Cooling fans...

[neal1980]

I have a turbocharged rover v8 4.6. I have a decent sized rad and I have fitted 2 spal cooling fans 12" each doing 2250m3/hr much better than the stock TVR fans.

The engine runs fine on the road but when I went drag racing a few saturdays ago in that really hot weather it struggled to bring it down. It would maintain the temp but not bring it down. So as I was only doing short runs it kept getting hotter and hotter.

I have a FMIC in the way as well now but this has a gap around 3-4" from the rad.

I cant find any fans that have a much higher m3/hr any idears??

Really dont want to move/lose the intercooler as I see no problems on the road.

Thanks

[stevieturbo]

Without seeing, cannot say. But as has been stated over and over again here..

Ensure the fans are either mounted tight to the core, or mounted and the airflow ducted through as much of the core as possible.

Fans are pointless if air just gets blown around the radiator and not through it.

And likewise in general. If hot engine compartment air is able to find it's way to the front of the rad, you're always fighting a losing battle. The entire core must be sealed from re-circulating hot air.

And the above assumes you actually have the best and most efficient core you can fit in.
And that the actual cooling system is able to work. ie adequate water quantity and proper header tank arrangement

[Incorrigible]

Agree with getting the air out, I suspect that a lot of hot air is hanging around in the engine bay. The later Chims had vents in the bonnet, which may help

The easy way to test this would be to measure the time taken between the fans coming on and off (assuming it's running a standard type of fan switch) with the bonnet open and closed.

If that makes a substantial difference then raising the bonnet by an inch at the back would help enormously

[seagrey]

I spotted a twin turbo v6 kit car a while back which had the engine bay fans from an old MR2 fitted next to the manifolds with a length of large bore ducting fixed to the cowling and running back down under the car,presumably to bring the under bonnet temps down,seems to work for rear engined stuff.

[neal1980]

I think you are spot on there...

I cut a large bonnet vent out yesterday / today and added an old spal fan underneath which sucks the hot air out. The temp goes right down to 79degree now so it must of been all the hot air hanging around trapped under the bonnet.

Thanks for the help peeps

[The Rustman]

Top tips above looks like you may have it sorted

It can also help to remove the fan switch from the radiator core ( if its there) and put an adjustable fan switch at the top hose outlet as near to the engine as possible. Revotec do various sizes of in line adaptors and an electronic switch for about 50 quid. This gives the fans a bit of advanced warning of the heat that's going to hit the radiator. You can adjust the fan to come on sooner as well.

[WokingWedger]

Incorrigible said:

The later Chims had vents in the bonnet

Dont they all have vents ?