98 540i 6, 525 whp, 120 mph 1/4, V3 Si S/C'er @16 psi, W/A I/C, Water/Meth, Supersprint Headers, HJS Cats, 3" Custom Exhaust, UUC Twin Disc, Wavetrac LSD, GC Coil Overs, Monoball TA, AEM FP, Aeromotive FPR, AEM Failsafe AFR/Boost, Style 65's w/275's, M5 Steering Box, Eibach Sways, M3 Shifter, Evans Coolant, 85 Deg Stat, PWM Fan, 10" Subs, B.A. speakers, Grom Aux/BT, Still Rolling as my DD!
IME, and I got onto it via the domestic supercharged crowd, another place to look for upgraded belts is the Gates Fleet line. These are sometimes (used to be?) called 'greenstripe' but I think the current proper name is 'fleetrunner'.
They are bright green on the back and are really sturdy and last forever. Designed for work diesels I think that spend 6 days a week running and idling for 12hrs a day. I wouldn't be surprised if the RPM "motorsports! racecar!" belts are virtually the same but just marketed at the enthusiast crowd vs the fleet buyer...
Playing games with multiple belt lengths and seeing what works, once you start modding and swapping pulleys is par for the course by the way... I definitely have a small collection of brand new belts of various brands and sizes from different configurations and test fits... I could open a roadside serp belt stand...
My STRONG suggestion is, to not make the mistake that a huge number of S/C guys seem to make, which is to directly equate belt length & tightness with grip and reliable power transmission.
TENSION SHOULD COME FROM THE TENSIONER SPRING AND A GOOD ANGLE, NOT FROM THE BELT BEING SHORT AND TIGHT (not yelling at you saggas, just emphasizing, cuz this is important!)
Here's the problems with trying to use belt-length as the primary tensioning mechanism:
Most importantly in almost all cases, shortening that belt is taking away wrap. Wrap is 9000x better way to get belt traction than no-wrap-but-tight-as-fork. Get a lotta wrap and you need very LITTLE tension to prevent slip. Super short belts with lotsa tension puts (as somebody else mentions here I think?) unnecessary load on bearings, and is counter productive. There's a number of threads out there you can find with guys going shorter and shorter on belts trying to reduce slip and going crazy because "it just seems to be slipping worse now!".
There's also a secondary bad effect from wrap in most configurations, which is... super tight belts most usually affects tensioner lever-angle too. The sharper the angle the tensioner arm has on the belt, the better. An arm that's nearly parallel to the belt isn't nearly as effective as the same one where the arm can ride perpendicular. Super tightening the belt again, (usually) takes away tensioner angle and mechanical advantage.
Of course good tension is a good thing, but I think most guys don't realize how a moderate amount of tension is totally and completely fine, as long as the belt has enough friction (wrap + ribs = all about the surface area), and the tensioner has good angle... Vs how maxing out the tensioner angle and wrap is actually taking away its ability to do its job.
So... saggas you may want to try a longer belt, if you gotta pry it on, it's probably too short...
By the way, pulley diameter on the tensioner can have similar effects, too large a pulley (like that massive RMS thing) might actually put less angle on the tensioner than a smaller one - though again depends on the geometry and where the tensioner sits vis-a-vis the belt etc. If you change pulleys, adjusting belt length longer to accomodate a bigger pulley probably not a bad idea. All goes back to the fact that, tension should come purely from the tensioner, and not super-static loading a short belt.
LOL.
Yeah the ideal thing is a parts shop that both 1. has a big inventory on the shelf, and 2. is cool with you wandering in the back and playing 'match up' games. As mentioned above there's likely multiple things that would work, some with modification, others without. That's exactly what these kit makers are doing - grabbing random domestic V8 serp tensioners and then either fitting as-is or making slight mods and then fitting them. The number of tensioners that look "almost exactly the same but not" is mind-boggling and same goes for pulleys...
2003 M3CicM6 TiAg
2002 540iT Sport Vortech S/C 6MT LSD TiAg
2008 Audi A3 2.0T DSG (the daily beater)
2014 BMW X1 xDrive28i (wifemobile)
Former:
1985 MB Euro graymarket 300SL
1995.5 Audi S6 Avant (utility/winter billetturbobattlewagen)
My belt was wearing more before the coating due to slipping. I also switched from the Gates Fleet belt to the Gatorback - also an improvement.
I understand that the Gates RPM belt is specifically made for superchargers, but they don't make a length my size.
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o 1997 540i6 o Dinan supercharger system o Dinan stage 3 suspension system o Dinan wheels o UUC EVO3 SSK/DSSR o SS Headers o M-Tech illuminated shifter o M5 3.62 LSD o Cubic trim o Gauge rings o OEM In-dash CD o Ultimate pedals o Hella AE's o M-Sport Steering Wheel o 400 RWHP o A/W intercooler o Killer Chiller
Yeah, that makes sense if your slipping. Right now, I have lots of wrap and no slip and my belt lasts a long time. Currently on a 2.87" 6 rib pulley. I may go smaller pulley at some point, so may need this coating then. Thanks for posting. I should be able to hit close to 20 psi if it doesn't slip.
- - - Updated - - -
I like those green fleet runner belts as GG posted above.
98 540i 6, 525 whp, 120 mph 1/4, V3 Si S/C'er @16 psi, W/A I/C, Water/Meth, Supersprint Headers, HJS Cats, 3" Custom Exhaust, UUC Twin Disc, Wavetrac LSD, GC Coil Overs, Monoball TA, AEM FP, Aeromotive FPR, AEM Failsafe AFR/Boost, Style 65's w/275's, M5 Steering Box, Eibach Sways, M3 Shifter, Evans Coolant, 85 Deg Stat, PWM Fan, 10" Subs, B.A. speakers, Grom Aux/BT, Still Rolling as my DD!
Yeah I have some brand new Gatorback belts in my vast collection of useless belts (Gatorbacks are what my used VF kit came with) but I like the Fleetrunners better...
2003 M3CicM6 TiAg
2002 540iT Sport Vortech S/C 6MT LSD TiAg
2008 Audi A3 2.0T DSG (the daily beater)
2014 BMW X1 xDrive28i (wifemobile)
Former:
1985 MB Euro graymarket 300SL
1995.5 Audi S6 Avant (utility/winter billetturbobattlewagen)
o 1997 540i6 o Dinan supercharger system o Dinan stage 3 suspension system o Dinan wheels o UUC EVO3 SSK/DSSR o SS Headers o M-Tech illuminated shifter o M5 3.62 LSD o Cubic trim o Gauge rings o OEM In-dash CD o Ultimate pedals o Hella AE's o M-Sport Steering Wheel o 400 RWHP o A/W intercooler o Killer Chiller
Thanks for your reply! - I am just now seeing it!
I took the Dinan 7 off the road all of 2018 for complete cooling system refresh, power steering lines replacement, Valve cover gaskets, and dozens of seals and washers, brake lines, belts, tensioners, etc
Just now back on the road in 2019.
The pulley for my applications measures:
Pulley Outside Diameter (mm): 78mm
Pulley Inside Diameter (mm): 17mm
Pulley Width (mm): 32.5mm
I ended up finding Gates 36094 ($19) that worked perfectly. (sadly made in China now)
For the spring tensioner - it appears physically to be the Dayco 89202. EBay has best deal I can find at ~ $46
There is not a '202' # on the back but there is a '201' as well as 3620164.
My spring tensioner still applies plenty of spring tension however the arm has some scary lateral play causing the belt to ride to the front edge of the pulley. Seemed to be excessive play and movement of the arm off the rotating axis.
I took a 16mm socket to the front side collar and hammered the collar to tighten it about a 1/16 or maybe even and 1/8" and then punched the center hollow shaft edges to hold the collar from backing off and reassembled with the mounting bolt to the SC bracket for temporary fix but do not trust it will stay put. However when back on the car the belt stayed in perfect alignment centered on the new pulley.
ppapadidio
"BK"
2000 Dinan 7 (740iL)
After all my previous drama with the Dinan setup, I had to abandon it and go with a pinch tensioner like the one RMS makes. The spring tensioner did not apply consistent tension and bounced around on the belt. It caused my belt to fail too many times to count... Especially if you go up from the stock 6psi of boost. It also required me to go with their bracket.. I still have all the old Dinan stuff if you're interested in buying it... Good luck!
'98 RMS stage 2+++++(491whp/390tq VAC cams, CES Cutring-9:1, Built blower, Meth etc)
'09 Saab 9-5 Combi 5mt 1 of 1(Built Motor, Brembos, LSD, the works!)
'22 Cadillac CT4-V BlackWing 6mt
'22 Cadillac CT4 2.0T Sport AWD (wife's)
'98 RMS stage 2+++++(491whp/390tq VAC cams, CES Cutring-9:1, Built blower, Meth etc)
'09 Saab 9-5 Combi 5mt 1 of 1(Built Motor, Brembos, LSD, the works!)
'22 Cadillac CT4-V BlackWing 6mt
'22 Cadillac CT4 2.0T Sport AWD (wife's)
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