans at idle/low speed... Might have to bite the bullet and spring for 12s.

GL

[drift freaq]

Let me sum it up plain and simple and yes I have tons of experience here.
Get rid of the suck ASS Koyo . They heatsoak after 20 minutes. If your going to go Aluminum get a Griffin or Fluidyne they are much superior to Koyo and do not heatsoak. Plus they run 10 degrees cooler than a Koyo because of better design. Ok I don't want to here arguements about this because I went through it, I know!
Koyo's suck end of story, so no whiny shit from SR owners about how your Koyo works fine. They may work fine with your 2 liter 4 cylinder that does not need as much cooling power, but they are basically a poor design sold cheap. End of story.
Steve and Mello both are correct besides your radiator heatsoak issue you definitely have a CFM issue . Unless those 10's are FAL's they are probably not pushing enough CFM. Dual FAL's are rated at 2500 cfm which would be enough for you. Either uprate your fans or even stick a stock s14 radiator in which is actually large enough with a pair of FAL pullers on the engine side and you would be good.
P.S. Hood vents due help but you you need to address the other issues first.

[lucky7]

i run a Ka koyo with my 25. hmmm, hope i dont run into any issues. i'll definately keep that in mind though if i start to see an increase in temps.

[moonshinekouki]

ok so i should be lookin for new fans?
my fans rihgt now are not shrouded or ducted
i should go and try to find out what fans they are damn it

[250sxdet]

I had the same problem when I first did my swap. Did you swap over your stock temp sensor? I was running dual 12" fans with the stock s14 rad and a nismo thermo it was no good. So i upgraded to an n1 water pump with a greddy radiator. I've had no problems with heating what so ever since then, even at the track. If youre going to track the car, i recommend you upgrade the radiator.

[Walperstyle]

Make sure the rad fan is pointing the right way.

If yes, then throw another one on the inside to increase the air. Make sure the fan doesnt cut out on you, i'd keep it on all the time, or wire it on a separate switch if you wanted manual control.

[Blackparade]

Griffin radiators are the shit! Defenitly look into that option. Im running a koyo right now due to the fact that it was taking my griifin forever to get here, and my stock rad exploded! grrrrr... had to get something, and every shop i know carries koyos. so....yea. Adress the fan situation!!!!!!!!

[LB.Motoring]

my Koyo worked Fine.

Just have a nice pair of fans, and a good shroud,

mine are both custom :)

[moonshinekouki]

any tips on making my own shroud ?
thank you
if worse coems to worse ill invset in a good set of fans even tho i spend like 350 on these fans.

thanks guys keep the oipinions comming in :)
mikey

[bardabe]

any tips on making my own shroud ?
thank you
if worse coems to worse ill invset in a good set of fans even tho i spend like 350 on these fans.

thanks guys keep the oipinions comming in :)
mikey

damn that sucks dude, I spent like 150$ on my fans but they push 2000cfm's each (4000 total) and I'm running a sucky ass S13 KA radiator right now. :hsdance: soon when i get my job I will pay off robby, get me an S14 ka radiator, and go to home depot and make a write up on how to make some good shrouds, I can;t stress enough what Dave said. Ducting will make the biggest difference.

[moonshinekouki]

what kind of fans did u get?
what is need to make the shorouddd
lol HELLLLPP

[bardabe]

PM Sent. ha ha RB owners trade secret.

[Tenchuu]

yeah i tried some high rated 10" fans with my swap... they didn't work. went with FAL dual pushers with should and it was allot cooler.

and i if you find a place that sells griffin S14 KA radiators be sure to let me know. i think that griffin does 1-2 runs of those radiators a year. and the most i have ever seen them ship to a business if about 5 of them (when i got a hold of the company and tracked down a shipment to a reseller en route).

[LB.Motoring]

Just made one from an aluminum sheet,

cut slits, bent it so its like a tray, then cut the 2 large holes for the super CFM fans, and done.

[moonshinekouki]

ok im going to try this out :)

[coreansurfer]

add a second relay to the fans, it'll majorly increase their output and help cool your car. that's what i did to my rb25, and i'm still running stock ka radiator.

[moonshinekouki]

^^^^
plzzz moreee detail

[MELLO*SOS]

He is saying to wire your fans properly.... As in, for each fan use thick gauge wire, ~10ga straight off the battery, through a ~20a fuse, through a relay, to the fan motor. Then you wire the relays to be triggered with a manual switch or however you like (ACC relay for on-with-ignition, etc). Make sure your fans are grounded with the same size wire you use to power them with. This will ensure your fans have enough juice for optimum CFM.. But even with proper wiring the fans might still be too small.

How do you have them wired up now? I don't think your wiring is the culprit unless it's some janky ghetto fab.

Step up to some 12s...

[Rezlo]

Let me sum it up plain and simple and yes I have tons of experience here.
Get rid of the suck ASS Koyo . They heatsoak after 20 minutes. If your going to go Aluminum get a Griffin or Fluidyne they are much superior to Koyo and do not heatsoak. Plus they run 10 degrees cooler than a Koyo because of better design. Ok I don't want to here arguements about this because I went through it, I know!
Koyo's suck end of story, so no whiny shit from SR owners about how your Koyo works fine. They may work fine with your 2 liter 4 cylinder that does not need as much cooling power, but they are basically a poor design sold cheap. End of story.
Steve and Mello both are correct besides your radiator heatsoak issue you definitely have a CFM issue . Unless those 10's are FAL's they are probably not pushing enough CFM. Dual FAL's are rated at 2500 cfm which would be enough for you. Either uprate your fans or even stick a stock s14 radiator in which is actually large enough with a pair of FAL pullers on the engine side and you would be good.
P.S. Hood vents due help but you you need to address the other issues first.

I run my RB25 in 100degree + South african days for a 60 mile trip to work and back and race it every weekend either drag or drift for extended periods, again in the south african climate, its also rather powerful ( I would like to think so running 11's anyways). I have never ONCE even come close to having dangerous water temps with my koyo, I run a nismo thermo and water pump with 2 CSR 12" fans that kick on at 160deg rad inlet temp, never seen them go over 185, with my old SR20 with its stock SR20 radiator and Nismo pump and thermo it would often go over 200f.

Just before everyone thinks koyo are trash.

[moonshinekouki]

^ u mind telling ur coooling set up
like duccts fans w.e ur running?
thanks
mikey

[Rezlo]

2X 12" CSR fans on a stainless shroud i made that sits about 10mm from the core,

I use an electronic CSR fan controler to turn the fans on at 165f

Apart from that nothing, i dont have the AC condencer though, but i run a 100mm thick intercooler.