Stiegemeier Blower Installation (continued)

When you receive your supercharger back from Stiegemeier take a good look at the port work. While much of the work is inside the case and not visible, a quick look at the manifold side is enough to be convinced of the potential.	The inlet side of the blower gives a glimpse of how much work has been done inside the case. Look at the attention to detail - the vacuum port hole has an air-foil shape sculpted before it to guide air flow.
Reassemble the intercooler and lower manifold. Use a thick bead of RTV silicone sealer as shown.	Set the intercooler into place and use the stock hardware to secure.
Place the supercharger onto the lower manifold using the stock gasket. Reinstall the injectors, bypass and other accessories removed during disassembly. The bypass needs 1/8th of an inch preload from the adjustment screw. Install the EGR once the blower and intake manifold are installed on the car.	Trust us, you'll be able to perform the reinstallation in half the time it took to pull everything apart. Not because it's less work, but because of the anticipation of how much power you'll make.

Dyno Results
A few days before we took the stock blower off for shipment to Stiegemeier we had the car dynoed. We installed a 2.93" pulley in place of the 3.10" pulley (approximately 10 psi of boost) we had been running (3.65" is stock and yeilds around 8 psi of boost.) The change from 3.10" to 2.93" on our stock blower netted 438 horsepower and 438 ft.lbs. of torque with a peak boost of 12 psi.

With no other changes except for the Stage IV port work performed by Stiegemeier on our stock Eaton M112, plenum and throttle body, the gains jumped to nearly 50 additional horsepower and 20 ft.lbs. of torque. We used the same 2.93" pulley as the before test and the exact same custom tune we've been running supplied by the guys at Runnin' With the Devil. The graph below shows the gains. Note the boost log - where the stock blower makes peak boost of 12psi at 4750rpm then falls off, the ported blower maintains 12psi to 6000rpm. The gains are undoubtedly attributed to the increased efficiency of the air moving through the blower. The result is not only more volume (and hence the gain in manifold pressure) but more importantly less heating of the air charge.

Dyno Results: 2004 Mustang Cobra SVT Type: Dynojet Location: GTR High Performance Stock Eaton Supercharger with 2.93" upper pulley Steigemeier Ported Eaton with 2.93" upper pulley

Stiegemeier claims horsepower gains of 60 horsepower with his Stage IV Eaton M112 (plus plenum and throttle body) porting package. We hit about 50 horsepower, and while we were very content with that, Bob Stiegemeier was concerend that we didn't meet the mark. He quickly analyzed our tuning configuration and pointed out that we were only running 19 degrees of total timing advance. He'd like to see 23 degrees for maximum power however only if 93 octane gasoline is available. Unfortunately in California the pumps peg out at 91 octane only. Bob also tells us that his Stage IV Eaton is designed to reach maximum efficiency at 15.75 psi of boost - which achieves 515 horsepower and torque with no other changes neccesary. We might find ourselves swapping pulleys soon once we "grow tired" of the measly 487 horsepower.

Posted by admin, 03/05/07 11:36am: This is interesting. I wonder if they can port a Kenne Bell? Posted by fordracerguy, 06/18/07 09:32pm: Kenne Bell is already pretty optimized. Posted by khill, 11/20/07 08:27pm: I wonder what they could do with a Roushcharger??? Posted by rcamp, 02/23/08 06:49pm: You need to study adiabatic heating and compressor efficiency some more. Your definition of efficiency is way off the mark.