I use the QED 78 degree stat. My car runs at between 77 - 80 degrees even during the 45 minute race at a very hot Snetterton.
I agree with you on the AC rad comment, I think it does block the coolant rad.
Sean…
- the jiggle valve isn’t essential with PRRT: on the MGTF and Freelander new circuits it has been deleted, I keep them on mine. As long as the valve works, it is marginally better to leave it on, but if it doesn’t it is a lot better not to have it!
- never noticed any significative difference between different stats regarding coolant level.
Nice one, Simon
For your information the K is at it’s most efficient for power at 73 deg.
may I ask where (read: in which exact point) should you see 73 deg.?
Finally it’s PRT not PRRT.
well… it’s PRRT as long as it’s Rover…
if yours is Another thermostat, the acronym has to change to…
The temps for running an engine are always measured as the coolent leaves the engine - ie at the coolant elbow.
I hope you’re aware a single point measurement in the coolant circuit doesn’t tell much about the engine real temperature… you can have 79 deg on the engine outlet either with 40 deg (and little coolant flow) on cyl #1 or 75 deg on the same cylinder under a much more serious flow.
I shall then repeat relevant temperatures should be measured inside the combustion chamber.
Increasing the coolant flow you can have a cooler engine even with higher water temps, reducing the gradient inside the engine as well.
But you have to measure the temp of the coolant somewhere, and that should be the same place for everyone. I think everyone is aware that the coolant will vary in temperature as it passes through the engine.
Sean…
But you have to measure the temp of the coolant somewhere, and that should be the same place for everyone. I think everyone is aware that the coolant will vary in temperature as it passes through the engine.
Sean…
agree. my point is you can’t simply talk about an “ideal” temperature, as this is just half of the story… without flow details it is (almost) pointless.
This is also relevant for those obsessed with constant temp readings: they are simply barking at the wrong tree.
However in terms of what the engine does at what temp, the PCD department found that the engine gave best power with the coolant measuring 73 deg at the elbow, regardless of what the engine was doing inside or anywhere else in the circuit. given a standard water pump, and there was a loss of about 3/4 bhp when the engine ran at 88 deg.
Interestingly, on an “average” system (i.e. standard thermostat and without a huge, super efficient rad) to achieve 73 deg on the outlet you need a fairly open stat, as the rad is a lot less efficient with those temps. This in itself does give some power gains, both for a more free-flowing pump and a smaller gradient inside the engine.
With a Pressure Relief Rover Thermostat (see the acronym) you can have the same gains also with a bigger rad and higher temperatures.
.
Simon do you know the part no for the grey 78oC stat?.
Interesting thread…
Dave
Your right David, very!
If only you could have talked about this a month ago.
2 weeks ago I bought a QED remote stat with the 82 in it.
Have I wasted my money? Should I have bought a PRRT???
Depends on how much you paid really. I went for the PRRT stat as you cant use any other remote stat with air con, but considering the rover stat is only �58 its probably the cheapest. How much is the QED stat and where does it fit into the cooling system?.
�155. Just trying to work out where it fits, i’m guessing in the hose out of the head near the temp sender. Does anyone know where to fit the other bit??? it says in to fit it in the hose to the header tank but theres two hoses it could go in and I can’t work out which on to put it in. (By the way I don’t have air con)