| Author |
Message |
advinnie
Samba Member
Joined: November 18, 2011
Posts: 1389
Location: oxfordshire
|
 Posted: Mon Oct 27, 2014 11:24 am Post subject: Do I need a balanced cooling fan at 6500rpm? |
 |
|
Hi all im building a 2188cc motor capable of hitting 6500rpm so should I be looking at fitting a balanced cooling fan or not? If not at what rpm can the stock fan take?
Cheers |
|
| Back to top |
|
 |
rs58rag
Samba Member
Joined: August 22, 2010
Posts: 419
Location: riverside,ca
|
| Posted: Mon Oct 27, 2014 11:51 am Post subject: |
|
|
| Get welded balanced fan now....cheap insurance. |
|
| Back to top |
|
|
Howard 111
Samba Member
Joined: July 09, 2005
Posts: 1827
Location: Virginia
|
| Posted: Mon Oct 27, 2014 12:19 pm Post subject: |
|
|
Agree. I never go above 6000rpm with my turbo engine, but run a balanced, welded fan. Some stock fans are so poorly built, I would worry all the time about using a stock fan. Like rs58rag said, it's cheap insurance.
_________________
1973 Karmann Ghia
Turbocharged, Fuel Injected
http://www.thesamba.com/vw/forum/viewtopic.php?t=531270 |
|
| Back to top |
|
|
Hotrodvw
Samba Member
Joined: July 06, 2004
Posts: 6327
Location: Orygun
|
| Posted: Mon Oct 27, 2014 12:25 pm Post subject: |
|
|
I ran my OEM unbalanced, un-welded fan over 7k on the dyno accidentally...and got lucky. I won't do it again LOL
Now have the OEM fan welded.....peace of mind is worth a lot IMO.
_________________
'67 Sunroof
Eric
78x94 with IDA's....oober fun
Horsepower is an addiction........Addictions cost
lots of money!
Hose & Fittings |
|
| Back to top |
|
|
advinnie
Samba Member
Joined: November 18, 2011
Posts: 1389
Location: oxfordshire
|
| Posted: Mon Oct 27, 2014 12:47 pm Post subject: |
|
|
| Thanks for the replys all i think a welded balanced fan is now on my shopping list |
|
| Back to top |
|
|
[email protected]
Samba Member
Joined: August 03, 2002
Posts: 12785
Location: Salt Lake City, Utah
|
| Posted: Mon Oct 27, 2014 3:11 pm Post subject: |
|
|
it depends on your fan belt. If you run a sticky and tight belt, yes get a welded fan. If you run a slickery belt a little looser, there is no need since the belt slips around 4k RPM crank speed.
_________________
It's just advice, do whatever you want with it!
Please do NOT send me Private Messages through the Samba PM System (I will not see them). Send me an e-mail to john at aircooled dot net
"Like" our Facebook page at
http://www.facebook.com/vwpartsaircoolednet
and get a 5% off code for use on one order for VW Parts ON OUR PARTS STORE WEBSITE, vwparts.aircooled.net |
|
| Back to top |
|
|
advinnie
Samba Member
Joined: November 18, 2011
Posts: 1389
Location: oxfordshire
|
| Posted: Mon Oct 27, 2014 3:15 pm Post subject: |
|
|
| Stock belts slip at 4000rpm crank speed shit j was driving at 4800rpm (90mph) for over 30 minutes im surprise my engine didn't over heat with the cooling fan not running at the right speed. |
|
| Back to top |
|
|
[email protected]
Samba Member
Joined: August 03, 2002
Posts: 12785
Location: Salt Lake City, Utah
|
| Posted: Mon Oct 27, 2014 3:28 pm Post subject: |
|
|
starts slipping. Doesn't slip completely! But the fan doesn't go any faster even though the engine does. This is not the case for "grippy" belts or Serp systems though, they are far more likely to blow up fans.
_________________
It's just advice, do whatever you want with it!
Please do NOT send me Private Messages through the Samba PM System (I will not see them). Send me an e-mail to john at aircooled dot net
"Like" our Facebook page at
http://www.facebook.com/vwpartsaircoolednet
and get a 5% off code for use on one order for VW Parts ON OUR PARTS STORE WEBSITE, vwparts.aircooled.net |
|
| Back to top |
|
|
modok
Samba Member
Joined: October 30, 2009
Posts: 26781
Location: Colorado Springs
|
| Posted: Mon Oct 27, 2014 4:58 pm Post subject: |
|
|
| advinnie wrote: |
| Stock belts slip at 4000rpm crank speed shit j was driving at 4800rpm (90mph) for over 30 minutes im surprise my engine didn't over heat with the cooling fan not running at the right speed. |
next time stop and see how hot the pulleys are!! smokin. But the belts still last a long time somehow, unless your pulleys are out of line.
I like to use the slightly smaller "1500" size fan.
Still cools about the same maybe better at 4000 rpm, I think the belt just slips less. Stronger too.
Balanced?? hopefully. All the OE ones were balanced (they have little weights welded on) but some new ones aren't, and some are wobbly too, I'd try to find a good one and have it tig'd. |
|
| Back to top |
|
|
mark tucker
Samba Member
Joined: April 08, 2009
Posts: 23937
Location: SHALIMAR ,FLORIDA
|
| Posted: Mon Oct 27, 2014 8:46 pm Post subject: |
|
|
| Im not sure about thatmuch belt slip, they last awefull long for a belt slipping that much. Ive shreaded lotsa belts on v8 stuff & slurpintime belts on superchargers oh so many times. but you should have a balanced fan. I have 1 and need 2......amoung other things. |
|
| Back to top |
|
|
rrcade
Samba Member
Joined: May 29, 2010
Posts: 735
Location: WI 1962 Bug 2276
|
| Posted: Mon Oct 27, 2014 9:15 pm Post subject: |
|
|
| Anybody got pictures of the aftermath of an exploded fan? |
|
| Back to top |
|
|
jeff68
Samba Member
Joined: November 02, 2007
Posts: 298
Location: Sarasota, Florida
|
| Posted: Tue Oct 28, 2014 7:03 am Post subject: |
|
|
Keep in mind that a hi-performance vw engine accelerates (reaches rpm) much faster than a stock engine (which the fan was designed for). So in other words it's not only peak rpm that makes a welded fan a very good idea, it's the increased forces put on the fan when accelerating the fan from low to high rpm. Even with a slipping belt (if it doesn't slip a lot) the fan is accelerating faster. That's why many fan failures (fans coming apart) happen when the engine is revving from low to high rpm. I apologize if you all knew this already, I just didn't see it mentioned is all.
IMO any Hi performance vw engine (one that revs faster and has a higher rpm potential than stock) should have a welded and balanced fan. |
|
| Back to top |
|
|
bluebus86
Banned
Joined: September 02, 2010
Posts: 11075
|
|
| Back to top |
|
|
vugbug68
Samba Member
Joined: June 25, 2006
Posts: 2696
Location: sacramento
|
| Posted: Tue Oct 28, 2014 9:36 am Post subject: |
|
|
Id say 6k is a good number as long as its a V belt and OEM fan (I've seen pretty crappy aftermarket fans)
I rev to 6k often but I run my belt pretty loose, never broke a belt or fan
_________________
71 Super - Backroad Thrasher
66 Corvair - Weekend Cruiser
90 4 Runner - Muddin |
|
| Back to top |
|
|
vwracerdave
Samba Member
Joined: November 11, 2004
Posts: 15303
Location: Deep in the 405
|
| Posted: Tue Oct 28, 2014 2:44 pm Post subject: |
|
|
Back a few months ago I was drag racing my Dunebuggy. I had a Bugpack welded and Balanced fan. I hit 7000 RPM with the stock sized pulley and fan belt. I felt a serious vibration and immediately shut it off. None of the blades came loose but they were all distorted so bad I couldn't get it out of the fan shroud without cutting it out. It damaged some of the vanes in my 36 HP doghouse shroud.
I run a Bugpack welded & balanced fan in my race car with a power pulley turning 7000 RPM's and never had any problems.
_________________
2017 Street Comp Champion - Thunder Valley Raceway Park - Noble, OK
2010 Sportsman ET Champion - Mid-America Dragway - Arkansas City, KS
1997 Sportsman ET Champion - Thunder Valley Raceway Park - Noble ,OK
Featured in Dec. 2001 HOT VW's Magazine page 63
Watch my racing video's http://www.youtube.com/user/okvwracer/videos |
|
| Back to top |
|
|
VWCOOL
Samba Member
Joined: June 02, 2006
Posts: 1821
Location: Down under
|
| Posted: Tue Oct 28, 2014 5:43 pm Post subject: |
|
|
The increasing horsepower draw from the fan means the fan belt begins slipping at around 4000rpm.
It simply can't transmit any more power. So spinning the engine faster doesn't actually spin the fan any faster. It is a 'self-preserving' system.. and the reason why a VW's maximum cruising speed is 4000rpm... that is the point of max air flow and hence cooling ability of the fan/system
Do NOT fit a serpentine belt. not. ever.
I have had one fan 'bend' but that was when a foreign object (tree leaf IIRC) entered it and unbalanced it.
I use 7500rpm in motorsport/drags/etc with a standard DP fan... inspected and driven from a power pulley, which of course slows the fan down a little. This has survived hundreds of runs but if it were to fail again, I would of course investigate a 'race prepped' fan as a replacement |
|
| Back to top |
|
|
Mikedrevguy
Samba Member
Joined: October 15, 2008
Posts: 2237
Location: Medford, OR
|
| Posted: Wed Oct 29, 2014 9:00 pm Post subject: |
|
|
This was my experience with a stock fan
I've got a fan welded and balanced by racinjason. Haven't blown it up yet.
_________________
74 1303 (RevBug): plan for German Look
76 914 with 2260
79 VW Iltis
69 Bwajaja
"The wise speak because they have something to say; while the foolish speak because they have to say something." Plato
Illigitimi non-Carborundum!! |
|
| Back to top |
|
|
advinnie
Samba Member
Joined: November 18, 2011
Posts: 1389
Location: oxfordshire
|
| Posted: Thu Oct 30, 2014 1:26 am Post subject: |
|
|
| Nice you got lucky |
|
| Back to top |
|
|
Greezy Joe
Samba Member
Joined: April 12, 2010
Posts: 1534
Location: Crawfordville, Fl
|
| Posted: Thu Oct 30, 2014 7:42 am Post subject: |
|
|
I ran a stock fan in my 2276, hit 6500 a few times. It didn't come apart but the pucker factor ate the drivers seat up  I got a welded and balanced fan for extra insurance and my drivers seat is OK now 
_________________
Current:74 Ghia Coupe w/ 2276
71 Ghia Vert w/ 1835
07 GMC Truck
12 Jeep Wrangler
73 Harley FLH 93 cid
89 Harley 883 Sportster (1200)
Owned before: 58, 69 Ghia Coupes, 64 Canvas Sunroof, 68, 72, 73, & 74 Bugs, 63 Single Cab, 65 Bus, 66 & 70 Camper
" Duct tape can't fix stupid, but it'll muffle the sound". |
|
| Back to top |
|
|
RailBoy
Samba Member
Joined: March 10, 2008
Posts: 2904
Location: Virginia
|
| Posted: Thu Oct 30, 2014 11:51 am Post subject: |
|
|
Damn RacerDave, so you twisted up a welded fan, wow, first time I have heard of that to be honest, and it was welded..... Wonder how often it occurs?
All that got torn up was the shroud, guess you were guess you had to trailor that car that night home,lol... RB
_________________
[quote="smitty24"]"HELP, I ported my own heads and now have fire coming out my ass" .[/quote]
 |
|
| Back to top |
|
|
|
