Ric

Anyone know the weight disbribution of a 4th-gen F-body right off the top of their head???

Cal

iTrader: (1)

It depends on what options the car has and how much weight you have removed from the car. But 55%/45% is easily within reach.

HPP

Cal, given you're a racer, I'm assuming you've had it on the scales? As such, I'm not doubting you, but I do find those numbers to be a bit boggling.

55/45 was what my GTA was. That had an iron block L98 that wasn't stuffed practically into the passenger compartment. It also had steel fenders and hood, and an aluminum intake.

My 02 WS6 has plastic fenders, fiberglass hood, aluminum block that is stuffed practically into the passenger compartment, topped off with a composite intake.

I would have to beleive that it would be *better* than 55/45.

I've heard a number as good as 57/43. I think it was on this forum somewhere, but I can't recall exactly now.

I really need to get some good corner scales. I hate not knowing for sure. :/

mitchntx

iTrader: (14)

Actually I think you meant 53/47 ...

My stripped, gutted, carved, cut and totally molested 96 LT1 with stock exhaust manifolds and Y pipe weighs 2950 with fluids and has a 51.5/48.5 F/R weight distribution.

Realize, that the battery is as far to the rear as I can get it, moved the seat 6" further back, nothing under the nose, no ABS, aluminum/plastic everything under the hood. And the gas tank was full of gas.

HPP

lol, yeah, I meant 53/47.

2950lbs?

I wish I could find some way to manage that, hell, even just a few hundred pound drop, without going to a stripper car. Where is all the weight in these things? A friends S14 is about the same size, and his engine is only a little lighter (less than 50lbs), yet his car is about 2800lbs. Is there lead ballast in these things somewhere?

If it's in the chassis, then they must be *strong* sum'bitches.

Anyway, you make me think of another question Mitch - which is better, lower weight, or better distribution? Obviously, "both" is the ideal, but excepting that.....

It's easy to take weight off the back of these cars - seat delete, less gas, dumped exhaust, light hatch (I hear the wing is very heavy too), etc. But all that's doing is shifting the balance further forward. T-Tops... that's something else, better to take them out (less weight), or store them in their holders (better distribution, taking that weight off the roof, and moving it lower and rearward)?

BlackHawk T/A

iTrader: (3)

Don't run without the T-Tops...the wind resistance isn't worth it...

Cal

iTrader: (1)

Lower weight is always faster inspite of distribution. Better weight distribution makes the car easier to drive fast.

mitchntx

iTrader: (14)

Cal is correct, to a point, obviously.

Moving the battery to rear was an instant help with distribution. I put mine in the well where the spare goes. I realize it's vulnerable, but ....

Removing everything (read EVERYTHING) from the nose loses 50 lbs ... the firebird sub structure for mounting the headlights and motors and attaching the upper cover, horns, cruise, etc ...

Lightweight aluminum bodied shocks ...

Moving the PCM into the driver's compartment ...

Getting rid of that damn heavy *** wiring harness!

all the matting and fire retardent under the dash ...

literally gutting the dash into nothing but a shell.

windshield wiper motor and assemblies ...

safe-lite windshield and using ony 1/3 the adhesive ...

All brackets for fuse panels and relay blocks gone ...

heat shields ...

Removing body seam filler ... that's some heavy stuff ...

MasterV8

iTrader: (7)

Maybe a stupid question but how much do you reckon the water container in the front of the car ways when full?

HPP

I'm not building a race car, and pulling some of that stuff out seems counter productive (at least for a mostly road car). So nobody has found the lead ballast yet then? lol

Just to play devil's advocate (sorry, honestly not trying to be argumentative), isn't "easier to drive fast" much like "faster"? That is - given a driver of X skill, the car that was the easiest to drive fast would offer the most confidence and allow the most attention to be paid to driving line, other traffic, etc.

Kinda like how a combat aircraft that requires too much effort to fly to it's limits will normally be shot down by an aircraft that is much easier to fly to it's limits, it's less exhausting to the pilot, and allows the head to be kept out of the pit and the mind focused on the other aspects. (this was an advantage of the FW-190's automated systems and single "power" lever, over the more exhausting and demanding early LaGGs and Yaks)

Plus confidence in the machine is a way to get closer to the limits of the machine as well.

Particularly for a novice like me. So I guess I'm better off not pulling the weight off the rear (where it seems easiest to get out)?

Ric

That's kind of the idea I'm looking at. Not necessarily making the car light as possible, but as evenly distrubuted as possible.

Believe it or not, I was only looking to see how much air I should be running in my tires... I have 21 lbs in the back and they still wear in the middle!

mitchntx

iTrader: (14)

HPP ... If the car weighs 4000 and has a 50/50 weight distribution, the motor has to push it down the track and brakes have to stop all that inertia. then you have to wrestle it through the turns.

If you pull 250 off the nose and 750 off the rear, yes, all of suddent your weight distribution is screwed, but with springs, shocks and sway bars, you can tune out the push. The motor accelerates the car faster and the brakes don't have to work as hard ...

matts22

iTrader: (2)

haha, guess I'm the only one who found that funny

Cal

iTrader: (1)

All depends on what kind of racing you are doing. For low speed AutoX, taking the weight off the top of the car by removing the T-tops is a good idea, and the added air drag at 40 to 60 mph isn't significant. For Open Road racing and Land Speed racing, have them in for less drag and more protection in case of a roll-over.

Back to the weight thing, realize that weight affects three things: straight-line acceleration, braking performance, and cornering power. So having more weight than necessary hurts you three ways on a road course. For the street, it also has a bearing on fuel ecconomy, and a car that can stop quicker is safer. Also, if you remove weight from above the car's center of gravity, you have lowered the center of gravity, which will also make it corner better. The only time you want a lot of weight is when you are going Land Speed racing, which is something I doubt many of you will ever do. For the one day a year I do that, I just add balast as low on the car as possible.

HPP

Cal and Mitch, good points.

I have no practical or hands on experience in this area, so I'm not trying to tell you otherwise. (I just like discussing cool things like this, and sometimes someone has to take the opposite stance. )

If the balance is within reasons, say, 55/45, it could easily be tuned. But what about 60/40? Or 70/30? (extreme examples that don't directly relate to our cars, again, just for conversation)

If you get too much weight up front, wouldn't that result in too much mass for the front tires to deal with effectively, since the front wheels are inherently limited in width? And if you try to balance it out with tuning, you're really just reducing the rear's total lateral grip to balance the understeer tendency, right? And too, when getting on the gas on the exit, weight transfers back, leaving less weight/friction/traction on the front wheels, but the same mass to deal with, compunding the problem.

Back to our cars though, what are the stock exhaust manifolds? Are they cast iron? Would mid-length headers be a weight savings? Are there any aftermarket K-Members out there yet that are lighter, and still trustworthy for street and road course racing? (seems most are considered to be too weak for much beyond drag racing)

Mitch, where did you move the PCM to? You said something about relocating it to the passenger compartment.

Oh, and while I'm rambling... lol, what about lateral weight distribution? I'm nearly 230lbs (at 6'2"). What kind of impact does that have on a car when cornering?

Cal

iTrader: (1)

Of course what I said about weight distribution is only true in reasoanble examples; if you had almost zero weight on the rear wheels, you wouldn't even be able to launch it.

Headers do offer a weight savings over stock manifolds, but part of that is because the two heavy cats usually leave the car with the manifolds. There are no tubular K-members available as of yet that are a good idea for street and road race.

To get weight off the nose, convert Camaros to front breathers removing steel bumper support and air deflector, move battery to rear, move or eliminate windshield washer reservoir, change to a smaller coolant overflow tank, convert to hood pins, convert to coil overs, convert to solid motor mounts, go to a carbon fiber hood and a lexan windshield, and dump the cruise, to name a few. Real brand race wheels and Goodyear road race slicks dump a surprising amout of rotating mass also, but can't be used on the street.

Ric

Cal, you care to elaborate on this??? I've been thinking about getting one when I inherit money, and would like to know a little more of your thoughts on one for the street/strip.