Like my title I am curious what the max boost the stock unported Eaton can produce efficiently? I will be using an aftermarket dual fan H/E if that helps any.
To find this out you put the car on the dyno and add boost to it increments at a time. When the car stops making hp and only makes torque you'll have found the sweet spot. About the time this happens your IAT2's will also start going up more than the other pulley combo's tried.
Nobody as of yet knows the answer to this question. But it's certainly more than 15 lbs of boost....... Serickson ran a 2.2 lbs upper and 15 lb lower for a 21-22 lb boost setup with his M122 and hit the highest MPH in the history of this car and this blower at 135.35. Obviously, it was producing some nice power. We're still trying to figure out how to keep the freakin blower cool at higher RPM's. Have barely arrived at the efficiency of the blower when heat is taken out of the equation.
To the guy with the 2.76 upper and 4# lower beware the limit on rpm on the factory eaton is 14,000 rpm and the combo u are using is turning 20,000 rpm. I'm just trying to forwarn u that i had 19,000 miles on my cobra and yes it acted like a kenne bell or a whipple for a brief moment but it shredded my coupler and my rear bearings in my eaton! I thought I had blown my motor when my engine died and the back wheels locked up. Of course your probably alot easier on yours than I was mine I hope lol!
There are literally hundreds of guys that have run this combination for years with no adverse affects on the blower or the motor.To the guy with the 2.76 upper and 4# lower beware the limit on rpm on the factory eaton is 14,000 rpm and the combo u are using is turning 20,000 rpm. I'm just trying to forwarn u that i had 19,000 miles on my cobra and yes it acted like a kenne bell or a whipple for a brief moment but it shredded my coupler and my rear bearings in my eaton! I thought I had blown my motor when my engine died and the back wheels locked up. Of course your probably alot easier on yours than I was mine I hope lol!
I drag raced the 2.2 upper, 10% lower, 21psi set up for 4 years. I finally wore out the bearings in the snout after over 300 passes. My combo included methanol injection, dual fan AFCO H/E and a 5.5 gal trunk mount inner cooler tank. The car was very consistent and the heat was easily controlled in between rounds with a large box fan and 20lbs. of ice in the inner cooler tank every 3 passes. I typically would not have to adjust my dial in more than 2 tenths from the first time trial at 9:00 a.m. to the last elimination round at 3:00p.m.
This combo really never seemed to max out as it responded to very change I made along the way......last session on the dyno before I changed to the TVS we made three back to back to back pulls on a 90 degree day.....it made 635, 629, 625, with torque in the 640 range on all 3 pulls. All numbers for my car are always on 92 octane pump gas and stock injectors
I would not be concerned with blower longevity or efficiency in the 17-19psi range.....a 2.6 upper and 10% lower is a great efficient combo that tons of guys run with no issues. A 2.4 upper or 15% lower is maxing out the blower and putting you in a position to run something other than pump gas and looking at some additional cooling mods. Hope this helps.:beer:
Jon Dewar is a local tuner, we use the dyno at PSI in Hillsboro Or. I have also ran a Lund tune as well. I'm not sure about the Lund tune but I know we ran 24 degrees of timing on Dewars tune. The only way I have gotten away with pump gas and big power and timing numbers is the meth. injection........never have figured out why more guys don't run it after posting the numbers I have with the stock blower and stock fuel system for so long.
Just curious, on all your dyno runs did the stock blower maintain 21# of boost all the way to redline? Thanks in advance for the info. ;-) Also, did you drive the car on the street?