BBC 572 questions.

Old 07-28-2009, 07:44 AM
  #21  
OneBadGMC
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Originally Posted by Dahlton
I was planing on using a wather/alky injection for cooling the air at higher boost (when racing).

Do you have any idea how much boost it would make if I run it approx 1:1?

BTW
Who makes the best Roots blowers theese days? I heard alot off good things about Kuhl superchargers when Mike Kuhl had his business.

Also one reason why I'm using carbs is that I've heard that part throttle "cruising" is impossible with a Birdcatcher, that it is sort of an on/off throttle?
Alky injection will help, but it doesn't come close to the volume of fuel needed to cool that blower, especially when it's under boost.

572 CID, 14-71 (about 520 CID Blower) at 1:1 will make approximately 12 PSI, with a final compression of 15.5:1.

Using the formula of {(CID X RPM) / 3456} X {Boost / 14.7) + 1} = CFM required, I can tell you that at 7000 RPM the motor will use ~2103 CFM. At 8000 RPM it'll use about 2400 CFM.

With just mild boost, and typical drag racing RPMs, you're coming woefully close to maxing out the carbs.

Best roots are going to be DMPE, PSI, SSI, Kobelco, Gibson-Miller, followed by Littlefield, Mooneyham, then the rest.

As for injection on the street, I would characterize it more as idle, high idle, WFO. I've driven injection on the street since 1995. Injection doesn't have nearly the resistance in your foot feel that a carb does because it uses ball bearings on the throttle shaft instead of bushing. It's very smooth. It can be controlled easily with a much better precision. Once you get used to it, it's not a big deal at all, just dont let your girlfriend jump behind the wheel or you'll be roasting the tires as soon as she hits the throttle.
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Old 07-29-2009, 01:31 AM
  #22  
Dahlton
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No worries! she can't even start it.... i have to main switches one in the car and one outside one power switch for the ignition and last the start button it is way too complicated for my toyota driving better half.


I was hoping that I would not have to turn it more than 7000 well 7500 max.

Maybe 8000rpm alky injected 540cid will be a nice EVO2 version

maybe to make things even worse I could use nitrous for cooling? the intake is already drilled!
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Old 07-29-2009, 07:29 AM
  #23  
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If you bottle the blower, you want the nitrous going in the top, not in the ports.

A 100 shot would do a world of good, simply from the cooling.
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Old 07-30-2009, 08:57 PM
  #24  
ashbros
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On gas guzzling pro street cars I will run a 100 shot when I stick my foot through the floor.
Its no where near the response of Alky, but it wakes her up a bit...
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Old 09-01-2009, 01:08 AM
  #25  
Dahlton
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So now I'm starting to think things over.
I think that I'll sell the carbs and buy a birdcatcher.
then sell the eagle crank and rods
and buy a callies magnum crank and oliver billet rods
and last but not least use e85 fuel

now two questions. if I swap from the 4.5 stroke to 4.25 stroke and want to use the JE pistons I have I need a rod that is 0.25 longer then the rod that I would use with the 4.5 stroke crank RIGHT? now I have a 6.535 rod so the new would have to be 6.785, and because oliver do not have a "shelf" rod in tha messure the next would be 6.800 that should not be a problem if the block is 10.200 and not 10.180 like it sayes in the JE catalog. they also have a shorter rod 6.735 would that be better?

Second how much HP can a Dart big M block handle with the ductile caps? (no billet).
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Old 09-01-2009, 05:11 AM
  #26  
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Originally Posted by Dahlton
So now I'm starting to think things over.
I think that I'll sell the carbs and buy a birdcatcher.
then sell the eagle crank and rods
and buy a callies magnum crank and oliver billet rods
and last but not least use e85 fuel

now two questions. if I swap from the 4.5 stroke to 4.25 stroke and want to use the JE pistons I have I need a rod that is 0.25 longer then the rod that I would use with the 4.5 stroke crank RIGHT? now I have a 6.535 rod so the new would have to be 6.785, and because oliver do not have a "shelf" rod in tha messure the next would be 6.800 that should not be a problem if the block is 10.200 and not 10.180 like it sayes in the JE catalog. they also have a shorter rod 6.735 would that be better?

Second how much HP can a Dart big M block handle with the ductile caps? (no billet).
Little late to be making those kinds of changes now.

If you already have the pistons/rods/crank... Either sell what you don't need and buy what you do, or live with the combo you picked out.

I wouldn't try and 1/2 ass it myself. If your 4.5" arm is new, more than likely they'll let you trade it in for a new 4.25 for just the cost of shipping.

If it's a tall deck (I didn't re-read the entire thread), your best rod for ring pack and rod length will be a 6.7" rod.

If the pistons are 'shelf' pistons and not customs, you may be able to swap them out too.

Don't know anyone running E85, nor have I ever messed with it. So if you go that route, you better have a competent tuner handy.

Main caps are more sensitive to RPM than power. I'm throwing 1600 HP at my GM Bowtie block nodular caps and the mains look brand new. Plans (if it doesnt sell first) are to go to upwards of 2200.
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Old 09-01-2009, 03:39 PM
  #27  
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The rod length change would 1/2 the stroke change .250 less stroke needs .125 longer rod to use the same piston.Bill.
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Old 09-06-2009, 06:21 PM
  #28  
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I HAVE NEVER HEARD OF TOO MUCH TORQUE, ESPECIALLY ON PUMP GAS,, I WOULDNT DETUNE WHAT YOU GOT, EASE INTO THE THROTTLE IF ALL ELSE FAILS.. MIGHT TAKE MORE TIME ON SUPENSION SETUP ALSO.. SOUNDS LIKE A SWEET SETUP AND I WISH YOU THE BEST OF LUCK..
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Old 09-22-2009, 01:57 AM
  #29  
Dahlton
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New question!

Header size?? any suggestions?
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Old 09-22-2009, 07:17 AM
  #30  
OneBadGMC
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2-3/8 to 2-1/2" primaries, by 4.5 or 5" collector.
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