Normal operating temp?

[kouki-gymkhana]

Hey guys, I'm happy to report that I am no longer a member of the non-running RB club, as my RB25 is now happy again with a fresh HG and some valve work, including the dead lifter that caused me to have no compression in cylinder #5. I drove the car for the first time in over a year a few days ago and it is SO SMOOTH!! I've fallen in love with this engine all over again!

I do have one issue, though, that I can't find even though I've searched. What is the normal operating temp for the RB25 in Celcius? I'm seeing between 80-90 C cruising on the highway, 90 C in stop and go, and 100 C in stop and go with the A/C on. Is this within the normal range? What temps are you guys seeing?

[Bluefire]

Might be a tad on the hotter side, but not a big problem at all... what are your cooling modification anyways...

[kouki-gymkhana]

Cooling mods: KA Koyo racing radiator with FAL 210s as pullers, pignose A/C fan as a pusher, lots of ducting, and multiple holes cut out of the bumper. I also have a new OEM water pump, low temp NISMO thermostat, and a bottle of water wetter in the system.

[002-M-P]

Cooling mods: KA Koyo racing radiator with FAL 210s as pullers, pignose A/C fan as a pusher, lots of ducting, and multiple holes cut out of the bumper. I also have a new OEM water pump, low temp NISMO thermostat, and a bottle of water wetter in the system.

Wow...

You might have too many fans. If those pullers might be restricted by that pusher blocking air flow. Not sure about that though...

[Bronze MFP]

personally i get a little worried when the temps go over 90*c, but i'm not running AC either.100*c is getting pretty hot and you def dont want it to go over that. 80-90 is about where it should be at.

[Darius]

I have the stock Z32 thermostat and I believe it is rated for something like 83 or 84*C ( I can't remember off the top of my head). I'm surprised that your highway speeds are keeping the coolant that hot.

Have you bled your cooling system adequately?

[gawdzilla]

seems a bit hot for the amount of cooling mods you have. could be the AC condensor blocking some airflow though...

mine would creep up to high 90s(C) crawling through traffic in a hot, humid mid 90s(F) day. 2 ebay 12" pushers and basically no ducting, regular 50/50 coolant.

what is the outside temp?
Modified by gawdzilla at 7:39 AM 6/1/2007

[cdorhout]

I run a Koyo radiator, and I've never seen mine go above 80C in normal driving. Almost always stays at 70C.

[Darius]

Aren't you running without a thermostat though?

[cdorhout]

No, I bought a OEM replacement thermostat when we first did the swap. My dual 12" inch fans run 100% of the time though. I don't have a temp switch hooked to them.

[kouki-gymkhana]

The temps I listed above are in the S. Florida heat. The temp yesterday was 87 F with 93% humidity. I think the temp was high on the highway because I had the A/C on while in stop and go traffic until I got to I 95 (about 11 miles) and the temp got up to about 95 C before I turned it off. Once I got onto the highway, it came down to about 82-85 C within about 5 mins.

The cooling system has been bled. I think the issue is that with A/C condenser not only blocks airflow to the rad but also gets hot as it functions. I have a big *** FMIC on the car as well so incoming air has to go through the FMIC, condenser, and then the koyo rad. My fans are set to come on at 70 C, btw because the thermostat doesn't open until 65 IIRC.

There are no signs of boiling over so I guess things are alright. I don't know what else to do to improve things aside from hack up more of the bumper or run without one altogether.

I think the overriding issue here is that the s13 shell does not have enough frontal area to allow for great cooling. If you look at all the Skyline models, you'll see that they look like bricks in profile because they require alot of incoming air to keep things cool. The s13 nose is like a friggin' pillbox window by comparison.

[Darius]

I think you hit the nail on the head. If you have all of that AND ducting, it is a matter of not having enough area exposed directly to incoming air flow.

[johnzm]

have you tried running without a nose on? i will be in the same boat as you very soon, i canont run my AC now with a 12 inch pusher and a 12 inch puller because unless i am rolling it overheats very quickly
Modified by johnzm at 8:05 PM 6/1/2007

[johnzm]

The temps I listed above are in the S. Florida heat. The temp yesterday was 87 F with 93% humidity. I think the temp was high on the highway because I had the A/C on while in stop and go traffic until I got to I 95 (about 11 miles) and the temp got up to about 95 C before I turned it off. Once I got onto the highway, it came down to about 82-85 C within about 5 mins.

The cooling system has been bled. I think the issue is that with A/C condenser not only blocks airflow to the rad but also gets hot as it functions. I have a big *** FMIC on the car as well so incoming air has to go through the FMIC, condenser, and then the koyo rad. My fans are set to come on at 70 C, btw because the thermostat doesn't open until 65 IIRC.

There are no signs of boiling over so I guess things are alright. I don't know what else to do to improve things aside from hack up more of the bumper or run without one altogether.

I think the overriding issue here is that the s13 shell does not have enough frontal area to allow for great cooling. If you look at all the Skyline models, you'll see that they look like bricks in profile because they require alot of incoming air to keep things cool. The s13 nose is like a friggin' pillbox window by comparison.

hey man, shoot me an email, i got some questions about your radiator fan mounting...

johnzm2ATgmail.comthanks!