Idle Water Temp

[YangLIU]

hi all,

recently i got a HKS OBD2 tool. these day I found the water temp is getting to 99-101 degree when stop and wait traffic light or heavy traffic. (but when driving, the water temp is 87-90 degree based on the environment temperature. actually the environment temp is around 22-25 degree these day in Sydney and it is not hot)

is it normal temp when idle? the stock water gauge is in normal status but you know the stock gauge is lazy unless the water is really really hot.

Edited May 8, 2015 by YangLIU

[Brick]

Yes it is normal

[YangLIU]

Yes it is normal

good to hear that.

[scotty nm35]

Another case of 'you are better off not knowing'

Just wait till the coolant hits 146c along with the oil temp.

[Brick]

There is a few good mods to drop those Temps and keep them more stable. Scottys cooling mod will help with stability, there are thicker core radiator options. And the nismo thermostat. Grab all those and it should drop into the 80s

[KiwiRS4T]

Forget the Nismo low temp thermostat it serves no useful purpose. Engines are meant to be hot.

[YangLIU]

There is a few good mods to drop those Temps and keep them more stable. Scottys cooling mod will help with stability, there are thicker core radiator options. And the nismo thermostat. Grab all those and it should drop into the 80s

i have alloy radiator and i think that's enough for daily drive.

[YangLIU]

Another case of 'you are better off not knowing'

Just wait till the coolant hits 146c along with the oil temp.

come on man.

[MozzMann]

IF and I mean IF you can find one get a copper core radiator, that is likely to be a big ask because they are expensive but much more durable that alloy as thermal cycling will eventually crack an alloy radiator.
Copper tends to handle the flex much better. Modern radiators with their folded clip tanks and "O" rings are cheap to produce and replace but the do have a finite life especially with the FRP used in the moulded tanks and other components.

As for the running temp the higher and more stable you can keep it the better, ie if it runs at 95 C that's fine if it stays 5 deg either side of that, but radical excursions above and below create a lot of thermal stress.
remember a 15 Lb cap for instance will raise the boiling point to roughly 120 C depending on the actual coolant you are using so if your engine is reporting 99-101 once hot that is likely about mid gauge scale.

I know racing is just a little different to street but the hotter the better without boiling is considered by many as the norm 30 psi in a race system isn't uncommon so engine temps can be much higher and the expansion difference lower at high temps thus closer tolerances can be used to produce more power.

Edited May 9, 2015 by MozzMann

[Ben C34]

Hotter the better?

Why? Heater works better?

Expansion changes at higher temps?

Seriously man?

It's linear.

[MozzMann]

" Ben" Again people DON'T read the expansion I am referring to as different rates are between the various dissimilar metals used in modern engines, even alloys of the same metal. Hence the hotter the better to a point as a design feature because that is how the motor has been designed, taking into account the expansion when heated so that at Operation temperature the tolerances tighten up and then change little as the internal temperature changes within the engine.

Take the average Alloy or part alloy engine these days, there are Chrome-Molybdenum springs used extensively along with thin hardened shims they sit on, sintered boron bronze alloy valve guides, or hardened steel chrome plated valve buckets and their valve clearance shims, Titanium or harden alloy retainer's are now common to reduce reciprocating weight in the valve train, Stainless or more common cast camshafts, billet steel or cast or even Steel alloy crankshafts, forged steel con rods, chromium or hardened steel alloy sleeves in an Aluminium alloy block they ALL expand and contract differently and why as has been stated the hotter the better up to a point and the design parameter's of the engine take into account the differing expansion rates so that when the engine is at Optimal operating temperature the internal tolerances are within design specifications and will go a long way to explaining why some motors chatter or make a bit of noise when cold but hum smoothly when at temperature.

[Ben C34]

Why us hotter better though?

The expansion rates of different metals is linear. They don't expand more from 0 to 40 than compared to 100 to 140.

They don't become similar at a certain range. The expansion rates that is.

I'm confused.

[Leroy Peterson]

...when the engine is at Optimal operating temperature the internal tolerances are within design specifications...

yes, and optimal operating temperature has recommended minimum and maximum temperatures.

might as well remove the entire cooling system due to "the hotter the better" theory and see how that works out for you.

[MozzMann]

Ben & Pulsar

Again your not reading this as intended.

Different metal expand at different rates now while this is Linear as you correctly point the rate between different alloys IS different , Copper expands and contracts at a significantly different rate to Titanium for the same temperature change for instance and out the result tolerances between components change. What I am trying to convey apparently unsuccessfully is the differences in expansion rates per temperature are taked into account when an engine is designed so that whet at the correct temp all works as it should BUT if the internals of the engine are too cold it will be as a general rule much less efficient.
As I said expansion rates ARE different between different metal alloys and this is taken into account so that at the nominal operating temperature of the engine all the internal tolerances ie clearances are with the design specifications.
What this means is if your engine is continually operating below the optimal temperature then you will get excess wear between components because the space between them is in excess of the designed parameter's .

Again as a general rule the hotter the better up to a point because the energy release from the fuel has a higher calorific value (read energy release ) at a higher temperature.

It's a bit hard to understand with modern injection system as they allow for temperature changes in the Engine Block, Air inlet charge and other factors, When older engines used a choke on a Carburettor to richen the mixture at cold temps but you get rid of this as the motor warmed up and got more efficient running with a leaner mixture.
The modern injected engine is in essence no different in operation but used sophisticated electronics to manage everything from Ignition and cam timing to fuel delivery and drive train management so we are not aware of the inefficiencies at low temps .

This however still does not detract from the statement " Hotter the Better " was referring directly to racing ( I was referring to racing here ) as the internal efficiency of the engine is significantly better at higher Temps . 95-105 for instance than it is at 75-85 and the sole reason why there is a thermostat in your cooling system to get the engine up to and keep it within it's designed operating range. . Now you can see what I mean I hope.

Side note the reason why you NEVER remove the radiator cap from an over heated engine is the sudden drop in working pressure will instantly boil the coolant potentially severely scalding you.

Edited May 9, 2015 by MozzMann

[zebra]

Lol

Thats why NASCAR, F1, Indy, V8 taxis etc all try and keep the engine temps as low as possible

[Ben C34]

What cars have stainless camshafts?

[zebra]

What cars have stainless camshafts?

The green dragons

[MozzMann]

It is pointless trying to explain when people simply do not read, There are operating criteria for specific engines as I have stated all along,

the higher the engine can operate within those criteria the more efficient it will be and depending on the design.

NASCAR and often in a multicar train running generally full tilt and NOT in clean air so boom goes your argument there and why they try to keep temps down as this allows a much wider temp range before problems occur. but hey have a real juggling act between covering the radiator opening to get speed or opening it up to run cooler.

As fo F1 and Indy they have no fans and as a result must build a buffer into the car where the air flow does the cooling but they don't overheat while in the pit (minimal coolant too as they want to reduce weight.)

V8 Series, depending on the engine builder might have a design temp anywhere from 80 to 120 deg and again often not in clean air so it is desirable to keep initial temps low to again have a buffer temp wise while in racing in nose to tail areas.

[Ben C34]

Why would they go for a higher temp ?

Yo heat up incoming fuel and air as much as possible, or so the clearances between parts are worse when cold?

Its not to make more power. Its for emissions.

[Ben C34]

I've read and re read everything you wrote.

Why does higher temp mean more power?