Dinan supercharger belt tensioner

[philly98540]

I also had my SC pulley coated by these guys. Works awesome.

http://www.carbiniteracing.com/pulley/pulley.html

Looks like a great coating. Does your belt wear much quicker?

[geargrinder]

For my application, I need a belt with spec of 8PK1415 (the 1400 is too short and the 1425) is too long. The only manufacturer I found that makes this length is Gates, but its in their standard line. They have an RPM line

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...

I'm also back to an 8PK1400 belt and have about 3/4" of space between the sides of the belt (Its really tight, so I'm forced to push it onto the top of the SC pulley and then use a wrench to turn the pulley until it seats all the way - def not ideal, but serviceable). Your application is different, though and I can't help you with the length. It should start with 6PK... Good luck - perhaps your current belt will last a bit longer?

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.

That would be the handiwork of RMS.

LOL.

If you look at the back of your tensioner, see if '202' is inscribed somewhere. Its in both part numbers I listed and also in my first pic from my 26Mar post. The pulley will likely need to be replaced, but I'm certain you can find something similar at your local parts store - bring the old setup with you and they'll help you find what you need...

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...

[540-S3]

Looks like a great coating. Does your belt wear much quicker?

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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[philly98540]

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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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.

[geargrinder]

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...

[540-S3]

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...

I tried the Fleetrunners as well, but for me the Gatorback worked better.

Anyone try the RPM belts?

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[ppapadidio]

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.

Hey, I can't tell from the pic, but your tensioner looks identical to the E36/M Coupe tensioner we have listed above:
Dayco part (89202)
Duralast part (305202) (Autozone)

You should be able to pick it up for $35-$45

If you look at the back of your tensioner, see if '202' is inscribed somewhere. Its in both part numbers I listed and also in my first pic from my 26Mar post. The pulley will likely need to be replaced, but I'm certain you can find something similar at your local parts store - bring the old setup with you and they'll help you find what you need... I had to go back and forth over a couple of days for various pulley and belts to arrive. The pulley should cost anywhere from $16-$65 depending on material and quality of bearing. Also someone above mentioned the tensioner to pulley bolt was reverse thread. They Duralast one I picked up was regular thread.

For everyone else, I ended up needing a new custom pulley as the 3ish inch one from RMS immediately stretched the new belt so that it touched itself - no not like the song. My buddy has a mill and lathe in his garage, so we spend 8 hours designing and building a 2.1" pulley using the 6203 spec bearings mentioned previously. I'm also back to an 8PK1400 belt and have about 3/4" of space between the sides of the belt (Its really tight, so I'm forced to push it onto the top of the SC pulley and then use a wrench to turn the pulley until it seats all the way - def not ideal, but serviceable). Your application is different, though and I can't help you with the length. It should start with 6PK... Good luck - perhaps your current belt will last a bit longer?

[///MGRILL24]

Just leaving this here to update a really old thread. I recently acquired a nice 2004 M3 with some Dinan upgrades and was looking for a replacement tensioner that was not $250. So what I have found so far is that the dinan tensioner uses off the shelf dayco parts. The only difficulty is finding them as a single unit. The pulley is a Dayco 89005. This is very similar to the original but the bearings are a bit bigger now (NTN 6303LU now vs NTN 6203LH in the original. Inside bearing diameter is the same outside is slightly larger, but the pulley diameter and width are identical). I haven't been able to find this pulley mounted to a tensioner yet but the one I got from Autozone is nearly identical. I hope to find some concrete source for this in a day or two. I have attached some pictures of the original pulley and the tensioner bodies for reference.
Attachment 576111

It looks like I have to buy a pulley "dayco 89104" and then buy a tensioner "dayco 89202" and put the two together. Is that what you found? S50 v2 vortech SC. Thank you good sir!

[sagggas]

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!

[Jamesons Viggen]

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!

Same thing just happened to me.

I was fine at 11-12psi.

But now that I'm shooting for 18psi the Dinan bracket and tensioner were causing belt slip.

So now I've got the RMS bracket and manual tensioner.

Feels good, I'll need a dyno to verify.

[GG///M3]

Same thing just happened to me.

I was fine at 11-12psi.

But now that I'm shooting for 18psi the Dinan bracket and tensioner were causing belt slip.

So now I've got the RMS bracket and manual tensioner.

Feels good, I'll need a dyno to verify.

It’s too bad RMS customer service isn’t better


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[Jamesons Viggen]

It’s too bad RMS customer service isn’t better


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Agreed.

Luckily all the RMS stuff I have acquired has been through people other than Osh/RMS lol.