Baffling radiator question
Discussion
Has anyone experience or experimented with baffling or shrouding around the radiator to make sure all the air goes through the radiator (not round the sides or over the top)? This would also stop hot air from the engine area zipping over the top of the radiator and getting blown back through. On my Seven this baffling was essential to make the radiator work but I have not seen any comments about this for TVR's. I am particularly interested in any baffling that has been tried between the top of the radiator and the bonnet (hood).
My M has an aftermarket radiator so I do not know how well a standard radiator is shrouded to prevent air taking short cuts but I don't think I have ever seen anything to close off the gap over the top of the radiator. On my car overheating only wants to happen on a very hot day when stuck in near stationary traffic. Once moving enough air goes through the radiator to keep my car cool on the hottest of days. Is this typical or do some "M"'s overheat when moving?
My M has an aftermarket radiator so I do not know how well a standard radiator is shrouded to prevent air taking short cuts but I don't think I have ever seen anything to close off the gap over the top of the radiator. On my car overheating only wants to happen on a very hot day when stuck in near stationary traffic. Once moving enough air goes through the radiator to keep my car cool on the hottest of days. Is this typical or do some "M"'s overheat when moving?
John,
I take it you are talking about your M with a 5 litre engine, if so cooling is going to be a much bigger task than for the standard 3 litre lump. What type of cooling fans have you installed. High power Bike fans are smaller and far neater and you can mount 2 side by side and seem to be far more efficient than the larger car type. I picked up a pair of bike fans on ebay almost new for £13 sterling for the 1600M. Rather an overkill but at least it will not overheat.
I take it you are talking about your M with a 5 litre engine, if so cooling is going to be a much bigger task than for the standard 3 litre lump. What type of cooling fans have you installed. High power Bike fans are smaller and far neater and you can mount 2 side by side and seem to be far more efficient than the larger car type. I picked up a pair of bike fans on ebay almost new for £13 sterling for the 1600M. Rather an overkill but at least it will not overheat.
pumpkin
If you shroud over the top of the radiator coming forward to the bonnet you may generate lift at speed which will definitely not be desirable!
Has your bonnet got any vents towards the rear, if not I would recommend putting an SE style vent in the bonnet, this is very discreet, I had one on my much modified Taimar, and it enabled at low speed and stationary somewhere for the hot air to go, other wise it tends to remain trapped towards the back of the engine bay (hot air rises!)
With the vent and with the fans on, you could feel the hot air passing up the windscreen on hot days by putting your hand through the sunroof! so it definitely worked.
I beleive that M series cars overheat as the hot air has nowhwere to go with the standard bonnet.
Hope that helps
davidy
If you shroud over the top of the radiator coming forward to the bonnet you may generate lift at speed which will definitely not be desirable!
Has your bonnet got any vents towards the rear, if not I would recommend putting an SE style vent in the bonnet, this is very discreet, I had one on my much modified Taimar, and it enabled at low speed and stationary somewhere for the hot air to go, other wise it tends to remain trapped towards the back of the engine bay (hot air rises!)
With the vent and with the fans on, you could feel the hot air passing up the windscreen on hot days by putting your hand through the sunroof! so it definitely worked.
I beleive that M series cars overheat as the hot air has nowhwere to go with the standard bonnet.
Hope that helps
davidy
Edited by DavidY on Thursday 30th April 00:17
The main thing is to stop hot air from the back of the rad from recirculating back to the front when it's stationary, but it does help to have the high pressure side of the rad sealed to maximise the ram air flow too. It was quite tricky to do on the V8S because of the way the whole front of the car hinges forwards.
Thanks for the comments.
I do not see how blocking the gap between the top of the radiator and bottom of the bonnet is going to generate lift at speed.
Any overheating problems I had were when stoped in traffic on very hot days. Sometimes I had to turn off the A/C! I can see that hot air blown through the radiator will tend to return forwards over the top of the radiator and will not be vey good at cooling the next time it is blown through. Bonnet vents seem rather small compared to the quantity of air blown through the radiator.
Has no-one tried to block or partly block this area between the bonnet and radiator top? I think there is quite a lot of space over the radiator. (I cannot check because mine is not yet back in one piece following a crash)
I do not see how blocking the gap between the top of the radiator and bottom of the bonnet is going to generate lift at speed.
Any overheating problems I had were when stoped in traffic on very hot days. Sometimes I had to turn off the A/C! I can see that hot air blown through the radiator will tend to return forwards over the top of the radiator and will not be vey good at cooling the next time it is blown through. Bonnet vents seem rather small compared to the quantity of air blown through the radiator.
Has no-one tried to block or partly block this area between the bonnet and radiator top? I think there is quite a lot of space over the radiator. (I cannot check because mine is not yet back in one piece following a crash)
I have a factory made fibreglass panel as fitted to early cars which does exactly that. If i knew how I,d put a pic on. Works very well and looks the part.
In fact i think I have a spare one in the loft, suppose i could mould some if there was enough demand.
In fact i think I have a spare one in the loft, suppose i could mould some if there was enough demand.
Edited by thegamekeeper on Thursday 30th April 14:17
If you put a vertical panel, then you will probably create a lot of turbulence, and possibly actually reduce the amount of air pass through the radiator
If you guide the air twords the radiator, ie your panel goes from the top of the radiator towards the top of the front opening of the bonnet then you will create lift. This only will apply to the low radiator though, with the later tall one you will be ok.
You can prove this by making a dummy model with a leightweight cardbaord box and blowing into it or using a small fan. Cut a hole in the centre of the bottom of the box to simulate the radiator. If you now stick another bit of cardboard from your radiator top to the corresponding outer edge of the box, and blow/use a fan you will see the box try to lift.
If you have a taller radiator then none of this applies!
davidy
If you guide the air twords the radiator, ie your panel goes from the top of the radiator towards the top of the front opening of the bonnet then you will create lift. This only will apply to the low radiator though, with the later tall one you will be ok.
You can prove this by making a dummy model with a leightweight cardbaord box and blowing into it or using a small fan. Cut a hole in the centre of the bottom of the box to simulate the radiator. If you now stick another bit of cardboard from your radiator top to the corresponding outer edge of the box, and blow/use a fan you will see the box try to lift.
If you have a taller radiator then none of this applies!
davidy
Ah, I had forgotten the angled radiator with the spare tyre. I have an aftermarket vertical radiator. I would not have thought anything under the hood made much difference to the aerodynamics of the car in terms of lift or drag because the quantity of air flowing through the grill and under the hood is quite small. (Not tallking about the airflow under the car here. That is a subject for a whole new discussion)
I still think that ensuring that the all air that goes through the radiator is fresh from the front of the car and not recycled is a good idea and if the ram air coming in the front when the car is moving is all directed through the radiator then some of the cooling problems that are often reported might go away. When I get my car back I might do some before and after tests with blocking the sides and top. It should keep the whole engine compartment cooler.
I still think that ensuring that the all air that goes through the radiator is fresh from the front of the car and not recycled is a good idea and if the ram air coming in the front when the car is moving is all directed through the radiator then some of the cooling problems that are often reported might go away. When I get my car back I might do some before and after tests with blocking the sides and top. It should keep the whole engine compartment cooler.
thegamekeeper said:
I have a factory made fibreglass panel as fitted to early cars which does exactly that. If i knew how I,d put a pic on. Works very well and looks the part.
In fact i think I have a spare one in the loft, suppose i could mould some if there was enough demand.
Is it like the one that's on my 3000M project, forms a tray to sit the spare on too:-In fact i think I have a spare one in the loft, suppose i could mould some if there was enough demand.
Edited by thegamekeeper on Thursday 30th April 14:17
These are intended to draw the air back through the radiator from the fan on the engine. Not sure it'll do anything with electric fans mounted on the rad though?
Paul
pumpkin
Later radiator you should be fine guiding the air through the radiator. If you are into experimenting, I would try raising the bonnet slightly at the rear (you can do this by packing out the mounts) to leave a small gap, this will then tell you whether a vent at the rear of the bonnet would be useful.
My much modfied Taimar with the low radiator (Adrian Venn Special) and a vent always ran at decent temperatures even on hot days and under a lot of load (track days). Even after serious abuse follwed by a stop, the fans would kick in and remove the hot air from under the bonnet through the vent.
Best of luck
davidy
Later radiator you should be fine guiding the air through the radiator. If you are into experimenting, I would try raising the bonnet slightly at the rear (you can do this by packing out the mounts) to leave a small gap, this will then tell you whether a vent at the rear of the bonnet would be useful.
My much modfied Taimar with the low radiator (Adrian Venn Special) and a vent always ran at decent temperatures even on hot days and under a lot of load (track days). Even after serious abuse follwed by a stop, the fans would kick in and remove the hot air from under the bonnet through the vent.
Best of luck
davidy
A vent at the rear of the bonnet (a bit forwards of the bottom of the windscreen) will let air into the engine compartment. This is a high pressure area where the air flow is slowed down by the upright windscreen. The slower the airflow the higher the pressure. It would be useful when the car is stationary or, when moving, to supply cool air to the air filter but will do nothing to help air flow through the radiator.
I gather from the rest of this thread that no one has really tried blocking all round the radiator so that all the air coming in through the front openings in the bonnet has to pass through the radiator (although TVR did something to encourage this on the "M"'s with angled radiators)?
I gather from the rest of this thread that no one has really tried blocking all round the radiator so that all the air coming in through the front openings in the bonnet has to pass through the radiator (although TVR did something to encourage this on the "M"'s with angled radiators)?
pumpkin said:
Sorry GreenV8S for almost ignoring you. Did it do what it was meant to do? Did you notice much difference to engine temperatures when stationary after doing the work? Was it cooler under the hood or even inside the car?
It helps reduce heat build-up if the engine is left idling hot. Without it, as the engine bay heats up the cooling system becomes a little less effective. Which can cause the engine bay to heat up further ... and so on.It didn't make any difference to cabin temperatures that I could tell. I have made lots of other changes over the years so it is hard now to be sure what gains came just from this mod, but it is certain that keeping the hot and cold air separate is very important for the cooling system.
In my case with the V8S bonnet the front opening is very generous and I have divided the 'cold' side into three bays: one feeds the main rad, one feeds an oil/air cooler, the other feeds the air filter. I've also got vents in the bonnet which help reduce heat soak when stationary and produce huge plumes of hot air when moving at high speed. It is very strange to see wool tufts standing straight up six inches at motorway speeds.
A couple of points
a. The Le Mans Grantura built by Ian Massey-Crosse has a very nice shroud built into the bonnet, which mates perfectly onto the front of the rad.
b. When I put a Lenham front end on my race midget it overheated at normal road speed, even though the set up was exactly as it had been with a standard front end ie deep core rad and kenlowe. I created a shroud in ali and ir has never overheated since even racing at track temperatures of over 40 degrees in France
Conclusion get the air through the rad - and that means every bit of air - and use a fan with a built in shroud.
FWIW my experience is that brass is just as effective as ali for custom rads and cost a lot less.
a. The Le Mans Grantura built by Ian Massey-Crosse has a very nice shroud built into the bonnet, which mates perfectly onto the front of the rad.
b. When I put a Lenham front end on my race midget it overheated at normal road speed, even though the set up was exactly as it had been with a standard front end ie deep core rad and kenlowe. I created a shroud in ali and ir has never overheated since even racing at track temperatures of over 40 degrees in France
Conclusion get the air through the rad - and that means every bit of air - and use a fan with a built in shroud.
FWIW my experience is that brass is just as effective as ali for custom rads and cost a lot less.
John,
My former V8 Taimar had an upright radiator that, as I was told, was from a Ford Mustang from the early-to-mid 1980s as was the engine. My car was fitted with air conditioning and had a 13" pusher fan in front of the radiator with no shroud and it never overheated, even on a hot day with the A/C running.
Marshall
My former V8 Taimar had an upright radiator that, as I was told, was from a Ford Mustang from the early-to-mid 1980s as was the engine. My car was fitted with air conditioning and had a 13" pusher fan in front of the radiator with no shroud and it never overheated, even on a hot day with the A/C running.
Marshall
Thanks Marshall. Mine has never boiled but I did have to switch the A/C off after about 3/4 hour of a 3 lane, stop and go, traffic crawl when the outside temperature was about 35C. The A/C radiator gets very hot in that sort of traffic which is not good for the system.
I just think that some decent air flow control will make it much easier to control the temperature without massive fans on full time in traffic by using the coolest air available for cooling and not using it again once it has heated up. I want to hear the engine, not the cooling fans!
I just think that some decent air flow control will make it much easier to control the temperature without massive fans on full time in traffic by using the coolest air available for cooling and not using it again once it has heated up. I want to hear the engine, not the cooling fans!
John.... you may have already seen this, if not, take a look...
http://www.tvrna.com/tech/tech-m01.html
http://www.tvrna.com/tech/tech-m01.html
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