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.
What is the max boost the stock Eaton is effcient?
- Thread starter kozumasbullitt
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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.
I guess i am trying to find out if 14-15 PSI will still be efficient when using an aftermarket dual fan H/E?
I think you'll probably be at it's limit at 15lbs.
I'm spinning a M122 (the blower on your car) to 19lbs of boost 
she sings with a 2.76 upper and +4lb lower (Terminator Pulley combo).
she sings with a 2.76 upper and +4lb lower (Terminator Pulley combo).
I'm running 14-15 psi now and she has more left in her. Going to try and touch 17.5 next year, quite a few guys running 20 psi. Just have good cooling mods and only do two quick pulls and let it sit, you will be fine. The heaton is a good blower if you run it right.
I believe when the max boost the stock blower makes and MAINTAINS that level of boost until engine redline, is when you can say you've reached the max efficiency of that blower. When the boost drops off before engine redline, you've exceeded the blower's max rotor rpm efficiency limit. Just IMHO
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 10 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.
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Water/meth injection in the lower manifold right between the blower outlet and intercooler would do wonders for IAT reduction, I bet.
blower speed
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!
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!
Most likely around 18 pounds of boost!!!
What is the equation for rotor speed for the m122?
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:
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:
There are literally hundreds of guys that have run this combination for years with no adverse affects on the blower or the motor.
Wondering who tuned that setup and where spark advance hovered at WOT under load? Very impressive you ran that setup so hard on pump gas for so long.
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?
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^Don't get caught up on boost and if it drops any. What you go off of is where the hp peak is and when it starts dropping with added boost and your IAT's start raising more. Or hp stays, torque rises, and IAT's go up more than normal for that day of testing.
Then you would find the maximum boost and then have to go test it at the drag strip against the next lower boost combination to see if max boost on the dyno makes the difference at the track also.
Then you would find the maximum boost and then have to go test it at the drag strip against the next lower boost combination to see if max boost on the dyno makes the difference at the track also.
Looking at the graphs there was no measurable drop off in boost between 5-6000 rpms.....the motor was making power to 6200 which tells me it was making a similar amount of boost thru the rpm range.
I not only drive on the street......this is a full interior 4,000lb car.....for the first 5 years I towed a trailer behind it with all my drag racing gear in it....I just recently picked up an enclosed trailer for the trips to the track but the car is still street driven with 16,000 miles on it.:beer:
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