Hey all. I am really trying to put together a list of parts that would overall give me a nice reduction in weight. All things considered. From the front to the back, and from the tires to the roofline. From accoutrements to the necessary parts.

The point of this is to find parts that I would not think of, and to sort of put together a list of lighter parts. I am looking for parts that apply to the 93+ Fbodys. The goal is to get solid numbers for differences in parts. Comparing the fact that some headers will weigh less than the cast stockers is something I am interested in, and the specific weight differences.

Now, I don't want to end up with just a rolling chassis(even if it is unibody), but I am looking to get rid of the stuff I don't use(AC, power seats, rear seat, so on). And it will need to be street legal, of course. That means no one piece CF front clips for me.

To get ya started, this is the sort of stuff I was thinking about:

- alum ds
- tubular k-member
- CF hood
- power seat delete

I am also interested in the differences between an LT1 engine and an LS1 engine in weight, and the difference in weight for the applicable bolt-ons(I have been toying with the idea of replacing the LT1 with an LS1 instead of upgrading the LT1). An LS1 with a composite intake seems like it would be an excellant opportunity to drop some pounds, not to mention the better base for performance upgrades.

And for an extra homework assignment, I have been trying to find solid info as to the difference in weight between a stock 10 bolt, a 9", a 12 bolt and (yes, I know) a C4 Corvette IRS. If any of you have solid numbers on those, I would appreciate the info. As it sits right now, a C4 IRS looks like it may have the ability to cut some serious weight(elimintation of springs, LCAs, panhard).

I know it is a pretty long post, with a bunch of requests for info in it, but end result I am hoping for is an ability to tally up the total differences for a prospective build.

 

This has all been done. I've seen the numbers somewhere. Do some searching or maybe someone else can provide a link.

 

i beleive its on brent franker's site....

 

I agree, posts have been made about weight reduction. There are a bunch of them. BUT, they just involve the same 'ol stuff each time. The guy asks what can I do for weight reduction? The answer: Depends on how serious you are. And then they list of stuff you can remove from the car. From AC to PS. Remember, I am not so much trying to strip the car, as I am trying to find low calorie alternatives.

I had searched for a couple hours.. besides a piece of paper with a few numbers on it, the only thing I had come up with was that link to LS1Tech. But that link was only so helpful. They were talking about lexan windows and removing airbags and complete HVAC removal. A bit much for me.

Teke, thank you! After some poking around on Brent's site, I found what you were talking about. Nice info there! That was something I did not find while searching CZ28.

I would like to expand on Brent's intent, and if there is some decent info gathered, I could send it over to him to update his page.

Thanks for the responses guys.

 

Trade for a coupe and save 80#.

How is the car being used? The C4 IRS would be beneficial for auto-X or road racing, but would be a step backwards for a 1/4-mile car. Just the framing necessary to adapt it to the F-Body unit body would probably negate any perceived weight savings.

What kind of power are you talking about? The stock 10-bolt is going to be lighter than a 12-bolt (only by about 10#) or a 9-inch. But are you planning to go far enough on power in the future to require one of those? For mega-monster power the 9-inch can handle the power, and with enough $$$$$$$$$ can be very light... sheet-metal housing, aluminum center section, gun drilled axles, lightweight spool, lightweight hubs. I kow a guy with a 4th Gen C4 running 9's all motor, and he ditched the IRS for a Fab-9 sheet-metal 9-inch.

All depends on the power level and how the car is going to be used.

 

The car is going to have a focus on handling. It may see some parking lot auto-x events, but not likely. I am spending a lot of time over at frrax.com taking notes on what they have working for them. I have not figured out what kind of power I am going to be looking for. Probably something mid to high 300's N/A(easy with an LS1, eh?).

The only reason a C4 IRS has come into the picture is the fact that I am a repeat offender when it comes to abusing rear ends. When I started looking for something beefier, I saw the same 9" and 12 bolt solutions as others, but when FbodyMotorsports mentioned they were in the final stages of development for their C4 IRS kit, I began to take a closer look.

- I can pick up a C4 IRS for ~1k or less
- No idea what the kit price is going to be
- No idea what the weight of a C4 IRS setup is(including dogbones, shocks, etc.).. but I did post a thread over on a Vette forum(EDIT got a reply, someone shipped a complete rear sans rotors with a shipping weight of 220lbs.)
- No idea if a Viper Super Dana 44 center section will work

Roughly:

Stock 10 bolt: ~170lbs
springs: ~13lbs
spring isolators: ~3lbs
rear sway bar: ~8lbs
LCA's: don't know
Panhard bar: don't know
Total: just shy of 200lbs without the LCA's and Panhard bar incuded..

I pm'ed LTBlackBird about the weight of the brackets(the kit) and he said that the brackets that needed to be welded in were a bit lighter than the material that was removed(kind of an Indiana Jones swap of weight)

Anyways, that was the line of reasoning behind even having the C4 IRS as an option.

I am still crunching numbers, and am really enthused about the ability of cutting some decent weight off of this car, while keeping the things that matter to me in it(power windows, decent audio, carpet, etc).

The thought of making it a roadster was something I have been seriously considering too. It is far from my daily driver, and the idea of removing the convertible top assembly all together is something I have been thinking about.

EDIT: got a reply from the guys over at the Vette forum. Looks like the complete rear end minus rotors is 220lbs.

 

heh, I've followed you around..

You know what, I say just do it! You obviously want to do a C4 irs swap.

Post your results and what you find, and it will shut everyone one up one way or another.. Hell, if your car was nice enough and if FbodyMotorsports would be interested, I would if a mag like GM high tech Perf might be interested to check i t out.. cause its such a rare swap. at the very least, you can be "that guy" that everyone points to when this question pops up again..

 

lol, just say IRS and I'm there.

I sell myself more and more on it each day, just trying to gather as much info as I can before I take the leap.

The big thing that has been staring at me is the price. This could be the thing for the guys wanting more than the stock 10 bolt, and less than a 2k rear(provided they aren't 1/4 mile guys).

Good stuff!

 

I would look into carbon fiber parts, or fiberglass for your body. BMR's tublar k-member saves 32lbs. They also have a arms and other front suspension parts too. you can get lightweight interior carpet, racing seats, etc.