i have a 98 cavalier project car that i want improve the power to weight ratio, well first im going to work on the weight side of the factor. post how far you guys have gone to shave all the excess weight off of your cars, i need some ideas.
These gains are inaccurate.
This provides good ideas for reduction, but don't expect that kind of power return. Lightening the car doesn't 'add' power, it restores lost power at the wheels because the car is pulling(pushing rwd) less weight.
example: Twin Cam listed at 150HP, average stock at the wheels as far as I've seen is about 120HP. Based on his calculations, a reduction of 573lbs would give the car 151 HP which is more than that engine could even produce in a pure stock build.
Not to mention his inclusion of the flywheel, which is rotating mass (like pistons, rods etc...) and removing that weight is much more valuable than removing body weight, (more power per lb restored). This also applies to wheels as well as they are at the 'end' of the driveline.
I have always been under the impression(and idk if its right, but it makes a lot more sense) that 10% reduction of BODY weight restores 1HP. So starting at 2700lbs you would need to shed 270 lbs and would put you at 2430. Now to get the next full HP you would need to shed 234lbs and so on(give or take because technically this will change slightly with every lb you remove not every 10% like my example). Likewise your MPG is increase by 5%, for ever 16% body weight reduction.
Rotating mass weight reduction is 12x more effective. So for every 1lb of piston, rod, wheel, anything that is moved by the combustion it would be like removing 12lbs of body weight.
In regards to the lower end, i'm going to go out on a limb and speculate that replacing the core of the rotating mass with lighter parts can not only restore, but ADD a few horsepower.
Like I said I don't know for a fact if this is correct, but it made sense when it was explained to me. Now that im interested again i'll try to find some legit proof for you.
