Engine Temps

[tacker]

Guys after some views from yourselfs about engine temps and what it should be and where it should be measured.

I am currently trying out 2 different radiators, i have a 4 core copper brass unit and a 2 core aluminium radiator. I run a track only R32 GTR around 400 AWHP so i dont have to take traffic stops in to account with an N1 water pump. Yesterday i ran the 4 core radiator without any fan in and day around 35deg and the car started to get a bit hot ( 100 ) at around the 15 minute mark of the 20 minute session. Would need to back off and short shift at 5000 rpm for a minute to see temps dropping back to 95 ish so the radiator is working ok.

My question is where do i measure the water temp, currently it is measuring the outlet of the engine in the hose to the top of the radiator tank, is this correct? Or should i put the viscous fan back on and will this make any difference as the track has only one point where you drop back to second gear for about 4 seconds before changing up. or is a thermo fan a better option, if i put 2 smaller fans on the bottom half of the radiator where the air flow is not so good will this help?

Also should the thermostat be removed as i have heard 2 different theories on this that it should be removed to allow more flow and it should be left in place as it slows the coolant flow through the radiator and allows the coolant longer in the radiator to cool more.

Your thoughts also on expanding the radiator tanks to hold more coolant say an extra 3 to 4 litres which should allow the collant more time in the radiator to cool be fore being circulated back into the engine

[T04GTR]

bigger is not always better

for the track 1 big thermo is better. (davis craig are shit so dont bother.)

you need to use a oem style one. out of a magna or something

[T04GTR]

run a thermostate. it will take ages to heat up ad then overheat.

[T04GTR]

a header tank is a good idea.

[someonestolecc]

I'd be thinking the sensor should be before the coolant goes into the engine block. This way you know the effect of the radiators effectiveness. It's reasonable to expect that the coolant exiting the engine should experience a drop with a lower temp coolant going in, but that may not always be the case..

Also, I'd always run a fan with a shroud, infact 2 of them. When I had my cef it had 2 thermos with a ford EL(or EF) shroud.. when the second fan was turned on cruising temps were down 5-10 degrees on the street. Track wise it just meant when the temps got up to 90 from hard use they stayed there and didn't budge up.

I didn't realise the stock radiator had that much trouble at that power levels.. anyway??

[someonestolecc]

for the track 1 big thermo is better. (davis craig are shit so dont bother.)

you need to use a oem style one. out of a magna or something

What do you base that on? Or are you joking??

[T04GTR]

real time testing with a supra

[tacker]

Yer i think its the lower half of the radiator needs fans as its blocked by the I/C

The top half is getting enough clean air as there is nothing blocking the flow of air, and hitting 230kms really helps cooling air flow through the radiator you can see the temp drop about 10 seconds after finishing the straight at those speeds.

I have no problem with warming the car up not tohard here in the middle east its always hot :-).

Will increasing the amount of coolant and allow more cooling time in the radiator. I know the radiator is working ok as it had nearly 25 deg of temp difference between the top and bottom tanks

[Roy]

Technically speaking i would be measuring the temps in and out of the radiator to suss the effeciency of the thing.

But, i would also be happy measuring the temp of the coolant going into the engine anb satisfying yourself that the coolant is at least going into the engine at an acceptable temp

But, before doing anything get down on the ground and suss out the current intercooler / radiator / front bar arrangment. I was thinking about getting a radiator but wanted to make sure the std one was at least working properly first.

So i ducted the dront bar so that any air going throught the front bar has to go through my intercooler, not around. So this help engine inlet temps. Then the air coming out of the back of the intercooler must go through my radiator, again not around. So some ducting and guides and foam around where the radiator mounts to the front radiator support. Seal it all up as best you can.

So for th ecost of $40 and some of my time i now never get over 78 engine temps when driving on the street and my engine temps at the track have dropped from around 93 to 87. Makes a big difference.

So if you are going to run the aftermarket radiators, make sure that you do the same thing and make sure you are makign the most of the air passing through the bar.

Also, may be worth looking at the intercooler you are running and looking at some of those swanky N1 ducts for the front bar. Airflow is king baby.

I wouldnt worry about the header tank. They look cool but the engine bay is already crowded and hte ARC ones arent exactly cheap. I would rather spend the money on an N1 water pump that wont cavitate the water as much

[someonestolecc]

real time testing with a supra

Not trying to put down your testing, but if you just had 2 radiator/thermo combinations then it's like lisa simpson's tiger rock theory to me

I'd go with a twin thermo setup with a shroud. Typically on a rectangular shaped radiator you'll typically cover more surface area, therefor pulling more air through the rad. There's also the benefit that if one fails you can still get home. I think a lot of performance type cars have 2 due to these reasons.

If you have a drag car or something, want to save the weight and have a square radiator then maybe... .... ... but agree probably makes no difference 9/10

edit: What Roy said as well x2, I'm going to be using really thin fibreglass.

[gtst25]

Don't under estimate the oem clutch driven fan - for the slight power loss you may get it might be worth reinstalling it with the oem shrouds and see how it goes for a day. If I had a track car I'd put a lot into ducting and a very big bonnet and turbo vent. Those running temps are pretty high - but then again it'd be nice to have temp senders on both inlet and outlet of the radiator.

Cheers

[tacker]

I have an N1 pump already so i will look at the ducting as i could not disagree with you on the ducting is king Roy.

The header tank i can get anything i want made as i have a really good contact in that regard, even though i know that if the cooling system is not good enough will not make any difference as it will still get hot at some time.

Will also put another temp gauge in the intake and see the diff. What about the thermostat should that still be run, not worried about warming it up over here.

[1400r]

stock setup no thermo's

[tacker]

nope stock set up didnt work, got hot too

[R31Nismoid]

Gotta look at other things that just the radiator itself.

As you said, your not running the stock fan, and that is exactly where your problem is.

A big radiator wont keep a car cool if there isnt a fan to help proceedings.

Stick the stocker fan in with the shroud, the 2-core ally rad, and you'll be laughing.

GTR's down here run pretty much that setup with a lot more power than you have, and they sit happy no worries

[tacker]

ok i also know that to be true just a bit of a struggle to get it happen here.

I have run a 3 core aluminium radiator with the stock fan, water pump and shroud still bumped into high 90's.

I can run all day at 85 with no fan but short shift @ 6000, my question is at what speed does the stock fan stop being effective and air flow take over. Also what RPM does the fan stop spinning as i doubt it is still pulling air in at 230km or 7500 rpm. And IF that is the case would the shroud not be a restriction of that forced air flow? The track has only one second gear corner with sees the car in second for about 4 to 5 seconds so the slowest point of the track is about 65-70 kph would the fan still be pulling air through at that speed

I had no problem at 30 degree but when it hit 40 + i have the issue and i would like find a solution.

I guess the alloy radiator stock fan, stock shroud and N1 water pump will be the next conbination to try. I also forgot to mention i have a vented bonnet with the vent right behind the top of the radiator which i would hope draws the air through as well.

comments please

Edited April 21, 2007 by tacker

[1400r]

just jap rad?

[tacker]

yes it is why is that a problem?

[Roy]

I wouldnt run without a thermostat. I would at least get one of the low temp Nismo ones. I have often thought about getting one myself.

Provided you duct that bad boy up right and you are still running std turbos then id say you will be fine. I know of a few people running the Just Jap radiators, but im yet to hear of someone running one in their track car. I also knwo someone who has a race radiator alloy 40mm, really nice piece of kit but his car sitll gets warm. It appears its all in the installation

[1400r]

had one in my s13 car overheated at Mallala before half a lap was completed chucked in a stock S14 rad temp didnt even move the whole prac session

try putting your stock rad back in or the other one you have as I know that J.J had problem with the filler necks being the wrong type and the cap not

sealing properly once the pressure starts to build inside them

otherwise I had mine checked out and fixed by a rad specialist but sent it back anyway