Fiddling under the bonnet
Discussion
blaineuk said:
badredwedge has done this mod, and put the holes in, the arch is double skinned and so you can draw cold air and no water/stones from the road
I did this same thing a week or so back complete with vent holes and a SS mesh cover. I have fitted a smooth pipe from the AFM. I fitted my header tank in the same place as yours but junked the overflow tank and ran the pipe to spit any water under the car. I drilled the vent holes as someone on here (rev I think) tells me the SEACS have this set up. I am not sure what good, if any this has done but it was that or sit and watch pop idle as I dont have a veg patch or a green house
Maybe I should have dumped the overflow bottle, I put the expansion tank too close to the AFM and had to move it accross 30mm to fit it in. Thats what happens when you rush to complete jobs because driving it beckons. I noticed the wing is double skinned but didn't think there was enough gap to vent air through. Will investigate that, cheers.
Going to be needing new boots shortly as 'drifting' is getting too easy to do!
Going to be needing new boots shortly as 'drifting' is getting too easy to do!
Dumping the "overflow" bottle will result in having to fill the coolant system more often as you will start loosing coolant. the "overflow" bottle is actually a recovery bottle ie it lets the system overflow into it when it is hot but then when it cools the coolant system creates a vacuum and draws the water back into the coolant system which is why the filler cap has a sprung seat on it.
I mounted the same but changed the cooling system completely so there's a Range Rover tank behind the plenum against the windscreen bulkhead. Then fitted a box around the filter and piped to a scoop under the rad - the 80mm pipe runs down where your expansion tank is - just enough room past the power steering pump.
After covering and warapping the whole lot with some air con duct insulation it reduced intake temps significantly - after a long run the un-insulated top of the box is actually cool to the touch. Probably OTT for the UK but with 40 deg + days here almost a must.
After covering and warapping the whole lot with some air con duct insulation it reduced intake temps significantly - after a long run the un-insulated top of the box is actually cool to the touch. Probably OTT for the UK but with 40 deg + days here almost a must.
castorcamber said:
Dumping the "overflow" bottle will result in having to fill the coolant system more often as you will start loosing coolant. the "overflow" bottle is actually a recovery bottle ie it lets the system overflow into it when it is hot but then when it cools the coolant system creates a vacuum and draws the water back into the coolant system which is why the filler cap has a sprung seat on it.
I cant see how water from the overflow bottle can get back into the system. It got into the bottle past the spring loaded rad/filler cap under pressure. The rad cap is in fact a one way valve, no way is water getting back past it, any vacuum created would just suck this valve shut. IMO the over flow bottle is just a waste of space, the only reason I can see for it is to stop expelled water running onto the exhaust, for example. So I junked it.
rad caps are a two way valve to allow air or with an expansion tank fitted coolant to return to the system as it cools down and creates a partial vacuum. without this two way valve coolant pipes or possably the rad would collapse on cooling.it will probably be ok to run without the expansion tank but monitor the coolant level more closely.
badredwedge said:All I know for fact is that some water finds it's way back in. Did the same thing on my old Mini as well.
I cant see how water from the overflow bottle can get back into the system. It got into the bottle past the spring loaded rad/filler cap under pressure. The rad cap is in fact a one way valve, no way is water getting back past it, any vacuum created would just suck this valve shut. IMO the over flow bottle is just a waste of space, the only reason I can see for it is to stop expelled water running onto the exhaust, for example. So I junked it.
OK this is my theory..
Though the spring loaded cap basically works as a one way valve it will need a certain pressure difference to ensure a 100% perfect vacuum seal. If this pressure difference is more than the cap spring pressure then when the system cools to ambient the pressure will drop to a partial vacuum. It is remarkably difficult to make a perfect vacuum seal under the best of conditions, so I doubt that a cap, that costs two pence to make, will ever seal 100%.
Eventually (assuming the cap isn't totally fragged) the vacuum will be enough to seal but whilst there is a slight leak, water from your overflow bottle can be drawn in by the pressure difference. The amount of water left in the system when hot will be determined by the maximum coolant temperature, the pressure relief valve (spring) and the atmospheric pressure on the day.
So without an overflow bottle your system will run with the lowest water level satisfied by the highest temperature on the lowest pressure day. After that you will be running with the top of the system filled with air. If you don't have an overheating problem you will get away with this but if everything's marginal, as is often the case with a BBW, then here is an easy way to keep the coolant system operating at it's best
Sits back, and waits for theory to be shot down in flames.
Leo
Edited to add... and whilst I was theorising chris390 got in there with a much simpler description. I think the "two way valve" is achieved by cheapness of design and relying on not getting a perfect seal. It all amounts to the same thing though however it's done.
>> Edited by leorest on Monday 27th February 09:48
Dont need to shoot your theories down in flames,as I wasn't giving you my opinion I was explaining the facts of how your cooling system works.
Next time you are stuck in traffic on a hot day you can always think to yourselves "That castorcamber didn't have a clue" just before your coolant system spits all of its coolant on the tarmac.
Next time you are stuck in traffic on a hot day you can always think to yourselves "That castorcamber didn't have a clue" just before your coolant system spits all of its coolant on the tarmac.
chris390 said:
rad caps are a two way valve to allow air or with an expansion tank fitted coolant to return to the system as it cools down and creates a partial vacuum. without this two way valve coolant pipes or possably the rad would collapse on cooling.it will probably be ok to run without the expansion tank but monitor the coolant level more closely.
Chris I still have the expansion tank its only the overflow tank I have done away with.
If this plastic bottle is of such great use, how many other cars are fitted with an expansion tank AND overflow bottle ??? I have run without it for a few hundred miles and no water loss the expansion tank is still at the full level, the only time the 400 spit any water out was the first time it reached running temp after it was topped up. My old 350 had not got a plastic bottle. When I first got the 400 it had been serviced 120 miles before by TVR and the only thing in the bottle was a spider, and some dust.
redwedge5 said:
This is the original set up on my SEAC. Not only is the induction pipe short, but those clever people at TVR have cut holes in the inside wing where the airfilter lies and this allows cold air to be pass through the air vents in the front spoiler and along inside the wing on that side to the cut holes and hence to the airfilter.
Dont know whether it makes any difference!
No plastic bottle
I agree with previous, it can draw water back into the expansion tank through a one way valve in the cap. As far as I can tell, the expansion tank doesn't get full enough to overflow, but its there just incase. The same principal was on the S2 I had and where to fit the flat cap/spring cap caused many a debate.
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