Mod-Wise dual fan cooling

[TVRwhoa]

Has anyone any experience of fitting the mod-wise dual cooling fan thingy, as my chim often sits in traffic and is always at 90 to 100 on the thermometer, it might be an idea to get one.

I wanted to know if anyone has fitted one, found them easy to fit etc

[tweety]

fitted their manual cooling fan switch kit and their amplified aerial kit. both are top quality, easy to fit and work really well. judging by this I would think the dual cooling kit will be well worth the effort.
cheers Al.

[joospeed]

is this the half speed fan thingy? .. if so i think peter humphries (green v8s) has one, reckons it's very good and relatively easy to fit. I'm not convinced - i reckon if you've got high temps (and the gauge isn't telling porkie-pies) then there's a fault and you should fix that first rather than mask the symptoms. However if you're satisfied that everything is in order and you'd still like the temp down ( your ecu may not learn and adaptive fuelling value) then that's fine too

>> Edited by joospeed on Tuesday 24th September 21:05

>> Edited by joospeed on Tuesday 24th September 21:06

[TVRwhoa]

Thanks Joolz it was me who asked about 30K service on
a chim earlier tonight, think I'll be bringing it to you in November !

How can I tell if its the guage telling porkies, I had a new otter switch fitted and new radiator in april, but still does the 90 to 100 bit quite regularly in traffic.

[joospeed]

quote:

Thanks Joolz it was me who asked about 30K service on
a chim earlier tonight, think I'll be bringing it to you in November !

How can I tell if its the guage telling porkies, I had a new otter switch fitted and new radiator in april, but still does the 90 to 100 bit quite regularly in traffic.

only sure way to tell is to get one of those digital thermometers or one of them there laser guided infra-violet sensing jobbies (technology, ain't it wonderful)... and compare it to the gauge reading.

[2 Sheds]

Joolz, i use crystal filled temperature stips (from Think Automotive 020 8568 1172)about £1 each, they only measure once, but i assume give a accurate reading.?

[shpub]

quote:
Joolz, i use crystal filled temperature stips (from Think Automotive 020 8568 1172)about £1 each, they only measure once, but i assume give a accurate reading.?

The infra red thing is a lot more fun. Point it at clouds and it will tell you how high they are because it will read their temp and that is proportional to their altitude. You can also use it to measure when meat is cooked on a barby, measure exhaust manifold temps to make sure that all cylinders are running correctly and best of all pretend it is a mobile speed gun and scare the idiots that speed through my village.

About £70 from Burton Power.

[GreenV8S]

quote:
is this the half speed fan thingy? .. if so i think peter humphries (green v8s) has one, reckons it's very good and relatively easy to fit. I'm not convinced - i reckon if you've got high temps (and the gauge isn't telling porkie-pies) then there's a fault and you should fix that first rather than mask the symptoms. However if you're satisfied that everything is in order and you'd still like the temp down ( your ecu may not learn and adaptive fuelling value) then that's fine too

>> Edited by joospeed on Tuesday 24th September 21:05

>> Edited by joospeed on Tuesday 24th September 21:06

Yes, I've got one of the Mod-Wise kits on the V8S. In my case it's particularly handy because it made it relatively easy to upgrade from one fan to two. Depending how your Griffith or Chimaera is wired, I guess it might also help cure the tendancy to blow fuses since it replaces the normal fusebox supply with its own direct feed.

I wouldn't claim the kit improves the overall cooling capacity, at the end of the day all it does is turn the fans on, and they'll either keep the engine cool or they won't. If they won't, there's something wrong that needs fixing. But, this kit does have one big advantage. It lets you ditch the standard otter switches, which TVR elected to put in completely the wrong place :shrug: and put adjustable ones in the bottom hose where they belong. This means it reacts far more quickly and accurately to changes in air flow through the rad, which in turn brings the fans in far more promptly when you slow down. Simply getting the fans on straight away instead of waiting five minutes until the engine has started to overheat gives the cooling system a huge head start over the heat soak. If there's really a problem with the cooling system then this is just delaying the inevitable, but I'm sure most people would be glad if it means the engine doesn't *quite* overheat in that queue.

By the way I've been investigating this problem over the last few months, and I've come to the conclusion that easily the biggest limiting factor to the cooling capacity when the car is stationary, is hot air recirculation. This is where hot air from the back of the radiator sneaks round to the front and gets sucked back into the fans. The V8S has a huge tripple core rad and two of the biggest fans I could find, at speed there's more than enough cooling capacity (in fact it runs cooler the faster I go). But with the bonnet down, it's really marginal when stationary, the fans run continuously and barely keep it under control. The amount of hot air recirculation is staggering, the air on the 'cold' side of the rad gets up to 70 or 80 degrees. Open the bonnet to kill the air recirculation and suddenly the fans only come on for a few seconds every couple of minutes, that's how much difference it makes. I've been trying various schemes to get round this problem, hopefully the latest duct dsign will cure it for good.

Fingers crossed,
Peter Humphries (and a green V8S festooned with temp sensors)

[Ballistic Banana]

Peter,

So stopping the air re-circulating back trough the rad would help in your opinion.
Just woundering what kinda concoction youu could com up with.
I have often thought that something in the Grill of my Griffith than would channel the airflow more directly through the rad would help but have also woundered if this might also have some effects on aerodynamics??? This would also stop the air recirculating back through the front of the Radiator,but then in turn is still keeping heat under the bonnet

I dunno just thinking out loud

BB

[dennisthemenace]

i wouldnt worry about your temp hovering round 100c as water doesnt boil till 115c under pressure on my van the temp sits at 95c most of the day and my kwak the fan dosent kick in till 105c unless its chucking water out of the overflow or expansion tank your worrying over nothing

[Jarrett]

I believe that this was one of the considerations in the design of the tuscan dual bonnet. The fans blow the warm air over the second bonnet and away from the engine. Thus it does not contribute to the engine heat soak.

I have driven my Tuscan RR on the track and through Paris traffic on a 35deg plus day (with the air con on and cold!) without the water temp going over 98 deg. Still get a red hot gear stick though if I push it hard.

My chim 500 frequently hit 105deg in bad traffic on hot days but never had an overheating problem. My dealer said that as long as you know that the cooling system is filled correctly and the fans are running properly then it should not overheat. If it goes off the dial or the fans are not coming on then turn it off quick.

My griff 500 used to overheat all the time until it had the relay fix (replaced the fuse version that used to blow all the time, honk the horn to check as they share the same fuse). Plus the otter switch was replaced with a lower temp version.

Both cars did 30K plus across the UK and Europe and so long as the above was alright then so were they.

Guess that the rule of thumb is get them serviced by people that know there stuff and check the levels and the guages frequently. You will soon learn from driving the car when is all ok and when isn't.

[shpub]

Pete

So your perfect V8S has the sensors in the wrong place. You really ought to get a Griff or a Chimaera where they are in the bottom hose effectively. To be exact in the bottom of the tank where the hose joins.

The ModWise kit is designed to help prevent heat soak by circulating the air under the bonnet. This it does well judging by reports. It does not increase the cooling capacity or help in stationary traffic. If the car is going to overheat it will overheat as in the end of the day the fans are either on or off and will cope or not. It might delay that moment but it will not prevent it.

The other thing is that Pete's car has a big engine in it which generates more heat than standard and this means that he is in the improve the cooling mode. The 520 engine puts out almost twice the amount of heat that the orginal did and so I spent the GDP of a small Carribean Island getting the cooling upgraded and sorted to cope. Do this type of a stuff to a standard car and there is a great liklehood that the car will be overcooled which as I have said before is very damaging to the engine and pocket.

Steve

>> Edited by shpub on Wednesday 25th September 06:56

[shpub]

quote:
i wouldnt worry about your temp hovering round 100c as water doesnt boil till 115c under pressure on my van the temp sits at 95c most of the day and my kwak the fan dosent kick in till 105c unless its chucking water out of the overflow or expansion tank your worrying over nothing

Yes but these are not your van or a kwaker.

TVR state that if the temp reaches 100 and stays there, stop as you have a problem and that problem could well be a head gasket failure or something similar. Carry on and the bill could be thousands for new cylinder heads or a seized engine.

I find it absolutely crazy that people ignore the temp guage warnings and just carry on because they assume that they are either wrong or don't apply to them because they ordered the "I can ignore all warning signs from the car" warrenty extension.

If the car reaches 100C stop the car and assume that there is a fault. Get the temp guage checked because they can be a few degrees out but don't simply carry on or the Engine abuse police will take the car away.

I am not ranting about nothing. I had a temp reach 100 when the head gasklet failed and dumped the coolent into the oil. I caught it early enough not to have warped the heads and instead of costing about £4K for new heads etc it only cost me a few hundred.

If your car reaches 100 but everything is fine, get the temp guage checked.

steve

[shpub]

quote:
Peter,

So stopping the air re-circulating back trough the rad would help in your opinion.

Bear in mind that the V8S has virtually no ducting around it and is simply a rad stuck up in the air with a fan attached that gets covered by the bonnet. The M series had a similar arrangment and used to spare wheel as a make do duct. Without it the car would often overheat. A lot of Pete's problems are specific to the V8S and not to the Griffi/Chimpari set.

Steve

>> Edited by shpub on Wednesday 25th September 08:49

[alex.mcintosh]

The cooling mod just plugs in on a Chim/Griff. Unplug your fans, plug in module, position new thermostats(or one if you are happy with the otter) on the hoses. Run one wire to piggy back the otter and thats it.

[GreenV8S]

quote:

quote:
Peter,

So stopping the air re-circulating back trough the rad would help in your opinion.

Bear in mind that the V8S has virtually no ducting around it and is simply a rad stuck up in the air with a fan attached that gets covered by the bonnet. The M series had a similar arrangment and used to spare wheel as a make do duct. Without it the car would often overheat. A lot of Pete's problems are specific to the V8S and not to the Griffi/Chimpari set.

Steve

>> Edited by shpub on Wednesday 25th September 08:49

True, the V8S (and other S series, I guess?) is nominally ducted by the bonnet and some framework round the radiator, but there are gaping gaps all over the place which cause the recirculation problem. I don't know how well Griffiths and Chimaeras are ducted. I seem to remember seeing a big gap over the top of the rad, in which case they are certainly vulnerable to the same problem - but I must admit it's been a while since I looked closely at one. The fact that so many people talk about overheating problems when its stuck in traffic makes me suspect they suffer the same problem, but I'm not sure without looking at one again.

Don't they still have the otter switch in the swirl tank though? Since that's in line with the top hose, it's definitely the wrong place for the otter switch.

Peter Humphries (and a green V8S)

[GreenV8S]

quote:
Do this type of a stuff to a standard car and there is a great liklehood that the car will be overcooled which as I have said before is very damaging to the engine and pocket.

I know this has been said before, but just to reiterate: the engine temperature is controlled by the thermostat. If the stat is fitted and working, it is not possible to overcool the engine by fitting bigger fans and radiators. The only time you get a problem is if you take the stat out, or fit one that opens at a ridulously low temperature (perhaps to work around other problems in the cooling system).

[shpub]

quote:
[I know this has been said before, but just to reiterate: the engine temperature is controlled by the thermostat. If the stat is fitted and working, it is not possible to overcool the engine by fitting bigger fans and radiators. The only time you get a problem is if you take the stat out, or fit one that opens at a ridulously low temperature (perhaps to work around other problems in the cooling system).

I know we have gone through this before but the stat is bypassed on the Griff and Chimaera. I checked on my Griff last week and there is warm water flowing through to the rad way before the stat opens. I have reports from owners that have fitted mega rads to them yet are running standard stats who are proud that their cars now run at 70 or below which again is below the stat opening temperature.

Had this on the 520 as well where the initial overcooling was caused by not having a stat at all. Engine builders tend to take them out. One was fitted because as Pete says, the stat controls the working temperature. Unfortunately it didn't but the bypass and super efficient rad still meant that it ran cool on cruising. Eventually dramatically reduced the rad air intake to address the problem. My conclusion is that the stat provides a very crude control but can be overwhelmed if other components are changed. With a big rad, the bypass can provide enough cooling to cool the car.

My conclusion is that the stat is not that an exact a device but an approximate control. In other words while your statement is true, the reality with the Griff and Chimaeras says otherwise which means there are other factors at work.

I also seem to remember a certain PH advocating bypassing the stat to help prevent thermal shock... Does this mean that there is a rethink?

The ducting has improved over the years with the Griffi/Chimpari and is in no way as dire as in the S series.

Steve

[GreenV8S]

I remember we had a long discussion about bypasses, and the fact that they are missing on most/all serpentine engine TVRs with all sorts of nasty consequences. Taking the stat out is one way to compensate for the lack of bypass, effectively the cooling system works flat out and gets the engine as cold as it can all the time. In this case, yes increasing the radiator area affects the running temperature. In fact the temperature will go up and down all the time depending on the weather, how fast you're going and so on. Obviously not clever for a normal road car. When I said the stat controls the engine temperature, I did say it had to be fitted and working didn't I? Start leaving out important bits of the cooling system and you're asking for trouble.

If the rad gets hot before the stat opens, this suggests to me the stat is either missing or not working. Stats often fail partly open, meaning you get too much cooling (and extended warm-up cycles, which bring in other problems) when its cold, and not enough cooling when its hot.

In case there's any confusion what the bypass is, the bypass allows water to circulate round the engine without going through the radiator. When the stat is closed, this (and the tiny dribble of water going through the heater) is the only flow your engine gets. The bypass has nothing to do with letting water past the stat into the radiator. If the stat is fitted and working and closed, there is no water flow through the radiator. (Slight caveat to this, some people like to drill a small hole through the stat so it never complete closes, to reduce the thermal shock when it opens. This gives just a trickle of water through the rad, which can make the top hose warm to the touch. But the flow rate will be so low that this this has negligeable effect on engine temperature, unless you're in arctic conditions.

>> Edited by GreenV8S on Wednesday 25th September 14:02

[shpub]

I hear all that but it still doesn't explain why so many cars don't behave like that. It doesn't explain why removing the number plate reduces the running temperature to such a level that the stat is not open unless there is some contributory affect caused by the radiator. It doesn't explain why cars with bigger rads run cooler and at temps below that of the stat where the stat is shut. If there is no bypass the stat should prevent the flow and the car not run any cooler. But they do and that is where I struggle reconciling what I see in practice with what I hear and agree with in theory. This tells me that there is something that doesn't agree here. You can explain this by saying that every car has a fault as that doesn't pass the sanity test either.

The only thing I can think off and this agrees with my experiences is that the bypass is more effective and allows the rad cvooling to play a bigger part in the process before the stat is open.

To me the theory does not explain the facts. This is why I really query that the stat is that effective at regulating the engine temp and that in reality it is the thermal balance of the system that comes into play. It can wreck havoc if it fails or is the wrong value but it does not determine exactly the engine temperature.

In my view, it is simply a device to help the engine get up to an operating temperature quicker. That temperature is defined by the thermal equilibrium of the entire system and will change if the engine is driven hard and will change if the radiator is cooled more and will change with disasterous results if one of those components fails. It is based on the temp where the heat created is matched by the cooling available. And yes the stat temp has a part to play as well but it is not as all powerful as it is often portrayed.

Your turn, Pete