Great write up packed with lots of information thank you for taking the time!! JIM
Fan 'delete'
- Thread starter Dino D
- Start date
Just to update this post.
If you plan on going around Lydden hill in 25c heat and want to run the aircon - she gets hot so you have to back off!
Never runs hot on the road, in traffic, on a good drive out but on an extreme track day it wants the extra cooling of the viscous.
So for track days it will go back on until I work out how to add a second electric fan (and do new engine mounts songhe viscous doesn’t kiss the radiator!)
If you plan on going around Lydden hill in 25c heat and want to run the aircon - she gets hot so you have to back off!
Never runs hot on the road, in traffic, on a good drive out but on an extreme track day it wants the extra cooling of the viscous.
So for track days it will go back on until I work out how to add a second electric fan (and do new engine mounts songhe viscous doesn’t kiss the radiator!)
- Joined
- Feb 18, 2016
- Points
- 231
- Model of Z
- Z3M Imola and Z4 (e89)
I have the lower rated fan switch, so dont go buying one just PM me 
Yes I do have have that.
Never had an issue before but Lydden Hill is a very intense track - it’s only one mile with a steep hill, there is no cool down time between corners etc - it’s just full on all the time. You only use 4th twice and only for a few secs. The rest of the time is 2nd and 3rd. It’s designed for Rally X cars not mere mortals like us!
I’ve been thinking of doing this mod for quite a while, read all the posts about it on Bemmer Forum’s years ago. The main reason for it then apart from alleviating the risk of fans breaking was less reciprocating drag on the engine so quicker pick up/bit of extra power, is this the case in practice?
I did the fan delete a few years ago. My reasons were simply due to my viscous fan being permanenty engaged and wanting to avoid the risk of the blades breaking up. There were a few reports of blade failure with newly replaced fans.
The viscous fan takes power directly from the engine when it engages. An electric fan draws power indirectly via the alternator, again only when it cuts in.
Subjectively I didn’t find any difference in power, although not having the viscous fan constantly "whooshing" meant it was quieter.
Looking on the internet estimates seem to be the viscous fan absorbs from less than 1bhp to 3bhp (only when it is running, of course). The electric fan will probably have a similar effect.
If you are looking for more power I would suggest that you look elsewhere.
Going back to your original issue Dino, if you found yourself smashing your fan blades this is a clear sign of weak engine mounts allowing the engine to rock into the shroud and clash with the rad. I know what your gear changes are like so it's very likely.
- Joined
- Feb 18, 2016
- Points
- 231
- Model of Z
- Z3M Imola and Z4 (e89)
Did this a few years ago and then put it all back to OEM. If you just driving around normally shouldn't be any issue, if you are driving very hard or hooning on track I wouldn't do it personally. The aux fan was not designed to cool the engine on its own, it is by name an auxiliary fan in place to aid the viscous if and when needed BUT its main function is to cool the AC.
I had some issues, though I would concede under extreme conditions, where using the engine to almost a maximum rpm but at relatively slow speeds for a lot of miles, therefore very little air throughput, and on a couple of very hot days the Aux fan just could not cope, 99% of the time is was more than adequate, the other 1% bothered me a bit. I also worried about not having a backup if the aux fan failed. I would, if there is a next time delete the viscous for a twin electric setup.
https://zroadster.org/threads/viscous-fan-delete-modification.13520/
I had some issues, though I would concede under extreme conditions, where using the engine to almost a maximum rpm but at relatively slow speeds for a lot of miles, therefore very little air throughput, and on a couple of very hot days the Aux fan just could not cope, 99% of the time is was more than adequate, the other 1% bothered me a bit. I also worried about not having a backup if the aux fan failed. I would, if there is a next time delete the viscous for a twin electric setup.
https://zroadster.org/threads/viscous-fan-delete-modification.13520/
Guys quick question for those of you thag might have changed or removed the aircon condenser before, how does it come out? From the front bumper out, electric fan out then condenser or is it from the back with viscous fan and shroud then coolant radiator then condenser.
Any help appreciated @spurs fan in a coupe, @Synclare @Sean d or anyone that had removed the condenser before
Any help appreciated @spurs fan in a coupe, @Synclare @Sean d or anyone that had removed the condenser before
Just seen this, yes my gear changes are spot on, it’s the rest of the car that just can’t keep up
I’m not 100% sure it was that as when the blades broke off I was just cruising but it’s not unheard off and I don’t doubt it possible, especially with the latest performance enhancements
A mechanic told me that if the blades and been bent in the past ie doing water pump etc it could eventually fail at that point and flick off - this is what it looked like in my case as whilst there are marks on the rad none of the other blades where damaged at all.
I’ve also had two new viscous units fail in the open position so got fed up - want to get an electric done- the fitting is easy but the electrics are the issue for me but something an auto elec could probably do in an hour or two.
Isn’t the condenser in front of the rad so from the front (or maybe just slid from underneath?)
Is it your 2.0l that you track without a fan in Spain?
Good thread. Timely too. After Skye it would appear my viscous fan is always on. Car is sucking up air like a whale shark. Will be keeping tabs on this one for sure.
Check your engine mounts, they're oil filled and a slight leak can allow "excess" movement which can result in the fan blades touching the shroud.Just seen this, yes my gear changes are spot on, it’s the rest of the car that just can’t keep up
I’m not 100% sure it was that as when the blades broke off I was just cruising but it’s not unheard off and I don’t doubt it possible, especially with the latest performance enhancements
A mechanic told me that if the blades and been bent in the past ie doing water pump etc it could eventually fail at that point and flick off - this is what it looked like in my case as whilst there are marks on the rad none of the other blades where damaged at all.
I’ve also had two new viscous units fail in the open position so got fed up - want to get an electric done- the fitting is easy but the electrics are the issue for me but something an auto elec could probably do in an hour or two.
Tony.
I’ve got all that too, never had a problem on road for years now, but track driving is another story!
If I wasn’t tracking it I wouldn’t bother. Even standing in queues of traffic on hot days the aux fan only works fine.
I could hear your fan everytime you was near me