Does anyone know the max CFM(airflow) for the stock 6.0l motor? I do not want the flow through the OEM filter, but the motor itself ie. from the Mass air meter onward. No info in tech folder.

 

Based on my calculations, it looks like it would be about 990 CFM. That is assuming STP (standard temperature and pressure), 4200 RPM, and 29 psi boost. The actual CFM may be lower due to the intake air temp being higher than 21 °C. But for a ball park number it should be OK.

Just as a side note, at 990 CFM the exhaust velocity out the stock tail pipe is about 151 MPH.

 

Very interesting. How does the intercooler and intake elbow play in this equation? What would the flow difference be with the High Ram intake and after cooler from Banks? (sure is a lot of bucks for these pieces though)

 

Thanks, laredo7mma. I am actually thinking of doing my own intake setup and am looking at several different set-ups using various filter designs and shapes. I just need a good base line to start. I think I am going to go with the actual surface area of the filter and improve on that. The stock filter does not have that much surface area so any larger K&N with more surface area should flow =to or greater than the OE set-up. Well let the games begin...

 

I don’t think the Banks’ system would effect the CFM of the engine unless the stock system is choking the airflow. The 990 CFM is an estimate based on quite a few assumptions. Fluid flow (air or liquid) is some pretty tricky stuff to calculate. I did not take into account anything execpt for what the engine can pump based on displacement, RPM, and intake pressure.

I think Banks claims that their product reduces pressure loss, which to me, suggests that they have less flow restrictions. But it is kind of misleading because pressure loss does not mean you are loosing boost pressure. Pressure loss in terms of fluid flow means your flow has sped up. The faster the flow through a pipe means the lower the pressure. The fluid flow through the pipe will speed up if the cross sectional area decreases. If the pipe has a lot of bends/irregularities then you can have efficiency losses which in effect is an area reduction. Pressure loss is measured between two points in a system. Usually before and after a nozzle or bend, so your loss can be described as a delta.

Faster flow is not necessarily a bad thing until you get to the point where your flow goes into transition and starts to get supersonic (about 1129 ft/s at STP). At that point it doesn’t matter how hard you try to push the fluid, it won’t flow any faster until you modify the pipe geometry. That is called “choked flow.” But the transition point changes with temperature, pressure, and what the fluid is composed of (the speed of sound in water is about 4850 ft/s). That is why exhaust manifolds can be smaller in cross-sectional area than exhaust pipes (the exhaust gas is a lot hotter in the manifold than in the exhaust pipe). By doing another quick calculation, the flow in the inter-cooler pipe would have to be around 2300CFM before the flow would start to go into transition. That is based on a 2.5-inch diameter pipe with a cross-sectional area of 0.0341 square feet (I don’t know what stock is).

If the Banks’ system is using bigger tubing/passages in their inter-cooler and ducting, then this would probably be better than the stock system because the flow is traveling slower and thus allowing more time for heat to be transferred out of the fluid. Plus if the turbo doesn’t have to work as hard to move the air, then turbo lag could be decreased.

I think that the Banks system would show increases over the stock system. From what I understand, Banks is very reputable and I doubt that they would make unfounded or false claims. But whether or not the gains are worth the investment, that is a personal choice.