OrangeL67
New member
We've all heard of belt slip, and we all know what it is. The problem is, if we don't know how to identify it, we probably won't know if we are being robbed of power by it. Before I go into detail, let me first say that a belt wrap system is on the same level as my cam/e85/& Intercooler in terms of providing power to the wheels.
Out of sight, out of mind. That is until you are pushing for a performance goal and can't seem to translate your mods into a desired 1/4 mile or trap speed. Remember, you don't have to have a 2.55 pulley to see belt slip. My 3.3 and 3.1" setup both had some belt slip. Minimal as it may have been, the signs were still present. The effects just were not enough at that point to concern me.
The first and most accurate thing you can do to ID belt slip is get yourself a boost gauge. On a 2.8" pulley, my boost would rise to 11.2-11.6 psi at 5000 RPM at WOT. Above 5k, it would drop quickly back into the mid-high 9psi range and would not climb far above 10psi thereafter.
Another very important thing to look for is rubber dust. This is black oily looking dust that accumulates around everything that is near the supercharger pulley. This dust is rubber from your belt slipping, just as you will get rubber all over your fenders when you do a burnout.
Notice the dust on the coolant bottle and the fuse box cover
And for those of you with hard-core setups (2.8 pulley and smaller) You may actually hear a screeching rubber burning sound at high rpm's. In a minor slip situation, you may hear a small chirp during shifts at WOT. In a more severe situation, you will hear the belt doing a burnout under your hood from 5000 RPM to Red line! you can even smoke the belt.
HOW TO FIX THE PROBLEM...
Smaller belts and oversize tension pulleys can help, but they can only do so much. Think about this; You want to twist a bottle cap off. You are strong enough, but cannot get a good grip on the cap. so you wrap your elbow around a light pole to get leverage on the bottle cap. This could help, but it's silly and it probably won't spin the cap anyway. You need to get a better hold on the cap itself. Better leverage increases your strength, but it's useless if you are already strong enough to twist the cap. The more effective way to open the bottle is to find a better way to grip the cap. When the belt is the correct size, and your stock tensioner is working fine, you need to address the core of the problem: GRIP.
This is where the Belt wrap system comes into play. This helps the belt contact 2/3rds of the pulley surface as apposed to a little over half.
Notice how the belt completely covers the front wall of the pulley in the picture using a W-Body Store Belt wrap system and compare it to the previous pictures
Installing this system not only stopped my boost from dropping after 5k RPM's, It also allowed me to GAIN 1.6 PSI from 5k to shift point maxing out at 12.5 pounds on a 2.8 pulley ( & 13.7 on a 2.6). This is a gain of roughly 3 &1/2 pounds of boost from 5k to redline on a 2.8! You can probably imagine the contrast of top end power with the belt wrap installed. Probably my best mod for the money spent. Just something to think about if you have a small pulley M90 build.
Out of sight, out of mind. That is until you are pushing for a performance goal and can't seem to translate your mods into a desired 1/4 mile or trap speed. Remember, you don't have to have a 2.55 pulley to see belt slip. My 3.3 and 3.1" setup both had some belt slip. Minimal as it may have been, the signs were still present. The effects just were not enough at that point to concern me.
The first and most accurate thing you can do to ID belt slip is get yourself a boost gauge. On a 2.8" pulley, my boost would rise to 11.2-11.6 psi at 5000 RPM at WOT. Above 5k, it would drop quickly back into the mid-high 9psi range and would not climb far above 10psi thereafter.
Another very important thing to look for is rubber dust. This is black oily looking dust that accumulates around everything that is near the supercharger pulley. This dust is rubber from your belt slipping, just as you will get rubber all over your fenders when you do a burnout.
Notice the dust on the coolant bottle and the fuse box cover
And for those of you with hard-core setups (2.8 pulley and smaller) You may actually hear a screeching rubber burning sound at high rpm's. In a minor slip situation, you may hear a small chirp during shifts at WOT. In a more severe situation, you will hear the belt doing a burnout under your hood from 5000 RPM to Red line! you can even smoke the belt.
HOW TO FIX THE PROBLEM...
Smaller belts and oversize tension pulleys can help, but they can only do so much. Think about this; You want to twist a bottle cap off. You are strong enough, but cannot get a good grip on the cap. so you wrap your elbow around a light pole to get leverage on the bottle cap. This could help, but it's silly and it probably won't spin the cap anyway. You need to get a better hold on the cap itself. Better leverage increases your strength, but it's useless if you are already strong enough to twist the cap. The more effective way to open the bottle is to find a better way to grip the cap. When the belt is the correct size, and your stock tensioner is working fine, you need to address the core of the problem: GRIP.
This is where the Belt wrap system comes into play. This helps the belt contact 2/3rds of the pulley surface as apposed to a little over half.
Notice how the belt completely covers the front wall of the pulley in the picture using a W-Body Store Belt wrap system and compare it to the previous pictures
Installing this system not only stopped my boost from dropping after 5k RPM's, It also allowed me to GAIN 1.6 PSI from 5k to shift point maxing out at 12.5 pounds on a 2.8 pulley ( & 13.7 on a 2.6). This is a gain of roughly 3 &1/2 pounds of boost from 5k to redline on a 2.8! You can probably imagine the contrast of top end power with the belt wrap installed. Probably my best mod for the money spent. Just something to think about if you have a small pulley M90 build.
