In preparation for a hike in power for my Striker I've been optomising the engine cooling. Not that I had any problems with the current 160BHP & 126 ft lbs but I'm expecting to increase power to say 250 BHP and 170 ft lbs.

So what sort of power figures are people running and cooling with a Polo rad or similar?

I would have fully vented the rad to the outside in the nose cone but there's not much room and would have meant a new custom rad.

I do however use Evans non-aqeuous coolant which I've used before on turbo cars where the engine bay has got extremely hot. Not expecting that sort of issue but its stable and eliminates hot spots in the cylinder head better than a water mix.

Once the air passes through the front grill it will be very hard to flow anywhere except through the intercooler and rad. Can you go too far?

I believe there are a few westfields with vauxhall XE 16v in with 250hp ish and polo rads.

Mine is 200hp/168lbft with polo rad and temp never comes up high. In fact you have to sit in traffic for a good 15-20 mins stationary before the fan even cuts in.

Ned has a bit more power and an Xe engine with polo rad.

Running 220bhp, 170lb/ft xe, only been on rolling road but was quite happy with just the polo rad all day long.

Ned.

[Edited on 31/5/07 by ned]

Its not obvious which one you have there but I think there are two thicknesses of "polo" rad, the thicker was actually fitted in a golf and is about 25% thicker due to an extra core.

Mines the 1.0 polo one, not the golfy one, think neds is the same as mine

Thanks for the replies, I'm more confident now about the cooling capacity. I can't imagine the rad could be much thinner and still flow any coolant!

The intercooler may reduce the radiator efficiency hence the effort to channel air through both.

im on 240/250bhp with polo rad on duratec but ive also got flared sides on the tub.its got oil cooler and dry sump .you do seem to have a lot going on in the nose cone why not fit a vent in top of nose or duct some air somehow to oil cooler .dont know what your body vents are like but youll have a lot of heat in engine bay and the only way out is down the trans tunnel

The caterham superlight duratec that we are racing this year has a pretty crude extra vant in the nose ducted into the oil cooler and then back out at the rear of the nose with a gurney ahead of it to pull the air through.

I'm twin turboing my R V8 and sort of hoping it'll be ok with Polo rad

ATB

Simon

[Edited on 31/5/07 by Simon]

hi,

my zetec is about normal power, but i was worried about cooling- mounted the rad at 45 degrees- top edge forward and made a duct out of large curved sheet of ali, which ducts the hot air up and out of a hole in the nose cone- fan never seems to have to come on

les

I dont think the rad size is important, its the fan size.

I have a 2.0i pinto and micra rad. With the micra fan the cooling was a bit marginal, getting nervously hot when in traffic, so I fitted a Peugeot 406 dturbo fan. When the engine is dangerously hot, I use the manual override on the fan and can cool the engine down to well below normal in less than 60 secs

Fan is important in traffic, but rad size is important when on the move!

If the rad is too small, the symptom is getting hot when on full throttle for long periods at speed.

The rolling road is the hardest on any cooling setup, and rest assured if Ned's 220hp XE was ok on the rollers then the polo rad will be fine for road use to over 250hp.

Thanks for all the suggestions.

The Striker nose cone is tiny and the bonnet protrudes in to the top part as well. Which made inserting an upper vent a little trickey. I played with several angles on the rad but again the nose cone doesn't have enough room for the square Polo rad to move much further forward than where it is now.

The Mocal cooler is actually now the Rotrex oil cooler so the demand isn't so high but I will monitor the temps on the rollers when I connect the Rotrex up. I've fitted a Ford diesel oil/water on the block and this has worked brilliantly in pre-warming the oil and cooling on the rollers when the air flow was limited.



[Edited on 1/6/07 by bimbleuk]

For the record my engine managed 267BHP and 195 lb ft on the rollers. So far apart from the average temp sitting 4 to 5 deg C higher the rad does seem to have the capacity to remove the heat under power. The Polo rad fan switch however decided it was time to expire so I'm using the ECU to control the fan instead.

you talk about optimising the cooling yet have the long bracket wit hthe big holes obscuring the bottom part of the rad - a redesign of the bracket should see that none of the rad is covered.

as they say, every little helps.

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Originally posted by bimbleuk




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bimbleuk - 20/6/07 at 03:01 PM

You have a keen eye there but the picture doesn't quite tell the whole story. There is an inch gap behind that cross bar and plenty of pressure from the air in front to make use of the whole rad face.

However there are two rows below the bottom cowling which aren't directly in any airflow so I'll be sorting that next. Either from reducing the number plate or venting the botom of the nose cone.

Any comments are always welcome though

Sod it I'm going to invest in a Magnehelic gauge (measures pressure differences) and do some proper testing!

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