FixedWing

I wonder if you even need to add this caveat? I would think reducing weight, even if it upsets the ideal balance of the car, will have benefits which will outweigh the less than optimal set-up.

Stephen

George A

Are you saying that 30 pounds removed from the front of 911 outweighs the benefits of having better front to rear balance? Why do you think so?

Let's say you needed it to make weight for PCA but weight did not matter for other clubs. You set your car up for PCA weight (spare in). Now, you do a NASA event where you can remove the spare. Are you saying no matter what, you would remove it? That's exactly what I thought but it didn't work for me.

George

DrJupeman

I'm not Stephen, but since he had replied to my thoughts, here is my $.02:

I think if you set the car up for the spare and then take it out on an adhoc basis without adjusting for the weight difference your laptimes may fall (braking and acceleration will be improved), however it won't be optimal and you may not be used to the "feel". This alone may hinder your laptimes.

Otherwise, decreasing weight increases the available traction the tires can give you for lateral acceleration (assuming you can still reach optimal tire temperature, etc - this is complicated).

Flying Finn

Mine's out (street and track).

Larry Herman

Mine never had a spare.

mitch236

Remember that your driving style will have to change slightly to compensate for the change in balance, otherwise lighter is better.

sjanes

I didn't find this. My car runs a better time with a full tank than an empty tank (it was setup with a 3/4 full tank). This winter, I'm putting in a lightweight battery and redoing the corner weights on a 1/2 tank.

Also, one of the instructors tried his car (lightweight 74 911) without the spare this summer to see what would happen. The nose of the car sat visibly higher and he complained that it didn't turn in as well and was slower. He put it back in.

mitch236

I'm not trying to insult anyone here but I wonder what a professional would think about this subject. I know that when I moved from a 951 to a 996, I hated all the understeer. Now I love the 996 and am much faster but it took a while to learn how to drive it well. I guess the same can be said, to a lesser degree, about changing the balance of an existing car. I think that if you took out the spare for a few months and compared times, your times would improve somewhat.

George A

Charlie,

Under that theory, removing 30lbs from the front of a 911 would yield the same exact performance improvement as taking 30lbs out of the engine compartment. Is that what you are saying?

I think "feel" plays a big role for someone at my skill level. Changing the car for different events introduces another factor I have to deal with at the track. I feel as I have way too many already. I think that eventually, you could get the car to be faster, but how long would it take and would it be worth it? Especially if have to go back and forth for different events.

George

38D

Laptimes would definitely improve, albeit a very small change. 30lbs is probably on the order of 0.1 - 0.2 seconds max at 2+ min track like Watkins Glen or Road America.

sjanes

I agree that things like a little more trailbraking to get the nose into the corner is helpful, but where I found the difference is the corners that are taken flat out. With those types of corners, you can't put weight on the nose without lifting, which defeats the purpose of removing weight.

As for a Pro, I assume they can drive around most handling problems, but they also have the equiptment at the track to rebalance the car if they want. I doubt too many pro drivers would go out for a practice session, come in and say "it turns in like ****, but don't bother to change it, I'll just drive around it"

FixedWing

I agree with Charlie and Mitch. Removing weight should always improve lap times even if it leaves the car less than optimally set-up. The problem is that the driver himself may need to change his style. If a driver prefers a car that turns in crisply and has a tendency to oversteer then he might not like the poorer turn-in and greater understeer. His discomfort would hamper lap times. But maybe it is up to the driver to modify his style to take maximum advantage of the car he now has?

As a seperate thought, I often think we set cars up to be to our liking and not necessarily to be at their fastestest.

Stephen

George A

Stephen, you hit that one right on target. I think I can discuss that one for hours. It really depends on your definition of "fastest" (without the extra "est"). You are talking about the difference between theoretical perfection and practical usefulness. What do you do, setup the car where you are fast now or set it up for where you could be faster later. You have a race coming up, what do you do?

BTW, I'm really against terms like "always". It seems like there are always exceptions.

George

sjanes

Or, that driver car take an hour and lower the nose of the car a bit (if you have torsion bars or coil overs) to get the proper rake back into the car. Although I do have to agree with your last statement

In one of Carrol Smiths' books (I can't remember which), it talks about setting up the car to suit the driver's ability. I'd have to look up the exact quote, but it says something like setting up the car to be "fast" is usless if your driver can't be fast in it.

forklift

Do Cup Cars have spares? and if not are they reinforced for impact in some way?