|October 19th, 2011, 05:50 PM||#1|
Join Date: Jul 2005
Location: Orlando/Daytona, FL
Now available smaller pulleys for 2011-2012 Roush 5.0L
I have spent a lot of time with the Roush blower on Rebecca's 2011 5.0L and have manufactured pulleys that will fit the needs of most people, starting at $129:
The Roush kit comes with a 90MM pulley (about 3.5in) which makes 7.5psi with average variable came settings.
The first step down is an 82MM pulley, I made this size because it is a good way to add 20-30HP and even more TQ, without maxing out the stock fuel pump and Roush supplied 47lb injectors. You can rev the car all the way out to 7500RPM and hold an 11.5:1 air/fuel ratio. This makes about 9.5psi.
The next step down is a 79MM pulley which I just came out with. Its for the guy that wants a little bit more, but doesn't want to jump down to 75MM and upgrade the fuel. If you are running a manual and rev limit it and shift at 7100RPM you will be fine on fuel. If you have an auto car, which I recommend shifting closer to 7500RPM for best ETs, the a/f will start to rise up to 12:1 by 7500RPM. This can be compensated for with higher octane gas that is more knock resistant at leaner A/Fs. This pulley makes 10psi.
When you jump down to the 75MM pulley, you should start thinking about fuel upgrades. The first to go are the stock 47lb injectors, you can still get away with the stock pump, especially if you turn up the alternator voltage a little at higher fuel flows in the tune. This pulley makes 10.5psi.
Next I have the 72MM pulley, your stock pump will begin to show weakness at this point, you will see the short term fuel trims trying to add a bunch of fuel at high RPMs. Time for a larger unit or a pump voltage booster (I will have a plug and play VMP Fuel Amp available soon). This pulley makes 11.5psi. Several auto cars have ran low 10s with this setup and race fuel.
The smallest of them all (so far) is the 69MM pulley. This makes a solid 12psi. Injector and pump upgrades required. 1" shorter belt recommended at this point, with a larger idler pulley. This pulley has put two full weight cars into the 9s with the stock airbox. With an open intake this pulley should make 15-16psi or more.
All of these pulleys are made from billet aluminum to my specs and black anodized, with the exception of the 69MM which is made from steel for strength and powdercoated.
I have plans to introduce an 8-Rib conversion kit for the Roush kits, which will also fit the FRPP Whipple kits since it is the same belt system.
When datalogging boost on the new 5.0Ls you have to be careful how you look at it. There is a port on the passenger side rear intake runner on the Roush and Whipple kits that you can get a measurement from, but it will vary a lot. The line that runs under the lower intake will give you a slightly more stable reading, but you should still look at it and take the average, not the peaks. Analog gauge tend to give a smoother reading.
If you are running an open element GT500 style air intake the boost will go up by about 2psi with the larger pulleys, and even more with the smaller pulleys. You have to watch out as this will quickly max the fuel system. I prefer to just pulley the cars down rather than install an open intake until you do fuel upgrades, as this allows you to reap low end TQ and HP benefits, rather than just peak HP benefits.
*Boost will be ~2psi higher if you pull the VCT back to zero like the FRPP tune for the Whipple.
Justin Starkey - VMP Tuning - Ford & GM Tuning
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