RB25 swap over heating issue - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

moonshinekouki · 05-28-2007, 10:02 AM

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 · 05-28-2007, 10:12 AM

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 · 05-28-2007, 10:20 AM

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 · 05-28-2007, 10:23 AM

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

moonshinekouki · 05-28-2007, 10:23 AM

s14koyo*
and sitting in traffic at a stop and go

nlzmo400r · 05-28-2007, 10:25 AM

Quote:

Originally Posted by moonshinekouki

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 · 05-28-2007, 10:27 AM

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 · 05-28-2007, 05:10 PM

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

Yum-Yum · 05-28-2007, 06:06 PM

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 · 05-28-2007, 06:12 PM

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

moonshinekouki · 05-29-2007, 02:04 AM

what kind of fans are you using yum-yuum?

how should i be bleeding my coolent system?

bardabe · 05-29-2007, 02:07 AM

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 · 05-29-2007, 12:31 PM

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

thanks

moonshinekouki · 05-29-2007, 02:22 PM

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

steve shadows · 05-29-2007, 02:25 PM

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 · 05-29-2007, 02:26 PM

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

steve shadows · 05-29-2007, 02:28 PM

Quote:

Originally Posted by moonshinekouki

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 · 05-29-2007, 02:35 PM

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

moonshinekouki · 05-29-2007, 02:42 PM

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* · 05-29-2007, 02:50 PM

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 · 05-29-2007, 02:52 PM

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* · 05-29-2007, 03:00 PM

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 · 05-29-2007, 03:04 PM

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 · 05-29-2007, 03:09 PM

Quote:

Originally Posted by moonshinekouki

im pretty srue th fans are blowiing through the rad

thats like very very important

haha

lucky7 · 05-29-2007, 03:09 PM

Quote:

Originally Posted by 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.

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

*MELLO*SOS* · 05-29-2007, 03:19 PM

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 · 05-29-2007, 03:44 PM

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 · 05-29-2007, 07:01 PM

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 · 05-29-2007, 08:48 PM

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 · 05-29-2007, 08:55 PM

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.

05-28-2007, 10:02 AM	#1
moonshinekouki Zilvia Junkie Join Date: Nov 2005 Location: Toronto Posts: 350 Trader Rating: (2) Feedback Score: 2 reviews	RB25 swap over heating issue 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 __________________

05-28-2007, 10:12 AM	#2
bardabe Post Whore! Join Date: Aug 2005 Location: SoCal Age: 35 Posts: 4,719 Trader Rating: (10) Rides Gallery: bardabe Feedback Score: 10 reviews	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? __________________ Review Thread

05-28-2007, 10:20 AM	#3
nlzmo400r Zilvia FREAK! Join Date: Oct 2003 Location: louisiana Posts: 1,248 Trader Rating: (0) Feedback Score: 0 reviews	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. __________________ 'my drinking team has a racing problem' [email protected] - gt32 .6bar

05-28-2007, 10:23 AM	#4
moonshinekouki Zilvia Junkie Join Date: Nov 2005 Location: Toronto Posts: 350 Trader Rating: (2) Feedback Score: 2 reviews	im running a s14 kouo rad and the fans im running are the flexi elite 10inch dual fans but no shroud __________________

05-28-2007, 10:23 AM	#5
moonshinekouki Zilvia Junkie Join Date: Nov 2005 Location: Toronto Posts: 350 Trader Rating: (2) Feedback Score: 2 reviews	s14koyo* and sitting in traffic at a stop and go __________________

05-28-2007, 10:27 AM	#7
moonshinekouki Zilvia Junkie Join Date: Nov 2005 Location: Toronto Posts: 350 Trader Rating: (2) Feedback Score: 2 reviews	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 __________________

05-28-2007, 05:10 PM	#8
moonshinekouki Zilvia Junkie Join Date: Nov 2005 Location: Toronto Posts: 350 Trader Rating: (2) Feedback Score: 2 reviews	k i bleeded the system and its still over heating..... __________________

05-28-2007, 06:06 PM	#9
Yum-Yum Zilvia Member Join Date: Apr 2007 Location: Richmond, VA Posts: 180 Trader Rating: (7) Feedback Score: 7 reviews	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.

05-28-2007, 06:12 PM	#10
JDS Performance Zilvia.net Advertiser Join Date: Jul 2006 Location: Concord, NC Posts: 3,127 Trader Rating: (53) Feedback Score: 53 reviews	why dont you let us know your steps to bleeding your coolant system __________________ http://www.240SXTECHDVDS.org http://www.JDSPerformanceTurbos.com

05-29-2007, 02:04 AM	#11
moonshinekouki Zilvia Junkie Join Date: Nov 2005 Location: Toronto Posts: 350 Trader Rating: (2) Feedback Score: 2 reviews	what kind of fans are you using yum-yuum? how should i be bleeding my coolent system? __________________

05-29-2007, 02:07 AM	#12
bardabe Post Whore! Join Date: Aug 2005 Location: SoCal Age: 35 Posts: 4,719 Trader Rating: (10) Rides Gallery: bardabe Feedback Score: 10 reviews	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. __________________ Review Thread

05-29-2007, 12:31 PM	#13
moonshinekouki Zilvia Junkie Join Date: Nov 2005 Location: Toronto Posts: 350 Trader Rating: (2) Feedback Score: 2 reviews	well i do feel alot of hot air comming out of the engine bay ill post pics up thanks __________________

05-29-2007, 02:22 PM	#14
moonshinekouki Zilvia Junkie Join Date: Nov 2005 Location: Toronto Posts: 350 Trader Rating: (2) Feedback Score: 2 reviews	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 __________________

05-29-2007, 02:25 PM	#15
steve shadows Post Whore! Join Date: Aug 2003 Location: LA and OC Posts: 8,202 Trader Rating: (5) Feedback Score: 5 reviews	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. __________________ Like Me on FaceBook !

05-29-2007, 02:26 PM	#16
moonshinekouki Zilvia Junkie Join Date: Nov 2005 Location: Toronto Posts: 350 Trader Rating: (2) Feedback Score: 2 reviews	will the coolent swirl tanks make a big differnce? wat fan would u recemond? thanks bro __________________

05-29-2007, 02:35 PM	#18
moonshinekouki Zilvia Junkie Join Date: Nov 2005 Location: Toronto Posts: 350 Trader Rating: (2) Feedback Score: 2 reviews	ok thanks bro its going to be hard for me cuz im in canada lol __________________

05-29-2007, 02:42 PM	#19
moonshinekouki Zilvia Junkie Join Date: Nov 2005 Location: Toronto Posts: 350 Trader Rating: (2) Feedback Score: 2 reviews	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 __________________

05-29-2007, 02:50 PM	#20
MELLOSOS* LAID OUT Join Date: Mar 2004 Location: LAS VEGAS Age: 43 Posts: 2,015 Trader Rating: (1) Rides Gallery: MELLO*SOS Feedback Score: 1 reviews	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.

05-29-2007, 02:52 PM	#21
moonshinekouki Zilvia Junkie Join Date: Nov 2005 Location: Toronto Posts: 350 Trader Rating: (2) Feedback Score: 2 reviews	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? __________________

05-29-2007, 03:00 PM	#22
MELLOSOS* LAID OUT Join Date: Mar 2004 Location: LAS VEGAS Age: 43 Posts: 2,015 Trader Rating: (1) Rides Gallery: MELLO*SOS Feedback Score: 1 reviews	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?

05-29-2007, 03:04 PM	#23
moonshinekouki Zilvia Junkie Join Date: Nov 2005 Location: Toronto Posts: 350 Trader Rating: (2) Feedback Score: 2 reviews	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 __________________

05-29-2007, 03:19 PM	#26
MELLOSOS* LAID OUT Join Date: Mar 2004 Location: LAS VEGAS Age: 43 Posts: 2,015 Trader Rating: (1) Rides Gallery: MELLO*SOS Feedback Score: 1 reviews	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

05-29-2007, 03:44 PM	#27
drift freaq R.I.P. Aya, always love Join Date: Nov 2001 Location: Los Feliz/Hollywood Posts: 18,564 Trader Rating: (215) Rides Gallery: drift freaq Feedback Score: 215 reviews	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. __________________ "Having a lot of tracks on a song is like putting stickers on a car to get more horsepower" New Video https://www.youtube.com/watch?v=uebV1OnbRsw Buy my mounts! http://zilvia.net/f/sale-items/51531...ns-mounts.html http://zilvia.net/f/tech-talk/317539...e-mouts-6.html

05-29-2007, 07:01 PM	#28
lucky7 Post Whore! Join Date: Mar 2005 Location: Oakland (OT) Michigan Age: 40 Posts: 3,353 Trader Rating: (0) Rides Gallery: lucky7 Feedback Score: 0 reviews	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. __________________ -Dane

05-29-2007, 08:48 PM	#29
moonshinekouki Zilvia Junkie Join Date: Nov 2005 Location: Toronto Posts: 350 Trader Rating: (2) Feedback Score: 2 reviews	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 __________________

05-29-2007, 08:55 PM	#30
250sxdet Zilvia Member Join Date: Feb 2006 Location: so cal Posts: 165 Trader Rating: (2) Feedback Score: 2 reviews	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.