First time at the drag strip

[Mest30]

Took the Marauder to US 41 with a few CVNers. I had a blast. Anyways, to the numbers.

1st run - 14.5131 1/4, 2.1270 60 foot time @94.47mph

2nd run - 14.6607 1/4, 2.2268 60 foot time @ 94.37mph

3rd run - 14.870 1/4, 2.2668 60 foot time @ 93.87mph (dont know what happened here, probably heat soak as I did 3 runs in under 90 minutes and waited another 90 minutes before doing my last run).

4th run - 14.5619 1/4, 2.1931 60 foot time @ 98.98mph

Pretty good if you ask me, espically for a 1st time dragster. My mods are excal2, 4.10s, intake spacer and JLT CAI. I have UD pullies and Stewart water pump but havent got them installed yet. One quick question. Why is my trap speed higher on my last run but the time is a bit slower? Probably because of the 60 time, but does that mean that my best run was probably left at the strip?

[MarauderBoy]

Mest30 - I think I parked next to you a couple of times but don't think we had a chance to talk. This was my first time out too, so I'll be interested to hear what others have to say about 60 foot times and a good run.

Nice times BTW!

[justbob]

Good run for your first time out! Keep it up. I've only gone out once myself and that was last year after owning it for three years. I wanna go again myself someday but i'm always workin or i have my three kids.

[sailsmen]

Traction.

Please post the temp/humid/elevation.

[Mest30]

Marauderboy, yeah, I saw you there. You're car is sick! I would have spent some more time talking to you and the CVNers there but it was my first trip ever to a strip so I was having a blast watching all the races.

Sailsmen, The temp was about 65 degrees, not sure about humidity. I think the sign by the track said 600ish feet above sea level.

[Bradley G]

667' according to the sign, not sure about the humidity.
The last run , the MPH trap speed seems off.

[red]

4th run - 14.5619 1/4, 2.1931 60 foot time @ 98.98mph
...
One quick question. Why is my trap speed higher on my last run but the time is a bit slower? Probably because of the 60 time, but does that mean that my best run was probably left at the strip?
With your mods, you should be running somewhere in the mid 90 MPH range, depending on the DA. The 98 mph is definitely an outlier and the slight increase in 60' over your 2nd and 3rd runs would not account for the gain. The computers do mess up (I have a few freak timeslips that I'm forced to dismiss). Can you post your slips? If not, what's your 1/8 MPH for the runs? Concerning the DA, give me the time (of day) for your runs and I'll get the info and calculate it for you.

Another possibility is spin off the line. I've run a slightly higher MPH with moderate spin off the line and no bogging after gaining traction. With perfect traction and launching off idle, your engine will be making lower HP (i.e., it's in lower RPM) and require more work to reach a high rate of acceleration--this can cause the motor to "bog". However, with the right amount of spin and gaining traction at an RPM that will provide enough power, you can decrease the amount of work (and distance) required to reach a higher rate of acceleration, which is what gains you MPH. The concept behind a high stall torque converter is similar (slip until you reach the power band, then transfer). There are several other factors which would affect any potential gain, including gearing. Tall gears can increase the probability of having too little power when you gain traction (since it's a longer gear), while short gears can decrease this probability. With that said, I've never experienced a 4 mph increase due to spin (N/A).

Was there anything else different between these runs?

[sailsmen]

Lack of traction gives higher trap speed.

An easy way to think of it is w/ lack of traction you are running in place and then after the green when you finally get traction you run.

Another way to think of it is that when you are spining you are making the track longer.

[red]

An easy way to think of it is w/ lack of traction you are running in place and then after the green when you finally get traction you run.
Agreed, with the clarification that there's a delicate balance between where you make power and where you make traction. This is the same trade you have with a manual when deciding launch RPM in order to avoid bogging and excessive spin (clutch slipping aside). Also, so it is not misunderstood, one should not expect this to be a Miracle-Gro for 1/4 mile MPH; meaning, a slight MPH increase could be the consequence of moderate spin if everything works in your favor.

[Mest30]

Sorry guys, that was a typo. The 4th run was 94.98 mph. Still my highest trap speed but 2nd fastest ET. Red, the first 3 runs were between 12pm and 1:30 pm and the last run was about 3:15 pm. I'll post my timeslips later tonight when I get home from work.

[red]

Sorry guys, that was a typo. The 4th run was 94.98 mph.

No need for calculating the DA. Figured it was incorrectly provided (why I asked for the slip) or a computer error.

[ChiTownMaraud3r]

Hey Mest, seems to be some good times. And nice meeting you again, in front of my house :D.

[Mest30]

Hey Mest, seems to be some good times. And nice meeting you again, in front of my house :D.

Nice seeing you, too. I was looking for you on Monday when I was at work to tell you my times but I didnt see your car.

[Paul T. Casey]

, but does that mean that my best run was probably left at the strip?

Yes. I would think with your mods you should be going 14.2 @ 96-98 mph every time. Sorry to be the bearer of bad news.

[Paul T. Casey]

Helpful hints:
Stock tires rear 22-24 psi, front 38-40 psi.
Avoid the water, but still "clean" your tires.
Line up straight (turning the wheel will slow you down).
Let the transmission do the shifting, you'll never be as quick as an auto.
Drive through the timing lights.

[Mest30]

Thanks for the hints. I pretty much did all of those things except I didnt measure the tire pressure.

That's not bad news at all. My goal was to get in the 14.5s and I did it. And if I can do even better next time, that would be great.

[Paul T. Casey]

You'll have to play with takeoff rpm also. Just a slight chirp when you leave is about perfect. That'll depend on track prep, weather, etc. With the 4.10's and factory stall, I'm guessing in the 1200-1500 range is it. For your best time, stage real shallow (just flick the stage lights on). This will give you a "rolling start" on the timer. If you're racing for real, just stage the same way each time as you do in your qualifying.

[Mest30]

I learned about the shallow stage after I got back from the strip. I didnt even know what a staging light was until the guy at the track told me to back up and pay attention to the lights.

[Bradley G]

I beg to differ Paul, John is not leaving that much MPH on the table.
Maybe the pullies and SW waterpump will net him a tenth or two.

Yes. I would think with your mods you should be going 14.2 @ 96-98 mph every time. Sorry to be the bearer of bad news.

[Paul T. Casey]

I beg to differ Paul, John is not leaving that much MPH on the table.
Maybe the pullies and SW waterpump will net him a tenth or two.

Could be, sometimes I forget how much the exhaust is worth too. Hard to believe I've got a half second on a geared car.