Just out of interest has anyone fitted one of these to their S2 Exige. I believe that the TRD 160 stat runs too cool and has an effect on the ECU but the 170 does’nt.
The car would then run cooler which means you could then fit a smaller supercharger pulley wheel say a 3:1, or am I talking a cr#p.
My car runs at a steady 89 degrees it used to run at 87 until the rad change due to plastic end cap failure,it now has a 42 mm alloy rad.
Deffo a good idea in my book …
I refrained from fitting one solely due to the labour required to swap em .
ANYTHING you can do to reduce under hood temperature on the car is a no brainer .
The engine coolant temp really doesn’t play a role in deciding if you can go to a smaller SC pulley. As you go smaller on the pulley, you are heating up the intake air more and more. So, it is the amount of intake air cooling you can achieve via your intercooler , along with a tune to ensure you are getting enough fuel for the added boost, which really are the deciding factors.
▲▲▲ agree here …
Intake temps are decided by airflow, boost pressure and design of intercooler. .
Thanks chaps, I already have a Pro Alloy a/a intercooler with side pod ducting fitted which should keep intake temps slightly cooler. The 3:1 pulley wheel is only one step down from the standard one so might be ok. Only tinkering with idea’s at the moment. I am surprised that people that are running 300hp and above with the extra engine bay heat have not had any need to run a cooler stat, that is why I posted this topic. It might be because they have fitted triple pass rad, which holds more coolant.
On another point does the re-circulation pump only work after the engine is switched off, and should you be able to hear it ?
I don’t understand the benefit in running a cooler opening rad? Once the whole system is up to temperature (over the temp of the thermostat) then what is the benefit of having a lower range one in? It is open all of the time anyway. My car on track is running around 93 degrees on a warm day and about 97 degrees on a hot day. Can someone explain the benefit?
Ade … Fancy putting a dirty great chargecooler rad in front of your cooling rad !!
Tut tut 
Your car runs hot ade, what temps did it run before the upgrade in power ?
My first Exige S ran at 87 degrees, the one I have now runs at 89. What temps are other peeps running at.
As you say ade " can someone explain the benefit of putting in a cooler opening stat"
As long as the cooling system can maintain the lower temperature then engine power should increase slightly as the intake charge will be slightly more dense.
Heat dissipation is a big issue in rear engined cars so ANYTHING you can do will help.
The reason manufacturers use an 88degree in most cases is to enable the heater to work more effectively.
Imagine the bad press if a car had the reputation of having a crap heater !
But given the power output of our cars and the engine placement etc a lower stat is never going to help then?
There must be some reason though because race cars use cooler opening stats and I am sure that some older race cars even had them removed altogether.
There must be an expert out there how knows.
A thermostat works to keep the temperature stable, whether it is 88, 83 or 2 degrees. The rest of the cooling system needs to be able to achieve your chosen temperature though. As said before most cars sold in the UK/Northern Europe need to keep at a certain temperature range for the heater to work well enough to warm in winter. As a bonus the hotter to the coolant temp, the better the idle/light/part throttle emissions are, up to a certain point anyway.
This is simples for older engines as they are massively overengineered, and the block/head are solid and stable, differential expansion rates are not so much of a worry. It gets more of a challenge when you have thin walled blocks and heads, steel liners in ally blocks,etc, which move around more as they heat/cool. K series is probably the best, or worst, example of this. Unfortunately.
Running a cooler stat is good, as this tends to give better power. Provided that the ECU takes this into account. If you are running 20 degrees below normal OE running temp, chances are you are always on the cold start map to a degree. This was the cheap and nasty way of ‘remapping’ early efi cars, simply by adding a resistor to the coolant temp sensor. Not so great.
If you fit a cooler stat, this only makes a difference if you have a cooling system capable of losing the heat. Run a standard stat/rad/cooling system on a standard car and its normally low 90’s. Run cool running stat same car and you get to mid 80’s. Add 60hp, chargecooler rad and AC in front of the main rad and temps may rise again on track, simply because the cooling system can’t dissipate the heat. At idle, it will drop back to the mid 80’s again.
Race cars with no stat is fine. It takes one more variable thing that can fail mid race out of the system. But then you normally need to add tape/blanking plates to the radiator, to get the temperature you require.
Thanks JDS that makes it easier to understand 
I have the lower TRD stat in the build car. What with that and the inclined front radiator position i have been struggling to get it over 78-80 celsius without having to blank off part of the rad with tape.
I was playing (sorry testing) adding strips and taking them away at Oulton and got it to hold mid to high 80’s before my un-timely departure off the track called it a day for me.
It should be good fully opened up on a hot european summer trackday as it hasnt been more than 10 degrees ambient in the time ive been testing it (exiges.com@Spa2015 perhaps…).
Is your stat the 160 or the 170 Gav ? Sounds as though it makes your car run cooler which must be a good thing to keep engine bay temps down, and help with heat soak issue.
Weirdly, the lower temp thermostat makes very little difference to engine bay temps.
Don’t forget that there is a +800 degree C exhaust in there amongst things. So 10 degree C or so difference in coolant/engine temps suddenly is brought into perspective.
▲▲ but a 10 degree reduction in gearbox temps is significant ▲▲
Not saying the thermostat would lower gearbox temps the full 10 degrees but as Tesco says … Every little helps 
We know the box doesn’t like temps over 100 and as its bolted to a large heatsink ie.the engine block it’s gotta help ?
^ Marginal at best.
The engine is cooled by water to target +/- 90 coolant and +/- 100 oil.
The gearbox is a free for all and self generates all the heat that it needs to see +110. If you are worried about gearbox temps, fit a cooler. Simples.
Or sell the car
^ that would do it 