Quarter-mile performance numbers?

[bamfordsgarage]

With the rebuild of my '47 D25 engine looming, I am gathering as-is performance numbers and engine stats such as 1/4 mile performance, compression readings, oil pressure, etc.

There is a well lit and lightly travelled section of 4-lane road a few miles from home, and I've been running up and down this evening getting my drag strip numbers. I used a handheld GPS and noted the speed attained as the 1/4 flashes by, and, on subsequent runs, a wall clock with minute hand to gauge elapsed time. I'm sure neither are all that accurate, with the ET even less than the trap speed. Shifts were made at an indicated 3,000 RPM, with one soul on board, the car-top carrier mounted and only moderate junk in the trunk. The car is all original, all stock, with a rather tired engine. I made nine speed runs, discarded the highest and lowest numbers, averaged the rest. I then ran only two timed runs and averaged the pair.

Standing 1/4 mile: Average speed 49.7 mph, 28 seconds ET. It was, of course, hard to maintain consciousness under such tremendous G-forces — I could feel my eyeballs being sucked back all the way to the trunk.

It would be interesting to learn what other owners have achieved over the 1/4 mile and how their cars were equipped.

[Don Coatney]

This is what you are up against.

Incredible*If you thought Top Fuel Dragsters were fast (over 300 mph in

less

than 5 seconds), this really puts it into perspective. This came

from a guy that makes connecting rods for the racing industry.*

*

ACCELERATION PUT INTO PERSPECTIVE*:

* One Top Fuel dragster

outfitted with a 500 cubic-inch Hemi engine

makes more horsepower

(8,000 HP) than the first 4 rows at NASCAR's Daytona 500.

* Under

full throttle, a dragster engine will consume 11.2 gallons of

nitro

methane per second; a fully loaded Boeing 747 consumes jet fuel at the

same rate but with 25% less energy being produced.

* A stock

Dodge Hemi V8 engine cannot produce enough power to merely drive the

dragster's supercharger.

* With 3000 CFM of air being rammed in

by the supercharger on

overdrive, the fuel mixture is compressed into

a near-solid form before ignition.Cylinders run on the verge of

hydraulic lockup at full throttle.

* At the stoichiometric 1.7:1

air/fuel mixture for nitro methane the

flame front temperature

measures 7050 degrees F.

* Nitro methane burns yellow. The

spectacular white flame seen above the stacks at night is raw burning

hydrogen, dissociated from

atmospheric water vapor by the searing

exhaust gases.

* Dual magnetos supply 44 amps to each spark plug,

which is typically the output of an electric arc welder in each

cylinder.

* Spark plug electrodes are totally consumed during a

pass..

*After 1/2 way thru the run, the engine is 'dieseling'

from

compression and the glow of the exhaust valves at 1400 degrees

F. The engine can only be shut down by cutting the fuel

flow....

* If spark momentarily fails early in the run, unburned

nitro builds

up in the affected cylinders and then explodes with

enough force

sufficient to blow the cylinder heads off the block in

pieces or split

the block in half !!

* Top fuel dragsters

reach over 300 MPH +.... before you have completed reading this

sentence.

* In order to exceed 300 MPH in 4.5 seconds, a dragster

must

accelerate an average of over 4 G's. In order to reach 200 MPH

well before reaching half-track, at launch the acceleration approaches 8

G's.

* Top Fuel engines turn approximately 540 revolutions from

light to light!

* Including the burnout, the engine must only

survive 9000 revolutions under load.

* The red line is actually

quite high at 9500 RPM.

* THE BOTTOM LINE: Assuming all the

equipment is paid for, the pit crew is working for free, & NOTHING

BLOWS UP, each run will cost an estimated $1000 per second.

0 to

100 MPH in .8 seconds (the first 60 feet of the run).

0 to 200 MPH in

2.2 seconds (the first 350 feet of the run).

6 g-forces at the

starting line (nothing accelerates faster on land).

6 negative

g-forces upon deployment of twin 'chutes at 300 MPH.

An NHRA Top

Fuel Dragster accelerates quicker than any other land vehicle on earth .

. . quicker than a jet fighter plane . . . quicker

than the space

shuttle....or snapping your fingers !!

The current Top Fuel

dragster elapsed time record is 4.420 seconds for the quarter-mile

(2004, Doug Kalitta). The top speed record is 337.58 MPH as measured

over the last 66' of the run (2005, Tony Schumacher).

So, in

summary...Let's now put this all into perspective:

Imagine

this.....You are driving a new $140,000 Lingenfelter twin-turbo powered

Corvette Z-06. Over a mile up the road, a Top Fuel dragster is staged

& ready to 'launch' down a quarter-mile strip as you pass. You have

the advantage of a flying start. You run the 'Vette hard, on up through

the gears and blast across the starting line, and pass the dragster at

an honest 200 MPH.... The 'tree' goes green for both of you at that

exact moment. The dragster departs & starts after you..

You

keep your foot buried hard to the floor, and suddenly you hear an

incredibly brutally screaming whine that sears and pummels

your

eardrums & within a mere 3 seconds the dragster effortlessly

catches & passes you. He beats you to the finish line, a

quarter-mile away from where you just passed him.

Think about it

- from a standing start, the dragster had spotted you

200 MPH....and

it not only caught, but nearly blasted you off the

planet when he

passed you within a mere 1320 foot long race !!!!

That.....is acceleration!

[Gwellman]

In the 60s, I bought ($35) a neighbor's 1950 Plymouth sedan in Detroit. It was a real rust bucket, holes in the floor etc.

I liked drag racing and went to the local drag strips often, but only to watch. When I got the Plymouth, I rigged a way to disconnect the exhaust pipe, milled the 60 thou (Dad,a Chrysler engineer helped me) and I went racing. I was in N Stock, the lowest class at that time. I raced Corvairs, Falcons etc, and could beat them all. My nemesis was a guy in a 50 Plymouth business coupe who could always just nip me at the end. Nothing gave me greater pleasure than beating the Corvairs..."sports cars" losing to a junker...ha ha

Anyway, as for times, I could get about 19.5-19.8 seconds at 67-70 mph. I got a good start by reving the engine popping the clutch, got a short burn out. I had a Sun 270 degree 0-5000 tach and I ran the engine up to 5000 before shifting which I did a full throttle. The car never broke...and I would have been really stuck if it did because I drove the car to the strip. And I still have the tach, now in a pristine 48 business coupe.

Interestingly, I tried different size jets in the carb but never found much difference. I tried shifting at different rpm points also but found the 5000 rpm shift point the best.

Now I am a retired scientist and I would have to tell you that the error in your method of measurement is probaby too large to make any meanful conclusions. The advantage of the drag strip was that the timing was very accurate, and even then there would be a few tenths of a second difference between runs.

[greg g]

I believe Mark A did a couple runs in the 19's at MOPAR Nationals a few years back.

His 50 Plymouth Business coupe is equiped with dual carbs and dual exhaust.

My seat of the pants timing equipment suggests, my dual carbed 230 in my bus coupe woud be pretty close to that also.

[homebrewer]

I ran my old P15 4dr thru a couple of times in the late 50's. Bone stock except for a split manifold. I don't remember the ET's, but I think the speed was about 63-64 MPH. Also ran a 33 plymouth coupe stock 4 cyl and it turned 61MPH. Those were the days. Ducktails, Pall Mall Reds tucked in your tee shirt sleeve, engineers boots, sunglasses, and of course your car club jacket. I still have my old car club plaque in the window of my coupe. Flywheels SF Cal

[Young Ed]

Now I am a retired scientist and I would have to tell you that the error in your method of measurement is probaby too large to make any meanful conclusions. QUOTE]

Right but hopefully he will have approximately the same amount of error after the engine rebuild and be able to do a comparison.

[B1B Keven]

Stock 218, 4 speed and 4:10 gears in my pickup.

20.53 quarter mile.

In the other lane was a 4 cyl. Vega which I beat by .02 seconds.

( oh ya, I had my tailgate down )

[TodFitch]

Now I am a retired scientist and I would have to tell you that the error in your method of measurement is probaby too large to make any meanful conclusions.

True for the following too.

Turns out you can get car performance apps for smart phones. At least you can for Android based ones and I expect you can for iPhones, etc.

Turns out that the GPS in my Nexus One has a bit of trouble keeping locked when mounted on the suction mount on the windshield of my '33. I'm guessing RFI off of the unshielded ignition system. Not normally a problem for navigation as things average out. But it does mean getting consistent results from acceleration tests is iffy.

But having an app that you tell to start which then waits for you to start moving to start its timer and then tracks you and records time to distances and times to speeds is a lot easier to deal with than an handheld dedicated GPS unit.

Another issue for me: There aren't very many roads around here that are flat, straight, posted for at least 50 MPH that aren't very crowded. So finding a time and place for testing takes some effort.

And I've never really been into racing, so I'm probably not the best driver to do the testing.

Anyway, with all those caveats, here are the results I got a year ago from my stock '33 Plymouth with about 25,000 miles on the rebuild of its 190 cu.in. engine.

[BobT-47P15]

I think my top speed in the quarter, when I ran it thru during the

HAMB drags here in 2006, was 57 mph.

I didn't take off very hard

as I didn't want to possibly damage the clutch.

And my differential is geared just a bit lower than a normal P15.

[bamfordsgarage]

Thanks, everyone, for your replies. Interesting information. Gwellman, I know my equipment and consistency is not up to the task but for my purposes the results should still be somewhat useful — the engine is definitely tired and I'm expecting a noticeable improvement after the rebuild. I'll post compression test results, oil pressures, etc. on a separate rebuild thread soon.

My only experience with formal drag racing was September 2003 at Drag Wars in Grande Prairie, Alberta. I took the body off my tired 1924 Model T speedster to make it as light as possible and went bracket racing. My shining moment (ohotos below) had me wipe the track with a young fellow in a GTO, who was also running his first ever drag race. ET 25.945 sec, trap speed 47.32 mph.

[Barabbas]

I had one run several years back--did a 20.1 @ 68 +. At the time my engine was a 230 bored .03 over, dual carbs (both in really bad shape) and single exhaust

[oldodge41]

TodFitch said, "Turns out you can get car performance apps for smart phones. At least you can for Android based ones and I expect you can for iPhones, etc."

I had to check it out and I downloaded a free app for my Droid X2 that is really neat. I tried it out in my OT truck that I know is off by a couple mph on the speedometer and the app confirmed it. I will now be able to remark my existing speedometer in the 41 without making multiple runs past one of those roadside radar speed signs as I had planned. Thanks for the heads up Tod!