5lbs off the drive wheels

[89boostedminivan]

i found a set of aftermarket alum 14's, they weigh 14lbs ea, then the 14" tire is like another 20lbs, stock steelies with tire weighs about 40.5-41lbs, would shaving like 5lbs off the drive wheels be noticeable?? ive herd from some guys unless you take off like 10lbs its not really noticeable or anything but then i herd guys saying 1-2lbs makes a diff? anyobe know how the HP changes when taking rotational mass off , like for every 1lb = X hp

[cordes]

For the money I think it wouldn't be worth it. If you put that money elsewhere you will feel it more. Also, you can't run some of the bigger brakes with some 14" wheels so that is a detriment too if you want to be able to stop well.

[89boostedminivan]

yeah your probably right

[RoadWarrior222]

On the drive wheels in particular though, loss of unsprung weight may have significant traction benefits.

Otherwise I think the "ricer math" says 1lb of rotational weight is worth 6lb of other weight, though some say as much as 10lb.

I think it might depend somewhat on gearing, torque multiplication and speed. Say at launch you have 2000ft/lb in 1st, 5lb on a 24" wheel is next to no difference, whereas in high gear and at higher revs coming off the torque peak, it saps relatively more power. So possibly the rotational vs normal weight thing has different empirical answers depending on whether you're doing quarter miles or circuit racing.

Fiddling with online quarter mile calcs gives one the impression that 10lb of sprung weight = 1HP, since it takes about 200HP in a 2000lb car to run 12.5 or 300HP in a 3000lb car.

So just on those terms, saving 10lb is like gaining 1HP, however, taking the rotational weight conversion, one might seem to have gained 6HP.

So then you have to figure where on the $$$/HP curve you're at. If you're at the point where motor improvements to get another 6HP cost more than a pair of alloys, then the alloys give better bang per buck. That would probably mean you'd already got all the "easy" HP. For instance if an intercooler install would give you 50 more HP and would come in at about $400 for IC, piping and other minor mods and supplies, you'd be spending $8 per HP, which would mean you'd need to pick up a pair of alloys for $48 to make them worth it rather than saving for an intercooler. If however you've got everything practically fully built and are contemplating $$$$ thermal coatings for the last few HP, then a decent set of lightweight alloys might be more attractive.

[89boostedminivan]

4 brand new 14" rims $40 then whatever to mount my 14" tires on them?? and yeah all the basics plus some are already done, van is weighing in rite under 2820 with half tank of gas currently :)