So I'm gonna start off with the water wetter/water and KOYO OTS 36mm radiator. hopefully that helps out, if not ill swap to my amuse bumper, and do shroud, etc and I guess like you guys said its trial and error. Thanks everyone.

 

It doesn't have to be trial-and-error, you aren't the only one who tracks an HR in hot weather. I'm tired of people spending 1000s while trying to reinvent the wheel. Z Car Garage is famous for that, "let's try this, let's try that" while you're the guinnea pig bc people are just guessing. I know you made a post and got some input, but keep talking to people. Go around the track and see what people are running on their HRs. I know there aren't many locally, but we aren't the only place in the world running HRs at HPDEs. Z1 may be correct that the Koyo is the easiest drop-in, but it doesn't mean squat if it doesn't work well enough.

I'd swap the fluid to all D/I water and water wetter, and bleed the eff out of that mother, then try another event. Add a cup of coolant so that it's obvious if you spring a leak. You can still have fun at a hot event if you find that this doesn't work well enough, just do a few laps at 80%, find someone you want to play with, drive a few hard laps with them, then back off again. That will save tires, pads, and fuel as well! Have you had any power steering problems?

 

+1

To those recommending burping it again, and trying a more water combo. That's a huge cooler, does if ever get hot while DD'ing it?

Edit:
Also how fast are those corners? Cause if it's under 60 rolling might not be enough to start air cooling the car...if that makes sense, you know you'd be pushing the car hard at low speeds without high speed air into the car. Similar to drift cars on slow tracks.... Also since you said it spiked quickly I'd look into removing or replacing that thermostat.

Keep us updated, also which track was this, sorry if I missed it. Wanted to know where the straights are or long rolling turns are at. Because it getting hot is ok, question is does it then get cooler while you are still pushing it?

 

He was at Thunderhill Raceway in Willows, CA. (Bypass config.)

He had cooling issues two to three turns after an nice straight, 110+ mph. Turn one is a 80ish+ mph left 'kink', two: a mid third gear constant 200 degree left turn, three: a tight low-mid third gear right turn.

I was at the same event running my HR Z. I ran through the afternoon with ambient air temps in the 100ish+ area with zero cooling issues. I currently have no cooling mods, including oil. Wasn't necessarily taking it easy either.

Rather surprised he was having issues so early in the day.

-Cory

 

^^^

thanks for the info, and with that being said....

burp the system
relocate the oil cooler and/or new radiator

Air bubbles in the system is a huge difference between optimal temps and Overheating.

Quick story:

03 Z (thermostat deleted) we replaced some hoses on, and filled her back up. Turnt it on and the car seemed fine until he revved it a bit...temps soared to 220 while idling...we massaged the bottom hoses a bit more and the temps came down to 190 in the matter of a minute.

whole thing took about 20 minutes of filling/pumping/revving to get it to stay at 180~190...

EDIT:
Also i'd get a readout for the engine temps so it can be recorded/monitored more precisely...

 

An air bubble in an untouched coolant system just seems unlikely unless maybe somehow somewhere you've got some small damaged in the system from an off or whatnot.

I personally think its the oil cooler placement blocking flow... you have to remember the a/c condenser is in front of the radiator and you've just put another core in front of that, which gets HOT. I mean you're at speed in those corners there's no other reason to IMO.

A bigger radiator might not solve the main issue. I'd see if a coolant flush with all water and maybe some water wetter helps and then look into moving that oil cooler.

Another suggestion is if you overheat, just blast the heater with the outside vents facing the window and see if it stabilizes.

 

Its very rare from what I have seen to see another HR Z at track events, it is usually DE Zs or Z34s

as far as KOYO, Patrick has one (except he has the giant 55mm one) and says he has 0 problems. I could try just throwing in WW/water and doing an event on stock radiator and see what happens. As far as the laps, I usually do that, few hard laps, few cool down, etc, but I was out there with my friend in his S2k on NT01, and was determined to pass him (which I did ) so it wasn't my normal habit. No PS problems, at least I haven't noticed anything.

Looks like someone said it already but it was Thunderhill raceway park. every turn is over 60mph except maybe 11? speeds on the straight are in the 123 range (realistically slower since my speedo is slightly off)

oh and as for the cooler letting my oil warm up, no lol not usually just driving around town. I have to put a block off plate infront of it on the freeway when driving to the track and stuff or else the oil doesn't get warm. The car isnt really a DD so It never worried me too much. I only got the 34R because Z1 was having a black Friday sale and IIRC it was the same price as the 25R so I said why not.

It just happens when you get quicker, your car works harder, etc. Last July I went there with 0 cooling mods and was running a lot slower and went 5 sessions no problem, it was also 108 type of day.

doubt my system has air, I have tracked the car a few times since the coolant was changed last and it just happened at the last event. I may dump the fluid and do WW/water and try an event again on stock radiator. I am rewiring up my water temp gauge anyway so I can see whats going on there, also gotta get a oil pan spacer and rewire my oil temp gauge.

^ yeah I know the heater trick, I just got nervous when it happened and pulled off, and then got towed into the pits lol.


On a side not I am going back to thunderhill on Friday, so I can get some seat time in, but it will be in an Integra not my Z lol.

 

There were 2 NISMOs and an HR there on Friday and/or Saturday. I believe both NISMOs had cooling issues as well.

 

Vinson was there on Friday, and from what he said his brakes over heated and his slave did too before his water/oil had a chance to lol

 

Data to consider:

The NISMO I just bought came from Texas. He has tracked it in the Texas heat numerous times, and has not had any issues with the coolant temp. He runs water wetter with DI water and glycol. Stock rad, no upgraded OC, no tune, just JWT intakes. The car is meticulously cared for though, so - as we've been discussing - before you throw a bunch of bucks at it, try bleeding/purging and changing the fluid, IMO. Some of the additional cooling may be from the open-face NISMO front bumper, so that comes into play. I have a slightly-biffed one you could try/borrow/buy if you like.

 

Do a leak down, possible slight head gasket leak, seen it on street driven DE's mostly. At least pull the plugs.

 

Scott - I ended up ordering a radiator, gonna do what you said and run DL/WW and a little coolant so I know if I'm leaking in that area ever. As far as the bumper, thanks but I have a amuse bumper in my garage I plan on using most likly, and no oil cooler and no radiator and no over heating? That doesn't seem logical lol it's like saying a 370z doesn't overheat at the track. Anyway, I was talking to a friend anyway and he suggested I buy one, his exact words were "you can never keep a VQ too cool" so I pulled the trigger. I don't doubt stock radiator and WW/DL could/would make me stay more steady temp but I might as well upgrade cooling.

Damien - hm the cars been fine since the track day, so I think it just over heated, but I need to change the spark plugs anyway (even though HR is reccomeneded not to change until 100k miles)

 

Oh if anyone cares I ordered the upgraded KOYO racing radiator, the 36mm one,
part # V2999

 

I hope its nothing! Few things to remember, fans are primarily for idle and below 30mph, the faster you go the more air you push through the heat exchanger, the system is entirely dependent on maintaining correct pressure via the radiator or reservoir cap spring to raise the boiling point of the fluid being used, water being the most efficient. We do need some of the additives in normal coolant to lubricate the water pump and prevent rust. If you can squeeze the upper rad hose at full warm up temp then change the cap and check for leaks.

 

That's the data that can't be argued. It is what it is. It's a track car, no major mods except for whiz bang suspension goodies and diff/gears.

 

Do you know what kinda temps the car sits at? I'm curious where my temps are at but I need to rewire my water temp and get a oil pan spacer so I can relocate my oil temp sensor.

Scott you bringing the nismo to citytech MRLS day?

 

I don't...

Mobile Rocket Launcher System? Haha... it's likely...

 

decided to finally get that nismo i see! congrats on the pick up!

 

can I see the nismo

 

Btw installed the radiator, and added water wetter/distilled water. Gonna rewire my water/oil temp gauge (potentially picking up AEM digital gauges)

Interested to see where my water/oil sits with the coolers!