pulley combo and boost pressure advice

Discussion in 'Manton Push Rods Top Alcohol Tech Questions' started by 60falcon, Mar 26, 2017.

  1. 60falcon

    60falcon New Member

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    Still building my blown BBF and not sure how to calculate HP and boost needed. i would like to start out tuning and learning around the 15-1600hp mark at the crank. how do i decide on a pulley combo and what amount of boost should i expect it to take to get there?

    526" BBF 11.5CR, trick flow A-460 heads advertised flow 463/364 @ .800, .839 lift 285/304 @.050, fresh little field 14-71 HH retro 2.5" setback on eliminator blower intake
     
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  2. Mike Canter

    Mike Canter Top Dragster

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    Call Andy Wilfong at Littlefield and talk to him and see what the lowest OD your blower can handle and how much boost. I would guess you need to be around 12-15% makinvabout 20 lbs
     
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  3. 60falcon

    60falcon New Member

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    I will give him a call. I didn't figure it would take much.
     
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  4. Mike Canter

    Mike Canter Top Dragster

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    You may need to adjust the length of the top opening to keep the air veocity up. Ask Andy
     
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  5. 60falcon

    60falcon New Member

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    Simple enough. Andy said alcohol likes air and we'll start out about 35% over he just needs the center to center from crank to blower. Very helpful and eager.
     
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  6. BEDNAR1320

    BEDNAR1320 Member

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    35% sounds like alot to start out, my 14-71 (not a Littlefield) makes 27#@13% on a 540 BBC.

    Andy should know about your combo with his blower though.
     
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  7. Bjs344

    Bjs344 Member

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    Andy doesn't like his blowers running slow, lol.

    I had one of the last 14s before the lb series came out, so a really good blower, and he recommended something similar.

    I started out at 12 under for a couple passes, then went to 14 over for awhile. 14 over went 6.37@215 at 2000 lbs in great air burning 3 threads. I went as high as 32 over with more conservative fuel and never went any quicker, but I damaged my good heads somewhere in the middle of that increase.

    I'm almost positive if I had started in the 30s that I would've broken a lot more stuff.

    As far as calculating hp, join spuds site and play around with his calculator.
     
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  8. BEDNAR1320

    BEDNAR1320 Member

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    IMO burning 3 threads if asking for trouble, be careful.......

    I recently went 3.75@193 in 500' air, 13% OD 27# @2000lbs.
     
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  9. Bjs344

    Bjs344 Member

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    Ya, i thought I was setup on a .46 or .47 and misjudged the air. Didn't hardly touch the bearings (maybe .001) but I still wouldn't want to try that every pass.
     
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