Ohhhhh you meant flat black, my bad. I wasn't even thinking that the current ones were gloss black.
No I mean black in general. They dont make one yet.
Ohhhhh you meant flat black, my bad. I wasn't even thinking that the current ones were gloss black.
FYI your blower is spinning @ 22,604 rpms @ 7000 engine rpm. That is 2,600 rpm past it's limit for making power according to the TVS compressor map. See below.
Dont they make aftermarket idlers that increase belt wrap on the snout? I had a metco when I ran the stock blower on my 500 with no belt slip(small upper). I also had one for my Whipple 3.4 from metco but never ran a small enough pulley up top to warrant it's use.
The lower
Lighter rotating mass, close in weight but enough to make a difference. Your gaining power due to the boost pressure increase but also gaining extra TQ due to the weight. The parasitic drag is going to be mainly from power robbing items like the blower, alt. water pump......but your a huge mustang shop guy....no? You know this already!
The difference in the belt wrap on the lower is going to be minimal at best.
Never planning on hitting 7k rpm anyway. But thanks for the input.
I see the graph is dated 2008, maybe they have improved. Never planning on hitting 7k rpm anyway. But thanks for the input.
Never gonna get to redline? Should have bought a Buick.
Weight is not the reason for the torque increase.
That is directly due to blower speed with less belt slippage.
Actually moving the weight away further from the the center of the crank will take more HP to turn . You always want the weight of a spinning object closer to the center if you are taking parasitic drag into consideration.
If you weigh the stock and a 10/15 percent OD pulley, the 10/15 percent is actually a couple ounces heavy than the stock pulley.
(Edit: The OD lower pulley is lighter than the heavy 2007 OEM pulley but heavier than the 08 -13' OEM lower pulley)
Don't they make aftermarket idlers that increase belt wrap on the snout?
Yes they do and they work pretty well, why because they are making the belt wrap around the pulley more(More work area to hold= less slippage).
There is a point to where you just can't get enough surface with the smaller pulley to carry the workload, especially when you are spinning the blower with an OD crank pulley already and using small upper. You have have a better chance of the smaller upper working if you do not run the lower crank, why less depend of the upper pulley (Blower speed)
Nicely put. :beer:
I just weighed all three lower pulleys.
Exact weights of the balancer's are:
The stock 07 is 21lbs, and the stock 08-12 lower is just about 10lbs, the IW 10% lower is 11lbs. I'm sure the 15% weighs even more than the 10% does.
I've seen numerous accounts of weighing the balancers and the results have always been as blackshelby listed. I've never heard anyone other than IW claim that the IW pullies are lighter than the stock one.
I don't think the minimal amount of weight we're talking about is going to have a dramatic affect on power either way; I think the fact that you get more surface area for the belt to wrap onto coupled with the higher rate of acceleration from the larger lower pulley is what creates your torque increase. 3 lbs is 3 lbs, but 3 lbs faster and earlier in the RPM range means more power across the board and more importantly more torque in the lower RPM range where a roots/twinscrew blower shines.
I understand what you say about the weight of the different lowers, also what black Shelby claims as far as what he weighed his at. Today IW told me that the weight difference was what they considered the reasoning for the TQ increase also(lighter than stock). It made since to me as all accounts of O.D. lowers created more TQ. vs. upper pulley only.
Your explanation makes the most logic to me on reasoning for the TQ increase. As IW is sticking to the lighter than the stock unit claim on the 13.