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Old 05-18-2010, 01:02 PM   #1
tony dirose
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Default Alcohol carb

I just switched my braket car over to alcohol carb , with a new hp 950 holley carb, i blocked the rear power valve and added jet ext, and increased the jet size up 10 to start with.The car was way rich, i started lowering the jets down 2 sizes at a time untill the mile per hour started to drop off, 144 [square] now my egts are 1300 deg going throug the lights, [1/8] the coolant temp. still will not increase on the pass and off idle it is still rich [blubbers] driveing it around the pits. it seams to run good the spark plugs look good , the car is a 3400 lps nova with a 11/1 406 sbc mild mech roller iron eagle 215 heads with a glide also i never pick up any et or mph from the gas to alch switch, car still runs the same as it did last year when it was on gas. any help would be greatly app,
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Old 05-18-2010, 02:37 PM   #2
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Default Re: Alcohol carb

Try going up .005 to .060 on the idle air bleeds, it should help around the pits. Go up to .065 if it needs more, if it is still to much you need to go down on the idle jets, try .002 at a time. Also if the bleed cause a stumble on light throttle, go down on the idle jets instead. You can make your own with a drill index and brass set screws, stainless will work if you cant find brass locally. DO NOT use regular steel set screws. When you get it better you may be able to go back up a little with the main jets. What gear, converter stall, and ET is the car running?
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Old 05-18-2010, 03:21 PM   #3
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Default Re: Alcohol carb

THE CAR HAS 4.56 GEARS CONVERTER IS 5800 RPM STALL SPEED CAR IS CURANTLY RUNNING 6.85 IN THE 1/8 AT 99.50 , BE FOR I STARTED JETTING IT DOWN IT WAS RUNNING PRETTY CLOST TO THE SAME ET,S BUT AT 100.50 MPH , STOCK JETTING WAS 157 CURANTLY ITS GOT 144,S SQUARE THE AIR BLEEDS [IDLE & HIGH SPEED]ARE AS IT CAME FROM HOLLEY.
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Old 05-18-2010, 04:25 PM   #4
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Default Re: Alcohol carb

Your gear and converter are probably real close to optimum, since alcohol gains most around peak torque is probably why you are not seeing gains you may be expecting. I think alcohol shows more improvement when the gearing and converter are less than optimum, 11 to 1 doesn't help as well. And the reason for the switch to alcohol was hope for better ET or reduced fuel cost? If you were looking primarily for better ET you may have been better off with a well built Dominator.
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Old 05-18-2010, 04:55 PM   #5
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Default Re: Alcohol carb

THE MAIN REASON FOR THE SWITCH WAS FUEL COST AND consistency I WANTED TO DABBLE IN SUPER PRO AND THE 2 CLASSES RUN BACK TO BACK , SO NO COOL DOWN TIME WAS NEEDED AND THERE ARE ABOUT 30 PIPE RACKS [DRAGSTER] AND 2 DOOR CARS , REALY DOSENT MATTER IT IS NOT ANY QUICKER BUT I KNOW THE CARB IS NOT CORRECT AND I DONT WNAT TO HURT ANY THING,
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Old 05-18-2010, 07:58 PM   #6
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Default Re: Alcohol carb

Try the changes I suggested, and go back to the jetting that puts the MPH back up. You can lean idle and transition as much as you can as long as it doesn't cause a lean stumble, as long as you have sufficient fuel at WOT you will be fine.
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Old 05-18-2010, 08:32 PM   #7
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Default Re: Alcohol carb

That 11-1 Comp is killing you most of the fuel is going out the pipes at the Comp. Alky is very hard to light and it really needs to be smashed to make power. You need at least 12.5-1 or more Comp. I would say you are not going to gain any power but it we be more consistent and it will run cooler.

All the Alky carbs I have used have a flubery mid range that is how they are. Really I think you may be fighting an engine that is not set up to run on Alky.
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Old 05-18-2010, 09:15 PM   #8
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Default Re: Alcohol carb

Compression is a taste low but will still work. Temp wise (egt) you are there. The coolant temp should increase 10-15 degrees at the end of the run from the starting line temp. What temp are you leaving the starting line at ? Are you able to put any heat at all into the engine when started cold ?
Do you have a ball valve connected to a hose in the intake plenum to lean it out when warming it up ?

Are you running your water pump all the time ?

What fuel pump are you running and what is the fuel line size from the cell to the pump, to the reg, to the carb ?

I've raced an alky injected 406 for years and left the line at 170-175 degrees. Water pump running all the time the engine was.
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Old 05-18-2010, 11:09 PM   #9
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Default Re: Alcohol carb

thanks horndog i have a magnaflow 500 with a #12 feeding it from the cell , a #10 to a mangaflow reg and from there 2 #8s to the carb , i have a lean out valve [ball valve] but dont use it as it will heat up , i leave the line at 160 deg [ i also use a 160 thermostate] if i keep the fan and water pump on it crosses the finish line at 160 , if i keep the fan and water pump off during the run it crosses the stripe at 190 deg i keep the fuel pressure at 7 psi and it stays there all the way through the run, the egts ar around 750 to 800 at the starting line on the 2 step car leaves just as it all ways has and was blurbring with the stock jetting [157] i just kept jetting it down untill it made a clean pass now its down to 144 square , i click it off in the lights and pulled a plug the ground strap is showing heat all most to the bend the porslin is white with a nice black ring at the base of it. the timing is set at 36 deg and is locked there, as i stated it is very rich when just off idle , when driveing it back to the pits, when it just idling it fine and seams to be at wot, once in a wile it will shut off when i lift in the lights but starts right back up and idles fine ???
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Old 05-18-2010, 11:12 PM   #10
tony dirose
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Default Re: Alcohol carb

69 chicken you may be right several guys where i race all use toilets there are a few with carbs but they dont know any thing about them, if they have a problem they send them out ???
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Old 05-19-2010, 12:00 AM   #11
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Default Re: Alcohol carb

Try increasing plenum volume
Close up ex lash if you can
C/ratio is ok -
Segment your timeslip and compare to gas incremantals.
Collector plays a major role - aswell.
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Old 05-20-2010, 05:02 PM   #12
tony dirose
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Default Re: Alcohol carb

hey jmarkaudio when you say change the idle jet, do you mean the main jet ??? i know about the air bleads etc . but i dont know about idle jets
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Old 05-20-2010, 05:29 PM   #13
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Default Re: Alcohol carb

Your idle jets will be one of two places. The bottom position is preferred, but either will work.

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Old 05-21-2010, 12:55 AM   #14
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Default Re: Alcohol carb

1300 is TOO hot! 1150 max on the egt in the 1/4
your compression is fine..don't listen to that crap...alky will pick up a low comp engine more than a high comp engine. St Louis area has been running alky in holley carbs since early 80s...yes early 80s thanks to 1 of our local racers. I personally have run it since 86 and ran a lot of 11:1 cr engines (jn 3600 lb car)that picked up 6 tenths in the 1/4 compared to box stock 750s and 850 gas carbs.
The off idle will always blubber...that comes from when the boosters start dumping fuel...don't worry about that.
Not to say out of the box holley alky carbs are good or bad...but you should have spent your $$ wiser and gone with BLP, APD (I only have used these 2, others Im sure make good product as well) or some of the others that are true carb gurus, not a bulk supplier.

Shoot me a pm with your phone # and I will give you the true poop on running alky without all the hype or mystery....it is EASY,.....too many over complicate it
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Old 05-21-2010, 06:50 AM   #15
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Default Re: Alcohol carb

I almost don't want to post anything because sc3283 seems to think he is the only one who knows or runs alky..
What ignition, plugs and plug gap are you running?
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