Race car ventilation
Discussion
Wondering what people do in this regard...pictures would be great.
I have a Clio Cup car with lexan all round, it has the Cup roof scoop (vent for passenger and driver) and a small flap in the drivers window.
There's no heater/fan (and I don't want one ideally...want to keep weight to a minimum and try natural flow solutions) and currently no other holes in the cabin, including to the engine bay.
I've seen a lot of cars with circular holes in the rear screens and 1/4 screens and small swivel perspex ducts for the windows aswell. Any advise on where these holes should be and why?
I've only just fitted the roof scoop due to it being unbearable with the recent heatwave, at one point I clocked 46deg in the car :O
I have a Clio Cup car with lexan all round, it has the Cup roof scoop (vent for passenger and driver) and a small flap in the drivers window.
There's no heater/fan (and I don't want one ideally...want to keep weight to a minimum and try natural flow solutions) and currently no other holes in the cabin, including to the engine bay.
I've seen a lot of cars with circular holes in the rear screens and 1/4 screens and small swivel perspex ducts for the windows aswell. Any advise on where these holes should be and why?
I've only just fitted the roof scoop due to it being unbearable with the recent heatwave, at one point I clocked 46deg in the car :O
The holes on the rear screen of the Ginetta G50's were there because they kept blowing out because wind got in the cabin and had nowhere to go, blowing out the rear screen iirc one nearly took of a marshalls head at Mallory when they first got delivered!!! don't know any more constructive reasons though im afraid
I would of thought the small holes just want to be in an area of negative pressure so the further rearward the better but probably not on the back screen as a clio will probably end up sucking the exhaust gases in so maybe just behind the B pillar? Then you'll want to create somewhere to allow air in at the front. I don't know how stripped the Clio cups are but could you open the area for the wipers and duct into the cabin from there(might be a little warm though from engine)? Maybe run a duct from the front bumper into the cabin like people do but to cool the brakes? It'll create more drag but the lower it is on the front bumper the cooler it should be and with the holes in the rear quarter glass should help a chunk whilst moving.
Thanks guys. Makes sense. Does anyone use the perspex window vents? The domed ones that can be rotated? So if I make a few holes in the rear 1/4 windows following the curve of the window vertically will that be enough to promote a flow of air from the roof scoop?
The front ducts where the fogs were are feeding the brakes and the passenger headlight is feeding the air intake.
The front ducts where the fogs were are feeding the brakes and the passenger headlight is feeding the air intake.
Race cars are hot, that's just the way it is. I wouldn't have removed the heater though as you'll need it to demist the windscreen when the weather turns. The scrutineers will check for it too.
Last weekend at Rockingham I had to run with the heater on full blast to stop the car overheating... It's not racing unless I get some heat stroke at some point in the year!
I run with a window net so I can open the windows. There's nothing wrong with opening the windows as long as they are only open a couple of inches.
Last weekend at Rockingham I had to run with the heater on full blast to stop the car overheating... It's not racing unless I get some heat stroke at some point in the year!
I run with a window net so I can open the windows. There's nothing wrong with opening the windows as long as they are only open a couple of inches.
Edited by bozla on Saturday 20th July 11:56
Have a look at mk1 SEAT Leon cup cars, they had a NACA duct at the back of the bonnet with flexible tubing through into the cabin.
I guess they used the pollen filter 'hole' to feed the pipework.
http://www.google.co.uk/search?q=leon+cupra+cup&am...
I can't find a picture of the pipework now, the picture I knew of (nerd moment) is now a dead link.
I guess they used the pollen filter 'hole' to feed the pipework.
http://www.google.co.uk/search?q=leon+cupra+cup&am...
I can't find a picture of the pipework now, the picture I knew of (nerd moment) is now a dead link.
Don't delete the aircon!!
I learnt my lessons after building several competition cars, last car I built I left the AC in & its possibly the best thing I ever did.
Most AC systems cut the compressor under full load anyway so in reality you are not loosing power under load, the pump cuts in under deceleration again.
I learnt my lessons after building several competition cars, last car I built I left the AC in & its possibly the best thing I ever did.
Most AC systems cut the compressor under full load anyway so in reality you are not loosing power under load, the pump cuts in under deceleration again.
Have you considered a cool shirt set up? We use on the in Golf since summer temps where we race can be very high (still 90˚F at midnight in a 24 hour race last year) and I found it brilliant. It really is one less thing to have to worry about, and you really notice it at the end of a stint.
cptsideways said:
Don't delete the aircon!!
I learnt my lessons after building several competition cars, last car I built I left the AC in & its possibly the best thing I ever did.
Most AC systems cut the compressor under full load anyway so in reality you are not loosing power under load, the pump cuts in under deceleration again.
This. Several friends have asked me for advice when building a track car, ignored me and then said they wished they hadn't later on...I learnt my lessons after building several competition cars, last car I built I left the AC in & its possibly the best thing I ever did.
Most AC systems cut the compressor under full load anyway so in reality you are not loosing power under load, the pump cuts in under deceleration again.
It's true about the a/c being only a tiny drag on power and economy. All GTE and most GT3 cars have it and I cannot see any sign of performance loss in the data. If there is any performance loss it's more than outweighed by the improved reactions and alertness of the driver. But it's true that there will be a small loss and on a Clio Cup you probably need every last horsepower. In DTM they remove the alternator belts for qualifying to liberate the last 0.5bhp, which is a trifle extreme.
It's crazy not to have a fan in a racecar at all. You need something for wet races (especially under safety cars, when airflow is minimal) and any extra flow is a bonus on hot days.
Be a little bit careful with entry duct positioning. What can happen (and I've seen happen more than once) is that the lovely warm air from the brakes and engine bay goes straight into the carefully positioned scoops and turns the cockpit into a fan oven...
It's crazy not to have a fan in a racecar at all. You need something for wet races (especially under safety cars, when airflow is minimal) and any extra flow is a bonus on hot days.
Be a little bit careful with entry duct positioning. What can happen (and I've seen happen more than once) is that the lovely warm air from the brakes and engine bay goes straight into the carefully positioned scoops and turns the cockpit into a fan oven...
Thanks guys. Its a Clio Cup so ac was never an option (id still have removed it!). I have a 19 row oil cooler and large alloy rad so I would hope that temps for the engine wont be an issue (havent before).
Is it worth fitting a 12v fan to the dash? Or maybe psu fans to the roof scoop vents?
For the naca ducts where should I fit them in the windows and do you just run ducting to point at the driver?
Is it worth fitting a 12v fan to the dash? Or maybe psu fans to the roof scoop vents?
For the naca ducts where should I fit them in the windows and do you just run ducting to point at the driver?
Dr JonboyG said:
Have you considered a cool shirt set up? We use on the in Golf since summer temps where we race can be very high (still 90˚F at midnight in a 24 hour race last year) and I found it brilliant. It really is one less thing to have to worry about, and you really notice it at the end of a stint.
This. It just depends on whether your car's under the weight limit or not, because the key consideration with the cool shirt is having a 20kg coolbox for a passenger..A few Vantage GT4 drivers use them, but that's dead easy because those cars already have a lead weight bolted into the passenger side, take that out and replace with the coolbox! If the Clio Cup is already at the weight limit, then you're probably better off with installing fans on your inlet ducts and hoping for the best.
I do agree with those saying you need a fan and heater, even if only for wet races and formation/safety car airflow, and suggest the cool shirt in addition!
nightSpirit said:
Thanks guys. Its a Clio Cup so ac was never an option (id still have removed it!). I have a 19 row oil cooler and large alloy rad so I would hope that temps for the engine wont be an issue (havent before).
Is it worth fitting a 12v fan to the dash? Or maybe psu fans to the roof scoop vents?
For the naca ducts where should I fit them in the windows and do you just run ducting to point at the driver?
The best flow for a duct is going to be without any bends in it at all - the Seat idea mentioned above of using one on the bonnet which would ram air into the car at a very satisfactory rate is a particularly neat solution. Presumably you have a hole in the bulkhead where the blower used to be, could you run some pipes through there?Is it worth fitting a 12v fan to the dash? Or maybe psu fans to the roof scoop vents?
For the naca ducts where should I fit them in the windows and do you just run ducting to point at the driver?
cptsideways said:
Don't delete the aircon!!
I learnt my lessons after building several competition cars, last car I built I left the AC in & its possibly the best thing I ever did.
Most AC systems cut the compressor under full load anyway so in reality you are not loosing power under load, the pump cuts in under deceleration again.
OP, I know it isn't an option for you, and I know this does not help you, but I had to chip in & agree 100% with this statement.I learnt my lessons after building several competition cars, last car I built I left the AC in & its possibly the best thing I ever did.
Most AC systems cut the compressor under full load anyway so in reality you are not loosing power under load, the pump cuts in under deceleration again.
I have an e36 track day car, this is my second & the first I removed the AC, this one I left in.
RIGHT CHOICE!
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