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I have a 1973 Opel GT that was raced in the mid-Atlantic area in the 90s. It was pulled out of storage some 20 years later and given to me. In 2016 I updated the cage a bit. Cleaned the fuel cell out, removed the lights, and added some small LEDs for night racing, plus to save the light pods from damage, and towed it down for a 10-hour endurance race at Sebring International. Did ok, though the carb gaskets were dry rotted and the car would only rev to 4k. We were the slowest car out there by far but finished mid-field. 80mph top speed, and a 78mph race average. Only used the brakes at the hairpin. It was fun, but scary being passed by 150mph cars.
Then made a few small changes by added rearview cameras, and fixing the carb. Next race at VIR South in 2017. Had some ignition issues, caught fire, fixed, got back out, and finished upper mid-field.

Got a job working full time with the sanctioning body and basically parked all my own race cars.

So... kinda want to take the Opel out again. I have some time this winter to get all the issues sorted, do a track day or two once the weather improves, and then take it to a ChampCar race. Maybe Sebring or Carolina Motorsports Park. So the first part of the prep is to see what we have. I never weighed the car because I really did not care. So today I did it.

She is a fat little thing.

Full ITA prep.
full cage 1.5"x.120 wall
Gutted.
Kirky aluminum road race seat (My kevlar Cobra Sebring full containment seat stuck out the window, I was sad)
Fiberglass dash, but with all the heater stuff in per IT rules of the 90s.
15-gallon fuel cell 1/2 full
Tube rear bumper to protect the cell. Overkill, but we got hit at Sebring and only got scratched paint while the car that hit me suffered massive front-end damage. It was a team car. The first rule of racing. Don't hit your team car. I was sad again for awhile. So glad I added the extra weight to the rear.
Right now it has Honda Civic aluminum 14x6 wheels with 185-60-14s. Was surprised by how comfy they were at Sebring. did well in the rain as they are all-season. It's what any self-respecting race car builder would use.
OK. so today I weighed the car.
LF 532 RF 491
LR 442 LR 460
Total 1925 Pounds


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I want to get it lighter. But as has been shown, I think I would destroy the car, which I don't want to do as it is rust-free, and has raced at Sebring.
I think I will cut the cage out and rebend a new cage using today's cage standards and use 1.5x.095 wall.
Thought I would update this post with real numbers as it shows up on the top of Opel GT weight Google search.

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Great story, Bill.
The little Opel definitely deserves to see the track again. I hope you are able to make it happen.
Others here may have some suggestions on how to make the car lighter. I think the curb weight of a stock 73 GT was a little over 2000 lbs.
 

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Thank you so much for posting. What a great fun project. I am jealous. I have never had a car on the track. Spent time wrenching on a drag car between races a few times; changing out valve springs, removing trans to reface the clutch disc, checking plugs, etc. Lots of fun. Guessing at my age, I won't likely ever get to get behind the wheel at a track, even though Hallett is just a little over an hour away from me.
Glad you rescued it.
How many feet of tubing in your cage? You will save about 1/3 pound per foot. Actually, .343 pound per foot. That's a lot of work.
Good luck and keep us posted.
 

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A set of Longacres scales goes a long ways. I would encourage every performance minded enthusiast to weigh all four corners. Unless you have access to a pull down rack or the plate that was used for fabrication, you can do no better. You will benefit from your suspension setup efforts. Good to see that you are having "fun" with it. Keep up the good work.
 

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Cool post. I actually don't know how to get weight out without hacking the poor thing up. We pulled about 80 lbs out of our race car by replacing the windows with plexi, gutting the doors, and pulling the headlight buckets out. but it sounds like you already did all that.

If the cage was designed for it, a lot of the unibody (particularly the trans tunnel) would become structurally redundant to the cage, and could be hacked out. The floor and trans tunnel are really heavy, covered in rustproofing, could be replaced with something lighter. If you drop the engine and trans a little by putting in some solid mounts, you can also open up a lot of room inside the cabin by re-making the trans tunnel too.
But if you don't want to hack it up, I'm at a loss.

The spec E30 wheels from 949 racing are hella light. But probably not a whole lot lighter than your civic wheels.

I'm guessing you already have a header.

I have often thought about grinding the rear axle housing thinner in non-essential places, or even cutting large sections of it out and welding in thinner metal to keep the oil in — either that or leaving it hacked up and putting in oil seals to keep the gear oil in the pumpkin (all of that is a ton of work for a few pounds, but it's unsprung weight).

Switching to discs on the rear brakes might save a little weight, but probably only ounces.

We are running an aftermarket civic aluminum radiator. The radiator is a touch lighter, but the capacity is greater, so it results in a net gain once you fill it.

The nose is surprisingly heavy (I cut the front one off at the middle of the front fenders once). I bet you could take 40 lbs off the car by hollowing everything out everything forward of the front suspension, including the insides of the headlight buckets. But once again, you don't want to hack the car up.

I guess you could have a custom, carbon-fiber Opel engine made up and paint it to look like the stock block...

Sorry, I can't think of anything very helpful.
 
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