Help Me Solve My Overheating Woes

[Simon-S14]

yeah i had a sheet of alloy extending from the front bar all the way back to the crossmember... didnt make a difference.

[Dobz]

I really don't think its that.

Reason I say this is because that's how a factory GTS-R is setup. Mine runs cool as and the I/C sits close to the Rad, and is virtually the same size. I get temps of around 70 on a 25 degree day, driving it hard its lucky to get to 85 so nowhere near 100. I run no extra ducting or anything.

It wasn't a triple pass like a PWR @ over 800+, it was from Race Radiators here in Melb and was around 650.

I think it would make a difference when using a stock radiator, i say this because it's happened to me before. i used to own an old s13 drift pig that was all stock apart from intercooler and exhaust.

Originally had the I/C about 50mm away from the radiator and my water temps were always fine at around 82-84 degrees, it was only after i decided to tuck the I/C all the way up to the radiator my temps started to hover around 90-92 degrees. I didn't think the problem could be the I/C being so close but sure enough I moved it back away and my temps were fine again. That's just my experience.

It would be a different story if you had a very efficient radiator like the PWR, they could have there airflow blocked off and they'd still cool well.

Edited November 8, 2011 by Dobz

[battery]

I think most will tell you that a 6 cyl engine in a four cylinder bay makes life difficult because hot post rad air has to find its way through the bay and out underneath . The very best radiators in the world do jack if the air through them has restricted flow downstream . It could be worth sticking this car on a hoist and having a look from under and behind the engine at where the air flows through - and removing anything thats not essential in the flowpath . Note that includes in the gearbox tunnel as well because if you have the large 25T box in there it takes up more room than the Ss one did .

Back to basics , you make more power you make more heat though rough rule of thumb is that only 33% goes down the cylinders and the other 66 is split between liquid cooling and exhaust heat . Any exhaust restriction won't help and if the tuning is iffy that could show up as elevated EGTs and coolant temps .

I don't know what oil cooler packaging works on S series cars but I do remember some Mazda Rotaries having reasonably effective oil coolers and they may have been long and not very tall , something to look into maybe .

I only ever had one GTR rad and that was a Koyo in a Bluebird . It has all single tubes as in the full thickness of the core and worked really well . I think multi row radiator cores are a bean counters decision not an engineers one because the gap between each layer does SFA for cooling . A real radiator has alloy vanes inside its tubes to break up laminer flow and make the coolant reject its heat properly . My personal opinion of multi pass rads is small cores in series and you have to hope each one can flow enough water to work properly .

I'm pretty sure most/all Skyline radiators have vertical flow because more tubes is better for flow and cooling than fewer longer tubes , its the same with intercoolers but packaging and costing means most are not .

Anyway as mentioned that viscous fan hub needs to be fully functional and a new genuine Jap one is probably the way to be sure .

I'd be running a real good group 4 synthetic oil as well if you have high heat issues and a high poundage rad cap to make sure the coolant doesn't actually boil .

The real danger isn't 120 degrees coolant temperature , its the coolant boiling and steam bubbles forming in the head and localisaed head temps cracking/warping things . I don't think its real well known that water boils at higher temps with higher cooling system pressure and its the rad cap that sets the MINIMUM pressure once warmed up . You have to make sure that all pipes hoses everything is fact is in good order so elevated pressures don't blow anything .

Just back to oil again I'd be watching oil temps and if its getting high enough to be a worry you may need a higher viscosity one to keep the film strength up . One that comes to mind is the highest of the three Mobil 1 Racing 4T bike oils , its a 25W50 and called "V Twin" and intended for Harlry Davidson V Twin tractors and the like . I know everyone has their favourite brand and theories on performance engine oils , mine is that real performance 4 stroke sport bike engines beat the christ out of the oil far more so than any car engine . BTW I realise that Hardlys are not sport bike engines (IMO) but this oil is in the same group of 10W40 15W50 25W50 so its good gear . 4T Racing has high concentrations of ZDDP or Zinc Di Alkyl Dithiophosphate which is the gun anti wear additives taken out of most of todays oils for Green Socialist Psycopath reasons - it poisons cat converters over time .

Hope this helps cheers A .

What would we do without these amazing posts I learn something new every time.

Edited November 8, 2011 by battery

[toffy]

Ok , i thought i'd go have a look round a 34 to see what the factory setup was like , i wouldn't think that there's 'alot' more room under a 34 bonnet than a s14 , i took a few pics incase it will help . Anyways , what does your car do whilst idling? , do the temps increase much under slow - straight driving? (and/or does the temps rise under any other conditions other than drifting?) , think about where the air is flowing while your sideways , i wouldn't think much would get to the rad (especially with some of the clips i've seen of you ) . if i were you i'd be adding some thermo fans on the front of the radiator and maybe some ducting out of the bonnet? .

p.s one thing i did notice with the 34 is that the radiator seals up pretty well against the support so the air that hits it has to go through . pics:

p.s.s : another thing with your thermostat , have you tried another new one? tridon are notorious for 1 out of 5 not working correctly , in my race car i actually wire mine open so it can't give me problems

Edited November 8, 2011 by toffy

[Simon-S14]

cheers for all the responses! some great ideas and theorys being thrown around so i hope this helps other people as well as myself.

anyway so i was swapping and changing between 3 diff radiator caps for last event or so... i pulled out the pressure tested and tested the radiator.. no leaks in the cooling system there however not a single one of the 3 caps i tested held pressure... so binned them all and fitted one that worked/tested out ok. also changed the fan hub to a known working one. See how it goes this weekend.

[Simon-S14]

ive always had some degree of issues.

anyway so i was swapping and changing between 3 diff radiator caps for last event or so... i pulled out the pressure tested and tested the radiator.. no leaks in the cooling system there however not a single one of the 3 caps i tested held pressure... so binned them all and fitted one that worked/tested out ok. also changed the fan hub to a known working one. See how it goes this weekend.

[koe]

There is no need to experiment.RBs are old engines.If you are into competition or real racing the set up is there.

My car runs no more then 170s F when pushed real hard with hitting rev limit at 9.5 total destruction.

Bleeder or swirl pods.The best way is to use a 16lbs radiator cap on the radiator it self and use a 18lbs radiator cap in the swirl pod.This bleeder tanks are RBs best friend and a good thermostat.Billion is the best.

I have never been in a rb running more then 180 f

Do not use coolant.

Water and water wetter

[Simon-S14]

why no use of coolant? need some form of corrosion inhibitor.

well after yesterdays track day... im fairly sure the head is cracked or something....

[koe]

why no use of coolant? need some form of corrosion inhibitor.

well after yesterdays track day... im fairly sure the head is cracked or something....

Well the answer is simple

Simple such on YouTube water wetter has all the info you need and why we don't use coolant anti freeze.

Then you will see that water wetter also need assistance of a way to Tottally eliminate bubbles in your coolant system.

This is where the swirl pod or bleeder tank comes into play

Then you will start to see it all makes sense.

Please notice you can't have one with out the other

The swirl pod will be your number one source of pressure.

This is why you will use a lower psi radiator cap to the radiator and a larger psi rated cap on your swirl pod.

This allows the radiator to open faster then the swirl pod in order for your swirl pod to work properly.

So the water wetter will replace your coolant mixture , the swirl pod will replace your radiator pressure relief and the billion thermostat will replace your thermostat which will allow more flow at lower temps.

Now you most figure out the radiator set up.

Aluminum radiators are just for weight reduction and not and will not improve your cooling system.

This means you will need more air flow.

It's easy to solve.

A proper duct to help exit the hot air out of your engine bay.

But this is based on the amount of heat your engine generates.

I am sponsor by fluidyne and my set up in this area is not compatible with yours.

Usually just relocate the radiator in a angle that will push the hot air away for your engine.

Hood vents are usually made for this.

Edited November 13, 2011 by koe

[zebra]

I've tried water wetter before on my rx7. Didn't do shit tbh

I always run good quality coolant. I would rather that than have the welch plugs pushed out overnight in winter as straight water will freeze

The swirl pots work very well though and cheers for the heads up about running a higher pressure cap on the pot

[Simon-S14]

oh well im going to start from scratch. with a tube frame rad support which should free up room for larger parts. So help me design a killer system that will hold temps no matter what

[Rolls]

Bleeder or swirl pods.The best way is to use a 16lbs radiator cap on the radiator it self and use a 18lbs radiator cap in the swirl pod.This bleeder tanks are RBs best friend and a good thermostat.Billion is the best.

I have never been in a rb running more then 180 f

Could you explain what a bleeder/swirl pod is and how it helps with cooling? Thanks

edit: found this

http://www.grahamgoode.com/cool.htm#swirl

Edited November 13, 2011 by Rolls

[toffy]

oh well im going to start from scratch. with a tube frame rad support which should free up room for larger parts. So help me design a killer system that will hold temps no matter what

look into au-current ford radiator setups with the header tank etc , that would be a good start on a budget , their swirl pot(if you would call it that) is in the header tank