What does a front bumper weigh?

[Doug Brown]

OK, more weights.

The steel part of the front bumper weighs 20.6 lbs. The plastic cover weighs about 3.4 lbs. The foam weighs 2.6 lbs. The parking lights weigh about 2.4 lbs. Grand total of 29.0 lbs

If you are welling to give up all form of front end protection (as for a race car), you can just screw the cover and the parking light lenses in place to give the appearance of a "front bumper assembly" and have a weight of 5.8 lbs -- a savings of 23.2 lbs.

I haven't weighed a rear bumper yet, but it is probably the same weight or little more because of additional steel re-inforcing plates.

[fastivaca]

Keeping weight forward of the front axle is a good thing in a Festiva. Check out this thread for the reasoning.

[ryanprins13]

Ya, if you want to race you want to keep weight ahead of the front wheels. If you dont then you want that protection. removing far rear weight like rear bumper and hatch would only be good if your doing straight line racing. The back end gets too light very fast. Unless you can do a bunch of suspension work to fix that somehow. Removing weight ahead of the gas tank and behind the front axil seems to work well


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[F3BZ]

so, the more lead plates i can bolt to the front the better? and some in the back too? i guess mazda has it all wrong trying to make their cars lighter for better handling and acceleration. there has to be a point of diminished returns. the only case i can agree where additional weight is a benefit is over the driven wheels of an overpowered and under tired car in straight line acceleration. i just can't buy that it is good to have excess weight swinging at the very ends of a vehicle when making quick changes of direction.

[TominMO]

Ya, if you want to race you want to keep weight ahead of the front wheels. If you dont then you want that protection. removing far rear weight like rear bumper and hatch would only be good if your doing straight line racing. The back end gets too light very fast. Unless you can do a bunch of suspension work to fix that somehow. Removing weight ahead of the gas tank and behind the front axil seems to work well

Yes, dieting will do wonders. Kinda why jockeys are short and thin.

[ryanprins13]

What does a front bumper weigh?

so, the more lead plates i can bolt to the front the better? and some in the back too? i guess mazda has it all wrong trying to make their cars lighter for better handling and acceleration. there has to be a point of diminished returns. the only case i can agree where additional weight is a benefit is over the driven wheels of an overpowered and under tired car in straight line acceleration. i just can't buy that it is good to have excess weight swinging at the very ends of a vehicle when making quick changes of direction.

Like i said, if you want to race. If thats what you want to do it is easy to get more power than traction in these cars. When that happens one way to help and fix it is by adding weight in front. Its not the only way. Weight transfer is fairly simple. Having a very low power to weight ration means nothing if you have no traction. Straight line acceleration is not just for drag racing. On a track you need to be able to accelerate after every corner, i would rather have a car thats 50-100 pounds heavier that doesn't spin every time i hit the gas than one thats 100 pounds lighter but i smoke the tires in 3rd. If you can find tires that will get all your power to the ground all the time and you can afford it by all means do that. Most people who get over 200hp in a festiva dont or cant. And of course there is a point of diminishing return, you dont put 1000 pounds on your front bumper and you know we didnt mean that.
You dont need to add weight to the back, it has enough. Just dont take it all out or you wont have traction in the rear under hard cornering or moderate cornering on a wet track. The tires do need some weight on them to stick. Again, you could stick a real expensive set of tires on the rear and maybe get rid of some weight but there we go with diminishing returns again.

Hypothetically think of a powerful motorbike. Rear wheel driven, all the weight up front, goes fast. Take the same bike and make it front wheel drive. All other things being equal you arent going anywhere fast, front tire will just spin. Take a long lever, attach it to the front of the bike, stick 200 pounds on it and youll be able to do something. It will never be as fast as the rwd bike but at least youll go somewhere and theoretically it could end up close. In a car thats fwd you loose all the added weight of the transmission, driveshaft, heavy rear axle, extra frame reinforcement that a rwd has. Move the fwd engine and trans ahead a bit, stick some weight down low on the front thats equal to maybe 1/2 a rear axle on a rwd car and you have all the traction you need with relatively not too expensive tires. Or you can skip all that and spend all your money on tires.

The original post was just informing people how much weight could be saved by removing said parts. The next 2 posts were cautioning that there are very few, if not no instances where you would want to remove weight or those particular parts from those 2 areas. If you want to go really fast they benefit you by being there, if you dont care and maybe just want better gas milage they still benefit you by being there if you hit or get hit by something.

[Doug Brown]

Hi - As Ryanprins 13 points out, I'm just putting the weights up as I take something off the car. Not to say the part or the weight is staying off forever......

My basic idea is that there are "good" and "bad" weights, so at least what I find out gives you an idea of what might be what.

What he also mentioned was the target area of "in front of the rear axle and behind the front axle". And there are some seriously heavy parts in this area. The doors, the dash with all its bits and pieces (which I have to weigh as it is incredibly heavy), the side rear wind-wing widows, heater, a/c and seats.

It should also be pointed out that this is for a non-street driven race car - which makes a huge difference as to what you are doing when removing parts. Also, I am not into turbo-charging where you can make a zillion horsepower and not really care about the weight. EFI is OK, carbs could be fun but a pain. So I am dealing with more limited low horsepower.

I don't know the weights yet, but if you have stripped out weight from the front area and then add a bigger engine, heavier transmission, bigger brakes and bigger sway bar, heavy knuckles shocks and springs it might not hurt to lose a couple of pounds up front. I may not be totally following the logic of some of what is said about FWD traction (although I do understand what they are getting at) it seems to me you would do better installing a limited slip differential, lowering the car and stiffening it up. And I'll admit I may be totally wrong, but those are my "first impression" thoughts.

I do really like this site - lots of great information!

[F3BZ]

i did concede that any unavoidable or added weight should be concentrated near or over the driven wheels. i'm no physics major but from what i retained from long ago college intro courses, the rate of movement is dependent on the friction between the tire footprint, the surface the tire is in contact with and the coefficient of friction between the two. less coefficient of friction can be offset by adding weight yes. but this force is mainly vectored (directed) downward. mr. browns post seemed to deal with the effects of weight on the ends of a vehicle. i am assuming a vehicle in motion and changing direction. once again, from what i recall, weight in motion can have vectors other than vertical. let's say a 50 lb bumper traveling forward at 60 MPH is forced by the vehicle it is attached to make a change of direction. for awhile at least that 50 lbs is going to want to continue on its original trajectory and will act through transfer through the body and suspension against the friction between the tires and surface. we hope the tires will win this battle but it may take a sightlier stickier or larger contact patch to do so (heavier unsprung weight).
similarly it is obvious that the rear of the car has to have some weight but in a FWD vehicle the weight isn't contributing to acceleration. but once again, what weight there is is distributed in vectors other than straight down when a change of direction is made. the more weight present during a change in direction will require more friction between tire and surface to counteract a slide. my contention is that by paring weight you reduce the chance of a slide. pare enough weight and you may be able to reduce the size and unsprung weight of the tires and still develop enough tire/surface friction to avoid a slide or lose control.
i'd like to have a physics major chime in on this who could set this straight. or debunk me. hey, i'm never too old to learn. i don't race or have a race car but i have gotten out of a festiva and right into a car over twice the weight and, driven over the same route, there is a HUGE difference in how i approach certain curves. i think the pitfall that a lot of members have is to build these cars for too much power. smoky burnouts is fun. nut crunching 60 - 100 MPH blast are fun. but due to size and layout restrictions there is only so much tire that can be fitted to make use of power.
maybe advance would be willing to strap a hunnerd pounds of cement in his spare tire well and report on how much better or worse his times were on an identical course even with increased tire size.

[Flyin4stroke]

I think I could go faster with full interior. Basically making too much hp per weight of the car.

[Advancedynamix]

All weight is counterproductive to some degree, but the further back the weight is, the worse it is for ALL types of performance driving (unless you consider spinning in circles to be performance driving).

[F3BZ]

i wonder how detrimental roof weight is. i'd eventually like to replace the canvas top contraption on my gtx with a standard roof.

[Doug Brown]

Hi F3BZ - a roof is an extremely important structural element of a car. It gives a lot of rigidity to the vehicle and prevents the chassis from twisting and bending. Most of my experience with race cars has been with Jaguar XK-E types (1961 & 1966) and Corvette Stingrays (1963) . The E-types took a tremendous amount of development work to get them to handle and it was found (and largely ignored by the factory) that the coupes (car with a fixed roof) was fair more rigid than the roadsters and the better model to use for racing.

The thought was that the reduction in weight would be a benefit, which was why they raced roadsters. However, they got the cars so light (making them out of aluminum) that they twisted like a pretzel and would tear apart and eventually had to be re-inforced with steel panels!

Coupes with a rollbar were the best - my 1961 car had a 5-pt rollbar which was very advanced for it's time and really strengthen the chassis and allowed all the other improved suspension pieces to actually work. Plus coupes are far more aerodynamic than a roadster.

Many manufacturers of convertibles would use a thicker gauge of steel in large areas of the car (making it heavier) to prevent the chassis from twisting.

I've been pretty impressed with the construction of the Festiva. The basic shell/tub is really pretty light and is pretty rigid, although the front of the car (radiator picture frame area and front lower a-arm mounting pads) need some strengthening (in my opinion).

This is where my "good weight / bad weight" comes into play. You can chopped the car into smithereens and you end up with a lightweight noodle, or you can still do extreme weight removal - but you have to replace it with something (roll bar / cage) to keep or improve on the cars rigidity. I think you can remove far more "bad" weight, put in a cage, and still have the car overall lighter and far more rigid - not to mention safer.

I sort of understand why people let the front end of the Festiva twist and weigh a lot to get traction (keeping the wheels on the ground) but there is a point where this has to be counter-productive.

And I do really love how creative people are with the Festiva's! Lots of really clever ideas to get the cars improved.

Anyway, my thoughts.

[F3BZ]

oh ya, agreed. some of the old and new convertibles weigh more than the sedan version and are still less rigid even after bracing. a few members have made pick ups out of their festivas. i wonder if they have any flex issues or made any strengthening braces? i have to replace the canvas on my car due to deterioration. just a rough guess is that with the big square of vinyl, the motor, linkage and framework, that top is probably 50# heavier over a standard steel one.