More Weight Reduction for Drag Racer

[Doug Brown]

At the moment, this will be the last of body weight reductions on RED, my Festiva BP drag racer.

As promised, to the front of the car!

Original steel hood and hinges -- 23.5-lbs

Lighten hood, no hinges (going to use pins) -- 14.6-lbs -- saves 8.9-lbs

This is one item that did not really lighten up much. There is a guy in the Philippines who makes a fiberglass hood - it may be lighter (???)

Original steel fuel tank - empty (no fuel pump, etc) -- 19.4-lbs locate in the rear of the car

Aluminum 1-gal fuel cell - has foam, no fuel pump -- 3.6-lbs locate in front right headlight area -- saves 15.8-lbs


I also got rid of the fuel tank filler hoses, filler pipes, filters, fuel lines and the entire fuel fill door-- Saved about 10-lbs.

Moving the fuel tank forward now puts the weight over the right front wheel for traction, instead of the original location over the rear suspension beam.
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It will be a while before I get around to it, but I am going to greatly reduce the weight of the front hubs, brake rotor and brake caliper. Hoping to save 8-lbs of rotating mass per wheel for both weight savings and increased HP from reduced weight.
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If you are ever in the New Bern, NC, 28560 area, drop me a note and stop on by!!! BBQ hamburgers await!

[firebush357]

I'm assuming you have a spread sheet with all of the weight savings numbers as you go correct? It will be cool to see how much it adds up to.

[F3BZ]

it will be a while before I get around to it, but I am going to greatly reduce the weight of the front hubs, brake rotor and brake caliper. Hoping to save 8-lbs of rotating mass per wheel for both weight savings and increased HP from reduced weight.
[/QUOTE]

i read this and spent 1/2 hr of mentalizing possible ways you will do this assuming not replacing the original components with some exotic and expensive alloy. i'm thinking you're nuts in a fun way but maybe a genius also. best i can visualize is shaving cross-drilled rotors to absolute min thickness. maybe hubs can be shaved too but how would you determine a fail point? calipers? i have no clue how you would mod those for any significant weight loss but i am following this build with interest and hope to see a record set.
don't forget to use short valve stems and leave the caps off!

[firebush357]

It will be interesting seeing how much weight you can safely take off the front Hub/Rotors.

There is a good bit of Material you can shave off of the Calipers but that doesn't affect rotational mass and would be very time consuming.

[Doug Brown]

As a teaser, at the moment, I plan on using regular Aspire/XR2 hubs lightened as much as possible (to be determined). Then, as F3BZ guessed, I'll use drilled solid rotors and have them turned down to only be 0.20" thick. For calipers, I'm going to use Wilwood lightweight calipers used for snowmobiles, etc. - they weigh 1.1-lb apiece.

So the big rotating mass weight savings will be the very thin rotors and the hubs to some degree. The calipers will just be overall weight savings.

My thinking on why I can get away with this set-up is I only have to do one stop from 110-mph (very optimistic!) ever hour or so and I have a gearbox/engine compression to help slow the car too. And the car will be much lighter than a stock Festiva......

That's the plan at the moment, subject to change and other ideas!

[ryanprins13]

Theres a guy on facebook doing 10 second 1/4miles in a festiva, you could chat with him about how long it takes him to stop. I thought he had a parachute but im not sure.
He is stopping from 135mph, your hoping for 110 but thats still pretty quick for sketchy brakes, lol.

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[fitsbain]

thought you were going with only rear breaks??

[Doug Brown]

I was originally going to go with only rear brakes, but the general consensus was I was pretty crazy to try and get away it. I do listen to you guys!!!

So I've come up with option #2, the light weight front brakes. The "no front brake" option would have let me get rid of the rotor and the caliper and lighten the hub as much as possible.

The "light weight front brake" option means I still have a lighten hub, so that weigh is a wash. By going to the light weight aluminum caliper I only add about 1.5-lbs per side with caliper and adapter. Since I'll be using a light weight aluminum caliper, they are made to be used with a disc that has a maximum thickness of 0.200-inch -- much lighter that the 1.125-inch vented rotor from an Aspire or XR2.

Since it is a drag racer, brakes aren't used continually - as long as they can stop me once every hour or so that will work, and they will have plenty of time to cool off before their next use.

Because it is a drag racer - ONLY - I can get away doing things that you could never do to a street car or a road racer. I think it says that in small print somewhere.....

Thanks for the interest. All ideas and suggestions welcomed!

[Advancedynamix]

I've personally slowed a full weight festiva from 141mph many times with only front brakes and it's much more comfortable than it is with rear brakes. Rear brakes lock up easily on these cars when slowing from high speeds and things get sketchy in a hurry. I definitely wouldn't want more braking force than the stock drums on a lighter car. Good luck with that. There is no weight on the back when you are braking.