Re: Big block with 6/71 roots project
[Re: Clanton]
#1467563
07/17/13 06:05 PM
07/17/13 06:05 PM
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Joined: Mar 2013
Posts: 13 Loire Atlantique
Filex
OP
member
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OP
member
Joined: Mar 2013
Posts: 13
Loire Atlantique
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Quote:
The 8-71 will be turned slower for the same hp and a little less heat but in your case I would think you would put that $$ into a water injection kit to run on cheaper fuel instead of the bigger blower.
Ok I understand, itīs clear, thanks !
You speak about water injection to run with cheaper fuel ? It's interesting ! Tell me more
I don't know anything about this !
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Re: Big block with 6/71 roots project
[Re: Clanton]
#1467565
07/17/13 07:01 PM
07/17/13 07:01 PM
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Joined: Mar 2013
Posts: 13 Loire Atlantique
Filex
OP
member
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OP
member
Joined: Mar 2013
Posts: 13
Loire Atlantique
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Quote:
Look at snow performance water injection on the internet.The water and alky cool the intake charge and slow the fuel burn for running less octane.
I will look that, thank you !
Somebody has a response for my last question ?
-> I want to know if I choose different parts (crank and rods in 440 source and Mahle pistons for exemple) I have to equilibrate the assembly ? Or it's possible to install the parts (each balanced) without doing anything else ?
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Re: Big block with 6/71 roots project
[Re: Filex]
#1467567
07/18/13 01:31 AM
07/18/13 01:31 AM
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Joined: Aug 2003
Posts: 43,719 Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,719
Bend,OR USA
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Quote:
Quote:
Look at snow performance water injection on the internet.The water and alky cool the intake charge and slow the fuel burn for running less octane.
I will look that, thank you !
Somebody has a response for my last question ?
-> I want to know if I choose different parts (crank and rods in 440 source and Mahle pistons for exemple) I have to equilibrate the assembly ? Or it's possible to install the parts (each balanced) without doing anything else ?
Balancing engine parts has two seperate operations, balancing all the pistons to the same weight with the wrist pins, same on the rods and then you have to get both ends of the rods the same weight on each end, half the rod is considered rotational weight and and the other half is not Maybe it is consider in some other way I have forgotten about . The crankshaft is spun balanced to the specific "bob weight" that your assembly ends up having, so no ,you can not mix parts and expect them to work well together without having them check for balancing first No sense in taking a chance when using a blower and wanting it to be trouble free. I had treid to make a post several days ago advocating you using a bigger blower than the 6:71, I like and use 10:71 on Mopar V 8 over 440 C.I. You can turn them much slower and build the same amount of boost with a lot lower intake manifold inlet temps. and a lot less parasitic drive loss(HP) by spinning the smaller blower at a higher RPM to get the same amount of boost as the bigger one spinning slower Be careful of what you ask for, you may end up with a real tire burner 600 Hp from a 440 based motor on pump gas is not hard to do with one carburetor, let alone a blower Another thing to consider on a street Roots blower motor is the static mechanical compression ratio, if you set the motor up with 8.5 to 1 comp. ratio and spin the blower at 7% underdrive to make 7 lbs of boost at 6500 RPM and end up with vacume at 4000 RPM and under at part throttle you may be better off increasing the compression ratio to 9.0 or higher up o 9.5 to 1 and spin the blower even slower like 10 % under so it starts to make boost at a higher RPM and still end up with the same amount of HP at 6500 RPM but a lot more torque and throttle responce under 3500 RPM at part throttle Sorry if this seems confusing but there are many different ways to go with a blower, on pump gas less pressure is safer
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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