I like how you keep changing the premise of the price vs weight to justify your comments.

Here's weight per GM
'06 Base C6 coupe 3179#
'06 Z06 3130#
Base coupe frame 421#
Z06 frame 285#

You said "I guess Z06 owners are paying that extra $10K for that 100 lbs lighter chassis for no reason".
Then you added a GS to the mix "I was talking about GM choosing to jack up pricing of Z06 by about $10K just to remove 100 lbs; was not comparing it to Grand Sport"
And now change the prices "The price difference between Z06 and GS is not $10K; it's rather $20K"

Back to the rotating weight story/theory as applied to the tires/rotors.

When you say "Some say rotating mass is actually worth a few times mass from anywhere else in the car.", it's still a theory until you can define it a little closer than "a few times". Maybe relating the "worth" to something might be helpful too.

 

There is nothing 'inconsistent' at all, and I will try to explain to you for one last time here:
Z06 curb weight of newer models is 3199 lbs. That's what I referred to, since there was no Grand Sport model in '06 to compare against to deduce what the impact of LS7 and chassis changes are, leaving everything else almost equal (like brakes, etc.). Curb weight of GS is 3310 lbs. That gives you 111 lbs of difference.



I tried to be very clear on this, but it appears I still failed and you still managed to take the $10K value out of context or managed to ignore my sarcasm

(1) Everybody knows that the price difference between base GS and Z06 is about $20K. I cannot change stories or prices here: there is nothing to discuss.
(2) Again, everybody knows from the crate engine pricing, that LS3 costs about $7K, while an LS7 costs about $15K.
(3) From (1) & (2), if at least $8K of it goes to engine (see (2)), then it follows that most of the rest should be the remaining upgrades to lighten the car. Rounding the numbers, ~$10K of that remaining $12K ($20K (see (1) - $8K = $12K), I presumed, should go to the chassis changes (since there is nothing else significant left in terms of differences).
I hope there is no misunderstanding anymore? The story or numbers never changed.



OK, since we established you know what moment of inertia is, you have to also know that it costs its own dead weight "and then some", right? Right?

Knowing the exact amount by calculation requires taking into account the homogeneity of the material (if not, you need to take an integral by varying radius and product of density at that radius, or in other words, circle), the overall diameter, and distortions (like bolts, balance weights), etc. Clearly, it is not easy to calculate but it doesn't mean there's no scientific answer. Actually, there are dynos specifically designed to measure rotational 'loss'. I believe this is achieved by letting the car slow down on its own with no braking after the dyno run, and calculating the friction and rotational mass (and therefore loss during the actual acceleration run of the dyno) by monitoring the rate of deceleration while varying the dyno's own resistance.



Okaaay, I'm not sure why you need these explanations, but here they are. For the sake of not spamming people any further, I won't keep replying; feel free to PM me for further explanations you might need

 

That statement's pretty much on target when you made assumptions right from the beginning.

 

There are guys using one of the Shorai batteries in the Lotus Evora with good success. I haven't looked at one for the C6 yet as my Deka is still going strong.

San

 

Not yet. Some of the Lotus Evora guys are using one. I'll let you know when I figure it out.

San

 

I had seen a reference to another lightweight battery that I hadn't checked out so I looked into it briefly.

The Ballistic EVO 16-cell battery has 500 CCA and 28 Ah (lead-acid equivalent). Weight is 3.6 pounds, cost is $236 and it's made in the USA. The only negative reviews I found were about the site's configurator, not the batteries themselves. The battery reviews I found were all positive, actually glowing. The battery only loses 10% of it's charge per YEAR in a static state.

They have an optional charger that charges and "balances" the individual cells. They claim that periodic balancing can extend the battery life by up to two times the normal lifetime.

The Shorai models I'd look at are LFX36L3-BS12 and LFX27L3-BS12. LSX36L3-BS12 is 540 CCA and 36 Ah. Weight is 5 pounds and cost is $350. LSX27L3-BS12 is 405 CCA and 27 Ah. Weight is 4.2 pounds and cost is $276.

All of the batteries above have the correct terminal orientation.

San

 

The issue is if you drive the car on the street, you don't have enough RC in it to operate properly when using a small battery. Lets say you are at a stop light with the AC on and the stereo on, the alternator may not have enough output and the battery does not have enough RC, so you end up wearing out the alternator becasue it is always trying to keep an under capacity battery charged.

Trust me, we over 100M car batteries a year, and I could tell ya stories!

 

You are indeed the expert!

I've always shied away from these small batteries, my friend Theofel put one in his car and had odd electrical problems (CEL's, other things) which went away when he installed a normal size battery. Matter of fact his alternator blew up last weekend...perhaps unrelated to the small battery he had for a while, perhaps now. Now I must mention he installed his in the rear cubby, that didn't help matters.

On the other hand another friend Justinjor has had great luck with his in the normal spot for months now.

Unless you're looking for the last .0005...I see no need to risk not starting, particularly when you drag race a lot and start and stop often in the lanes.

 

How old is your Deka and does it need a maintenance charger if driven often?
I'm hoping to get my easily reversible race weight below 2900# this season without breaking the bank. If it wasn't for cranking power, I'd string together a bunch of rechargable "D" cells.

The 5# Shorai sounds good until you get to the price. The extra 12-13# for an extra $250 isn't worth the .01 seconds for my 1/4 mile time.

 

Sorry, my Deka has only been in the car for three and a half years. I wish I had a dollar for every PM I've received for the write-up. None of the people who have used it have ever reported anything negative to me about it.

The batteries I listed above have more CCAs and Ah stats and are a fraction of the weight of my Deka, which was a fraction of the weight of the stock battery. You're more than welcome to stick with heavy batteries, I tend to try to reduce weight (which is the topic of this thread).

The Shorai I purchased for my ZX10R has been absolutely perfect. Let it sit for a month (or more) and if fires up instantly with no hesitation. It's never been on a battery tender. Lithium Iron (ferrous) kicks butt.

I may well purchase another lightweight battery to be the "guinea pig" again, because many predicted gloom and doom when I installed my Deka. No gloom or doom arrived.

San

 

The Deka is 3.5 years old. I put my Deka on a tender every once in awhile when I'm not driving the car often. I think some damage was done by one of the body shops that drained it completely on several occasions. I live close to work (5-10 minutes away) so that really doesn't help.

The Shorai has never seen a tender and cranks up with authority every time. Honestly I'm leaning towards the Ballistic EVO 16 cell after reading the reviews. Looks to be the same technology.

I don't drag race. I shave weight for acceleration, handling and braking.

San

 

Dang....late to the discussion.....lol. And its right up my alley...

First off I run a "small" battery 24/7. Granted my car is not a daily driver...but have never...ever, ever had a problem, which maybe actually worse(car sitting in the garage for extended periods). Batt. has been in the car for 2+ years (11.7scr 346")...the batt. weighs about 6lbs and is in the original location.

And about static weight or dynamic.....I look at it like this...in this hobby we all love, it never hurts to reduce weight....be it static or dynamic (rotating). Here is a calc for you math wizards....http://hpwizard.com/rotational-inertia.html

Thanks.....fyi, I'm at 2950ish w/18's and 19's on a C5Z...with zero loss in creature comforts.

 

Wow! I'm on my 3rd battery in 4.5 years, so maybe a permanant switch will work for me.

You have a much greater need for light weight to justify the bigger price.

 

Since we're in a conversation about batteries also I thought I would throw in one I found over on the BMW M5 boards, the VoltPhreaks batteries.

They're popular on with the M5er's because their cars tend to be very high drain even compared to C6's.

Also LiFe batteries like some of the Deka's mentioned here. Not sure if pricing is along the same lines though.

http://www.voltphreaks.com/products_street.php

 

I think I'm one of the people who PMed you for the write-up.


I have had 0 issues with my Deka up front with many days/nights at the dragstrip with extra starts/stops due to racing.

I now have the battery in the rear hatch and about 6 weeks later, I still have not had an issue. I anticipate an issue when the winter rolls around and I need to keep my bottle heater on when the car is off but I'll cross that bridge when I get to it.

 

The Deka is an AGM, not Lithium. The Deka I bought is under $100 shipped.

San

 

It's also available at your local autozone for $89.99

 

Glad it's working for you.

San

 

Can you guys send me the details on this battery as a Google search found a few options and I'm not sure which one to steer towards. I also checked autozone.com using their search option and didnt find anything.

Whats the weight of the Deka?

 

http://forums.corvetteforum.com/c6-t...tall-pics.html

San