1/4 mile vs 1/8 mile

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dodgetexan

dodgetexan

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I have a question. If you were going to build two cars, one for the 1/4 mile and one for the 1/8th mile, what would be the differences between the two? I would assume a lower axle ratio would be better for the 1/8th mile but what about the engine, horsepower, trans, converter, weight, etc...? What changes would need to be made to optimize each car for the different distances?

I'm curious because the area where I live has about an equal number of both kinds of tracks and I've never raced the 1/8th mile before. I'm currently building a car for the 1/4...I'm wondering if I should also build another one specifically for the 1/8th.
 
If it's a bracket car gear if for the 1/4 and you can still run the 1/8.
 
I had a car with 32x16 slicks and 4.88 gears.7,200 at the end of the eighth wouldn't make the 1/4 it ran 5.60 on motor
 
Build the car for the 1/4, and have two sets of gears. Only change the gears if you feel energetic and that extra couple of tenths matter to ya that weekend. Other than that, race it as it sits. That will wrap it up.

my opinion is you want to cross the line 200 rpm's below your shift point. That is easiest on the car and your still pulling in the power band. Makes it harder for you opponent and easier for you if it's splitt'n hairs at the end.
 
What gears would you recommend? I'm going to be running a 4.30 in the 1/4 mile car.
 
you would have to use a gear calculator, and know what rpm's you shift at, if you want to get it down to a science. Not sure at all if it's that critical. Again, 1/4 cars work fine in the 1/8. If you want just a gear number thrown out there for the 1/8, bump those 4.30's up to 4.88.
 
I'm just wondering if there would be any advantage to having separate cars that are optimized for each type of track. Even if there's just a slight advantage it might be worth doing it if it would help to win races.
 
I think your just trying to justify buying another car without guilt... LOL
 
I already have another car...just wondering what to do with it. :evil4:
 
dodgetexan said:
I'm just wondering if there would be any advantage to having separate cars that are optimized for each type of track. Even if there's just a slight advantage it might be worth doing it if it would help to win races.
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If you're bracket racing, no IMO.
 
justinp61 said:
If you're bracket racing, no IMO.
Click to expand...
110 % Agreed , picture bracket racing it doesn't matter how fast you go just how consistent you are. Make sure you have an automatic transmission And practice launching your timing doing the same thing exactly the same every time and you'll win races. 1/8 or 1/4 mile
 
Yes, I am building the car up for bracket racing. The other car will probably become a race car too sooner or later. I just haven't decided exactly what I'm going to do to it yet.

(Sorry j par) :D
 
speed and power have nothing to do with a bracket race car. It is all consistency. You are chasing something that does not matter in bracket racing. The faster you make it the more you have to work on it. the result is a inconsistent bracket car. Then in the end you get beat by a station wagon running the ac. 1/4 or 1/8 as stated above gear to run both. If you want to bracket race and win build something that requires zero or minimal maintenance at the track. If you have to jack with the car between every elimination round you are just having fun and donating your entry fees.

One of the most deadly 1/8 th mile bracket cars I ever saw. 360-2 barrel, 904 2200 converter, 3.91 gears, spool, 10 inch slicks, traction bars. All in the light. guy never worked on the car. he cut awesome lights and he won time, after time, after time.
 
dodgetexan said:
Yes, I am building the car up for bracket racing. The other car will probably become a race car too sooner or later. I just haven't decided exactly what I'm going to do to it yet.

(Sorry j par) :D
Click to expand...
No problem - just brought home another car today no room.....
 
My car only went 5/100ths faster in the 1/8 going from 4.30s to 4.88s. So not worth changing gears for different tracks.
 
I lost a half of a tenth and gained 1 mph in the 1/8 when I broke my 5.14's and put some 3.50's in the 9 in that I am running. I was also crossing the finish line in 2nd gear. 6.39 @ 109
 
acpat said:
speed and power have nothing to do with a bracket race car. It is all consistency. You are chasing something that does not matter in bracket racing. The faster you make it the more you have to work on it. the result is a inconsistent bracket car. Then in the end you get beat by a station wagon running the ac. 1/4 or 1/8 as stated above gear to run both. If you want to bracket race and win build something that requires zero or minimal maintenance at the track. If you have to jack with the car between every elimination round you are just having fun and donating your entry fees.

One of the most deadly 1/8 th mile bracket cars I ever saw. 360-2 barrel, 904 2200 converter, 3.91 gears, spool, 10 inch slicks, traction bars. All in the light. guy never worked on the car. he cut awesome lights and he won time, after time, after time.
Click to expand...

When i first started racing(bracket racing) there was a 71 chev station wagon with a old man(I was 16) racing it, stock street tire. never done a burn out, just pulled up to the light. Thought it was a real jock. I never won against him in the 3 years that i raced him. he ran 19.00 all day every day and i was running 15's at the time. Now of course, i was trying to run faster each and every time i when out, so consistent wasn't in my wheelhouse. But it still pissed me off every time i raced him.

We all want to go faster, no matter how fast or slow we are. but the name of the game is consistent. learn to cut a good lights, run the same number and you will win races 1/4 or 1/8 mile.

Get both cars on the track and see which one makes you happiest. sell the other car and pour all the money on the ride you keep.
 
Sounds like everybody is pretty much in agreement that a car set up for the 1/4 is equally good in the 1/8th. Alrighty. Y'all have me convinced. I'll go ahead and build this car for the 1/4 and run it in both and see what happens. Then I'll decide what to do with the other one. Maybe I'll build it up for one of the NHRA classes. We shall see.:glasses7:
 
You need to choose a rear tyre with the correct roll out to give you the mile an hour you want then cross reference the MPH to ET on any number of online calculators. the Start Line Gear Ratio will be first gear ratio x rear gear ratio. Then you need to look up what you need based on vehicle weight. So you want to run 120 MPH or so on the 1/8 mile you will need say 4.88's with a 31" tyre @6500 rpm. SLR is 2.45 x 4.88 = 11.95 but things like engine stroke and vehicle weight will determine what is optimum for your deal.
So the SLR will get you off the line the tyres will give you the MPH which is directly related to ET. Bit of time with a calculator will save you a heap of money buying parts that may or may not work together.
 
Is there a calculator to figure out what is the optimum gear ratio for the 1/8 mile. All the tracks in my state are 1/8.
 
I'm going to buy another torque converter more on the tight side to get my "good" 60ft times back and am going to set up my 5.38 gears so I can take my boring bracket car to a match race heads up deal once in awhile. It's the only 1/8th mile track out here.
 
I have a friend who runs both with the same car and doesn't change anything. He wins a lot too. He runs a 4.86 gear in a Ford 9".
 
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