Aster bracket guys
#3
Tip: make a bolt with the head of the bolt cut off that is the same size as the allen bolt (3/8 I recall). Remove the driver side allen bolt (the not large one, the one just next to it. Insert the bolt thru the j bracket and head unit.
This home-made pin will hold the head unit in place as you install or remove the remaining allen bolts. When removing head unit it will be held in place by the pin - no need to worry about dropping it as you remove the remaining bolts.
When installing the head unit simply slide it with the pin in place onto the jbracket.. The pin holds it as you move it back and forth to start the remaining bolts. No need to fight having to hold the head unit in place as you try to screw in the remaining allen bolts - or worse cross thread them. The pin also makes it easier to get the belt onto the blower pulley as you rock the head unit back and forth (riding on the pin) as you put on the belt.
Works like a charm.
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#8
IMO it depends upon how much boost you want to make and your pulley configuration. Also assumes you are running eight rib pulleys. It also depends on which blower you are using - P1, D1 etc. and how fast you are spinning it.
So if you want to spin it up to 6800 rpms it might slip on top end compared to spinning it to 6200 rpm where it might not. Since I have an 4l60e I can't spin the engine to 6800 rpm or more.
If you are running less than 10 lbs of boost and your charger pulley is larger than 4 inches and the crank pulley is 7.65 and you are running the Gates FleetRunner green belt and see no belt dust (caused by slippage) then probably don't need one.
However, with the same combination above and you are seeing belt dust then a simple test might be to try the Gates RPM product line. It's a product line recently introduced by Gates strictly for FI cars and the fact that a lot of factory cars now have FI. Gates and users say an RPM belt eliminates belt slip because of it's construction and materials used compared the green belt.
So for a $50 investment one could try an RPM belt first. If it works then you are done but if NOT then SD Concepts and Aster are options.
Another option is to add a second idler pulley to the J Bracket. The second idler pulley will help with belt slip because it adds more belt wrap. I have tried a second idler pulley but with a 7.65 crank pulley and 4.00 SC pulley I can't find a belt that will fit. However there are other pulley combinations that might (4.50, 4.37, 4.20 and so on). I even reduced the size of the idler pulley down with a 50 mm idler pulley off of CTS-V. A downside with an second idler pulley is that you have to machine your j bracket to keep the allen bolt that is behind the idler pulley or leave the allen bolt out. Or drill and machine a second hole in the j bracket that is exactly 180 degrees opposite of the largest bolt on the j bracket driver side of the bracket. This additional bolt hole accepts the largest allen bolt and IMO secures the SC more securely to the j bracket.
A second idler pulley is cheaper if it works.
A third option is the install a larger crank pulley going from 7.65 to 8.65. The larger the crank pulley the more belt wrap. If we assume there is at least 60 percent belt wrap on either pulley the 8.65 pulley gives you approximately two more inches of belt wrap than the 7.65 pulley.
However to compensate for the larger crank pulley and still maintain the same rpm on the sc you will have to change the sc pulley.
A larger crank pulley and sc pulley with new belt is cheaper if it works.
In hindsight - had I known about the RPM belt line - the best option for me would have been to install a larger crank pulley, smaller sc pulley and use an RPM belt.
This option is cheaper by about half of the cost. That said I intend to only run about 12 lbs of boost. This option might not work if you wanted to run more boost and spin the blower to its maximum rpm. However, I have already purchased an Aster bracket so too late now.
FWIW - a new j bracket from Procharger is about a couple hundred dollars.
To summarize - hot rodding/making horsepower costs money. It is what it is.
So if you want to spin it up to 6800 rpms it might slip on top end compared to spinning it to 6200 rpm where it might not. Since I have an 4l60e I can't spin the engine to 6800 rpm or more.
If you are running less than 10 lbs of boost and your charger pulley is larger than 4 inches and the crank pulley is 7.65 and you are running the Gates FleetRunner green belt and see no belt dust (caused by slippage) then probably don't need one.
However, with the same combination above and you are seeing belt dust then a simple test might be to try the Gates RPM product line. It's a product line recently introduced by Gates strictly for FI cars and the fact that a lot of factory cars now have FI. Gates and users say an RPM belt eliminates belt slip because of it's construction and materials used compared the green belt.
So for a $50 investment one could try an RPM belt first. If it works then you are done but if NOT then SD Concepts and Aster are options.
Another option is to add a second idler pulley to the J Bracket. The second idler pulley will help with belt slip because it adds more belt wrap. I have tried a second idler pulley but with a 7.65 crank pulley and 4.00 SC pulley I can't find a belt that will fit. However there are other pulley combinations that might (4.50, 4.37, 4.20 and so on). I even reduced the size of the idler pulley down with a 50 mm idler pulley off of CTS-V. A downside with an second idler pulley is that you have to machine your j bracket to keep the allen bolt that is behind the idler pulley or leave the allen bolt out. Or drill and machine a second hole in the j bracket that is exactly 180 degrees opposite of the largest bolt on the j bracket driver side of the bracket. This additional bolt hole accepts the largest allen bolt and IMO secures the SC more securely to the j bracket.
A second idler pulley is cheaper if it works.
A third option is the install a larger crank pulley going from 7.65 to 8.65. The larger the crank pulley the more belt wrap. If we assume there is at least 60 percent belt wrap on either pulley the 8.65 pulley gives you approximately two more inches of belt wrap than the 7.65 pulley.
However to compensate for the larger crank pulley and still maintain the same rpm on the sc you will have to change the sc pulley.
A larger crank pulley and sc pulley with new belt is cheaper if it works.
In hindsight - had I known about the RPM belt line - the best option for me would have been to install a larger crank pulley, smaller sc pulley and use an RPM belt.
This option is cheaper by about half of the cost. That said I intend to only run about 12 lbs of boost. This option might not work if you wanted to run more boost and spin the blower to its maximum rpm. However, I have already purchased an Aster bracket so too late now.
FWIW - a new j bracket from Procharger is about a couple hundred dollars.
To summarize - hot rodding/making horsepower costs money. It is what it is.
Last edited by dlandsvZ28; 07-16-2018 at 11:06 AM.
#9
Gates RPM Product line for supercharged applications:
"RPM (Racing, Performance, Muscle) is a new, no compromise belt built specifically for supercharged applications.
Whereas 99% of all belts on the market today use a polyester tensile cord, the RPM series uses an aramid tensile cord. This is the same fiber found in bulletproof vests and is 10x stronger than steel and 5x less elastic than polyester. When polyester heats up (which it does even from normal use) it will stretch out. As you can imagine, when that belt stretches out you experience belt slip and boost loss. Eventually the elastic properties of the polyester will fail and the belt that was once 100” will stretch to 100.25”, at which point the tensioner can no longer compensate for the stretch and generally results in belt failure.
Due to the strength and minimal elasticity of aramid fiber, the RPM series of belts will not stretch which allows the belt to maintain its true length throughout its service life. This results in more consistent boost and in some instances, users have reported a 1-2psi increase merely from switching from HD belts to RPM belts. We actually have some user submitted under hood video on our Instagram page (GatesRPM) that clearly demonstrates the difference between polyester and aramid corded belts.
Another main benefit of the RPM line is the use of two layers of adhesion gum. These layers create a sandwich around the tensile cords which transfers the load to the strongest part of the belt; the jacket (or smooth backside of the belt). FleetRunner HD belts got a reputation for strength because they use one layer of adhesion gum, standard micro-v belts forgo any adhesion gum.
RPM belts also utilize a patented rubber compound with the highest coefficient of friction available and are built in common OE supercharger sizes as well as many sizes used with aftermarket setups. The RPM line has expanded to 299 part numbers with new numbers being added every quarter. "
Link below - is an interesting read on how to tension the RPM belt compared to a Green. Completely opposite to promote long belt life.
https://www.svtperformance.com/forum...lower.1140578/
"RPM (Racing, Performance, Muscle) is a new, no compromise belt built specifically for supercharged applications.
Whereas 99% of all belts on the market today use a polyester tensile cord, the RPM series uses an aramid tensile cord. This is the same fiber found in bulletproof vests and is 10x stronger than steel and 5x less elastic than polyester. When polyester heats up (which it does even from normal use) it will stretch out. As you can imagine, when that belt stretches out you experience belt slip and boost loss. Eventually the elastic properties of the polyester will fail and the belt that was once 100” will stretch to 100.25”, at which point the tensioner can no longer compensate for the stretch and generally results in belt failure.
Due to the strength and minimal elasticity of aramid fiber, the RPM series of belts will not stretch which allows the belt to maintain its true length throughout its service life. This results in more consistent boost and in some instances, users have reported a 1-2psi increase merely from switching from HD belts to RPM belts. We actually have some user submitted under hood video on our Instagram page (GatesRPM) that clearly demonstrates the difference between polyester and aramid corded belts.
Another main benefit of the RPM line is the use of two layers of adhesion gum. These layers create a sandwich around the tensile cords which transfers the load to the strongest part of the belt; the jacket (or smooth backside of the belt). FleetRunner HD belts got a reputation for strength because they use one layer of adhesion gum, standard micro-v belts forgo any adhesion gum.
RPM belts also utilize a patented rubber compound with the highest coefficient of friction available and are built in common OE supercharger sizes as well as many sizes used with aftermarket setups. The RPM line has expanded to 299 part numbers with new numbers being added every quarter. "
Link below - is an interesting read on how to tension the RPM belt compared to a Green. Completely opposite to promote long belt life.
https://www.svtperformance.com/forum...lower.1140578/