I am sorry, this is for straight line (1/8, 1/4 mile) racing. I don't know about autocross. Some times you need the weight in autocross?.?.?



It was kind of the "rule of thumb" at the 1/4 mile track. I have been using it since 1997 and it seems to be pretty accurate...

 

100 lb = 10 hp, 10 hp = 0.1 seconds off. This formula sucks in real life.

Here is something you maybe interested.

http://www.epi-eng.com/BAS-PwrTrq.htm
http://auto.howstuffworks.com/horsepower4.htm

 

http://www.neons.org/faq/faq/FAQ_LE.html

 

good links!

 

The only difference you will notice is when your sitting on the side of the road thumbing it ( j/k)
____________________
Rally Red EVOVIII

 

If you are going for overall weight reduction, it's a good start. It's what, at least 45 pounds with the spare and jack?

Just drive around with less than a half tank of gas. That makes up for the spare and you at least have it just in case.

I'd rather lighten the front end where most of the weight is. (small battery and titanium strut bar for starters)

 

I agree that the spare itself won't make a big difference, but add all the weight reductions together. Example :

Lighter battery(in Front) = - 18 lbs
Lighter Exhaust = - 15 lbs
Remove Spare and Jack = - 45 lbs (approx)
3-5 cans of fix a flat and AAA card = +2 lbs
Total = 78 lbs

You could add other weight reductions in, but in the end that 78 lbs could be the difference between a 11 sec or a 12 sec time.

BTW - I know someone will do it so I will add "Waiting for a tow truck at 3AM because you don't have a spare = Priceless"

 

well, 78 lb is more like .008 second difference. If you're running 12 second flat, you could always get into 11's.

 

Anyone know of any good ideas on ways of supporting the trunk mat when it has no spare tire?

 

Just wondering, is the spare tire well in the trunk deep enough to put a full sized spare back there without issues of the mat and carpet laying flat and level? I didn't bother to actually look at that on my test drives.

 

Use the existing long screw that holds the spare down and put a wood block on top of it....actually the block of wood is nailed into the wooden floor piece. I used a wooden circle block thats about 1 inch thick and 3 inches in diameter. Since the block is thick I can adjust the height from there and level out the wooden trunk board. I went to the stereo shop and made them cut me an exact piece like the stock board but using thicker wood. I belive the thickness of my new board is about half inch. If you like I can get some pictures of how I have mine done.

 

yea this is something i wouldnt risk doing unless your at the track and 25+ pounds are holding you back from a better time.

 

haha well living in hawaii + AAA means i'm never gonna need a spare.
im never more then 15 minutes from home, haha

 

holy hell, this thread is over a year old..

 

I took mine out. Only reason I did is I don't carry the wheel lock key in the car with me, so even if i had the spare tire in the back i wouldn't be able to take off the wheel.