quote:

Originally posted by NC3x58:
One thing I have always heard is that gas is more predictable while methanol is definitely more consistent and will typically stay within a number all day long. Gas may move 2-4 depending on the weather swing's/time of day you run etc.

This is where running gas on days where you run 2-3 days without a time trial each day, can be more beneficial. Not saying alcohol can't be used in this situation, it just requires more knowledge on the weather and how your car reacts with the weather changes. Gas is quite simple, temperature/air density are the two biggest factors in predicting ET with gas. Alcohol depends a lot on humidity, water grains in the air etc.

In your exact scenario, the alky will run within .01-.02 (at most) different each day. So saying alky isnt as predictable is false. Gas just follows air more, meaning that if the weather changes, so does et. Alky does NOT do that, no where near like gas. Alky cars, tend to follow track more than weather, and if you have a car that does not care too much about track conditions, then you will have a deadly car. Providing the carb is correct for application.

quote:

Originally posted by 329L:

quote:

Originally posted by NC3x58:
One thing I have always heard is that gas is more predictable while methanol is definitely more consistent and will typically stay within a number all day long. Gas may move 2-4 depending on the weather swing's/time of day you run etc.

This is where running gas on days where you run 2-3 days without a time trial each day, can be more beneficial. Not saying alcohol can't be used in this situation, it just requires more knowledge on the weather and how your car reacts with the weather changes. Gas is quite simple, temperature/air density are the two biggest factors in predicting ET with gas. Alcohol depends a lot on humidity, water grains in the air etc.

In your exact scenario, the alky will run within .01-.02 (at most) different each day. So saying alky isnt as predictable is false. Gas just follows air more, meaning that if the weather changes, so does et. Alky does NOT do that, no where near like gas. Alky cars, tend to follow track more than weather, and if you have a car that does not care too much about track conditions, then you will have a deadly car. Providing the carb is correct for application.

I agree with what you are saying 100%. Some people just have difficulty dialing the following day because it can definitely be tricky to figure out exactly where the car will land in that .01-.02 which is also what I have noticed in our own dealings with alcohol. 9/10 times I will dial the car on the upper end to make sure I can cover the dial, a lot of guys though just run it out the back door without even looking over. My point was mainly, gas will ultimately run the same number at the same temp and density altitude no matter what.. Alcohol could run off a number or two at the same temp/DA because of the water in the air. Mainly saying there's more to look at when predicting an ET at the beginning of a new race day than gas.

All of our experience had been in super pro/box racing with both fuels. Is one fuel do better with the footbrake launch/response than the other fuel as far as consistently controlling reaction times?

quote:

Originally posted by 478c:
All of our experience had been in super pro/box racing with both fuels. Is one fuel do better with the footbrake launch/response than the other fuel as far as consistently controlling reaction times?

I would say no.. But I do not have a ton of experience with foot-braking so I can't say for sure. I would say either fuel is fine, as long as the carburetor is properly tuned as to not stumble when launching, that would be your biggest concern. Which also probably includes choosing a properly sized carb for the application. A smaller carb is likely more appropriate to give you the best throttle response regardless of fuel choice.

I will add that alcohol will tend to be more forgiving if your carb tuning is not spot on. When you hit that sweet spot with gas the fuels that we have today don't have as much difference in consistency as way back. I'm a footfeeder and tuned my own alcohol carb. It's a 4150 Gold Claw RS that was a 775 when I started with it. I made new sleeves for it so now it's a 975.

You will find that for footbraking cfm in my opinion is something that you have to consider more than if you leave on the carpet. I'm not saying that it isn't important for performance either way, just that fine tuning for leaving off the foot it's more of a consideration.

I can't drive worth a darn but I have gone 5 days without changing the dial in and pretty much run the same out the back door. .140 + 60 ft in an Oldsmobile usually running 6.60 on gas off the foot.

I've run both this year. Won races with both. 2 separate fuel systems in the car and can change from one to the other in about 15 min. I actually like both. Car reacts faster and runs faster on alky, duh. Pit manners are 10x better on gas. The pros and cons go on and on. I like the tree spot a lot better on gas. I like the better launches and predictability over the total day of alcohol. I like dumping the same jug in the jrs and my car. I hate the current race gas prices. I like never turning on the fan, but don't like having to build heat. I can keep going. Learn as much as you can about carbs. There are a lot of things that will make experience with either fuel much better. I ran gas for 20+ years so alcohol was a big learning curve. Get every size drill bit there is from .010 up. Have fun!

This is an example you take for what it's worth.
A few times this season I have made 14 to 17 runs in a day at a race.
Alcohol carb of choice is a 4150 alky carb built by a local racer, Terry Heller. It has been money for two full seasons. Electric pump set at 27 psi at the regulator and 6.5 psi after. Warms up fine, I use a 1/2" vacuum line in the intake to create a "vacuum leak" to build heat faster. Use it staging quite a bit as well to get it to 175 before each run.
I don't search for the fastest setup anymore, I want one that prints tickets and basically never needs the hood opened on race day. Right now, I have that.
In my opinion, you don't need the latest and greatest "trick of the week", Money will not win these days. You need a car that will repeat for 8-10 rounds (more if doubled) but more importantly you need to drive the start line and finish line within the same window as the car performs. The "pair" (you and the car's performance) are what a winning package actually is.
Good luck to all of you the rest of the season.
Jok

I footfed for 18 years on pump gas...I never could get the consistency I wanted...I did OK mind you and won events more due to cutting lights and my driving...I went to the button off the bottom about 4 years ago and my consistency increased immediately...probably because I was now launching at the exact same rpm every pass...

They stole my pump gas car so now I race an S-Dime on 112 race gas...too soon for results...all of my serious foot brake friends use methanol...runs cool for hot lapping and is stupid consistent...I can't as I am too old for the maintenance involved...sigh...

Fwiw,

I used to race s/pro, footbrake and an index class with a slow Chevelle. I would run alky except for index because it was not allowed years ago.
"My" car was slightly better on alky for consistency.
I would swap carbs for index racing. I had two fuel systems. Alky: front cell and endele pump. Gas: rear cell and bluepump with Holley reg.

This is with a 11 second car with a GM ZZ4 crate engine.

Both carbs were box Holley's. Gas is 750 dp with choke horn milled off and I changed linkage to 1:1. Throttle response is awesome with 1:1. I always told people that drove my car that it would get away in the the burnout and they laughed. Sure enough, the air shifter kicked in!

Alky is 750HP. Changed jets and that was it.

Also ran a K&N filter and with out.
No difference for me.

My 2¢.

quote:

Originally posted by fuzzy dice:
I footfed for 18 years on pump gas...I never could get the consistency I wanted...I did OK mind you and won events more due to cutting lights and my driving...I went to the button off the bottom about 4 years ago and my consistency increased immediately...probably because I was now launching at the exact same rpm every pass...

They stole my pump gas car so now I race an S-Dime on 112 race gas...too soon for results...all of my serious foot brake friends use methanol...runs cool for hot lapping and is stupid consistent...I can't as I am too old for the maintenance involved...sigh...

What maintenance? I have (3) cars, so one usually sits alot. Maybe 2 months at a time. I start it up and load it in the trailer....

quote:

Originally posted by Jonesz:

quote:

Originally posted by fuzzy dice:
I footfed for 18 years on pump gas...I never could get the consistency I wanted...I did OK mind you and won events more due to cutting lights and my driving...I went to the button off the bottom about 4 years ago and my consistency increased immediately...probably because I was now launching at the exact same rpm every pass...

They stole my pump gas car so now I race an S-Dime on 112 race gas...too soon for results...all of my serious foot brake friends use methanol...runs cool for hot lapping and is stupid consistent...I can't as I am too old for the maintenance involved...sigh...

What maintenance? I have (3) cars, so one usually sits alot. Maybe 2 months at a time. I start it up and load it in the trailer....

I was going to give a similar reply. I think the only thing 'extra' that I do based on fuel type is pull the carb, drain and spray it out with WD-40, then store in a warm location over the winter. I also spray fogging oil down the intake runners while spinning the engine over and tape off the intake plenum.

quote:

Originally posted by ferndaleflyer:
I can't drive worth a darn but I have gone 5 days without changing the dial in and pretty much run the same out the back door.

^^^ - Do NOT believe the first part of that statement.