"I can't tell much of a difference so far; in an SCCA sanctioned autocross you're never really out of 2nd gear and corners are sharp and spaced closely so the supercharged horsepower presents little, if any advantage because I can almost never put the throttle to the floor. The car is still very driveable and I have a blast with it while doing reasonably well, but the blower is not much of an advantage there. It does much better on longer courses where you can use the power"...Yeah I haven't really gotten any faster with more power either in SM2

 

Before I'll get into the rest of what you said, a bit of history on me. I have a Bachelors in Education (math area concentration) and a Masters in Math. I'm a retired Police Officer from NY injured at the Trade Center. I got my teaching licenses for two states. I bring it up for a few points; 1-There isn't anything in math/physics that's beyond me and 2-having been a NY area police Officer, I know what its like to argue with one. My question for you is: What drag race cars have you built and have any of them lifted the front wheels on the launch? I ask because I want to know what your drag race car qualifications are. If you have no experience in this area then I know I'm just dealing with another NY area brother who wants to debate.

Having built drag race cars that lift the front wheels on the launch I can say you are 100% wrong. The use of the term 'fulcrum' is correct and it takes into account all the forces working on an accelerating car.The battery cant be moved far enough back to get the weight transfer needed to get the weight fully onto the rear wheels due to the C6's wheel base length. The battery weight as you said earlier in this thread not being 'over the rear wheels' shows you don't understand the concept. The battery itself in this case, is not being used as the actual weight pushing down on the wheels but rather to make the fulcrum closer to the rear wheels. By the way, any weight you add to the car rear of the rear wheels is 100% on the rear wheels.

The fulcrum is meant to be just in front of the rear wheels so that is the pivot point where all the force is on the leading edge of the contact patch. The proof that its not too far back is that the front wheels aren't lifting before the cars break traction with the battery in either location. If the tires are spinning, the battery hasnt been moved too far back.

For a drag race car, the battery being as far back as it can be placed is best.

In our cars there are two plausible places to put the battery: in the engine compartment (in the stock location) or the rear compartment on the passenger side. Having done everything I can for traction on my car north of 800rwhp, I find from having factually put it in the back, traction is better and the nose feels lighter. I dont know if a position other than the rear compartment is more optimum but I know I'm not putting it higher up in the center of the hatch area or some other silly area that is visible, interferes with the storage of the hatch, and raises the center of gravity. So I apologize for implying that the battery is optimum placed and I guess maybe I should have said of these two locations, the rear compartment is best.

 

I don,t have any math books and not sure I would understand them if I did, but my battery is in the back as well and seems to work just fine.

 

I have not done this relocation mod.

Question: I am having my hardbar penske 8200 coilovers upgraded with the 16 way Piggyback canisters to adjust dampening. the rear canisters i had in mind to place in the cubbies...is it a good idea to put both the canister and the battery in that one cubbie????
thanks

 

I fully understand that everyone that is measuring performance in 0.01 second increments is consumed with weight reduction and weight distribution, so I'm surprised no one mentions the Nutri-System diet as a genuine performance modification ().... seriously, you guys consumed with run times ever consider reducing your own weight to enhance corvette performance?

 

You'd think that someone who is looking for weight savings/performance would weigh the stock battery?

The stock battery is not 44lbs, it is in fact 35lbs.

When I purchased the braille 15lb battery, I weighed the stock battery several times because I also thought the stock battery was over 40+lbs. So the weight saving on this posters application is very small for the 21lb battery along with the battery relocation. Still, it is weight savings, little, but every little bit counts.

 

Good point, I personally went the way of Oldmansan & put my Deka under the hood.

That's not a belly, it's a battery for a Love Machine

 

That's very true. Of course there is the possibility that Powerlabs had a much heavier/non stock battery in there already as well...though yes, your math would certainly apply for the average C6 owner with a stock GM/AC Delco battery that would be attempting this mod.

 

As long as that lightweight battery the nuts to over come the
V/D from all that cable. I think I would have went regular battery.
Little heavy but stronger output!

 

No need; I'm 156lbs with <12% body fat

 

Now that's a performance modification that I can't afford!!

How much disadvantage (1/4 mile time) does an identical car to yours have with a 256 lb driver? I guess we can start handicapping drivers like we do jockeys at the horse track...

BTW, didn't mean to hijack this thread - I admire your mod.

 

Well, the general rule of thumb is a tenth (0.1 seconds) for every 100 lbs you add or take away. So a stock LS3 Vette might run a 12.5 with a heavy guy driving instead of a 12.4. Driver skill would make a much bigger difference, IMO.

Andy

 

I've head the same rule for around 35 years that I have been around drag racing.
As far as the driver making the difference is concerned: The driver makes ALL the difference.

So, hit the Nutri-System diet, move your battery to the rear of the car, burn off all excess fuel and you will Change your 12.7 car into an 11.7 car.

 

Powerlabs, Nice thread here about moving the battery to the rear compartment. On another note how is your new build coming along ?
Maybe your done but just did not post your observations on the new ZR-1
Cam and new found performance.

 

Hi,

The build is going great; I will start driving it next weekend. 500 miles of break in though, so it'll be a while till I can say anything about the performance...