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Post by race454 on Apr 14, 2012 6:17:17 GMT -5
Hay everyone. My 17 year old son runs a bomber circle track class and I build his motors and do my best to make it turn. our car is one of the fastest out there but last year was his first . I am toying with idea of running e50. the rules indicate no alcohol but they don't test and it does not indicate i cant use e50.
My question is will the stock internals of a 4412 Holley have the volume to handle the increased fuel? and where should i start with the jets. I have no problem doing some mods to the carb but they need to be hard to find. What would be the best way to test the mix? I have ran alcohol before in drag racing (774 hp). but that was with a enderli hat and mechanical injection. Thanks for any help Bill
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Post by triplenickel on Apr 14, 2012 17:41:01 GMT -5
I've posed a similar question on here in the past. The general consensus was that e40 was the limit that could be used with the gas setup with a 4 to 5 jet size increase. If premium gas is used to bring % down to 40, 11:1 comp is about the limit. Adam can give you some good advice as he builds combos for round track.
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Post by race454 on Apr 14, 2012 20:02:26 GMT -5
Well we ran shell 93 last year with 11.8 comp,406 sbc, flat top piston with lots of quench but a 2bbl race motor with cast intake and exhaust manifolds never fills the cylinders. every one thinks we are nuts but we were about the only one who had no motor problems and when we tore it down it looked like new. looks like we will only be trying e40. Thanks for the help. BillC
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Post by adamsvega on Apr 16, 2012 5:56:34 GMT -5
ITS NOT GOING TO BE THE OCTANE THAT HURTS YOU . as you saw the cyl's stay "egr like" when wide open .its the idea of stock internals" the 4412 is half a small dp carb and will respond to same methods .as far as getting away with it yes ethanol 40-50% will still be masked by scent of gasoline .
every thing else can be modified to resemble a stock carb and run e70-e85 . you will have to get real friendly with a drill or ream and get some well plugs .
i thing the advantage of cooling that cast iron intake and a small TQ from idle would benefit the combination .it would also also allow a flatter timing curve to get off corners .
speedway has a small alky pump .a s/s screen filter get the booster pin holes opened to 165 should get you close enough to up the jets and tune it .if you run a power valve we can play with that circuit too as some guys like to size it for about 4 -5 jets .... to pull fuel on tracks they gotta lift on ... big thing is the air bleed up top ... if you cant "modify" or have removable air bleeds we have to drill and fill to get tune right
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Post by race454 on Apr 17, 2012 7:45:05 GMT -5
Could I drive a pics of led shot in the air bleeds and drill it to size?
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Post by race454 on Apr 17, 2012 19:34:37 GMT -5
ITS NOT GOING TO BE THE OCTANE THAT HURTS YOU . as you saw the cyl's stay "egr like" when wide open .its the idea of stock internals" the 4412 is half a small dp carb and will respond to same methods .as far as getting away with it yes ethanol 40-50% will still be masked by scent of gasoline . every thing else can be modified to resemble a stock carb and run e70-e85 . you will have to get real friendly with a drill or ream and get some well plugs . i thing the advantage of cooling that cast iron intake and a small TQ from idle would benefit the combination .it would also also allow a flatter timing curve to get off corners . speedway has a small alky pump .a s/s screen filter get the booster pin holes opened to 165 should get you close enough to up the jets and tune it .if you run a power valve we can play with that circuit too as some guys like to size it for about 4 -5 jets .... to pull fuel on tracks they gotta lift on ... big thing is the air bleed up top ... if you cant "modify" or have removable air bleeds we have to drill and fill to get tune right |
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Post by race454 on Apr 17, 2012 20:00:26 GMT -5
Adam, thanks for the reply.
OK I checked out my other 4412's. I have one with the booster holes at .165 or maybe a little bigger. the boosters are the steeped, down-leg boosters and have had the inside polished smooth. Will the .165 support more than e50 or would e50 be the max. I will pick up a set of small drill bits to establish the air bleed holes.
I picked this carb up with a box of carb parts. When I tried it ,it ran way to rich. Now I think I know why.
Thanks again Adam.
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Post by adamsvega on Apr 18, 2012 5:41:09 GMT -5
THIS POST IN NO WAY ADVOCATES OR CONDONES CHEATING . JUST THE FEASIBILITY OF SAID USE.lmfao
measure of a dog leg booster is tough as it tapers . but a 165 should work well . your tune up will be just like my primary side of vacuum index carb . how big is the throttle plate and what size is the venturi compaired to say a 750 or 650 .steped dog legs in a small 650 based carb and on a 2 barrel will draw hard on the jet and need less .i would start off with 75's and a PV in 750 base or 72 and pv in 650 .. try 28 high speed and a 65 idle . once ya get w/o figured out we can size the pvcr to get it on throttle snappy off the corner
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Post by race454 on Apr 18, 2012 6:25:34 GMT -5
The throttle plate is 1.75". I will have to check the venturing. From what I can see there Is no taper on the id. Of the boosters. Is this for a e85 tune?
I was told by the track management that they gave the ok for some racers last year to buy willys carbs ($800) . 4 that I know of. The rules still state stock 4412.
Sorry for ranting and thanks again Adam.
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Post by adamsvega on Apr 19, 2012 5:44:49 GMT -5
THERES NO RANTING IN DIRTTRACK!!!! YOUR JUST TALKING LOUD ENOUGH TO BE HEARD IN THE PITS >>>>>LMFAO
just a humorous discussion on how you could "catch" some body iffing they were cheating and how they did it.see if they allow billet blocks or billet adjustables . it would be real easy to convert back and forth .and if you can have a flowed top and adjustable air bleeds it would be worth it too. most stock classes though say no "visible mods" and willys makes a e85 e98 and meth versions
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Post by race454 on Apr 19, 2012 8:13:43 GMT -5
It will have to be stock appearing. Are the .165 booster good 4 e85? I have a old holley methanol meetering block from a 850 would that be better to start with?
I am a drag racer and my son decided he wanted to go in circles so we built a car and I built the motor. We put it all togeather by the rules. There was only 1 car that could pull us down the straightaways. It took us the hole year to get the car set up so it would turn. So it is very frustrating when we worked our butts off and some one gets a green light to cheet. He did get rookie of the year and took 3rd in points. Not bad for never racing on dirt before. Thanks for the help.
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Post by adamsvega on Apr 19, 2012 18:59:03 GMT -5
AN 850 block....humm..... i get some welch plugs for the top and open them up and measure them .ill bet they are about right . and the 165 booster should pull hard enough . .
if your on and off the gas we can use a modified regulator to use vacuum to pull the fuel psi down from 8 w/o to 2 at idle and keep the block filled and float high with a wedge float
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Post by jparker1229 on Jan 14, 2013 17:28:56 GMT -5
Bump
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Post by adamsvega on Feb 2, 2013 12:46:34 GMT -5
2x
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Post by rayderluvr on Jan 3, 2014 19:39:04 GMT -5
My son and I both run circle track with holley 4412. E85 is legal, but carb must be stock appearing. I don't want to spend $475 each to have our carbs changed over, what can I expect by only changing jet size?
Thanks..
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