gkzr1

I have been doing some various testing with different belt setups and idlers lately and have found some interesting info.

First off these bando belts SLIP, especially on cars with 2.3 pullies. It is recommended by LPE that you run 76mm idlers on both sides to make their 82.5 inch belt fit correctly which is correct, BUT if you are getting slip you may want to double check on the amount of tension you have after putting some miles on that belt. Just out of curiosity, I went ahead and tried to install the stock 90mm idler on the drivers side to tighten up the belt a little bit and add some more belt wrap. What do you know, it fit, so I went ahead and tried the 100mm idler... yes the 100, that tightened everything up nicely and still kept the tensioner within spec. I only have a few hundred miles on that bando belt and it has already stetched enough to fit on the 100mm drivers side idler.

Side Note:My 2.3 is notched and also has a carbinite racing coating on it which is definitely creating more belt dust and premature belt wear. This is still concerning because I would be you guys with a couple thousand miles of a slipping bando on a 2.3 pulley probably have belts that have stretched. Go ahead and try to fit that 90 on the drivers side to get some more belt wrap. While you do, check your belts to make sure you dont have excessive wear, and look around near your passenger side 76mm idler right above the thermostat to make sure there isn't an alarming amount of belt dust in there.

I currently have a brand new 2.3 on the way from LPE that I am going to be testing in combination with a Gates Green Micro-V Fleetrunner belt. Because gates doesn't make the proper size belt for our application, I bought their 12 rib 2083mm belt. I cut it down to 11 rib and will be running (2) 50mm CTS-v idlers on each side to give me the slack I need to make the belt fit. I have already test fit the belt and it fits very very snug but is not maxing out the tensioner. Once the new pulley gets here I am going to take the car out one day doing multiple 3rd and 4th gear pulls logging boost to see which setup is slipping the least/making the most boost. Im hoping the gates with the non-notched pulley won't slip and will stop this crazy dusting issue im having due to the notches/coating.

Will be reporting back within a week or so with results.

C5kid

My bet is that the non-carbinite pulley & Gates Green Fleet belt will help.

Gates also makes a belt that has diagonal cuts, I had great success with those belts on my C5. I had 3.0" pulley on a P1 that had no belt slip. I'll try to find one and snap a pic when I get home.

gkzr1

I know for sure it will cut down and almost stop the dust. I may start seeing some more slip though, if thats the case I will notch the pulley again but will not get it coated.

GIO-305

So I guess doing the carbinite coating is not worth it? Is it eating up the belt?

gkzr1

unfortunately yes, it is chewing up my belt very very bad. I scraped this off the flat area above the thermostat housing after one night of some racing in mexico.

GIO-305

Yea Pete was talking to me about it and said that was happening to others

C5kid

I could see the carbinite coating working for a strictly drag strip car. Street cars, it's just too aggressive, unless you wanna change belts with every oil change.

ss2z06

That's great information! Thank you for posting and testing! I'm surprised I haven't seen vendors really get involved with a solution. What size is the stock idler? I am waiting to install my 2.3 and od pulley. I got the 76mm idler but may switch that around depending on your results. Is part of the issue the stock spring loaded tensioner not being able to keep it tight enough? If so I know this was a common issue on c5's and katech made an adjustable tensioner. That may help with some of the problem if anyone makes one for our setups. What did you do to groove your pulley? Any pics of that by chance?

911/Q45

Not to be too much of a dick, but this illustrates the difference between factory and aftermarket engineering.

gkzr1

I do have some pictures I can post up later tonight or tomorrow. The stock idlers are 90mm on the driver side and 76mm on passenger side. No one currently offers a manual tensioner to my knowledge. To notch the pulley we put 5 angled cuts with a dremel in the pulley and than I had it sent out for the coating. Both the gatorback and bando dusted the same amount so that is pointing toward the pulley. The notches probably to contribute to the wear/dust issues but the main issue is the carbinite coating.

gkzr1

So by saying you don't mean to be "too much" of a dick, you are admitting you are being a dick... Not sure what drove you to make that remark but regardless, anyone who has experience modding cars knows there are always speed bumps along the way. I posted this thread up with information about belt slip etc. to share my experience and help anyone who may be having the same issues. I don't think anyone who is reading in this thread wants to hear you preach about how modding cars causes problems... If you don't have anything constructive to contribute, please stay out.

911/Q45

It's probably constructive for anyone who is considering modding to also consider the comparitive thoroughness of the engineering done by the factory vs. the aftermarket. Dick or not, I think there is value added to applying this lesson at the very point of failure.

whatcop?

Just for reference my stock belt was slipping. Its a poor design on the factories part. The tensioner pulls up and out away from the supercharger pulley which is a horrible setup. Look at the CTSV or ZL1 and they both have proper belt wrap.

gkzr1

Like Whatcop said, stock belts slip, I also found belt dust in my idlers after only 1,000 miles on my car. Thoroughness? Thorough enough to notice that 2009-2011 the brakes vibrated? Thorough enough to not have valves dropping like flies in zo6s? How about the tons of catalytic converter failures on bone stock cars? Again, I posted this info up to inform those who want to mods their cars of some of the speed bumps they may run into and to also help those who currently have the issue. You sound like someone who likes to troll the forum and act like your car is perfect from the factory because your too much of a.... Ahem.. to mod it. If that's not the case than I don't know why you even took the time to post here.

Nanook

Very interesting topic...which raises the question..how can we ascertain maximum efficiency of our belt driven blower and to what degree it may be slipping...if any ?

911/Q45

I found no evidence of slippage after over 30K miles of hard use. My blower belt has the same amount of dust on it as the other belt. My brakes have also never vibrated through two sets of rotors and 5 sets of pads. My frequent track use has led to cat failure, but I've not heard of any aftermarket cats that are better than the factory ones. I guess I'm not naive enough to believe that the aftermarket can add lots of power without negative reliability consequences. My dad told me never to wrestle with a pig because you can't win, the pig likes it and you get covered with poop. I'll quit wrestling now, good luck with your mods.

whatcop?

The slippage on a stock belt is small but its still slippage. The belt will eventually wear and show more signs of slippage. If you had data logs to compare with when you bought the car vs. now I wouldn't be surprised if you were losing a little boost or it was starting to fluctuate. The stock analog gauge is not very accurate at all so its a bad comparison factor.

Also you live in a warm weather climate which helps a belt to grip. Secondly you road course which means you build up more heat in the belt to make it grippy while you are doing your warm up laps so by the time you bring down the hammer it will slip less. For us that drag race we like our cars nice and cold to maximize power so we are more prone to seeing slip. Also gkzr1 is up in PA and their temps have been getting low so that will make the problem even worse.

I am willing to bet if you got a brand new belt and compared it with yours the ribs on the belt on your car would be skinnier. Also compare the tensioner position on your car vs a newer car and you will see yours is probably almost maxed out.


Another thing to keep in mind that as we add power we spin the crank faster which in turn spins the belt faster which in turn can cause more slip. If the tensioner was correct on the car this whole issue would never appear.

Nanook

These modded beasts running big boost..18+ must be in a real ongoing battle with this..is direct drive an option ? What's a stock belt cost ? If the belt is wearing what's the result on the pulley ?

gkzr1

Dust isn't just going to accumulate on your belt.. If its only slipping slightly you won't notice it unless you compare it to a brand new belt like WhatCop said. It doesn't matter if YOUR brakes have never vibrated, you obviously missed the point. There are plenty of modifications you can do without affecting drivability. I'm willing to go past that point and loss some drivability if need be to get the power I am looking for, and that is my decision. To be quite honest my car drives like stock, this belt slip issue is the only problem I have had and am in the process of fixing it as well. I know one thing, you sure are naive enough to believe that GM built a perfect dream machine that has no issues.... Keep sippin down that kool-aid man.

whatcop?

No direct or flip drive systems available. I'm not sure about the stock belts, but the Gatorback and Bando belts from LPE is $99 and the Gates belt that gkzr1 is trying is $60. On my pulley I was able to datalog and see the boost loss. The pulley due to the slipping and I am assuming heat generated actually wore through the anodizing. I can now see the bare steel on the pulley. I partially think the ribs on the pulley are not thick enough to begin with so they are partially causing the slip issue. The fact that the anodizing only wore away on the tops of the pulley ribs really makes me think the belt isn't sitting properly on the pulley.