Twin Eaton M112's ?
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Twin Eaton M112's ?
Just a quick question lads. RV8 4:6 with the normal goodies, in the process of converting it to fuel injection (Mega Squirt) in-keeping with the Eaton needs, inlet manifold/trumpets bored out from standard to 44mm ID, shortened trumpets as per V8 developments pattern. Made up a twin plenum cover. Now I have two inlet holes and two superchargers available just wondered what effect fitting two units would have; firstly re CFM, Eaton as above runs around 720 cfm @ 12,000 rpm I think also would this affect the boost as I don't want to run really more than 8psi as only have cast pistons 8:4.1 CR.
Any help would be appreciated chaps.
Any help would be appreciated chaps.
- topcatcustom
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- Rossco
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I doubt it would run cooler as your would be right on the lower limit for the M112.
My calcs show that at 6200rpm you would be just into the sweet spot.
At 3000rpm your adiabatic efficiecy would be down around 30-40% which means loads of heat being generated. In fact somewhere around 130 degrees centigrade of added heat without an intercooler as opposed to about 85 c if you used a single M112.
If you want a twin setup why not look at two M45's
My calcs show that at 6200rpm you would be just into the sweet spot.
At 3000rpm your adiabatic efficiecy would be down around 30-40% which means loads of heat being generated. In fact somewhere around 130 degrees centigrade of added heat without an intercooler as opposed to about 85 c if you used a single M112.
If you want a twin setup why not look at two M45's
Last edited by Rossco on Wed Dec 10, 2008 8:20 am, edited 1 time in total.
Did some math on the setup you’ll mention.
With your 280ci engine and the 112ci blower you’ll get:
Single Eaton 112 setup:
8.3psi with 2.25 overdrive ratio, that’s 13500 blower rpm @ 6000 engine rpm.
Dual Eaton 112 setup:
7.8psi with 1.1 overdrive ratio, that’s 6600 blowers rpm @ 6000 engine rpm.
The actual boost can vary by cam profile and head design. For example, I lost 2psi when I switched over to Merlin heads but it delivered way more horsepower. Boost readings are only a measurement of backpressure in the intake.
Single Eaton112 is possible cause they’ll become inefficient above 15000 blower rpm.
Dual Eaton 112 means that they’ll have to run half the speed meaning less heat and more long livety and less noise.
For your interest, the calculated corrected CR for your engine will be 13.1 :1
With your 280ci engine and the 112ci blower you’ll get:
Single Eaton 112 setup:
8.3psi with 2.25 overdrive ratio, that’s 13500 blower rpm @ 6000 engine rpm.
Dual Eaton 112 setup:
7.8psi with 1.1 overdrive ratio, that’s 6600 blowers rpm @ 6000 engine rpm.
The actual boost can vary by cam profile and head design. For example, I lost 2psi when I switched over to Merlin heads but it delivered way more horsepower. Boost readings are only a measurement of backpressure in the intake.
Single Eaton112 is possible cause they’ll become inefficient above 15000 blower rpm.
Dual Eaton 112 means that they’ll have to run half the speed meaning less heat and more long livety and less noise.
For your interest, the calculated corrected CR for your engine will be 13.1 :1
- Rossco
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The killer here though is the very low inefficiency of the twin setup at such low rpm and boost. At 30% efficiency you'll generate more heat than if you were running a single M112.JP. wrote:
Dual Eaton 112 means that they’ll have to run half the speed meaning less heat and more long livety and less noise.
Don't make the mistake of assuming that just because a blower is running slowly it's running cooler. The airflow at the lower end of it's efficiency range is very turbulent and this turbulence generates a huge amount of heat.
- topcatcustom
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An tubular chassis for LR like this :
http://www.ppcages.com/displayimg.php?u ... in/006.jpg
http://www.ppcages.com/displayimg.php?u ... in/006.jpg
- Rossco
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ooooo now that's sexyWotland wrote:An tubular chassis for LR like this :
http://www.ppcages.com/displayimg.php?u ... in/006.jpg
Many thanks gentlemen for your calculations and advice. Did actually purchase two new M45,s a while back from Speed Shack Westdrayton but advice from a serious blown Cobra owner was much the same as yours re heat etc so I sold them on.
The idea for twins mainly came from this site some months ago re a 4:6 Mustang with twin M90's, apparently it was reported to have more Torque than the Queen Mary! I shall stick to a single unit then and no doubt will be back with many more questions as the mod's progress next year, cheers chaps.
The idea for twins mainly came from this site some months ago re a 4:6 Mustang with twin M90's, apparently it was reported to have more Torque than the Queen Mary! I shall stick to a single unit then and no doubt will be back with many more questions as the mod's progress next year, cheers chaps.