|Thermostat or not?

[rsfruitbat]

Hi
On the rally I noticed that running with a later "sealed" thermostat gave very different water temps.
I normally run the older Sud style thermostat where you can take the top of the housing off. I then remove the stat completely. Using this style the engine takes longer to warm up but runs generally cooler, about 5C. Probably a wider variation of temps.

With the sealed stat engine warms up quicker but then stays warmer. On the stage about 5C hotter than no stat. Switching fan on didnt seem to reduce temperature as effectively as previously.

My gut feeling is to go back to the Sud one.

Any thoughts? What do people do when racing?

rsfruitbat

[Veesix75]

No thermostat in mine

Tim

[KevJTD]

I do think there are different scenarios needed for racing and rallying.

first off, the role of the thermostat.
it is simply used to hold a volume of water inside the engine at a steady temperature, bleeding water out as it reaches the desired temp into the cooler radiator, steadily circulating things around.

in racing I can see how having no stat would be an advantage (to a point) in that the water is free to circulate back to the cooler rad without any obstruction.
sometimes though I feel that it could run too cool?
a motor running too cool is almost as bad as running too hot when it comes to being thrashed, although of course it's not as bad. there is though an optimal window

in racing when it's pretty much pedal to the metal a whole lot of the time then allowing the very hot water to escape quickly is a good thing

now in rallying there is a much wider variety of driving conditions, the road sections between stages for example

with no stat in at all the engine would cool down way below a "normal" temp i'd say?

now, a standard 'stat is set to open around 88 degs and keep that volume of water around that temp.
with a bit of spirited driving (eg on stage) though the flow could be restricted enough to make the temp creep up a bit above what the 'stat can control.

my own solution would be to retain the split housing but fit a 'stat that has a lower opening temperature range, eg an 82 deg one.
that way it keeps the engine at a better temp when on road sections than it is without one but also allows a bit more room when on stage.

something like this...most 'stats are of a similar dimension to be useable

http://www.ebay.co.uk/itm/261433714561? ... EBIDX%3AIT

[rsfruitbat]

Thanks Kev, veesix.

we dont do many multi-venues these days. Tends to be single venues with just queuing and then a stage, then service, repeat.

We are at llanbedr this weekend so I'll see how it goes there.

rsfruitbat