how many holes to drill in thermostat to increase cooling efficiency?

[brett_celicacoupe]

as per title.

2JZ has trouble maintaining the optimal operating temperature. this is even more profound when the AC is on.

so... increasing the flow should increase heat transfer from the engine to the fluid and the fluid to the air.

how many holes and what size should i put in the thermostat?

my thoughts were 2 x 8mm

bear in mind the climate where i am is usually hot anyway.

anyone experimented with this and had some success?


cheers,
Brett

[thechuckster]

if it flows too fast, the radiator doesn't work efficiently and you make things worse ... at least that's my take on it.

Assuming the radiator has been flushed, the fins are OK and all the cores open, I'd suggest you look at ducting to the front of the car to:
-get more air flowing into the void from front bar to radiators
-make that void slow the air speed down
-seal that void up so air cannot flow out the sides or underneath
-make sure you have some kind of undertray so hot air existing the radiator(s) can flow thru the engine bay rather than meet a high pressure and turbulent zone courtesy of no undertray

You'll get better heat transfer if the air flowing thru the radiator(s) is slowed.

What temp is the bottom hose from the radiator?

[oldcorollas]

i thought hole in thermostat was to allow fluid to flow thru engine when radiator is TOO effective or air too cold.. so that the temp remains more stable (albeit a bit lower) and the thermostat opens gradually.

once a thermostat opens up, it should be no issue.. unless it is stuffed and not opening far enough?

hmm, if the heat from AC core is enough to cause radiator to not work as well, then maybe radiator is not happy...
to add to chucksters points, make sure around the rad core is sealed so no air can bypass around it into the engine bay. this can make a big difference

[The Real Roadrunner]

don't bother drilling the thermostat out, it will generally only compound the problem.

What have you got pulling air thruogh the rad? if its thermo's then chances are you wont be able to do much with it.

I find engine fans to be eleventy billion times better but thats my personal preference.

if the rad size is close to that of an MX83 and you want to keep thermo's get some of a U12 bluebird / ford corsair. they suck harder than Eldaro and Guilty combined.

Chuckster,

No such thing as flowing too fast, both with air or water. the more flow the better it cools.
but you need to keep some sort of pressure buildup on the block and rad tubes for better heat transfer and to stop air bubles from forming thus causing hot spots.

Read thru this from post 14 onwards, pretty good arguement.
http://www.bmsc.com.au/forums/rallyi...ra-forums.html

cheers
linden

[brett_celicacoupe]

thanks for your reply linden.


the current setup is using twin AU thermofans running full time.

its worth noting that for a while i was running a JZA70 hydro fan on this and another radiator. i basically had the fan running at full speed, with the pump solenoid on. it more or less had the same problems.

ill also clarify the conditions under which the 'raised temperture' occurs. with all setups i have tried, the engine temperature would rise after a minute or so at speeds over 100km/hr. it does usually reach an equilibrium though at about 1 bar below maximum on the Z12 cluster (you should be familiar with this).

if the AC is brought into the equation then pretty much at speeds above 50km/hr after the engine is warm, the temperature will continue to rise until the temp gauge starts flashing.


i have a feeling the air entering the radiator is fairly warm as the air goes through the following;
1.trans cooler - it sits behind the grille and is the same size as the grill
2. intercooler - 600x300x76
3. very small ps cooler - probably adds negligible energy to the air inflow
4. AC condensor
5. radiator.

when you look at the front bumper, all the openings have are directly covered by coolers that arent the radiator.

i have also tried significant ducting between the very front of the car all the way back to the xmember. no observed difference


im half tempted to just add a transmission cooler to the very front of the car (still behind bumper) to help cooling at higher speeds. i would just plumb it into the cooling (water) system of the engine

[Draven]

what type of rad you running?

I know norbs had issues with 2j + ma61, even triple-cored

[wilbo666]

Why don't you remove thermostat completely and see if it helps?

Easier than drilling holes

Cheers
Wilbo

["Z" UTE]

Have you looked at the possibility that the water pump is FUBAR?. These engines have been around a while now, and it would not surprise me to find a shagged set of pump vanes in one.

cheers Chuck.

[brett_celicacoupe]

what type of rad you running?

I know norbs had issues with 2j + ma61, even triple-cored

just the standard Z12 thing

[RAd28]

wild shot, but try something like a water wetter... will lower the surface tension of the water etc etc... some claim improve performance... but i read somewhere they atleast dropped the temperature enough to be worth the $$...

there was one in particular, came from europe, but the name eludes me....

[wa5]

Are you sure that your temperature guage is reading correctly? IE does the engine have the right sender in it? Might be worth your time to plumb another guege into the system.

also, how is your radiator cap?

Personally, I dont subscribe to the belief that the thermostat raises the pressure in the engine block to an amount significantly higher than the radiator side of the system.

[thechuckster]

piss the AC off and drive faster with the windows down?


edit: seriously, do you have the underside of the car looking like this? Cause you need a shiteload of air to take heat out of all those radiators

and

(thanks to Stumpy for the pics)

[brett_celicacoupe]

driving faster makes it get hotter.

it pretty much just keeps climbing and doesnt stop while sitting on 140.

its kind of like an indirect speed limiter

edit; and AC rules. no way id give it up in this climate!

[cambelt]

1x 8mm hole helps things a bit, just drill the little poppet valve out. will make it run a bit to cold i winter .
99 % of 2JZ-GTE convesions run too smaller radiator as the cars that there in dont allow for bigger rads .
Dave

[brett_celicacoupe]

good to hear,

i may try this tomorow and report back