Stock Elise /exige rad capabilities ?

[mighty kitten]

I wonder how the stock rad copes with higher power outputs ? I have an ongoing issue with my car that is sort of fixed by running an electruc pump at the front to keep the coolant flowing partly due to the rad being quite tall and bolt upright . I had a nose round some cars at a track day at cadwell last weekend and the stock item looks like it will fit and as its around 6 shorter height wise I can lay it back quite a bit giving the engine pump a much easier job . How do people go on with 400+ hp cars for cooling ? Tia

[randy]

Installed in an Elise the rad works very effectively. Don't assume you will get the same result in a different car though as the airflow characteristics through the rad have a more pronounced effect on cooling capability than anything.

Have you got pictures of your rad installed in your car? I've done a reasonable amount of work in this area so if you post up some more information I might be able to offer a few suggestions.

[mighty kitten]

Engine is in the back and the pipes are 32mm running down the tunnel with a Davies Craig pump on the rad inlet and control unit with sensor in the cylinder head . The issue is flow as it works perfectly on track days keeping temps to 90c no matter how hard it's driven but without the pump it just pushes water out of the header tank after you let it idle after a session . I've got room to bring the lower edge of the rad forward and down by a few inches and then lean it back to lower the inlet which is how the lotus rad sits from what I can see but a less tall rad would obviously lean back a lot further

[randy]

Unfortunately that photo doesn't tell me very much... Need to get an idea of flow paths both in and out and also how well the rad is sealed up.

That said, if you are staying cool on track then its not a rad size issue. Firstly, do you know what ignition advance you run at idle? Do you know the spec on the fan and does the airflow have an easy enough path for the fan to suck in cold and throw out hot?

Unless your water pump is goosed its unlikely to be that. A mechanical pump will flow more as the revs rise but there should be plenty enough flow at idle to keep the requisite water flow there. Given the pressure created by a mechanical pump, sitting the rad down will do sod all.

[mighty kitten]

Rad has top and bottom tanks so being vertical the engine pump has to push the water up to the top of the rad where the lotus sits a lot Lower in relation to the engine making the job a lot easier . Twin fans in a sealed shroud and I run an 82 degree stat in summer .

[randy]

mighty kitten said:

Rad has top and bottom tanks so being vertical the engine pump has to push the water up to the top of the rad where the lotus sits a lot Lower in relation to the engine making the job a lot easier . Twin fans in a sealed shroud and I run an 82 degree stat in summer .

That answers none of the questions. If you can take a number off the back of the fans you will most likely be able to dig out a spec, then you can get an idea of the flow rate at a given pressure drop. The fans might be shrouded but is the radiator? This is clearly a modified car... whats the ignition advance at idle?

Engine water pumps will move well over 100ltrs per minute against a good head pressure, gravity over 100mm of vertical height doesn't bother them too much.