Who else has gone nuts lightening your C4?

I've stripped, cut, removed and "tweaked" mine to the point that the body panels fly in the wind. It's dry wieght is about 2500#. 2829# with driver and 1/2 tank of gas.

Beyond the normal: "take out the spare tire, etc" Does anyone want to share on what they've done or sources on what they've purchased to make thier car light and race ready?

Also, how have you redistributed your wieght to improve your performance?

Here's a pic of my frame after I'd stripped the body off (pic at left). Several hours of work with a grinder and plasma cutter netted me a garbage can 1/2 full of various tabs and unnecessary bits of metal. The frame is stiffened with a latticework of thinwall tubing. The rollcage is standard thickness 1 3/4" DOM.

There was a tremendous savings in lightening the fiberglass panels. Most were double thickness, in which the second layer could often be honeycombed, or done away with completely.

The doors were amazingly heavy. A few hours of gutting netted big savings. The door bar was redundant to the NASCAR bars of the cage and posed the most challenging in efforts to separate from the door skin.

The next large savings was in the rear glass. This was replaced with lexan rivited to an aluminum frame. I would not take out the glass windshield if I had it to do over again. The weight savings of the lexan replacement was only about 10# and this wasn't worth the difficulties that the lexan posed in durability.

Getting rid of the zf-6speed trans and flywheel was probably the largest single weight savings, although it was the most exspensive to reconfigure. The clutch and flywheel weighed something on the order of 50+# and was replaced by a button style triple disc set up (approx 10#). The 175# ZF 6-sp was replaced by a 75# Jerico 4-sp.

The motor was moved down, rearward and tothe right to help with CG. The battery was moved to the right rear floor and the batt cables were made out of 1 ott Al wire. The dry sump tank was positioned low just behind the RR tire. The exhaust is short and light. It is a conventional crossover header that dumps into a 3 1-2 --> 5" y pipe ---> single flowmaster and exits from below the passenger door.

 

Last time I weighed my 96, it was down to 3055 with 1/3 tank of gas. But, that was many parts ago. Need to weigh it again. I removed the stock battery, and laid an Odyssey dry cell motorcycle battery in the spare tire well.

 

Forum member Nitrous Sam has some pretty good threads about dropping weight. His goal is 2500# if I recall correctly. I think that was dry weight but I could be wrong.

 

I guess 2500# can be done. I'm just wondering how I can do it a little better.

 

Interesting write up - I debated taking out weight from my stock 88, but then I changed my mind and just went and bought a c4 with an LT5 in it hoping the HP gain would make up for the weight I wasn't losing.

I'm working on the suspension changes, so not up to weight removal and never wil be to your extent but, wow, I wouldn't have imagined you could remove so much weight. I just bought an 11 lb battery tonight for starters.
Anyway, I was really impressed reading what you've done.

 

It seems that the standard for C4 Roadracers is 2700-2750lbs.

Mine is currently 2945 w a full cage and Nascar bars on both sides. My plan however...... CF Hood -60, CCW's w/ Hoosiers -40, LW battery -15, Remove mufflers -30, 30 mm hollow sway -10, Remove pax race seat and belts -25, Rear lexan -30, Al FW / clutch -30, misc brackets -10......you get the idea. Under 2700 lbs w/ 1/4 tank.

My cage weighs 150 lbs so the 2500 lb C4 seems pretty doable without going nuts on Titanium, etc..

Nitrous Sam , yup he is the one working towards 2500 lbs.

Good Luck.

 

SpeedJ2, do you have some pictures of all your work? Sounds like fun!
-=Rick

 

 

You and NitrousSam would be best buds!

 

I've been working on trying to make my car alot lighter but still retaining a somewhat stock look. The carpet is being changed out to a super thin lightweight material that will not only conform better to the car but will have alot more deep rich look to the color (black). The black rubberized insulation has been removed and is a prettty cool deal since you can hear the motor/tranny more but only when you get on it hard. Insulation will only be over the rear wheel tubs to eliminate tire noise. still very quiet on the inside.

 

what are you guys using for rear springs and shocks for a 2700lb car...?????

 

Vettetech/jeffvette: I can send you some pics, but I'm having trouble posting pics here... an old clunky computer + dial-up...

MRC24x: Where did you get ahold of the hood? I lightened mine by removing all of the substructure. It works ok, but it really balloons up at speed!
Also, an uninteded consequence of removing the inner fender is that this allows rocks to be thrown up, striking and cracking the fiberglass hood assy.

It was amazing to me how heavy the dual exhaust system can be. Mine old one was more than 75#. I ended up going with a thinner wall stainless single pipe system with a significant weight savings.

Another heavy item that was easily replaced was the starter. The stock starter on the '84 was nearly 30#. You can substitue a later model one in the 15# range cheaply, or by one in the 8-10# range for a bit more $.

Nowwhat: The correct spring rate for my car was 425# front/ 375# rear. Shocks are Bilstein coilovers. Front shock rates are 100/300; rear rates are 500/150.

 

I started a diet this January, I'm hoping to lighten my car weight about 40 pounds...

 

I'm still narrowing down which hood. It's going to depend on my engine Dyno #'s. I'm running in a HP/WT class so I need to be careful. My first choice would be to have Merle at Exotic Muscle make me one. He said he can make it as light as 10 lbs if needed and mount it w/ dzus fasteners/pins.

My springs are VB&P Extreme adjustables. Front ride height only and Rear is rate and/or height adjustable.

Nitrous Sam has some good posts on the individual items if anyone wants to do a search for more info. The heavier items that I would get rid of first ; 1) Stock seats= 40lbs each vs, Race seat @15-20.
2) Stock exhaust= heavy and worthless
3) Fiberglass skin for the roof (Melrose T-Tops)
4) Gut the Doors/carpet/insulation/brackets...
5) Heater/A/C/cruise/stereo/speakers/spare....

Of course this isn't a street car but if it's just a weekend strip car then start with the above. The best part is you are making money during this phase of the build up by selling those parts!
1-5 = 350+ lbs.

 

great info thanx.....

Best place to buy....????

 

"Several hours of work with a grinder and plasma cutter netted me a garbage can 1/2 full of various tabs and unnecessary bits of metal"

Doing same diet act with my strip only car. Amazing amount of weight in redundant brackets and bolts.

If track only car , there is 40lb in the rear alum bumper/tank support without the weight of the stock tank which is not light

 

SpeedJ2, please, please send me pics of this process and keep posting here about what you've done. I bought my C4 with the intention of lightening every part and this is extremely interesting.

 

I sent him a PM with my email. So far no pics.

 

Bumping thread so he'll see it when he returns...

If you need somewhere to host the pics, photobucket.com will do it for free, and you can just link to it on there...

 

I'll host them for a few months. Just email them to me. vettehistory@gmail.com