Weight reduction

[sendler]

Originally Posted by oldtamiyaphile

In theory it does. But unless your car is particularly weight sensitive

Yeah. As in a 6,000 pound pick up truck. Saving 30 pounds is crucial.

[kir_kenix]

Originally Posted by sendler

Yeah. As in a 6,000 pound pick up truck. Saving 30 pounds is crucial.

Probably not crucial, but it does add up after a while. Remember that GVWR & GCWR comes into play far more regularly on a pickup as well. Doing a few things to save a couple hundred pounds on your tow vehicle and trailer can mean several hundred more pounds of payload when towing, and several hundred less pounds to speed up/slow down the rest of the time.

Is it worth dropping hundreds or thousands of dollars into shaving a few pounds? Of course not, the payback might take a million miles. Is it worth swapping heavier parts in need of repair/replacement for lighter/stronger ones? Yes, pretty much every time.

For example: We pull a gooseneck 14' dump trailer full of gravel pretty regularly. It has a 14,000 gvwr. There are many tow vehicles that are rated to pull this much weight, but frequently this would exceed the GCWR of the tow vehicle because of how it is equipped from the factory. This is much, much more common than what people would expect. Any weight savings from the vehicle (while maintaining braking/steering/etc ability) effectively gives you the ability to pull a larger trailer without exceeding the GCWR. This can also mean fewer trips and make more $$$$ per trip.

Some people don't care about these ratings, and many of the vehicles you see going down the road are grossly over loaded. The place that we get our gravel from weighs us when we go in, and will not load the trailer to its capacity if they know they are going to grossly exceed your gcwr or rear axle rating (they are pretty anal as they have state contracts...but cheapest place around). So in this scenario, or any scenario where you are hauling/towing you can see that shaving weight is important.

It also takes a lot more fuel to get a 7000+lb vehicle up to speed, and much more braking to slow it down. All of this is wasted fuel. At speed, on level ground I agree that it probably doesn't account to much in fuel usage though.

[oil pan 4]

Originally Posted by sendler

Does a lighter battery save fuel? What is the payback on the Lithium battery? Or thousands of dollars of rear end pieces?

I don't know what the pay back on the battery is. It was originally done for my suburban to delete the lead acid batteries up front to make room for a second turbocharger and to fit the largest off the shelf air filter I could find under the hood, after I built an air cleaner around it.
Then the Camaro needed a new battery and since the suburban lithium batteries are on quick disconnects. It wasn't a huge stretch of the imagination to fix that problem.
So the lithium battery mod really didn't cost anything and has already saved me cost of at least 1 battery.

Don't worry about the rear end, it will serve many functions beyond the what the GM 7.5 inch 10 bolt could ever dream of in addition to saving weight.

[oil pan 4]

Originally Posted by kir_kenix

when towing

Its getting a hitch.

Originally Posted by kir_kenix

Is it worth dropping hundreds or thousands of dollars into shaving a few pounds? Of course not, the payback might take a million miles. Is it worth swapping heavier parts in need of repair/replacement for lighter/stronger ones? Yes, pretty much every time.

The 7.5 inch 10 bolt has over 200,000 miles on it, they are difficult to rebuild and just as fun when it comes to gear ratio swaps and easy to screw up.
If the ring and pinion are put together and out several thousands of an inch after a rebuild or gear swap it will run fine for a few thousand miles then fail catastrophically with out warning.
Did I mention I was going to do some towing with it.
I could push and push and push ever closer to disaster, then when it breaks I will surely be at least a few hundred miles from home and wishing I got the 9 inch, because I will have just spent a good portion of what one would have cost on a tow job and replacing the broke down 10 bolt with a worn out one from some random junk yard.

[kir_kenix]

Originally Posted by oil pan 4

Its getting a hitch.


The 7.5 inch 10 bolt has over 200,000 miles on it, they are difficult to rebuild and just as fun when it comes to gear ratio swaps and easy to screw up.
If the ring and pinion are put together and out several thousands of an inch after a rebuild or gear swap it will run fine for a few thousand miles then fail catastrophically with out warning.
Did I mention I was going to do some towing with it.
I could push and push and push ever closer to disaster, then when it breaks I will surely be at least a few hundred miles from home and wishing I got the 9 inch, because I will have just spent a good portion of what one would have cost on a tow job and replacing the broke down 10 bolt with a worn out one from some random junk yard.

I agree with you on every point oil pan. I was more chiming in about some of the comments that may not have seen the validity of your proposed mod. That ford 9 in (or whatever you decide to put underneath) will be better options for you, considering the towing you have planned and especially with a peppy 5.3 in front. I think your Camaro could be a pretty darn good tow vehicle as long as the brakes are properly spec'd for the load you are planning.

If this mod was going to cost you thousands of dollars to shave a few pounds or have essentially the same strength as stock...well that might be a different story. As it stands, I think you are making a very good mod that will pay for itself in longevity/strength/peace of mind.

[oil pan 4]

My trailer load is going to be my 4x8 trailer with just bulky stuff on it.
Just moving tires, a transmission, maybe an engine, some lower mass high volume build materials. The trailer (250lb empty) plus load will rarely if ever will total more than 1000lb.

[Gasoline Fumes]

I went a little (a lot?) crazy with my door!

[deejaaa]

Originally Posted by Gasoline Fumes

I went.....crazy with my door!

did you weigh the removed mass?

[oil pan 4]

Holely crap!
After 20 some years of shutting the factory door on the Camaro developed a couple of cracks on the interior sheet metal where the interior door handle attached. I welded it back together some time in 2006 or 2007.

[Gasoline Fumes]

Originally Posted by deejaaa

did you weigh the removed mass?

Yes. 1.88 lbs including the plastic pocket on the door panel and a few other miscellaneous things. I'm guessing at least 1 lb for the holes. Probably not worth the effort and I'll probably do the other doors someday!