AdrianC wrote:
Is too powerful a fan a good thing? I'm not sure it would be.
Your right it would cause more thermal shock to the engine, especially as the DF is wired for single speed which means the fan would run on fast speed only, and the DF has a smaller capacity radiator.
Double, double quote lol.
Thermal shock....lol...who are you kidding....typically the fan only knocks around ten degrees off....hardly shock. Not like pouring boiling water on an icy windscreen
Personally I would be more worried about switches and wiring being up to taking the extra load.
It all gets very complicated especially when you include the interaction from the thermostat and it's reaction to the inrush of colder coolant..... I do tend to take an overview based on prior knowledge and avoid 'reading and researching' unless I have to (my job involves so much of it I don't go out my way to add to what I already do) although it usually is possible to find information to back up both sides of a theory.
I worked in papers for some years and if the journo's wanted to record 'the publics view' for an article they would carry out something called a vox pops.....basically a series of questions designed to extract a 'point of view'. It was generally accepted that you could get 'any answer' you wanted by manipulating the original questions.
When I read technical journals I'm afraid I do so in the knowledge that they are based on a series of opinions. To end up in print the authors have generally earned the respect of their piers and the right to 'have those opinions' in their particular context. Research isn't necessarily a 'black & white' paper of right and wrong answers, sometimes there are degrees of right and wrong.
Thermal shock.....well I guess there is going to be research, some of which might be backed up by some sort of facts but always in a particular context and that context is sure to be different to the one we are talking about and there in lies the variation in opinion & execution and use of that 'research'.
On this one I think that I know enough to say that 'thermal shock' just wouldn't be an issue ......the difference in efficiency between two fans, one 200watts and the other 500 is an unknown, just because one is more than double the power doesn't necessarily make it more than twice as efficient at cooling. At what critical point do we get the phenomenon of 'Thermal Shock' if this is factual, how much can the coolant be cooled by and by how fast before this occurs.
The standard or uprated fan is thermally controlled so turns off at the same point, so we are obviously talking about how quickly it cools as opposed to by how much it cools....so therefore, is their a optimal graph.......
I know...I'm having a laugh but at the same time I am also pointing out the obvious flaws with a 'phenomenon'...if you can call it that, such as this one.
California Dreamin wrote:the difference in efficiency between two fans, one 200watts and the other 500 is an unknown, just because one is more than double the power doesn't necessarily make it more than twice as efficient at cooling.
True, but you'd like to think that a new fan off a specialist manufacturer is at least as power-efficient as a 30yo one.
Just buy the one meant for the van and be done with it (I think b'werks sell them as well?)
People fit kenlowes in place of standard fans to get more HP, ours aren't turned by the engine, so no real need
my turn to be a pedant you dont gain horsepower as such , it just that as there isnt a fan drawing on it then more is available for the transmission and onwards and as for making a differfence. yes they do even on a nice 440 or 383 you can hear the engine note change on idle when they kick in
back to narnas and custard
mm
lloydy wrote:Just buy the one meant for the van and be done with it (I think b'werks sell them as well?)
People fit kenlowes in place of standard fans to get more HP, ours aren't turned by the engine, so no real need
I would have done, but the only one Brickwerks has in stock is for a diesel. I have had a chat with Kenlowe and the 14" one is the one they recommend.
genuine one still available from VW-classicparts 251 959 455 C about euro175, doesn't look like there is a cheaper aftermarket one made of that particular version
Cheers Aidan that's helpful. That original fan is not much cheaper that the Kenlowe one and I have decided to go with the Kenlowe option, which I have had really positive feedback about. What's also good is that the guys from Kenlowe are really helpful on-line and over the phone.
Thanks for the advice guys. I had my fan replaced today by a Kenlowe one, while I was at work. I'm glad I didn't have to do it. It was a bit of a faff. The mechanic created a few new swear words evidently.
A noise like a washing machine full of nuts and bolts has been replaced by the purr of the new fan. It's so quiet. Now ready for the traffic jams on the way to Bustypes on Friday!
Sorry guys no pics. The procedure started with removing the rad. They managed to do this without needing to empty the cooling system - clever. Having done that they removed the old fan and mounting frame. They then had to modify the new mounting frame to ensure it fitted perfectly behind the rad (it would not fit in front of the rad as it would have touched the body frame). Then it fit snugly behind the rad - just.
It took several hours to do this, connect up the new wiring system, the electronic brains and make sure everything was working properly, including adjusting the temperature cut-in. The final comment was it is not recommended to try this job on a driveway at home. It took several hours to do this with all the facilities of a garage. Now ready for Bustypes tomorrow!
Last edited by Ralf85 on 17 Apr 2014, 15:48, edited 1 time in total.
you dont gain horsepower as such , it just that as there isnt a fan drawing on it then more is available for the transmission and onwards and as for making a differfence. yes they do even on a nice 440 or 383 you can hear the engine note change on idle when they kick in 
