How will you go faster?

[289nate]

A tent dropped in the 60 ft has been about 1.5 dropped in the 1/4 mile in my personal experience.

[David Redszus]

A functional cold air supply to the air cleaner can be worth an easy quarter second on almost any day and will help with consistency. I think the formula is one percent power for every 10 degrees.

If conditions are:
29.92inHg
60F
0RH

then the following power losses would be encountered based on temperature caused density changes:
40F = +1.98%
50F = +0.98
60F = 0%
70F = -0.95
80F = -1.87
90F = -2.77
100F = -3.64

But changes in temperature almost always bring changes in Relative Humidity along with it.
Now the air density (and trapped mass) has changed as has air viscosity.

But there is more fun to be had.
Changes in air temperature will produce changes in air density which will affect both power AND aero drag.

[Bigchief632]

According to info in a book "How to hook and launch", a tenth at the 60' translates to nearly 3 tenths at the stripe.

No. Who wrote the book? Let me guess, ok, ok, don't say. But, whatever you improve your 60 ft by, it'll double in the 1/4. I could spend the next 6 months posting time slips to show you. So, if you improve your 60ft by half a tenth, it'll be a tenth quicker in the 1/4. A tenth better in 60 ft, will be 2 tenths, etc. As long as that's all that has changed. About half that in the 1/8. Whoever wrote that book must not actually race I'm assuming? Pretty common. The cool thing about drag racing, is the numbers are quantifiable. Unlike truck pulling, or road racing, etc. .002 is .004, etc etc

[skinny z]

Engine peaks at 7200, 7700 through traps, 1500 RPM window, needs a 6200 converter.

500 RPM overspeed.
That's a little of nugget of data I can work with.
Thanks.

[skinny z]

...whatever you improve your 60 ft by, it'll double in the 1/4.

I can offer similar results.
I've also learned it works in both directions. 60' went south by about 2/10ths from a PB. The ETs followed by a margin of almost two to one.

[Bigchief632]

...whatever you improve your 60 ft by, it'll double in the 1/4.

I can offer similar results.
I've also learned it works in both directions. 60' went south by about 2/10ths from a PB. The ETs followed by a margin of almost two to one.

Right. For the guys who race, and have a stack of time slips, start comparing the numbers. You'll see that's what it is. Sorta like multiplying your 1/8 times by 1.57, or dividing 1320 by your mph, or your et, it'll show you what you did, or could run based on one or the other. Obviously there's variables, that will throw it off a little, but it's amazingly close.

[skinny z]

A functional cold air supply to the air cleaner can be worth an easy quarter second on almost any day and will help with consistency. I think the formula is one percent power for every 10 degrees.

If conditions are:
29.92inHg
60F
0RH

then the following power losses would be encountered based on temperature caused density changes:
40F = +1.98%
50F = +0.98
60F = 0%
70F = -0.95
80F = -1.87
90F = -2.77
100F = -3.64

But changes in temperature almost always bring changes in Relative Humidity along with it.
Now the air density (and trapped mass) has changed as has air viscosity.

But there is more fun to be had.
Changes in air temperature will produce changes in air density which will affect both power AND aero drag.

What do you calculate as a % loss if the engine is ingesting hot air from the radiator? I reckon under hood air temps easily exceed 150F at times.

[F-BIRD'88]

According to info in a book "How to hook and launch", a tenth at the 60' translates to nearly 3 tenths at the stripe.

No. Who wrote the book? Let me guess, ok, ok, don't say. But, whatever you improve your 60 ft by, it'll double in the 1/4. I could spend the next 6 months posting time slips to show you. So, if you improve your 60ft by half a tenth, it'll be a tenth quicker in the 1/4. A tenth better in 60 ft, will be 2 tenths, etc. As long as that's all that has changed. About half that in the 1/8. Whoever wrote that book must not actually race I'm assuming? Pretty common. The cool thing about drag racing, is the numbers are quantifiable. Unlike truck pulling, or road racing, etc. .002 is .004, etc etc

U guy have got that 60 ft to ET change relationship inverted back ward.
If you chop x off your ET. it typically also chops Y off the 60 ft.
But if you just cut the 60 ft by x amount its worth X amount at the stripe.

[F-BIRD'88]

A functional cold air supply to the air cleaner can be worth an easy quarter second on almost any day and will help with consistency. I think the formula is one percent power for every 10 degrees.

If conditions are:
29.92inHg
60F
0RH

then the following power losses would be encountered based on temperature caused density changes:
40F = +1.98%
50F = +0.98
60F = 0%
70F = -0.95
80F = -1.87
90F = -2.77
100F = -3.64

But changes in temperature almost always bring changes in Relative Humidity along with it.
Now the air density (and trapped mass) has changed as has air viscosity.

But there is more fun to be had.
Changes in air temperature will produce changes in air density which will affect both power AND aero drag.

What do you calculate as a % loss if the engine is ingesting hot air from the radiator? I reckon under hood air temps easily exceed 150F at times.

At the track, on any given day for best ET your staging lane cool down regime is critical.
You want warm oil, warm trans/ rear axle. but COLD INDUCTION.. and cool engine water temp (under 100°F)
when you stage the car..
You will want to open the hood and remove that air box/ air cleaner assembly to let the carb and intake manifold cool down as much as possible between rounds.
Install it just before your lane gets called.

Even a small electric fan underhood helps push the hot air out from under hood with the hood open to get rid of the heat. The dry ice on the intake manifold works. Just make sure you don't bring dripping water to the starting line... If the track has a water hose pit for engine/ rad cool down its great.. Again avoid bringing dripping water to the starting line. If you water spray the rad to cool it down fast, drill water drain holes in the bottom of the rad support to avoid trapped water under hood.
What ever you do you want to avoid draging dripping water to the start line..

[F-BIRD'88]

Engine peaks at 7200, 7700 through traps, 1500 RPM window, needs a 6200 converter.

500 RPM overspeed.
That's a little of nugget of data I can work with.
Thanks.

Your engine will need a lot more "over speed" thru the traps than his. Think 1000 rpm at minimum for yours.
8% "over speed" RPM is typical.. Your car will want more than 8% to et best.

[Bigchief632]

According to info in a book "How to hook and launch", a tenth at the 60' translates to nearly 3 tenths at the stripe.

No. Who wrote the book? Let me guess, ok, ok, don't say. But, whatever you improve your 60 ft by, it'll double in the 1/4. I could spend the next 6 months posting time slips to show you. So, if you improve your 60ft by half a tenth, it'll be a tenth quicker in the 1/4. A tenth better in 60 ft, will be 2 tenths, etc. As long as that's all that has changed. About half that in the 1/8. Whoever wrote that book must not actually race I'm assuming? Pretty common. The cool thing about drag racing, is the numbers are quantifiable. Unlike truck pulling, or road racing, etc. .002 is .004, etc etc

U guy have got that 60 ft to ET change relationship inverted back ward.
If you chop x off your ET. it typically also chops Y off the 60 ft.
But if you just cut the 60 ft by x amount its worth X amount at the stripe.

Uuum, no, lol. What comes first? The chicken or the egg? I reread what you said. Yes, if you cut .001 off your 60ft, it'll be .002 off your et. Half a tenth, is a tenth, etc etc. Go get your stack of time slips, err uhh, if you have any, and you'll see.

[F-BIRD'88]

No. Who wrote the book? Let me guess, ok, ok, don't say. But, whatever you improve your 60 ft by, it'll double in the 1/4. I could spend the next 6 months posting time slips to show you. So, if you improve your 60ft by half a tenth, it'll be a tenth quicker in the 1/4. A tenth better in 60 ft, will be 2 tenths, etc. As long as that's all that has changed. About half that in the 1/8. Whoever wrote that book must not actually race I'm assuming? Pretty common. The cool thing about drag racing, is the numbers are quantifiable. Unlike truck pulling, or road racing, etc. .002 is .004, etc etc

U guy have got that 60 ft to ET change relationship inverted back ward.
If you chop x off your ET. it typically also chops Y off the 60 ft.
But if you just cut the 60 ft by x amount its worth X amount at the stripe.

Uuum, no, lol. What comes first? The chicken or the egg? I reread what you said. Yes, if you cut .001 off your 60ft, it'll be .002 off your et. Half a tenth, is a tenth, etc etc. Go get your stack of time slips, err uhh, if you have any, and you'll see.

I have been drag racing for some 40+ years.

[prairiehotrodder]

I have stacks of timeslips and every time i think i know something, I end up being wrong. I grew up reading car craft and hotrod magazines and they all said to use mild parts and build torque. Just that you don't win any races that way. As far as what works and what doesn't, I've found big differences when running 15's but ET comes harder in the 9's. I like removing weight, somehow it makes me feel good.
Brian

[mt-engines]

U guy have got that 60 ft to ET change relationship inverted back ward.
If you chop x off your ET. it typically also chops Y off the 60 ft.
But if you just cut the 60 ft by x amount its worth X amount at the stripe.

Uuum, no, lol. What comes first? The chicken or the egg? I reread what you said. Yes, if you cut .001 off your 60ft, it'll be .002 off your et. Half a tenth, is a tenth, etc etc. Go get your stack of time slips, err uhh, if you have any, and you'll see.

I have been drag racing for some 40+ years.

Then you know how the timing system works? Correct

[rfoll]

According to info in a book "How to hook and launch", a tenth at the 60' translates to nearly 3 tenths at the stripe.

No. Who wrote the book? Let me guess, ok, ok, don't say. But, whatever you improve your 60 ft by, it'll double in the 1/4. I could spend the next 6 months posting time slips to show you. So, if you improve your 60ft by half a tenth, it'll be a tenth quicker in the 1/4. A tenth better in 60 ft, will be 2 tenths, etc. As long as that's all that has changed. About half that in the 1/8. Whoever wrote that book must not actually race I'm assuming? Pretty common. The cool thing about drag racing, is the numbers are quantifiable. Unlike truck pulling, or road racing, etc. .002 is .004, etc etc

Dick Miller, this guy isn't a nobody.