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Re: Blower Size On Smallblock??
[Re: Blucuda413]
#1629386
06/05/14 11:32 PM
06/05/14 11:32 PM
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Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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Quote:
What size blower is the largest which can reasonably be made to work on a smallblock?? Is it a 6-71, 8-71, or 10-71?? The Indy site shows a 6-71 on a sbm but they also use an offset distributor. Is the offset dizzy required? BTW would go on a 454" smallblock.
If you plan on a 454ci down the road you better think
BB and base your blower on that.. if it turns less
speed it makes less heat
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Re: Blower Size On Smallblock??
[Re: Cab_Burge]
#1629391
06/06/14 09:34 AM
06/06/14 09:34 AM
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Joined: May 2011
Posts: 4,489
northern,Ohio,USA
Clanton
master
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master
Joined: May 2011
Posts: 4,489
northern,Ohio,USA
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Quote:
The bigger the blower rotors the less RPM on the blower needed to make the amount(volume) boost you want, the less rotor RPM the less heat the blower makes, hot air is less dense than cooler air  I'm thinking your going to need at least a 8:71 , if you could run a crank trigger ignition then a 10:71 would be even better yet  
I believe it is SSI that makes a front offset blower,if you went with a 10-71 it may not be too long.I think you need an 8-71 and it would be fine.
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Re: Blower Size On Smallblock??
[Re: Blucuda413]
#1629397
06/06/14 01:27 PM
06/06/14 01:27 PM
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Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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Quote:
This may sound stupid but I plan to develop both a roots blower system and a Procharger system. I have the Procharger and the installation brackets and am gradually buying all the other parts. I also have a 12-71 that I must trade for a smaller blower. For that system I have a birdcatcher for fuel. I plan to build my own manifold when I get the right size blower. My question on the roots was to figure out what size I could use without too much hassle. These are both long term projects but you have to start somewhere. BTW I need about 900hp to attain my bucket list ET of 8.99.
JMO.. but I would run either a 6-71 or a 8-71.. if
you go larger on a SB it might be way too long to
fit
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Re: Blower Size On Smallblock??
[Re: Clanton]
#1629399
06/06/14 02:01 PM
06/06/14 02:01 PM
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Joined: Jan 2003
Posts: 684
St. Charles, MO.
Slingshot383
mopar
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mopar
Joined: Jan 2003
Posts: 684
St. Charles, MO.
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Clanton, fuel injection with nozzles at the hat is different than running with carbs on top, then if you add the down nozzles, you can really tune for each cylinder and make the blower work a lot better. I'd be more concerned on keeping the bottom of the motor together running either style blower at the 900 - 1000 hp level on a small block.
1994 Undercover Chassis 125" altered
stack injected big block, soon blown and injected
Member of The Torque and Recoil Club
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Re: Blower Size On Smallblock??
[Re: FastmOp]
#1629401
06/06/14 03:14 PM
06/06/14 03:14 PM
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Joined: Jan 2005
Posts: 2,540
Milwaukee WI
TRENDZ
master
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master
Joined: Jan 2005
Posts: 2,540
Milwaukee WI
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Use the 12 71 but mount it out front. you can intercool it and use standard intake manifolds. Plus, it would be way cooler than doing it the "standard way"
"use it 'till it breaks, replace as needed"
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Re: Blower Size On Smallblock??
[Re: Blucuda413]
#1629403
06/09/14 02:20 PM
06/09/14 02:20 PM
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Joined: Jan 2003
Posts: 684
St. Charles, MO.
Slingshot383
mopar
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mopar
Joined: Jan 2003
Posts: 684
St. Charles, MO.
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Clanton, in his second post, he said he had a bird for the roots blower, that's where I got it from.
1994 Undercover Chassis 125" altered
stack injected big block, soon blown and injected
Member of The Torque and Recoil Club
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Re: Blower Size On Smallblock??
[Re: Slingshot383]
#1629405
06/10/14 02:45 PM
06/10/14 02:45 PM
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Joined: May 2011
Posts: 4,489
northern,Ohio,USA
Clanton
master
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master
Joined: May 2011
Posts: 4,489
northern,Ohio,USA
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Quote:
Clanton, in his second post, he said he had a bird for the roots blower, that's where I got it from.
OK then. 
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Re: Blower Size On Smallblock??
[Re: Blucuda413]
#1629409
06/11/14 06:20 PM
06/11/14 06:20 PM
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Joined: Jun 2010
Posts: 462
Stockholm, Sweden
fed
mopar
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mopar
Joined: Jun 2010
Posts: 462
Stockholm, Sweden
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How do you modifie the tunnelram for the blower?
I have a 6-71 and a Holley Pro dominator intake that i would like to use on my 340.It made 640HP on the dyno with a singleplane and a dominator.
Any pics on an tunnelram/blower intake?
Cuda, -70
Valiant-65 AWB,
Valiant Signet200 -65 Topchopped dragcar.
Topolino Fuel Altered.
NostalgiaFED Sold,
SuperComp Bantam Altered, Sold
Ex Harlan Thompsons Nitro funny car American Graffiti Sold,
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Re: Blower Size On Smallblock??
[Re: Blucuda413]
#1629414
06/12/14 01:04 PM
06/12/14 01:04 PM
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Joined: Oct 2007
Posts: 4,208
New York
polyspheric
master
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master
Joined: Oct 2007
Posts: 4,208
New York
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There's another intangible factor involved that I didn't address.
GMC etc. blowers do not actually compress the charge internally, all boost occurs when the engine's capacity is fully satisfied (manifold vacuum is zero) - boost is pressure against the previous intake cycle. If the blower is too small or spun too slowly not only is boost = zero, you will have big pumping loss and vacuum @ WOT: negative horsepower.
This means that the time to develop pressure is somewhat affected by plenum volume - more storage = slower to pressurize.
Regarding discharge port location, it's not clear in my remarks. Any straight rotor should just have the window (more or less) centered over the plenum like dual carbs. Any helix rotor will tend to charge nearest the front, even if the port window is rectangular. I have a gut feeling that some running older helix blowers with square windows have plated the windows into triangles to reduce charge temp and improve mix distribution, but they're not talking about it!
Boffin Emeritus
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