Ever hear the general rule of thumb that 100# is worth 0.10 in ET? Ever wonder how true that is?

Today was the last race of the year for me (SVT Cobra Club meet in SC). It's a really good hooking track, and I wanted to run a test on the
aforementioned theory.

First, I made a baseline pass. I cooled the car off and made another pass with 250# of play sand in the trunk. The results were surprising to me. In fact, that rule does seem to be pretty close to being exact.

I also set my personal best today on the 4th pass. Unfortunately we never saw better than 1455 DA. I had been counting on running this November event in sea-level like air, but it wasn't meant to be.

Here's my data from today:

First baseline pass

RPM : 2200
60' : 1.514
330': 4.552
1/8 : 7.107@95.73
1/4 : 11.24@116.9

Pass with 250# of sand:

RPM : 2200
60' : 1.579
330': 4.691
1/8 : 7.299@93.55
1/4 : 11.51@115.3

Rest of the day (no sand ballast):

RPM : 2200 2200 2200 1800 1800 2200
60' : 1.520 1.517 1.543 1.539 1.547 1.525
330': 4.550 4.531 4.578 4.573 4.567 4.551
1/8 : 7.094@96.14 7.067@96.38 7.115@96.33 7.119@95.97 7.102@95.67 7.091@96.30
1/4 : 11.20@117.5 11.17@117.8 11.21@118.7 11.23@118.1 11.19@118.6 11.19@117.8


Just thought I'd share. It has motivated me to try to find 180# of weight to pull. smile.gif

-gw

I guess it depends on where the weight is, with the added weight of a full gas tank mine seems to run quicker because of the better 60ft times.

Originally posted by Rapid Robert:
I guess it depends on where the weight is, with the added weight of a full gas tank mine seems to run quicker because of the better 60ft times. True, I suppose, if you have traction issues. Even with a nearly empty gas tank I can dead hook at Carolina Dragway. It really is a top-notch hooking track.

-gw

Your 60ft and 1/8th miles were almost always better with the added weight in the trunk, however your mph was quite a bit slower on most runs. And you also could launch at 2200 each run, where as only 1800 in a couple runs without the weight. I think if u had the weight more in the center of the vehicle i'd show a bit of difference, but a very interesting test.

I just sold my 388 to a friend, they freshened it and used the same cam, heads, headers etc. I'd guess his car weighs at the most 3000 lbs (gutted drag car). Mine is 3550 (full street car). My best was a 11.90@113. With a bog off the line and his 2200 converter vs my 4000 he ran a 11.72 at 118.

Weight stinks!

Originally posted by -SS454-:
Your 60ft and 1/8th miles were almost always better with the added weight in the trunk, however your mph was quite a bit slower on most runs. And you also could launch at 2200 each run, where as only 1800 in a couple runs without the weight. I think if u had the weight more in the center of the vehicle i'd show a bit of difference, but a very interesting test. Say what?

I only made one pass with the sand in the trunk (the 2nd pass) and everything slowed down dramatically, including the 60'.

The varying launch RPMs were just another thing I was testing. I believe it doesn't matter if I launch at 1800 (where I've been bracket racing all year long) or higher with respect to ET. It definitely affects the reaction time though.

-gw

Oh im sorry. The way you had your post written, and my **** poor lack of careful reading made me think that u did like 5 runs with weight, 5 runs without. Forgive my mistake. I was wondering why that 1 run was way slower haha. Great test, useful information smile.gif

Gordon, that's interesting, I was just reading an article somewhere over the weekend with a bunch of fancy calculus regarding weight and ET. Their calculation was that 100 lbs equaled .0115 in ET.

So, (250)(.0115) = .2875. Your results showed .2700? Pretty close...