Ya caught my interest with the aluminum intake bolts. May I ask where you sourced them?

 

I welded up a very similar looking post-Y setup for my C4 using aluminum tubing and aluminum sheet for the muffler structure. Did the same on my '69, and nothing has melted yet.

 

Hello Topspeed1:

A very interesting build you have there....
I really like how you demonstrate to everyone how a well designed light weight car is better than a heavy one with more power.
Reminds me of the Hellcat vs Corvette races. Chrysler never learned anything in their development of the Challenger. It was a heavy pig back in the day when my brother brought home his 426 Hemi Challenger back in 1970 with 58% of the weight over the front wheels, and it still is to this day. When my brother took his Challenger to the strip he promptly got "tuned-up" by modified Chevy Novas and Ford 351 Cleveland Mustangs that were way lighter.

For additional weight savings have you considered replacing the heavy cast iron brake rotors with carbon-ceramic discs?
There would be an easy 10+ pound weight advantage to be gained there, and it would all be un-sprung weight making it that much sweeter.

By my calculations the following would represent your total weight savings:
(4x10 lbs per corner for brakes) + (4x10 lbs per corner out of your wallet) = At least 80 lbs!


Best of luck with your build.
I am curious how low you can go on the total car's weight.
Best regards,
Mr. Bear

 

In the quest for less weight. I have switched to later model rear knuckles. I am attempting to not have to use the 3lb wheel adapters due to the wider track width of the later models. Also I have a 25mm hollow swaybar I am swapping in. It weights 6.8lbs compared to the solid 24mm at 9.2.







I am also using this as an opportunity to install the poly bushings I have had sitting on a shelf for ever.

 

I'd like to see a picture of your transmission mount setup if that's a possibility. Thanks.

 

Hello Topspeed1:

Since lighter rotors may not be an option based on your lack of response to my previous post, I thought I would offer another suggestion that is more budget friendly since you are already at this stage in your build.
Obviously you have a VERY lightweight car so you likely don't need massive diameter solid sway bars which can be very heavy. I would like to propose running hollow sway bars in case this opportunity has been accidentally overlooked. Your bars do not appear to be very large however a photo without measurements does not always tell the whole story. My apologies if you have provided the measurements in a previous post that I missed, but I thought I would throw this out there just in case it was an overlooked opportunity to save some additional weight while offering a possible performance upgrade by switching from a small diameter solid set of bars to a larger set of hollow bars.


Best regards,
Mr. Bear

 

I agree with this. The hollow bar I have is a 26mm but I am looking into other options. The car isn’t going to need a huge sway bar. I already need to lower the spring rates on my coil overs. They were set up for a way heavier car. In regards to the carbon brakes cost is my issue at this point. I thought about the stock zr1 brakes. It appears the rotors weigh 13.5 lbs. which would be a savings over what I have

 

Some new parts came in yesterday it was exciting.

I decided to switch to a tilton 5.5 in triple disk clutch and button flywheel with reverse mount starter and clutch mounted starter ring. this new set up saves 30lbs of roatational weight over my fidanza aluminum flywheel and act clutch. That is crazy weight savings.

I also just got a qa1 carbon fiber driveshaft. it weighs 5.6 lbs. That thing is light.

And wilwood two piece rear rotors. which save about 2lbs per side.

 

Another upgrade i did this week which unfortunately gained 1.5lbs was changing to solid motor mounts. in the process i moved the motor about 3/4in further rear .

 

I thought I commented here but don't see it. I have a few thoughts for you to consider. The Z51/52 braces I didn't find to be of a lot of value and they are super heavy. The ones by the oil pan and by the hood pin area. I removed them and jacked up the car on one side and the bolt would still start no problem (as a simple test if the brace did anything). Further testing or remake them of aluminum. You might not need sway bars at all.

The harness bar mounting in the hatch was pointed out to me by R&D many years back. I was baffled but it's true that where you have it is just fiberglass and it will tear out easy. What I did was to cut a rectangle out down to the frame steel for the rear fasteners.

The header on the pass side it wouldn't bother me to notch the frame and patch. Which ever is easier I guess. At least with solid mounts the engine won't be shifting that way (I've seen 3/8" movement there).

 

Really nice fab skills and kick *** car!

Without a parking brake the rear knuckle can be trimmed, minor but it's neater.

I posted a lot of weights in a sticky thread: https://www.corvetteforum.com/forums...-and-info.html

 

I ended up modifying the pass header for more clearance . I haven’t thought about the braces but that’s a good idea. Correct me if I’m wrong but wouldn’t the lighter the car is the less the frame would flex? So it would be less necessary on a light car?

 

Great thread, I will confess that I was a "weight weenie" with mountain bikes, after doing the same on Superbikes. Try to avoid that on the Corvette, but old habits die hard. Here's my opinion on the guidelines I try to follow for weight savings because I think it's important to focus on benefit for the dollar. In other words, those expensive light weight wheels are worth it.

First order of significance is tires, wheels, and brake rotors/hats/hardware (unsprung rotating weight). 275's are a lot lighter than 315's and can be more effective on a 2500lb car in some cases. Also there's a 3-5 lb difference between some of the competitive brands, Hoosiers are real light if you're going slicks or race tires. Wheels, the three piece racing wheels with spun barrels are very light, and also the weight is closer to the hub compared to forged wheels. Cast wheels are sometimes very heavy. I use the open Ti lugnuts also, some people use the aluminum ones. The Porshce 951 I have had magnesium lug nuts (currently aluminum). All of those need anti seize. On the suberbikes, it was common to have gun drilled titanium hardware, very strong, very light, trick stuff, especially on the radial caliper bolts. The rear brakes on the earlier cars using the drum for the parking brake are pretty heavy, so I removed it same as the OP, and used same offset aluminum hats.

Second order of significance is unsprung weight... especially on the outboard side of suspension components, shocks, springs, arms, links, calipers, hardware. On the Corvette I've used chromoly tube bolts from Colemans Racing for all suspension links, except lower A-Arm inboard bolts.

Third order of significance is weight towards the front of the car, especially higher up, can be aluminum heads first and block second, light weight headlights, alternator, light weight carbon hood, exhaust... don't have the carbon hood myself, but it is a big bang for the dollar even at $2K. Battery (LiPO or LiFe), un-needed accessories, AC, blower motor, heater core.

Fourth are weight over the middle and rear and weight at the extremities at the rear - Polar moment of inertia. For the front this is much more significant as it reduces the reaction time of the front turn in, and sits in the previous category. For the rear it's mixed. I've driven a high PMI car and they are magic for controllability, and adding more weight to the rear tire. My Corvette handles better full of gas than 1/4 tank, better rear grip. Dragracers also like to have the weight higher, but for turning it's a compromise, I would shoot for a balanced set up first and then traction during accelerating. The Tesla is a pig but all the weight is very very low, so AX turning performance is outstanding. I add lead ballast to the rear on the corvette. Interior, sound deadening, carpet, seats, are pretty good for this, although I thought that the standard seat in the 1986 was actually very light.

Hardware is fun to change, but it's not significant for the $ especially in the third and fourth categories.

I also treat all of the titanium hardware mostly for aesthetics, using my "secret" process for dark color. They can be bought that way with DLC coating which is even better. I've used a lot of aluminum alloy hardware in the past for low load areas especially, haven't done that much on the corvette, except for all the ground wire connections on the heads and block. Once again, both aluminum and Ti hardware need anti seize or it will micro weld and gall pretty easy. Not fun. Titaniun Exhaust I assemble slip fit with high temp red RTV so that it can be assembled easier as it slips and slides, and disassembled later.

 

already done the lithium battery, aluminum block, headlight delete. Gutted hood.

I know my wheel setup is on the list. Currently running TSW setup and they are pretty light. Thinking about going to 18s all around.

any sources on 3 inch slip fit titanium tubing?

 

There's no off the shelf stuff, and it is not the best place to save weight. You gotta make you own, or find a shop to do it, there are a few around who specialize. Needs a lot of purge to tig weld properly.

Here's a source for raw stock:
https://store.tmstitanium.com/produc...P-Grade-1/161g

The thin wall stainless stuff is pretty light and 25% of the cost, and I can make a 304 stainless exhaust system that saves over 30lbs from stock. I mentioned Titanium exhaust because a lot of people get them stuck together, and another example of needing an anti-seize strategy... I've had a lot of titanium exhaust systems in the past, and it has draw backs. Especially joining Ti pieces to 304 Stainless using slip fit and springs to attach. I didn't notice you using any anti-seize, but then this post is more for others to see discussion than it is to instruct you of course.

 

Yeah I see weld on slip joints available. but to save time I was hoping someone sold some that were already done like with stainless. Also I am using anti seize before final assembly on the aluminum and titanium fasteners. as messy as it is. haha. I come home with it everywhere.

 

my new bellhousing came in. 8lbs 10oz. They make a magnesium version too. Maybe at somepoint Ill buy one. It weighs 6lbs. But I got a good deal on this one.

 

Curious… What does the engine weigh at what configuration? Did you get a chance to weigh it? Curious as I’m building a lightweight car also (but will ballast at the right rear) and I believe I’m well under LS1 weight. Just weighed the engine, twice as the first time seemed a little half assed and second time I was precise.

My staring point was ~3200 with full fuel and heavy ZF trans, no AC, and lightweight wheels brakes shocks, and no rear sway bar… 1986.

 

I didn’t get a chance to weigh the ls3 before installing but I know my transmission weighs about 70lbs without the bellhousing. I have some new parts coming in this week. Excited to get this thing back together

 

Been thinking about all the bracing in the car. How much of it is actually needed? Could I replace some of them with aluminum or carbon fiber? Just thinking out loud.