The 283 in my altered is 12:1 with an ancient TRW cam that matches the 30/30 - the heads are 1.94 fuelies the intake is a crietz 2x4 - prob 300hp or so - of course I want a small hilborn, but that is not in the cards right now - my carbs are 625 afb's with early tops. I figured I was stuck with gas, but I'd really like to run alky through them.....I know i can get all metal oversized needles and seats and perhaps remove the meetering rods (or just up the jets) but what else will I need to modify? Part throttle performance is not real important, but it needs to idle in the pits and transition off the line.....anybody gone this route before? am I nuts? anyone have a hilborn they'll sell me cheap? got the crietz setup to trade.... Altered4 by ididntdoit1960 posted Nov 23, 2015 at 9:35 PM
Add two to three points to your compression, go to bigger fuel lines and high VOLUME pump. Some of the main wells may be too small to flow enough fuel. Do not let the fuel sit in the carbs for too long, have a way to drain the fuel. I used a semi filter with a drain at the bottom. Check your sparkplug color at the very bottom of the center porcelain, should be light gray.
No.......your not going to run alky through a gas carb....... way more involved than just jet size....... and I wouldn't attempt it with an afb
I know there is a lot to it......if you could elaborate on why not to do it with an AFB I would really appreciate it - trying to learn - thanks
Virtually every metering passage needs to be altered to run alcohol , including the idle circuit the air bleeds etc. there is info out there on building Holley alcy carbs.....don't know about carters....
Several stock car divisions run alky carbs, but I believe everyone runs Holley's, they are pricey and work well.
in the day time you can not see the flames if you have a fire. Water will find its way to your fuel. Every time you park you car you will need to run the carb dry. This is also called pickeling the fuel system. then drain the fuel from your tank, and store in a proper barrell. Its called a poor mans supercharger for a reason. I have a friend who ran the stuff. and every time I look at his face and arms I know why I will not race with it.
I ran a 331 Hilborn injected Chevy on alcohol back in the 60's in my dirt modified. I still have all my hair. Never had a problem. In fact, I was so happy running it, there were tears in my eyes whenever we fired it up
I ran it for 12 years at the drag strip. I used a Holley 750 modified for it. My car ran 11.00's with a 455 Pontiac, 750 Holley, and 12:1 compression. I used about 5 gallons for every three passes counting burn outs and the drive back up the return road. It might use half that on gasoline. I only ran about 7.5 psi fuel pressure with 1/2 line and dual regulators. It was more about volume then about pressure. If I kept the tank partially full and the fuel system stayed wet, I could get through a whole season of racing without working on it. When it dried out, the gaskets and pump would go to crap. You will need to oil the pump and regulators if you dry the system all the time. They may have additives now similar to 2-stroke oil, they didn't in the early 90's. Use very little rubber line or silicone line. My Holley had extra tubes added for air volume and I believe Holley Dominator plates and gaskets with dual large accelerator pumps and 86 jets all around. My engine was always rusty looking inside due to condensation. Saturday morning prepping for that nights racing involved draining the water out of the oil pan. Cooler weather made it worse. I suppose a hotter thermostat might have helped dry out the oil, but I didn't think about it I guess. I never had any problems with fire, it makes nasty exhaust fumes so be sure to stay in the open, no garage running. I ended up with a full exhaust system just to keep the fumes out of the car. For the longest time I always had terrible head aches when I got home from the track, they went away when I installed the exhaust system. Switching from gas to methanol , with no other changes cut about 1/2 second of the et and added mph, don't remember now how much though. Adding more compression took more et away, don't think you can have to much! Joe
I get the pros and cons of alky and I know it needs twice as much......my question is how can I get 2 625 afb's to flow enough to run my 283 and idle/transition properly - my answer so far is it cant be done....and thats fine, but at the risk of sounding like a 2 year old........why?
As was said above, volume may be why. Gas is .5 lbs per horsepower hour, meth is .9 lbs. With that info you can calculate delivery needs and fuel flow through the carbs. To say a flat out "No you can't..." may or may not be wrong. Alky carbs are expensive for the same reasons stated above, all the work required to get enough volume. Just to throw something out there as food for thought. How about E-85? I'm not sure of the lbs/HP hr needs but there's been some guys going really fast with the stuff. It's my understanding that the pitfalls of straight meth are not the same as E-85 but some serious gains can be realized. Spend some time with an intensive google search and you may find it to be a viable alternative for what you're using, as in it may be possible to mod your carbs to run the stuff successfully.
What we used to do was drain the tank and run gasoline though the carbs after we were done racing. it makes for an eye burner and you trash a set of plugs but it cleans the alcohol out. I don't know about current data but we used to say that it take 3 times as much alcohol to run a motor as it does gasoline. so as rick has mentioned larger fuel lines ( like min 1/2"), high volumn pump. I would suggest keeping your rubber lines to a minimum and run as much hard line as possible. I have not run alcohol through an AFB but I have run it through Holleys and though an S&S carb on my bike (many years ago on both). I do know for a Holley you can buy everything you need alcohol specific, down leg boosters, oversized pumps that are alcohol specific, alchy needle and seat (larger and alcohol resistant). Compression is your friend, while your little motor should run OK @ 12:1 it would do much better @ 14:1.
If you are dead set on running alky and carbs, I think you will have to go with some converted Holleys. I have never seen anyone do it with AFbs, I guess it could be done, but at what expense, dont know.
It's 2.1 times the volume to create the same amount of btu energy. You have to measure the jets by area and not by number size
14 to 1 comp. ??? I 'd say you better be upgrading those 1.94 heads to real fuelies (2.02's), a lowly 283 with a 30/30 with even 12 to 1 comp. will thank you.
A lot of Hambers won't like my answer, but it is the most comprehensive, simplest, and cost efficient way to achieve an alcohol (fuel)intake system. Use electronic fuel injection! You can use the AFB's as throttle bodies, and just fabricate a non obtrusive fuel rail to fit F.I. bungs installed in your existing intake manifold. a high pressure F.I. fuel pump in-line will work, and an aftermarket control system such as Megasquirt from D.I.Y would be easy to install. The injectors could be off the shelf high volume units. At the end of the day you would still have to flush the system with gasoline. I also think the 2.02 heads would be a must. If you do it right no-one would know, you weren't carbureted.
I have run two drag cars on alcohol, if you try to put two or three times to fuel in your engine your gonna have trouble. Alcohol only needs 1.4 times gas to run properly. There is a problem on the street with keeping the engine temp high enough to make it run clean. We would have to lean out the carb a lot just to get it up to temp,and it would cool down before we could get back through the pits. It is corrosive but that can be handled. I don't think you can move enough alcohol thru a AFB to run it at a higher rpm. Holleys are heavily modified to get them to work. I am changing mine to E85 and it is a better alternative ,for me anyway. I would not store either one inside any building on my place, way to scary.
I actually considered using the gutted afb's as throttle bodies and convert to mechanical injection - but by the time im done I might as well buy an 8 stack set up
I thought about e85 - not widely available here, but ok for a drag car - there are places that convert eddy carbs for it.....perhaps ill give them a call....but again, it gets pricy....if I want to step up to alky from gas, it looks like a hilborn will be my best bet
ididdoit - You keep asking, the answer is still "NO". You cannot get the passages in the AFB large enough. It's iffy in the Holley's. I think Holley "may" make an alcohol carb. You CAN do it with a bank of Stromberg 97s'..! Been done for years. Just put an injector on it and be done with it. Mike
yes - you and goatroper hit it right on this one......ill run it on gas for now and step up to injection once the rest of the car is dialed in unless I find a sweet deal between now and then...
Just set it up to run on E85 [between 105 and 110 octane] and cheap Average E85 price in the USA is $1.90 http://e85prices.com/
Yep, I would be all over E-85 if I were you. By far the cheapest route and easiest route. The nice part of using it in a race car is that you can order spec fuel to make sure it is consistent. E-85 ranges from 51% to 83% Ethanol at the pump.
In case you consider e85, I just converted my two Holley's over to e85 using Quick Fuel's metering blocks. 105 octane, outstanding cooling characteristics (match made in heaven for forced induction), $2.09 a gallon....what's not to like? It took a couple of weeks of fiddling with the tuneup to get the car pulling like it should for someone like myself who is carb capable but had never messed with a vegetarian tune. For e85, you need to increase the volume of fuel the engine sees from fuel lines, to pump, to internal carb passages and of course jetting by roughly 30%. My fuel system was already set up overkill and had plenty of room for expansion so I simply needed to do the carb modifications. Added 10 jet sizes all around and bumped timing up by 2*. Very throttle responsive and angry cackle to the idle now. Hits hard as hell when you wing it open. A true e85 carb would likely perform a little better but I want the option to easily go back to gas should I decide to. Might see a minor pick up in ET from slightly increased torque. Consistent performance. Methanol needs even greater volume. Like 2x plus comparing it to gas. Fuel pressure needs to be low at idle and ramp up as rpm increases.... = belt driven fuel pump. Outstanding engine cooling effects. Holley makes alcohol (methanol) specific carbs but the optimal way to run methanol is injected. Hilborn, flying toilet, or electronic similar. Big pick up in torque on methanol = noticeably lower ET's. Consistent in different weather. FWIW
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