MSNZ and rearward facing bonnet vents

[strx7]

Best diagram ever... but the weight from the fan motor etc would defeat the purpose of the FG bonnet.

If air is blowing IN to the engine bay via a front facing vent, I'd have thought the air would get sucked out under the car, much like factory plastic covers were designed to do.

vents facing fowards like that generally help pressurise the engine bay meaning less airflow thru the radiator

[KinLoud]

Aha - thats fairly easy to deal with...

Radiator:
- block off gaps and holes that the air could flow through rather than going through the radiator.
- make a lip that goes below and forward from the radiator to help create a pressure difference between the front and rear of the radiator.
- electric fan is most efficient is behind radiator rather than in front
- yeah a good fitting undertray helps heaps in the same way as lip below radiator mentioned above

coolant:
- RACE DAY ONLY! replace coolant with plain water as it will transfer more heat! BUT it won't stop corrosion so put correct coolant back in afterwards to stop your alloy head turning into swiss cheese.
NOTE - this is really only a temporary fix!

Ken
Auck
021 408 863

[cat007]

coolant:
- RACE DAY ONLY! replace coolant with plain water as it will transfer more heat! BUT it won't stop corrosion so put correct coolant back in afterwards to stop your alloy head turning into swiss cheese.
NOTE - this is really only a temporary fix!

Coolant has the ability to raise the boiling point - so without it, you have the chance of boiling your cooling system....??

[fivebob]

Do you realise that your diagram shows the vent exit being placed in the high pressure area in front of the windscreen?

Even with a fan it probably won't be very efficient, without a fan the air may well flow back into the engine bay.

[Adoom]

Do you realise that your diagram shows the vent exit being placed in the high pressure area in front of the windscreen?

Even with a fan it probably won't be very efficient, without a fan the air may well flow back into the engine bay.

Its not to scale... In reality it would be quite far forward of the high pressure area at the base of the windscreen.

[Adoom]

Aha - thats fairly easy to deal with...

Radiator:
- block off gaps and holes that the air could flow through rather than going through the radiator.
- make a lip that goes below and forward from the radiator to help create a pressure difference between the front and rear of the radiator.
- electric fan is most efficient is behind radiator rather than in front
- yeah a good fitting undertray helps heaps in the same way as lip below radiator mentioned above

coolant:
- RACE DAY ONLY! replace coolant with plain water as it will transfer more heat! BUT it won't stop corrosion so put correct coolant back in afterwards to stop your alloy head turning into swiss cheese.
NOTE - this is really only a temporary fix!

Ken
Auck
021 408 863

I have two electric fans on the front. There is no room at the rear to fit anything. The rad cannot be any bigger. It takes up all the space.
Making an undertray is also on the list of things to do.
I 'think' I am getting overheating problems on the track because the IC is blocking off the airflow to the rad. I have bugger all space to move stuff around.

[strx7]

if you're having overheating problems, GO FASTER, it gets more airflow...

[darkwolf]

coolant:
- RACE DAY ONLY! replace coolant with plain water as it will transfer more heat! BUT it won't stop corrosion so put correct coolant back in afterwards to stop your alloy head turning into swiss cheese.
NOTE - this is really only a temporary fix!

Coolant has the ability to raise the boiling point - so without it, you have the chance of boiling your cooling system....??

I may be wrong here but the only reason that a water cooled system will boil is because of air in the water. A sealed system, like in your car for instance, should be fine.

/me prepares to be shot down.

EDIT: also note that water transfers heat better therefore the effects of air flowing past the radiator is greater than with (anti-freeze/boil) coolant in it.

[pc]

Cut a huge hole in the firewall in the passenger seat area and another huge hole on the rear hatch of the car. create a really large alloy tunnel between the two.
high pressure area at the front, low pressure area at the back, lots of air flow through the engine bay, no extra drag

[Malcolm]

I may be wrong here but the only reason that a water cooled system will boil is because of air in the water. A sealed system, like in your car for instance, should be fine.

/me prepares to be shot down.

EDIT: also note that water transfers heat better therefore the effects of air flowing past the radiator is greater than with (anti-freeze/boil) coolant in it.

Ask, and you shall recieve! The presence of air does not affect the ability of water in a cooling system to vapourise. What a sealed system does do is to allow you the pressurise the cooling system, which raises the boiling point of water. It just so happens that I'm studying for a thermodynamics exam tomorrow, and can tell you that the boiling temperature of water when pressurised to 1bar is just over 120 degrees. As the coolant temperature increases you increase the efficiency of the cooling system and the thermal efficiency of the engine - so you do have the option of pressurising the cooling system to the point that water wont boil - provided the engine is safe operating at the elevated temperature.

You're correct about anti-freeze typically reducing the effectiveness of a cooling system, however pure water is vulnerable to localised boiling around the cylinders, which reduces heat transfer from the cylinder to the coolant. This is why water wetter is often used in place of glycol, it improves wetting around cylinders (effective contact between cylinder and water) and inhibits corrosion which is also something that decreases performance of a cooling system when using pure water.

[matt dunn]

I 'think' I am getting overheating problems on the track because the IC is blocking off the airflow to the rad. I have bugger all space to move stuff around.

I know of personally at least 3 cars that had overheating problem directly caused by the intercooler in front of the radiator,

one was our focus. Fitted another better type of intercooler and the overheating was solved.

Also know another car with a 2JZGTE that overheated after 4 laps of qualifying,
removed the intercooler and put a piece of ally pipe in it's place and it finished the 3 hour race.


How much gap between the radiator and intercooler?

[Adoom]

I 'think' I am getting overheating problems on the track because the IC is blocking off the airflow to the rad. I have bugger all space to move stuff around.

I know of personally at least 3 cars that had overheating problem directly caused by the intercooler in front of the radiator,

one was our focus. Fitted another better type of intercooler and the overheating was solved.

Also know another car with a 2JZGTE that overheated after 4 laps of qualifying,
removed the intercooler and put a piece of ally pipe in it's place and it finished the 3 hour race.


How much gap between the radiator and intercooler?

Bugger all... maybe 10-15mm of gap then 60mm of plastic fan before the radiator.
If I cut some stuff and modify my IC piping I might be able to move the IC forwards a couple cm.
If I extend the top radiator support brackets I can tilt the top of the radiator back a little, because the clearance problem is at the bottom, off the crank pulley.
But the IC sits at the bottom of the radiator, moving it up would be hard because of limited space to run the IC piping.

[~SlideWays~]

Reckon you should put a line of 2" ish air holes in the bumper for intercooler/radiator. Could even hide them behind the number plate for stealthy goodness.

[Leon]

Find low pressure area. Make holes. Mesh holes. Profit.

[darkwolf]

How well would a cooling panel perform if you placed it between radiator and front bar? It should at least cool the radiator more efficiently than letting all that air come over the top of it.

Or alternatively replacing the radiator with a thicker core and as you suggested mounting it on an angle. Possibly run two radiators on either side of the IC on a horizontal angle (don't know how well this would work as I'm an accountant not an engineer)

[Adoom]

How well would a cooling panel perform if you placed it between radiator and front bar? It should at least cool the radiator more efficiently than letting all that air come over the top of it.

Or alternatively replacing the radiator with a thicker core and as you suggested mounting it on an angle. Possibly run two radiators on either side of the IC on a horizontal angle (don't know how well this would work as I'm an accountant not an engineer)

Front bar? WTF is a front bar? Do you mean the intercooler?
Cooling panel? WTF is one of those? Do you mean some sort of shield to stop the air going around the rad?

The core is already 40mm thick. Its a xflow radiator. Water goes in the top right, across the top of the rad, down the left side, across the bottom and out the bottom right.
When I said mount the radiator on an angle, I meant I can tilt it back maybe 30mm before it hits something.
I cant quite picture a horizontal angle...... there is no room to move stuff more than a few cm.

[~SlideWays~]

I think he's meaning a plastic/alloy horizontal panel from bottom of radiator to front bumper (crossmember maybe...can't picture under your car) and/or another panel from top of radiator to some other mounting point to create a high pressure area... or basically stopping air going under and over the radiator.

From memory your radiator is placed way back and the air will probably go around the side, top and bottom rather than through. I had the same problem with my half sized one, so made some panels to force air through it.

[Adoom]

I think he's meaning a plastic/alloy horizontal panel from bottom of radiator to front bumper (crossmember maybe...can't picture under your car) and/or another panel from top of radiator to some other mounting point to create a high pressure area... or basically stopping air going under and over the radiator.

From memory your radiator is placed way back and the air will probably go around the side, top and bottom rather than through. I had the same problem with my half sized one, so made some panels to force air through it.

Geeez Gav. Do some work or something

[~SlideWays~]

I think he's meaning a plastic/alloy horizontal panel from bottom of radiator to front bumper (crossmember maybe...can't picture under your car) and/or another panel from top of radiator to some other mounting point to create a high pressure area... or basically stopping air going under and over the radiator.

From memory your radiator is placed way back and the air will probably go around the side, top and bottom rather than through. I had the same problem with my half sized one, so made some panels to force air through it.

Geeez Gav. Do some work or something

Bah...

[Adoom]

Oooooh ohh oohhh I can use my new plasma cutter to cut the alloy sheild thingies!!!