Scottish Elises

Heard about this before as it gives a much higher boiling point but thought the reduced thermal capacity outweighed the advantage? This says its actually better at heat transfer than water??

http://www.evanscoolants.co.uk/all-perf ... ducts.html

Surely this would be a big advantage to a K?
Craig.

Hmm, I can't help thinking this is a bit rubbish your water doesn't turn to steam as it's under pressure. Even when it's running at 120 degree's and your engine is verging on dead the coolant is still liquid. I am not sure what pressure the coolant system runs at the the corrisponding boiling point of the coolant is so I can't be sure.

What do the F1 teams use ? money is almost no object and heat transfer will be the most important thing for them.

Yeah Im struggling to see the advantage myself but have a couple friends with Evos that are using this. The company admit you may get a small increase in running temp but is it an issue. I guess the idea is you may get small hot pockets on any engine which could introduce lots of small bubbles? Maybe it reduces the likelihood of cavitation from the water pump? Anyway thought it might be interesting.
Craig.

I would be very wary of anything that changed the viscosity of the coolant - I haven't looked at this stuff in detail so not sure if relevant, but on the elise the balance between the bypass and the rad loop is quite important and anything that reduces flow through the rad might give you problems on idle, especially on the S2.

Cheers,
Robin

I like the sound of that, I've heard of water wetter before but not this. Think I'll try it in the MX bike as it overheats regularly (bad design and me not going fast enough).

My initial concern with anything like this is you would be using it on cooling systems which has been designed for water and all its properties...

Also isn't boiling off a bit of a safety feature?
If your coolant boils off it takes loads of heat with it hopefully cooling the engine for long enough for you to notice and park it?

If your cooling system is working in the first place then why mess?

They used this on one of the Wheeler Dealer restorations. Ed thought it was the Dogs B#ll#cks, especially in old cars which are prone to overheating.

IIRC the main advantages were more efficient heat transfer and the lack of steam means no pressure in the system (other that from pumping around), which puts much less stress on the whole system and reduces the risk of leaks. The cost was about £60 for the particular car he was doing vs £10 for conventional coolant.

I don't think there was any requirement to replace the waterless coolant.

I was quite impressed with the principle, but you can't beat aircooled

Hmmm, I have heard that the coolant system must be fully flushed of old coolant and then completely dried of any existing water / water-based coolant (how easy this is, I'm not sure!), otherwise the remaining water will have an effect on cooling performance of new coolant / coolant system (predicatably)...

Seems alot of hassle for what is a bit of a sticking plaster solution...

If in doubt, break an egg into the system to stop leaks

Or use a turd of bars-seal

Pressure in the system doesn't come from steam it comes from water expansion (i.e. whilst it is still liquid water, not vapour/steam); unless this stuff is magic it too will expand when heated (despite not "boiling" to steam) and thus compress the air in the header tank. The pressure may be different but will still be there.

Cheers,
Robin

Must be some hogwarts action then, as one of the things they demonstrated on Wheeler Dealers was that you can run it up to temp, take the cap off the rad (in an old TR6) and it doesn't p*sh everywhere with the pressure. That was one of the benefits they said it had - didn't put the cooling system under pressure. Suspect, of course, what you say is true, but perhaps this expands meaningfully at a much higher temp than water + coolant.

Why does the Elise and variants run a pressurised system anyway - is it to reduce the required cooling system capacity (i.e. allow for a smaller radiator, piping, tank)? Or was it a requirement of the original K-Series engine?

Just wondered because obviously I've had other cars (MR2 as an example) that doesn't run a pressuried system, but has a generally similar cooling system / engine layout, and comparable temperatures (usual issues cooling a mid engine)?

Ross

The fountaining happens because the water boils when the pressure decreases (boiling point drops with pressure). This creates an explosion, effectively, as the coolant can boil all the way throughout the system, which causes rapid expansion of the coolant (to steam) and in turn evacuates the fluid/steam through wherever the path to atmospheric pressure is.

That doesn't mean the system isn't up to pressure even below boiling point.

If you run your engine up to 90C and remove the expansion tank cap (don't do this unless you're fcuk mad though) it won't fountain out at that point, but it will go "pshh".

The system is pressurised to make sure the coolant doesn't boil. It allows you to have >100C in local hot spots without forming vapour which will cause all sorts of circulation problems.

The only way to run non-pressurised is if you know the coolant will never reach 100C or you just don't care.

Cheers,
Robin

Shug wrote:Must be some hogwarts action then, as one of the things they demonstrated on Wheeler Dealers was that you can run it up to temp, take the cap off the rad (in an old TR6) and it doesn't p*sh everywhere with the pressure. That was one of the benefits they said it had - didn't put the cooling system under pressure. Suspect, of course, what you say is true, but perhaps this expands meaningfully at a much higher temp than water + coolant.

iirc... that system was impossible to get pressure into regardless because Edddd had left the cap off the header bottle.