If weight in the back is so great, should we ballast the car? What is the handling advantage of having 40 extra pounds in the trunk?
Podium? You guys have a podium and trophy presentation after taking laps for fun? Good for you.
Didn’t know we were talking about what can go around the track fastest for $80k. Nor fighting for podium positions on the Internet.
If that’s he case, than I wouldn’t take either. I would buy a Palatov.
“The area between the last turn and the first turn where there is a grid marshall standing on a lifeguard tower in front of a checkered line across the track that isn’t a finish line because it’s not a race” is what I meant by podium, my pedantic forum pal.
Prove to me you are not a robot.
Actually, that’s what many track prepped cars do.
Not a “ballast” per se, because you don’t want to add weight needlessly. But to re-distribute towards the rear is a good thing.
Think about it this way:
The common saying is traction is like $1. You can spend your $1 however you like, but the max you got is $1.
So for your front tires, you can spend it 50c on braking with 50c remaining on cornering grip…but you cannot maximize both. Super simple concept…probably too general. But gets the point across. Now if you factor in weight…you got the following:
- Factory weight distribution is 55/45 (or 56/44 depending on where u read). This is STATIC and AT REST.
- You are on the track, hauling…going 110mph. You have a corner coming up. You have a couple options…do you: spend your $1 by maximizing braking ability (and thus braking hard in a straight line), or do you “diversify your spending” via trail braking into the corner and turning in as you slowly release the brake? Arguably, the latter is going to be the faster way around a turn.
In #2 above, what is eating up your traction is the front end weight. When you are braking, you are throwing weight forward. The tires can only hold so much weight before it breaks traction. Now, combine this with cornering (because you’re trail braking), and you got even less traction because your tires are both slowing your car down and attempting to change its direction.
One of the most effective ways to increase the cornering limits in scenario #2 above, is to alter the weight distribution. So any way you can move weight from the front and put it to the back is to your advantage. Even the head of AMG himself (and Mclaren engineers) say the “ideal” weight distribution is 45/55 (the opposite of what we have!).
If you look at any track prepped car or race car, you’ll see battery moved to the back and even driver seat moved way way way back, with pedals relocated further back in the car. Afterall, moving the driver is the easiest way to shift weight distribution around without affecting any major hard mounting points. For example, look at any rally car–the passenger seat is moved way back. But in general, the driveseat is moved back too…but there is a limit to how far back you can put the driver before sight lines become crap. The passenger on the other hand…
If it were me, and given my driving style, i’d put as much stuff back there as i could.
It is for this reason I also track with my spare tire still in the trunk. Take it out–you will notice what I’m saying. The car will understeer more on entry. Also notice the car pushes more when you have a passenger up front. Same concept. Same difference as your fuel goes lower. Your weight distribution is only 55/45 on full tank. I believe it drops 1% by the time you hit half tank.
arg i meant to add this tidbit as well…
I mention static weight distribution is 55/45.
Imagine you’re threshold braking at 110mph. Your dynamic weight distrbution during that activity is probably more like 85/15.
That’s a lotttttt of weight on the front tires. So yes, absolutely, anything you can put in the back instead of the front is going to help keep your car stable and maintain front end weight. It “extends” your traction circle…so that the front tires start to brake away later.
I think adjustable dampers are a better way to control weight transfer under braking, than attempting to re engineer the car 20 pounds at a time. I just like lithium over a bucket of acid splashing around in the trunk, a battery technology which dates back to ancient Rome.
http://calvusguy.blogspot.com/2013/07/the-roman-battery.html
That is true.
But if we’re talking about the topic of weight, changing out the seats is a bigger performance gain over a battery for the same cost 
Changing the seats is not trivial and it pretty wasteful when Audi/Porsche has some of the best automotive seats in the business. I’m not aware of anyone that can defeat the airbag sensors in the seats reliably. Most of the weight is in the seat motors in the bottom, rather than in the backrest. You could gut the seat motors out and install manual tracks, but the weight is in the floor boards. I actually prefer manual seats, as power seats are quite slow to slide forward.
I generally don’t replace things that aren’t broken or performing below my expectations, but I’m sure you can find exceptions like exhaust.
I found a good pic, so i thought i’d throw it up for sake of discussion.
I spoke about race cars relocating driver seats rearward to improve weight distribution. Check this out:
Notice both seats are behind the b pillar, and the pedals have been relocated forward of the original dash location (!!!).
Stuff like that is a huge difference. Something that an amazing set of struts alone cannot fully account for.
Beautiful!