This is an interesting post (referring to "rear radiator thread" http://forums.aussieveedubbers.com/viewtopic.php?tid=44693 - thread post has been split into it's own thread). I've just flicked through it all during lunch. Great to see the modelling Wes has done as well.

I've a 600x300 intercooler in my wing with twin 12" thermos under it. That works really well for intake temps, which generally get down to ambient air temps and have seen 14deg on a cool night in Darwin.

My radiator setup on the other hand 'sucks' to say the least. It is a V8 commodore radiator mounted vertically in the tilt front frame but has no ducting at all, relying on the thermo fan to draw air through. Problems are getting air in, then getting it out and not heating fuel etc through the process (which it does currently). Another problem with the tilt front setup is that whilst it looks cool it means I have no factory sheet metal to shroud off to. I also don't wish to go the easy route and put holes in the nose, I like the smooth look the car has. In the new year I will be reviewing design for a satisfactory design to suit my application - possibly in consultation with guru Wes (if he is interested).

There has been suggestion I should turn my wing into the radiator and use the current radiator setup for cooling of a water to air intercooler. It would no doubt work really well but I'm not overly keen to cut and modify what is there.

I'll post some pics up so you can see what not to do.

Cheers.

Post some pics Reub, and I'll have a think about things that may or may not work.

I don't know if it's possible, but you should try to drive around with your one piece front removed. If it still had issues then you've got some other problem (water pump, dunno). If that's the case then no amount of modifying the front will work.

Here are a few... You can see the 'temporary' scoops I've made witch do actually make a difference when driving.

Hi Reub

I'm still mazed out how well your car turned out.

I will put my 2 cents worth in. I agree holes in the front would spoil the cars look

You need duct it at the front so that the fan can only draw from a cool air source at the front of the car, also duct the hot air away under the car, maybe some ABS plastic or thin aluminium sheet for the front duct with a rubber edge so that it mates with the tilt front and only draws air from under the tilt front.

Now you probably have heated air swirling around and getting picked up by the fan again.

Wes idea about trying it without the front is good idea if you can drive it that way.

Steve

Reub, I take it your current radiator is less than 600 wide (core). If so then yes I agree a wider radiator is going to help. Clearly the shape of your front end suits ducts on the side, but your current radiator is too narrow to take advantage of this. Wider will definitely help there.

As Steve points out your main problem is probably recirculation. Your fan at the moment is probably just pulling the hot air from the back of the radiator around the sides and top and into the front of the radiator again. I imagine your front has swirling eddie currents of air flow behind it when your moving, this will only make the recirculation more of an issue. You basically need to make some shrouding to stop the air from being able to come around the radiator. You could do some tests with cardboard and a roll of duct tape. Just put shrouds from the top and sides of the radiator back to what's left of the body / under the fuel tank.

Thanks for posting more pics with the nose down (man I love that colour...lol).

As the car is 'low' ducting from the sides where the nose tapers was my idea as well as fully isolating the back of the radiator from the front so air can only be drawn/directed via the ducting. Sufficient shrouding of the fuel tank is also required as being aluminium it acts as a huge heat sink and on long drives you can imagine the heat of the fuel.

Yep...the current core is approx 450h x 530w.

you should check out some V8 supper cars they have neat radiator ductng, you dont want air going around the side or over the top of the radiator. you want to create a vacuum so all the iar is either pushed or sucked through the radiator core .

Hi

My old car with a turbo WBX only needed a very small inlet to run cool all the time. It didn't have the power output of your motor of course. But on the open road the temperature would drop form the ram air effect.

Getting the fans at the back will help give the incoming air a better shot.

Steve

My air inlet, this was aimed at the base of the radiator.

Hi Reub,
I agree with all the above, ducting and shrouding are the key. Try looking at late model Corvettes as they didn't have much of an intake on the body (if at all?). Would you consider running some custom horn grills ducted to the rad?
I'd also try and panel in the outlet, at least stop it getting up into the fuel tank and its surrounding volume.
Rich

Cool car Reub!

Like Ricola said, maybe you could install some original horn grills, like subaru boxer did : link to subaruboxers cooling thread
He directed the air trough the horn grills via tubing to the radiator.
I would paint them black or body color instead of chrome on your car.

And you could also do something like this:



If you cut out the red lines, it would hardly be noticeable, but will allow air flow to the radiator.

And shrouding the radiator is a must, imho.

Strangely, I''m starting on my radiator fit today...

I've always been told that fans will work better at drawing than pushing- but I don't have any figures that prove this.

I'm in two minds about shrouding the fans to the radiator in a front mounted, adequate airflow setup. At anymore than a slow pace there's more (potentially) natural flow than fan forced air. Provided the fan is tight up against the radiator I dont see the need for a rear shroud. My theory is that the rear shroud will be just making it harder for air to go through the core at speed- theres more resistance to it coming out thus higher pressure in front.

As far as ducting the air away from the rear, yes definetly need to divert it out and away from the tank. I'm hoping that diverting the hot air down and out behind the front wheels/under the car will be directing it into a low pressure area for a draw through affect as well.

Thats a awesome looking car- think your going to need some more airflow though...

Hi

If you look at some VW & Audi cars, at the have the rear of the radiator its shrouded around the fan, but part of the shroud is a rubber flap, when the car is at speed and the fans aren't working the rubber flaps open by the push of the air flow, but when fan is on, the rubber flaps get sucked onto the radiator surface so the air coming through the fan gets a concentrated pull and helps prevent recirculation.

Steve

Hi Reub,
my suggestions would be to look at the way corvettes are set up, also,
are you moving the hot air away from the back of the radiator ?
Do you have room to run any ducting from the front / inside of the brakes / wheels ?
i used to run some of the flexible ducting available from hardware stores on my turbo diesel hilux for colder intake & it worked very well... ( except for lots of people telling me something was hanging off under my car !! ) just a thought.
What about a thermo fan behind the radiator as well ?
Try talking to Norm at Aussie Desert Coolers in Victoria, he is full of knowledge & cooling solutions.
Noddy

firstly top effort on a bloody well turned out dub.

ok when i was looking at what options i had with my rad i looked at a lot of different options. From what i can see of ur set up there are two things u mite want to try before a major rework.

U need a shroud with ur thermo fan, at presant its cooling the area the fan covers while the outer areas are getting none plus if u make a scoop with it u will be sure of getting clean air rather than the dirty warm air ur system will be getting at presant. I know it doesnt seen like much but i am in the middle of making one for mine as a tempory one i made has proven a temp drop on highway driving.

the other thing u should try is a different rad, when i was looking at different ones for mine i had a brand new V8 commodore one and both of my local rad shops said that the ford ones cool better as the are a two band not three. The three bands(commodore) are thicker and dont cool as quickly as the thinner two bands. They restric the air flow slightly. A local here that does a lot of rallying used to have a three band in his sr20t powered datsun and when he changed the rad to the ford he said there was a 2-5 degree drop when he was out on full throttle racing.

and lastly i have to say UNREGESTERD!!!!!!!!! how could u? stuff renos,work,kids,family!!!!! get out and play!!!




steff.......

Quote:

Originally posted by reub-revhead Here are a few... You can see the 'temporary' scoops I've made witch do actually make a difference when driving.

The key is to separate the hot air from the cold by somehow isolating either the intake or exhaust air. You could build a plenum on the front of the radiator and route duct(s) to a high pressure area somewhat away from the radiator. You could go the other route and route the hot air to a remote low pressure area with a plenum and ducts. Since you're looking to reduce heating of your fuel tank this might be the way to go.

The reason to seek out high and low pressure areas is to reduce the need for the fan to run all the time to move air.

The ducts need to move a lot of air so they need to be relatively large.

hey reup just a thought about this issue and im not too sure exactly what types of room, things you have got in the way nor the actual air flow figures for what is required and the likes, butis there any way you could run a pick up scoop on the underside of the body behind the suspension and ducting your airflow to the front of the car at all?, so imagine a wrx intercooler scoop on the underside of your car forcing the airflow from there upto the rear of the radiator with a pair of thermos on the front pulling forward to the front of the car then run a pair of outlets to just behind your inlet scoop to make sure it doesnt suck the hot air back through the system, but up here the roads are bloody hot so then you will also have to take into consideration the heat coming straight off the bitumen. im sure somebody will point out blatant errors with this but you never know it might help somebody out by taking a different approach to a problem. i just thought that that way you could keep the extremely sexy lines of the car how they are at the moment and change the things that you cant see. another thing is there any benefit to runing dual rads up front so outlet of one into inlet of the other? iv seen that done on 4by4's that dont move very fast but rev quite high

Geez I would love to see the look on people's faces when you open the front up at petrol stations

or it sitting on the back wheels as it leaves the servo

Cheers all...i'll keep people updated when I eventually get around to it. Shame my car isn't priority at the moment... ah well. There are also other upgrades planned....power may be one of them

Reub,

Call me on 0416 115 993.

I tested several setups on a few bugs now and have realised that it is all about pressure. If the air pressure behind the radiator is not significantly less than in front then your rad will never work properly, not even with the fans going.

You need to shroud past the back of the radiator so the passing air can cause a low pressure area behind it.

Best eample of this is the black plastic tray on new cars. This makes sure the air travels past the front half of the engine bay thus causing a low pressure in the engine compartment and draws air through the condensor, rad and oil coolers.

They did a test on a wrx, and took off the black tray. the air rushed in directly behind the radiator and pressurised the engine bay. The tests showed that air was actually going backwards out the bonnet scoop and the car overheated.

Call me and i will show you what to do with your current set up.

matt

Ill post some more detailed photos of my new set up from a couple of different angles.

Reub, you do need to have the front of the radiator shrouded, so the air does not simply pass around it. The shroud then needs to continue passed the radiator on all sides to enable the faster air passing past and under the radiator to cause a low pressure behind it. Thus drawing the air through the radiator.
The front shroud should seal against the inside of the one piece front using rubber or foam stripping like you use under doors for example. Therefore any air ducted to the radiator cannot escape the front area.
Shrouding past the back of the radiator can be as short as 50mm although if its a bit deeper it will work better.

You do not need to get a new radiator, just tweak the sysytem you have. I will have a look at your photos and post again.

matt

yeah check out any Commodore - there is a black plastic 'spoiler' under the nose of all of them (especially prominent on the VN when looking from the front).

This is to help with cooling by causing a venturi effect under/through the engine bay

If you are old enough it's the same for the XU1Toranas - little chromey thingo under the front

Reub,
I aint no expert but can agree from trial and error with both Glenns (VWCOOL) and Matts last posts. I put a small lip under front to try and give that venturi effect and I have shrouded my radiator and filled gaps as best as possible.

Apart from the bullsh#t issues with tank expansion (now sorted) I found out today how better its working as I had my first longish freeway trip. Did not budge past 180F or 82C. Prior to this I found it stayed cooler at say 60-80km/h driving instead of the 110km/h freeway stuff as I am assuming air including the hot stuff was just blowing around everywhere and not escaping as it should.

My only access for air is a small opeing behind the number plate and a cut out in the bottom of the apron (Type 3). So I dont think your small access of air is so much the issue as you only have to look at how pathetic the air inlet is for some japanese cars.

Alright guys, I'm back to considering this problem....

Some serious consideration is being given to installation of a radiator in the wing and changing of the intercooler to a liquid to air setup retaining a small radiator up front and the waterlines through the car. The consideration with this is that there is no problem with airflow though the wing, however there may be consideration as to heat soak from the sun on the top face of the radiator.

There is definately no way that I will be putting holes in the nose of the car, however appropriate ducting etc is still a consideration as well.

I thought I'd put it up for some discussion..so feel free to add your expert (and not so expert) feedback.

Did you try out any of the ideas mentioned Reub? I'd say ducting in the front should be your first move, I wouldn't go swapping intercooler/radiator positions...

I wouldn't swap positions, I reckon you just need to put a little effort into getting the front set-up to work.

As has been said many times before , it's all in getting fresh air through the radiator NOT resurculated air .
I would try and piece together a fibreglass shroad that fully covers the front of the radiator in a wedge shape so that the higher it gets where the air presure is at its lowest it is closer to the radiator and as big as possible at the bottom .
And of coarse of the bottom front side of this mount your intake scoops fully sealed in to the cowl / shrowd .
Its hard to see from the photo's and not having seen the car live for many years , is it at all possible to also make a similar shroad for the rear of the radiator , with much bigger oulets A MUST and dump the wasted air behind the front wheels .

Although all the above sounds difficult , i'mm thinking it's got to be simpler than relocating