Title: Keeping the fan belt on?? Post by: benlawrence on April 07, 2014, 19:42:58 pm Im sure you guys have covered this a zillion times over the years, but as the title, we are struggling to keep belts on at the track, we have spent a good amount of time making sure the alignment is spot on between top and bottom pulleys, with an original diameter aftermarket bottom pulley and v belt both engines say farewell to their belts pretty much every run. To the point that i dont bother running one now. So this year weve gone for a power pulley to reduce the fan speed, but this hasnt cured the belt being thrown on my friends car (ive not run mine yet), in fact hes now throwing it more with the smaller bottom pulley. We both agreed that the serpentine belt system is not an option as our back to back tests on the dyno resulted in losses of over 20bhp running that system.
Would any of you loungers be able to steer us in the right direction with a belt setup that will stay in place to 8k rpm? Im fed up of chasing and retrieving them like a gun dog :D Title: Re: Keeping the fan belt on?? Post by: Peter on April 07, 2014, 21:15:00 pm what helped for me was to give the belt some slack,
so it slips a bit easier, and use a good generator pulley too! my belt lies kind of deep in the top pulley, so it cant be thrown off easily.. a power pulley helped in my friends bus, it ate belts like crazy I saw the belt sometimes 'rolled over' due to the generator pulley edges, they didnt have the same slope, after changing to an original top pulley the belt hasnt come off anymore... Title: Re: Keeping the fan belt on?? Post by: modnrod on April 07, 2014, 22:19:37 pm Use a 9 or 9.5 section belt instead of 10 to drop the belt into the pulleys.
Make it a bit looser than normal to give it plenty of slip, not bite and throw. Make a curved belt "flapper-stopper" (uhmmm, that's a technical term right there ;D) to follow the belt on the left, no preload. Title: Re: Keeping the fan belt on?? Post by: Bruce on May 02, 2014, 02:15:24 am Change the brand of the belts you are using. They fly off when they stretch. A stronger belt won't stretch as much.
Title: Re: Keeping the fan belt on?? Post by: glenn on May 02, 2014, 03:51:29 am Gates belts don't flip.
Title: Re: Keeping the fan belt on?? Post by: Iryanu on May 02, 2014, 09:05:27 am (http://i9.photobucket.com/albums/a51/UnmuffledRyan/Bug/013_zpsae1af4db.jpg)
This was belt number 3... Changed the top pulley for a flat-4 one and not the cheap Chinese chrome plated nasty with cover and all is well again. No belt problems since. I would always throw or snap the belt at the same junction too. It's a renowned testing road, I measured it out and it's just about a quarter mile before you need to brake for the roundabout. ;D Title: Re: Keeping the fan belt on?? Post by: Erlend / bug66 on May 02, 2014, 09:14:43 am Gates belts don't flip. Mine did all the time, before I changed to a narrower belt. And slack. Title: Re: Keeping the fan belt on?? Post by: leec on May 02, 2014, 10:14:11 am Anyone got a link to the narrower/gates belt?
Lee Title: Re: Keeping the fan belt on?? Post by: glenn on May 02, 2014, 12:26:26 pm Gates 7355 XL
Title: Re: Keeping the fan belt on?? Post by: Fiatdude on May 02, 2014, 16:31:38 pm I like a little slack and this top pulley -- its a video, so click it to see the slack
(http://i586.photobucket.com/albums/ss306/Fiatdude/th_firedup4-17-14_zps379605cf.jpg) (http://i586.photobucket.com/albums/ss306/Fiatdude/firedup4-17-14_zps379605cf.mp4) Title: Re: Keeping the fan belt on?? Post by: Paul H on May 08, 2014, 17:24:07 pm We both agreed that the serpentine belt system is not an option as our back to back tests on the dyno resulted in losses of over 20bhp running that system. Would any of you loungers be able to steer us in the right direction with a belt setup that will stay in place to 8k rpm? Im fed up of chasing and retrieving them like a gun dog :D The last high RPM motor I tested with a V belt and full size pulley took 22hp If you insist on running full size pulley with V belt I suggest you buy belts in bulk or get a gun dog collar and some Pedigree Chum. Have a look at many of the "exploded fan" threads for some free 20/20 hindsight Title: Re: Keeping the fan belt on?? Post by: dannyboy on May 08, 2014, 23:07:33 pm i run a serpentine system on my old race motor it never shit itself up to 8k, but the best bit i found was the ease of removing/replacing at the start/finsih of a run. an alan key is all you need to take it off and replace it in seconds ;) the same belt has been on it for 3 seasons of racing and i only started removing it on the last season i used that motor
Title: Re: Keeping the fan belt on?? Post by: BeetleBug on May 09, 2014, 20:46:44 pm I just don't get it guys. Unless you are in desperately need of electricity (big nitrous system etc) why on earth are you willing to loose 15-25 HP? Remove it before you go racing and install it after a race. Or at least mount a power pulley when racing. Above a certain rpm (not as high as you might think) the fan stalls anyway.
If you race you race. No more, no less! Title: Re: Keeping the fan belt on?? Post by: TyeDyeBug on May 09, 2014, 21:18:28 pm X2!! It's not worth the headache LOL
Title: Re: Keeping the fan belt on?? Post by: dannyboy on May 09, 2014, 23:00:57 pm I just don't get it guys. Unless you are in desperately need of electricity (big nitrous system etc) why on earth are you willing to loose 15-25 HP? Remove it before you go racing and install it after a race. Or at least mount a power pulley when racing. Above a certain rpm (not as high as you might think) the fan stalls anyway. i totally agree when on the track whats the point of going a bit slower just to say you ran slower but had your belt on??? If you race you race. No more, no less! but then its the same as running 11somthing na and not fitting gas and running 10 something :D :D :D :D Title: Re: Keeping the fan belt on?? Post by: speed7 on May 12, 2014, 11:36:19 am Hi ,
I take off the belt at the beginning of a race weekend and put it back on before leaving for home. In the meantime I use a replacement belt I made in a material that is used for transportation belts. It's 10mm in diameter , round (and green) and can be soldered together using a normal soldering tool. It allows revs up to approx 3500 rpm and can be mounted and taken of by hand without loosening the alternator pulley ( of which the thread will be damaged after a number of WE of you do ...) That way running back and waiting allows you to cool the engine and charge the battery. Greetz Marc |