How much boost should I expect?

Discussion in 'Manton Push Rods Top Alcohol Tech Questions' started by gt_diesel, Jun 25, 2009.

  1. gt_diesel

    gt_diesel New Member

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    14-71 Standard Helix Kuhl.... Fresh with 0 passes....

    498" BBC

    Heads flow around 400 @ .800 lift.

    Camshaft is an .800 lift

    Plan on turning it around 7000 or 7200 rpm.

    With the blower at 1:1, 10% and 20% overdrive.

    Compression is 10.7 to 1

    Also, what HP should it be running with each pully setup?

    What kind of 1/8th mile ET's should I be looking for with a 2650# door car ( with driver ) 4-speed Lenco, 4.30 gears, and 34.5 tires.

    Going out saturday for testing and am hoping to go 4.90's off the trailer with the 1:1 pully setup...

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  2. Mike Canter

    Mike Canter Top Dragster

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    So you are saying that you have the same amount of teeth on both pulleys??? Which is 0% OD. If that is so then you are going to be real disappointed.
     
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  3. mbaker3

    mbaker3 New Member

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    Mike,

    The way I am reading it he wants to try it at 1:1 (0% od) then 10% and then 20%. Read it again and see if I am reading it right.
     
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  4. hotrodharlkey

    hotrodharlkey New Member

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    thats way i'm reading it also.
     
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  5. gt_diesel

    gt_diesel New Member

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    Yes.... 0 percent, then 10, then 20.....
     
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  6. gt_diesel

    gt_diesel New Member

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    Why would 0% overdrive be dissapointing.... The whole car is new, so we are doing it to get a few easy passes on things before we start upping the boost.

    The 14-71 should be putting out plenty of volume... (I was told by the blower people that I should see over 25psi with no overdrive)
     
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  7. Mike Canter

    Mike Canter Top Dragster

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    OK then go and try it but I think you will be disapointed because you will not make enough boost on a standard blower and with that low motor RPM and that low compression. Remember it takes horsepower to run a blower and you want to make enough hordepower for power plus run the blower.
     
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  8. 69outlaw

    69outlaw New Member

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    We ran a standard Kuhl blower about 8 years ago At 40% over we made around 35 pounds of boost on a 509 BBC. It ran 5.0s in a 2800 pound door car. I would like to have a standard blower that will make 25 lbs at 1:1. My opinion is if you are not goimg to drive the blower take it off and just run injection.
     
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  9. craig moss

    craig moss Member

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    I had a std kuhl with the delta bottom. 35od made 25 psi bbc same flow numbers Mike is spot on! I bet it makes about 8- 10 psi at 0 od just a guess its hard to say. What cam do you run?
     
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  10. RUGSTER

    RUGSTER New Member

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    Start it off with AT LEAST 10 over! Hell i've not long finished a new engine for my door car,It's a tiny 355" chevy with a Teflon HH Retro 14-71 and i'm starting that at 10 % over!:eek:
    Remember, your engine has fairly big holes to fill and stat. compression is down there a bit.
    The very first time i drove a blown alky car, it also was a 350" SBC with an old standard helix 8-71 on it at 3 over. To say the least, i was a little disapointed with the performance(although it only showed around 600*The next meeting the guy tuning it changed the OD to 14%.
    That was a BIG change! It didn't scare the shit outa me but it wasn't far off!!:D It made 30 psi of boost on the next 3 passes for the day and then i was hooked:p
    My advice, start out with 10 or more, and tune it to suit.Coz once you get it runin' sweet at "0" if that's possible, you'll want more and change the o/drive and it all starts again.
    Trust me. i've been there:D
    Jason.
     
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  11. gt_diesel

    gt_diesel New Member

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    I thought the 25 pounds they told me sounded high, but wanted a second opinion. I have pullies for 20 over sitting in the car trailer, so changing them is a non issue. It does kind of irritate me that I was convinced that 20 percent was too much to start with and to buy the other pullies.

    Last season I ran a 548" BBC with Dart 360's and a .816 lift camshaft... That had a 14-71 High Helix Littlefield at 44% overdrive... It made 37 pounds of boost and ran 4.70's at 2900 pounds with a powerglide. It was my first year with a blower car.

    I sold that chassis and bought an old Nitrous Pro Mod... The car ran 4.40's with a 632 on two small stages.

    I bought the motor off a guy who said it was somthing it wasnt... I ended up having to change all kinds of stuff... The Kuhl blower that is on it is brand new, and I was told that 20% was too much to start off with and was convinced to buy the other pullies.

    What do you guys think with 20% over?
     
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  12. jim phillips

    jim phillips ta/fc

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    hell turn it 40* over compression is low it art to run 4.90s if it has any balls needs big tires if its a powerglide

    several years ago i put my little 468 bbc with a 1271 @47* in my buddys super pro 66 nova backhalf car 2800lbs 14x32x15 went 5. flat off the foot brake when i tried to leave on the trans brake it would just blow the tires off like a it was a burnout just not enough tire
     
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  13. RUGSTER

    RUGSTER New Member

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    Hell yeah Jim!! that's the ticket! "Spin it up some:D" No use goin' out there with a lazy sack off shit right?:p
     
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  14. RUGSTER

    RUGSTER New Member

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    Hey! 25psi with NO OVERDRIVE??:eek: with a standard twist??:eek:
    at what RPM are they talking.....15000??:rolleyes:
    What size pulley's on the top? it looks like a monster!
    That's 8mm right? Tell me it ain't 1/2" pitch:rolleyes:
    Jason.
     
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  15. jim phillips

    jim phillips ta/fc

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    my uncles always told me a dime size pulley on top and a manhole cover on the bottom is how you make one run ( lol ) and thats how i started a small pulley on top and a big one one bottom and when i hit it the first time i thought i had messed around and built some thing i wasnt going to be able to drive but man what a ride went 201 my first 1/4 mile pass but the 1/8 goes buy pretty fast but that was years ago

    what kind of injector is that just curious
     
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  16. gt_diesel

    gt_diesel New Member

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    It is 8mm... I think I am gonna throw on the 20% pullies tonight when I get home from work.

    That is a Buzzard Catcher... It came of a Mud Runner so it has an adaptor to run a filter.

    How much boost do you think with the 20% pullies on there... I would like to start out with at least 20# this weekend.
     
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  17. RUGSTER

    RUGSTER New Member

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    Depending on how hard you turn it, say 7500, i'd say around 20 psi.:p
    Give it a whirl with the 20 over pulley's and tell us all how she ran!!:D
    Can't wait to find out!!
    GOOD LUCK BUDDY and be careful!!
    Jason.
     
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  18. gt_diesel

    gt_diesel New Member

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    Sure thing... I will post some pics and let y'all know how it goes...

    I will probably order up some 35% overdrive pullies next week...
     
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  19. RUGSTER

    RUGSTER New Member

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    He's seen the light!! Yay!!!!!!!!!!!!!!!

    Heyyyyy!!:D Now we're talkin':cool:
    Wow that was easy to get ya to change your mind!
    Wish my wife was that easy when i bring up buyin' an Alky F/C!!:D

    Jason.
     
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  20. Comax Racing

    Comax Racing Member

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    Blower

    When I bought my first blower 14-71 HH Retro from Mert he said he wasn't going to sell it to me unless I ran it at 27% or more because I was wasting my time. I took his advice nad was glad I did.

    My vote is to cranker up:D

    Corey
     
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